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  • 1.
    Affas, Fatin
    et al.
    Karolinska Inst, Solna, Sweden.
    Nygårds, Eva-Britt
    Karolinska Inst, Solna, Sweden.
    Stiller, Carl-Olav
    Karolinska Univ Hosp, Solna, Sweden.
    Wretenberg, Per
    Örebro University, School of Medical Sciences. Karolinska Inst, Solna, Sweden.
    Olofsson, Christina
    Karolinska Inst, Solna, Sweden.
    Pain control after total knee arthroplasty: a randomized trial comparing local infiltration anesthesia and continuous femoral block2011In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 82, no 4, p. 441-447Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND PURPOSE: Pain after total knee arthroplasty (TKA) is usually severe, and epidural analgesia or femoral nerve block has been considered to be an effective pain treatment. Recently, local infiltration analgesia (LIA) has become increasingly popular but the outcome of this method regarding the analgesic effect has not been fully evaluated. We compared local infiltration analgesia and femoral block with regard to analgesia and morphine demand during the first 24 h after TKA.

    METHODS: 40 patients undergoing TKA under spinal anesthesia were randomized to receive femoral nerve block (group F) or peri- and intraarticular infiltration analgesia (group LIA) with a mixture containing ropivacaine, ketorolac, and epinephrine. All patients had access to intravenous patient-controlled analgesia (PCA) with morphine postoperatively. Pain intensity at rest and upon movement was assessed on a numeric rating scale (0-10) on an hourly basis over 24 h if the patients were awake.

    RESULTS: The average pain at rest was marginally lower with LIA (1.6) than with femoral block (2.2). Total morphine consumption per kg was similar between the 2 groups. Ancillary analysis revealed that 1 of 20 patients in the LIA group reported a pain intensity of > 7 upon movement, as compared to 7 out of 19 in the femoral block group (p = 0.04).

    INTERPRETATION: Both LIA and femoral block provide good analgesia after TKA. LIA may be considered to be superior to femoral block since it is cheaper and easier to perform.

  • 2.
    Al-Khalili, L
    et al.
    Department of Surgical Science, Karolinska Institutet, Stockholm, Sweden; Dept. of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; Integrative Physiology, Dept. of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
    Krämer, D
    Department of Surgical Science, Karolinska Institutet, Stockholm, Sweden; Dept. of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
    Wretenberg, Per
    Örebro University Hospital. Department of Surgical Science, Karolinska Institutet, Stockholm, Sweden.
    Krook, A
    Department of Surgical Science, Karolinska Institutet, Stockholm, Sweden Dept. of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
    Human skeletal muscle cell differentiation is associated with changes in myogenic markers and enhanced insulin-mediated MAPK and PKB phosphorylation2004In: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 180, no 4, p. 395-403Article in journal (Refereed)
    Abstract [en]

    AIM: We hypothesized that myogenic differentiation of HSMC would yield a more insulin responsive phenotype.

    METHODS: We assessed expression of several proteins involved in insulin action or myogenesis during differentiation of primary human skeletal muscle cultures (HSMC).

    RESULTS: Differentiation increased creatine kinase activity and expression of desmin and myocyte enhancer factor (MEF)2C. No change in expression was observed for big mitogen-activated protein kinase (BMK1/ERK5), MEF2A, insulin receptor (IR), hexokinase II, and IR substrates 1 and 2, while expression of glycogen synthase, extracellular signal-regulated kinase 1 and 2 (ERK1/2 MAP kinase) and the insulin responsive aminopeptidase increased after differentiation. In contrast to protein kinase B (PKB)a, expression of (PKB)b increased, with differentiation. Both basal and insulin-stimulated PI 3-kinase activity increased with differentiation. Insulin-mediated phosphorylation of PKB and ERK1/2 MAP kinase increased after differentiation.

    CONCLUSION: Components of the insulin-signalling machinery are expressed in myoblast and myotube HSMC; however, insulin responsiveness to PKB and ERK MAP kinase phosphorylation increases with differentiation.

  • 3.
    Arborelius, U P
    et al.
    Kinesiology Research Group, Department of Anatomy, Karolinska Institute, Stockholm, Sweden.
    Wretenberg, Per
    Örebro University Hospital. Kinesiology Research Group, Department of Anatomy, Karolinska Institute, Stockholm, Sweden.
    Lindberg, F
    Kinesiology Research Group, Department of Anatomy, Karolinska Institute, Stockholm, Sweden.
    The effects of armrests and high seat heights on lower-limb joint load and muscular activity during sitting and rising1992In: Ergonomics, ISSN 0014-0139, E-ISSN 1366-5847, Vol. 35, no 11, p. 1377-1391Article in journal (Refereed)
    Abstract [en]

    The loading moment of force on the hip, knee, and ankle joints of nine healthy men rising from four different types of stools were compared, together with the levels of myoelectrical activity (EMG) in four leg muscles. Two types of stool (stand stools) had higher seats than a normal chair. The other two were of ordinary seat height, but one also had armrests. The bodyweight carried by the different stools when sitting was also measured, and the subject estimated the effort required for each trial. The mean maximum knee moment was over 60% lower when rising from the high stool than from 'ordinary' seat height. The difference between the high and low stand stool was also significant (p less than 0.001). Using the high stool or help of the arms reduced the mean maximum hip moment by about 50%. The mean maximum ankle moment was only marginally influenced by the different stools. Knee moment was influenced more by seat height than was hip moment. Vastus lateralis activity was significantly higher when subjects rose from 'ordinary' height than when rising from either stand stool (p less than 0.001). The rectus femoris muscle was little activated and the semitendinosus muscle was activated earlier when rising from higher seat heights. All subjects estimated the effort of rising from the higher stand stool to be lower than from the lower stand stool or from 'ordinary' height without arm rests. It was concluded that stand stools are good alternatives for workers who change frequently between sitting and standing work.

  • 4.
    Benoit, Daniel L
    et al.
    nstitution for Surgical Sciences, Section of Sports Medicine, Karolinska Institute, Stockholm, Sweden; Department of Orthopaedics, Karolinska Hospital, Stockholm, Sweden; Department of Mechanical Engineering, University of Delaware, 106 Spencer Lab, Newark, DE 19711, United States.
    Ramsey, Dan K
    Department of Physical Therapy, University of Delaware, Newark, DE, United States.
    Lamontagne, Mario
    School of Human Kinetics, University of Ottawa, Ottawa, Canada; Department of Mechanical Engineering, University of Ottawa, Ottawa, Canada.
    Xu, Lanyi
    School of Human Kinetics, University of Ottawa, Ottawa, Canada.
    Wretenberg, Per
    Örebro University Hospital. Department of Orthopaedics, Karolinska Hospital, Stockholm, Sweden; Institution for Surgical Sciences, Section of Orthopaedics, Karolinska Institute, Stockholm, Sweden.
    Renström, Per
    Institution for Surgical Sciences, Section of Sports Medicine, Karolinska Institute, Stockholm, Sweden; Department of Orthopaedics, Karolinska Hospital, Stockholm, Sweden.
    Effect of skin movement artifact on knee kinematics during gait and cutting motions measured in vivo2006In: Gait & Posture, ISSN 0966-6362, E-ISSN 1879-2219, Vol. 24, no 2, p. 152-164Article in journal (Refereed)
    Abstract [en]

    Eight healthy male subjects had intra-cortical bone-pins inserted into the proximal tibia and distal femur. Three reflective markers were attached to each bone-pin and four reflective markers were mounted on the skin of the tibia and thigh, respectively. Roentgen-stereophotogrammetric analysis (RSA) was used to determine the anatomical reference frame of the tibia and femur. Knee joint motion was recorded during walking and cutting using infrared cameras sampling at 120Hz. The kinematics derived from the bone-pin markers were compared with that of the skin-markers. Average rotational errors of up to 4.4 degrees and 13.1 degrees and translational errors of up to 13.0 and 16.1mm were noted for the walk and cut, respectively. Although skin-marker derived kinematics could provide repeatable results this was not representative of the motion of the underlying bones. A standard error of measurement is proposed for the reporting of 3D knee joint kinematics.

  • 5.
    Benoit, Daniel L
    et al.
    School of Rehabilitation Sciences, University of Ottawa, Canada; School of Rehabilitation Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa, Ont.; Canada.
    Ramsey, Dan K
    Department of Physical Therapy, University of Delaware, Newark, DE, United States.
    Lamontagne, Mario
    School of Human Kinetics, University of Ottawa, Ottawa, Ont., Canada.
    Xu, Lanyi
    School of Human Kinetics, University of Ottawa, Ottawa, Ont., Canada.
    Wretenberg, Per
    Örebro University Hospital. Institution for Surgical Sciences, Section of Orthopaedics, Karolinska Institute, Stockholm, Sweden; Section of Orthopaedics, Karolinska University Hospital, Stockholm, Sweden.
    Renström, Per
    Institution for Surgical Sciences, Section of Orthopaedics, Karolinska Institute, Stockholm, Sweden; Section of Orthopaedics, Karolinska University Hospital, Stockholm, Sweden.
    In vivo knee kinematics during gait reveals new rotation profiles and smaller translations2007In: Clinical Orthopaedics and Related Research, ISSN 0009-921X, E-ISSN 1528-1132, Vol. 454, p. 81-88Article in journal (Refereed)
    Abstract [en]

    In order to identify abnormal or pathological motions associated with clinically relevant questions such as injury mechanisms or factors leading to joint degeneration, it is essential to determine the range of normal tibiofemoral motion of the healthy knee. In this study we measured in vivo 3D tibiofemoral motion of the knee during gait and characterized the nonsagittal plane rotations and translations in a group of six healthy young adults. The subjects were instrumented with markers placed on intracortical pins inserted into the tibia and femur as well as marker clusters placed on the skin of the thigh and shank. The secondary rotations and translation excursions of the knee were much smaller than those derived from skin markers and previously described in the literature. Also, for a given knee flexion angle, multiple combinations of transverse and frontal plane knee translation or rotation positions were found. This represents normal knee joint motions and ensemble averaging of gait data may mask this important subject-specific information.

  • 6.
    Broström, E W
    et al.
    Department of Women's and Children's Health, Karolinska Institutet, Karolinska University Hospital, Solna, Stockholm, Sweden.
    Esbjörnsson, A-C
    Department of Women's and Children's Health, Karolinska Institutet, Karolinska University Hospital, Solna, Stockholm, Sweden.
    von Heideken, J
    Department of Women's and Children's Health, Karolinska Institutet, Karolinska University Hospital, Solna, Stockholm, Sweden.
    Larsson, P
    Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden.
    Wretenberg, Per
    Örebro University Hospital. Department of Molecular Medicine, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden.
    Iversen, M
    Department of Physical Therapy, Northeastern University, Brigham and Women's Hospital, Boston, MA, United States.
    Change in Gait Deviation Index after anti-tumour necrosis factor-α treatment in individuals with rheumatoid arthritis: a pilot study2013In: Scandinavian Journal of Rheumatology, ISSN 0300-9742, E-ISSN 1502-7732, Vol. 42, no 5, p. 356-361Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: Anti-tumour necrosis factor-alpha (TNF-α) inhibitors provide fast, effective resolution of rheumatoid arthritis (RA) inflammation. In this study we aimed to quantify the impact of TNF-α treatment on gait dynamics.

    METHOD: The sample comprised 16 subjects [11 female, median age 56 (range 48-66) years, median disease duration 9.5 (range 4.6-20.6) years] with RA who met the American College of Rheumatology (ACR) criteria, had lower extremity involvement, did not use walking aids, and had started TNF-α treatment within 1 week of baseline gait analysis. Gait analysis focused on three-dimensional (3D) lower extremity joint kinematics, kinetics, time and distance parameters. The Gait Deviation Index (GDI) and GDI-Kinetic were calculated. Data on gait, disease activity, and physical disability were collected at baseline and at 3.5 months.

    RESULTS: Following treatment with TNF-α, statistically significant improvements were found in disease activity [using the 28-joint Disease Activity Score based on C-reactive protein (DAS28-CRP); median difference (m(d)) = 2.3, p < 0.01], physical disability [Health Assessment Questionnaire (HAQ) m(d) = 0.4, p < 0.01], and pain during walking [visual analogue scale (VAS) m(d) = 11.0, p < 0.05]. Reductions in gait deviations were noted (GDI m(d) = 3.7, p = 0.04; GDI-Kinetic m(d) = 4.1, p = 0.05) along with reductions in dimensionless time and distance parameters. A moderate to good negative correlation existed between baseline GDI and GDI change scores (r(s) = -0.7, p < 0.01).

    CONCLUSIONS: Treatment with TNF-α improved gait dynamics in adults with RA. Significant gait deviations were, however, still present after treatment. In this study, GDI and GDI-Kinetic scores appeared to be useful outcome measures to quantify changes in gait deviations after this intervention.

  • 7.
    Ericson, A
    et al.
    Department of Orthopaedics, Karolinska Institute, Karolinska Hospital, Stockholm, Sweden.
    Arndt, A
    Department of Orthopaedics, Karolinska Institute, Huddinge University, Stockholm, Sweden.
    Stark, A
    Department of Orthopaedics, Karolinska Institute, Karolinska Hospital, Stockholm, Sweden.
    Wretenberg, Per
    Örebro University Hospital. Department of Orthopaedics, Karolinska Institute, Karolinska Hospital, Stockholm, Sweden.
    Lundberg, A
    Department of Orthopaedics, Karolinska Institute, Huddinge University, Stockholm, Sweden.
    Variation in the position and orientation of the elbow flexion axis2003In: Journal of Bone and Joint Surgery, ISSN 0301-620X, E-ISSN 2044-5377, Vol. 85B, no 4, p. 538-544Article in journal (Refereed)
    Abstract [en]

    We analysed the axis of movement in the normal elbow during flexion in vivo using radiostereometric analysis (RSA). The results show an intraindividual variation in the inclination of the axis ranging from 2.1 degrees to 14.3 degrees in the frontal and from 1.6 degrees to 9.8 degrees in the horizontal plane analysed at 30 degrees increments. The inclination of the mean axis of rotation varied within a range of 12.7 degrees in the frontal and 4.6 degrees in the horizontal plane. In both planes, the mean axes were located close to a line joining the centres of the trochlea and capitellum. The intra- and interindividual variations of the axes of flexion of the elbow were greater than previously reported. These factors should be considered in the development of elbow prostheses.

  • 8.
    Esbjörnsson, A-C
    et al.
    Department of Women's and Children's Health, Karolinska Institutet, Karolinska University Hospital, Solna, Stockholm, Sweden.
    Rozumalski, A
    Gillette Children's Specialty Healthcare, St Paul, MN, United States; Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States.
    Iversen, M D
    Department of Physical Therapy, Bouve College of Health Sciences, Northeastern University, Boston, MA, United States; Division of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.
    Schwartz, M H
    Gillette Children's Specialty Healthcare, St Paul, MN, United States; Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States; Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, MN, United States.
    Wretenberg, Per
    Örebro University Hospital. Department of Molecular Medicine, Section of Orthopaedics, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden.
    Broström, E W
    Department of Women's and Children's Health, Karolinska Institutet, Karolinska University Hospital, Solna, Stockholm, Sweden.
    Quantifying gait deviations in individuals with rheumatoid arthritis using the Gait Deviation Index2014In: Scandinavian Journal of Rheumatology, ISSN 0300-9742, E-ISSN 1502-7732, Vol. 43, no 2, p. 124-131Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: In this study we evaluated the usability of the Gait Deviation Index (GDI), an index that summarizes the amount of deviation in movement from a standard norm, in adults with rheumatoid arthritis (RA). The aims of the study were to evaluate the ability of the GDI to identify gait deviations, assess inter-trial repeatability, and examine the relationship between the GDI and walking speed, physical disability, and pain.

    METHOD: Sixty-three adults with RA and 59 adults with typical gait patterns were included in this retrospective case-control study. Following a three-dimensional gait analysis (3DGA), representative gait cycles were selected and GDI scores calculated. To evaluate the effect of walking speed, GDI scores were calculated using both a free-speed and a speed-matched reference set. Physical disability was assessed using the Health Assessment Questionnaire (HAQ) and subjects rated their pain during walking.

    RESULTS: Adults with RA had significantly increased gait deviations compared to healthy individuals, as shown by lower GDI scores [87.9 (SD = 8.7) vs. 99.4 (SD = 8.3), p < 0.001]. This difference was also seen when adjusting for walking speed [91.7 (SD = 9.0) vs. 99.9 (SD = 8.6), p < 0.001]. It was estimated that a change of ≥ 5 GDI units was required to account for natural variation in gait. There was no evident relationship between GDI and low/high RA-related physical disability and pain.

    CONCLUSIONS: The GDI seems to useful for identifying and summarizing gait deviations in individuals with RA. Thus, we consider that the GDI provides an overall measure of gait deviation that may reflect lower extremity pathology and may help clinicians to understand the impact of RA on gait dynamics.

  • 9.
    Feng, Y.
    et al.
    Department of Neuroscience, Karolinska Institute, Stockholm, Sweden.
    Grooten, W.
    Department of Physical Therapy, Karolinska Institute, Stockholm, Sweden.
    Wretenberg, Per
    Department of Orthopedics, Karolinska Hospital, Stockholm, Sweden.
    Arborelius, U. P.
    Department of Neuroscience, Karolinska Institute, Stockholm, Sweden.
    Effects of arm support on shoulder and arm muscle activity during sedentary work1997In: Ergonomics, ISSN 0014-0139, E-ISSN 1366-5847, Vol. 40, no 8, p. 834-848Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to evaluate different arm supports by comparing the activity of shoulder and arm muscles during various work tasks, with and without the lower arm supported. Twelve female subjects, aged between 23 and 37 years, were asked to perform three types of tasks: typing, simulated assembly work (in two different positions), and pipetting. The supports used were: fixed arm support (FIX), horizontal movable arm support (HOR), and spring-loaded arm support (SLA). During the experiments, the electromyograms (EMG) of four muscles were simultaneously recorded: m. deltoideus anterior and lateralis, m. trapezius pars descendens and m. extensor carpi radialis brevis. Normalization was made against maximum isometric contraction. The mean values of the normalized EMG levels showed a reduced EMG level of the shoulder muscles when using arm supports in all the tasks, and for all muscles but the wrist extensor, compared to the EMG levels without arm supports. The horizontal movable support was more effective in reducing the EMG levels of the shoulder muscles than other arm supports, in tasks at table height. Thus, it is possible to reduce muscle activity of the shoulder region by using arm supports. Further research is needed to make biomechanical calculations to compare the EMG level of these muscles using suspension and the effects of inclination of work task.

  • 10.
    Feng, Y.
    et al.
    Kinesiology Research Group, Karolinska Institute, Department of Neuroscience (Anatomy), Stockholm, Sweden.
    Grooten, W.
    Kinesiology Research Group, Karolinska Institute, Department of Neuroscience (Anatomy), Stockholm, Sweden; Department of Physical Therapy, Karolinska Institute, Stockholm, Sweden.
    Wretenberg, Per
    Kinesiology Research Group, Karolinska Institute, Department of Neuroscience (Anatomy), Stockholm, Sweden; Department of Orthopaedic Surgery, Karolinska Hospital, Karolinska Institute, Stockholm, Sweden.
    Arborelius, U P
    Kinesiology Research Group, Karolinska Institute, Department of Neuroscience (Anatomy), Stockholm, Sweden.
    Effects of arm suspension in simulated assembly line work: muscular activity and posture angles1999In: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126, Vol. 30, no 3, p. 247-253Article in journal (Refereed)
    Abstract [en]

    The electromyogram and posture angles of the shoulder and arm were recorded during sitting manipulative work in three positions, with and without the forearm suspended by a balancer. A Selspot system was used to record movements. The results from 12 female subjects (mean age 29 yr) showed that the activity in deltoideus anterior decreased significantly by using a balancer. Lower mean values were also noted for deltoideus lateralis and the trapezius muscles. The neck inclination increased with higher work area position, but was independent of the use of a balancer.

  • 11.
    Grondal, L
    et al.
    Department of Molecular Medicine and Surgery, Karolinska Institute, Red Cross Hospital, Stockholm, Sweden.
    Broström, E
    Department of Woman and Child Health, Karolinska University Hospital, Stockholm, Sweden.
    Wretenberg, Per
    Örebro University Hospital. Department of Molecular Medicine and Surgery, Section of Orthopaedics, Karolinska Institute, Stockholm, Sweden.
    Stark, A
    Department of Molecular Medicine and Surgery, Section of Orthopaedics, Karolinska Institute, Stockholm, Sweden.
    Arthrodesis versus Mayo resection: the management of the first metatarsophalangeal joint in reconstruction of the rheumatoid forefoot2006In: Journal of Bone and Joint Surgery, ISSN 0301-620X, E-ISSN 2044-5377, Vol. 88B, no 7, p. 914-919Article in journal (Refereed)
    Abstract [en]

    In a prospective randomised study 31 patients were allocated to either arthrodesis or Mayo resection of the first metatarsophalangeal joint as part of a total reconstruction of the rheumatoid forefoot. Of these, 29 were re-examined after a mean of 72 months (57 to 80), the Foot Function Index was scored and any deformity measured. Load distribution was analysed using a Fscan mat in 14 cases, and time and distance were measured in 12 of these patients using a 3D Motion system. We found excellent patient satisfaction and a significant, lasting reduction of the Foot Function Index, with no statistically significant differences between the groups. There were no significant differences in recurrence of the deformity, the need for special shoes, gait velocity, step length, plantar moment, mean pressure or the position of the centre of force under the forefoot. The cadence was higher and the stance phase shorter in the fusion group.

    These results suggest that a Mayo resection may be an equally good option for managing the first metatarsophalangeal joint in reconstruction of the rheumatoid forefoot.

  • 12.
    Grondal, Lollo
    et al.
    Departments of Molecular Medicine and Surgery, Karolinska Institute, Stockholm; Departments of Orthopedic Rehabilitation, Red Cross Hospital Stockholm, Sweden.
    Tengstrand, Birgitta
    Departments of Rheumatology, Karolinska University Hospital, Huddinge, Sweden.
    Nordmark, Birgitta
    Departments of 3Rheumatology, Karolinska University Hospital, Solna.
    Wretenberg, Per
    Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden.
    Stark, Andre
    Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden.
    The foot: still the most important reason for walking incapacity in rheumatoid arthritis - Distribution of symptomatic joints in 1,000 RA patients2008In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 79, no 2, p. 257-261Article in journal (Refereed)
    Abstract [en]

    Background and purpose: Our knowledge of frequency of foot involvement in rheumatoid arthritis (RA) is still often based on a study from Finland in 1956. Great changes in the treatment of RA may have led to a different situation. We investigated the distribution of joint involvement in RA patients today, with special attention given to the feet and subjective walking ability.

    Methods: 1,000 RA patients answered a questionnaire concerning joints affected, joint surgery, foot problems, and subjectively experienced reasons for walking incapacity.

    Results: In 45% of the patients, the forefoot was involved at the start of the disease. In 17%, the hindfoot/ankle was involved at the start. Only hand symptoms were commoner. 80% of patients reported current foot problems, 86% in the forefoot and 52% in the hindfoot/ankle. Difficulty in walking due to the feet was reported by 71%. For 41% of patients, the foot was the most important part of the lower extremity causing reduced walking capacity, and for 32% it was the only part.

    Interpretation: After the hand, the foot was the most frequently symptomatic joint complex at the start of the disease, but also during active medical treatment. The foot caused walking disability in three-quarters of the cases and-4 times as often as the knee or the hip-it was the only joint to subjectively impair gait.

  • 13.
    Krämer, David Kitz
    et al.
    Department of Surgical Science, Karolinska Institute, Stockholm, Sweden; Dept. of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden .
    Al-Khalili, Lubna
    Department of Surgical Science, Karolinska Institute, Stockholm, Sweden; Dept. of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden.
    Perrini, Sebastio
    Department of Surgical Science, Karolinska Institute, Stockholm, Sweden; Dept. of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden.
    Skogsberg, Josefin
    Gustaf V Research Institute, Karolinska Hospital, Stockholm, Sweden .
    Wretenberg, Per
    Department of Surgical Science, Karolinska Institute, Stockholm, Sweden.
    Kannisto, Katja
    Gustaf V Research Institute, Karolinska Hospital, Stockholm, Sweden .
    Wallberg-Henriksson, Harriet
    Department of Surgical Science, Karolinska Institute, Stockholm, Sweden; Dept. of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden.
    Ehrenborg, Ewa
    Gustaf V Research Institute, Karolinska Hospital, Stockholm, Sweden .
    Zierath, Juleen R.
    Department of Surgical Science, Karolinska Institute, Stockholm, Sweden; Dept. of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden.
    Krook, Anna
    Department of Surgical Science, Karolinska Institute, Stockholm, Sweden; Dept. of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden; Integrative Physiology, Dept. of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden .
    Direct activation of glucose transport in primary human myotubes after activation of peroxisome proliferator-activated receptor delta2005In: Diabetes, ISSN 0012-1797, E-ISSN 1939-327X, Vol. 54, no 4, p. 1157-1163Article in journal (Refereed)
    Abstract [en]

    Activators of peroxisome proliferator-activated receptor (PPAR)gamma have been studied intensively for their insulin-sensitizing properties and antidiabetic effects. Recently, a specific PPARdelta activator (GW501516) was reported to attenuate plasma glucose and insulin levels when administered to genetically obese ob/ob mice. This study was performed to determine whether specific activation of PPARdelta has direct effects on insulin action in skeletal muscle. Specific activation of PPARdelta using two pharmacological agonists (GW501516 and GW0742) increased glucose uptake independently of insulin in differentiated C2C12 myotubes. In cultured primary human skeletal myotubes, GW501516 increased glucose uptake independently of insulin and enhanced subsequent insulin stimulation. PPARdelta agonists increased the respective phosphorylation and expression of AMP-activated protein kinase 1.9-fold (P < 0.05) and 1.8-fold (P < 0.05), of extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase (MAPK) 2.2-fold (P < 0.05) and 1.7-fold (P < 0.05), and of p38 MAPK 1.2-fold (P < 0.05) and 1.4-fold (P < 0.05). Basal and insulin-stimulated protein kinase B/Akt was unaltered in cells preexposed to PPARdelta agonists. Preincubation of myotubes with the p38 MAPK inhibitor SB203580 reduced insulin- and PPARdelta-mediated increase in glucose uptake, whereas the mitogen-activated protein kinase kinase inhibitor PD98059 was without effect. PPARdelta agonists reduced mRNA expression of PPARdelta, sterol regulatory element binding protein (SREBP)-1a, and SREBP-1c (P < 0.05). In contrast, mRNA expression of PPARgamma, PPARgamma coactivator 1, GLUT1, and GLUT4 was unaltered. Our results provide evidence to suggest that PPARdelta agonists increase glucose metabolism and promote gene regulatory responses in cultured human skeletal muscle. Moreover, we provide biological validation of PPARdelta as a potential target for antidiabetic therapy.

  • 14.
    Lindgren, J. V.
    et al.
    Swedish Hip Arthroplasty Register, Gothenburg, Sweden; Karolinska Institutet, Department of Molecular Medicine and Surgery, Section of Orthopaedics, Stockholm, Sweden .
    Wretenberg, Per
    Örebro University, School of Medical Sciences. Swedish Hip Arthroplasty Register, Gothenburg, Sweden; Karolinska Institutet, Department of Molecular Medicine and Surgery, Section of Orthopaedics, Stockholm, Sweden.
    Kärrholm, J.
    Swedish Hip Arthroplasty Register, Gothenburg, Sweden; Institute of Clinical Sciences, Department of Orthopaedics, University of Gothenburg, Gothenburg, Sweden .
    Garellick, G.
    Swedish Hip Arthroplasty Register, Gothenburg, Sweden; Institute of Clinical Sciences, Department of Orthopaedics, University of Gothenburg, Gothenburg, Sweden.
    Rolfson, O.
    Swedish Hip Arthroplasty Register, Gothenburg, Sweden; Institute of Clinical Sciences, Department of Orthopaedics, University of Gothenburg, Gothenburg, Sweden.
    Patient-reported outcome is influenced by surgical approach in total hip replacement: a study of the Swedish Hip Arthroplasty Register including 42,233 patients2014In: The Bone & Joint Journal, ISSN 2049-4394, E-ISSN 2049-4408, Vol. 96-B, no 5, p. 590-596Article in journal (Refereed)
    Abstract [en]

    The effects of surgical approach in total hip replacement on health-related quality of life and long-term pain and satisfaction are unknown. From the Swedish Hip Arthroplasty Register, we extracted data on all patients that had received a total hip replacement for osteoarthritis through either the posterior or the direct lateral approach, with complete pre- and one-year post-operative Patient Reported Outcome Measures (PROMs). A total of 42 233 patients met the inclusion criteria and of these 4962 also had complete six-year PROM data. The posterior approach resulted in an increased mean satisfaction score of 15 (sd 19) vs. 18 (sd 22) (p < 0.001) compared with the direct lateral approach. The mean pain score was 13 (sd 17) vs. 15 (sd 19) (p < 0.001) and the proportion of patients with no or minimal pain was 78% vs. 74% (p < 0.001) favouring the posterior approach. The patients in the posterior approach group reported a superior mean EQ-5D index of 0.79 (sd 0.23) vs. 0.77 (sd 0.24) (p < 0.001) and mean EQ score of 76 (sd 20) vs. 75 (sd 20) (p < 0.001). All observed differences between the groups persisted after six years follow-up. Although PROMs after THR in general are very good regardless of surgical approach, the results indicate that some patients operated by the direct lateral approach report an inferior outcome compared with the posterior approach. The large number of procedures and the seemingly sustained differences make it likely these findings are clinically relevant.

  • 15.
    Martinez-Murillo, Paola
    et al.
    Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
    Pramanik, Lotta
    Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
    Sundling, Christopher
    Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden; Immunology Division, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia.
    Hultenby, Kjell
    Division of Clinical Research Centre, Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden.
    Wretenberg, Per
    Department of Orthopedic Surgery, Karolinska University Hosptial, Stockholm, Sweden.
    Spångberg, Mats
    Medicine, Astrid Fagraeus Laboratory, Karolinska Institutet, Stockholm, Sweden.
    Karlsson Hedestam, Gunilla B.
    Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
    CD138 and CD31 Double-Positive Cells Comprise the Functional Antibody-Secreting Plasma Cell Compartment in Primate Bone Marrow2016In: Frontiers in Immunology, ISSN 1664-3224, E-ISSN 1664-3224, Vol. 7, article id 242Article in journal (Refereed)
    Abstract [en]

    Plasma cells (PCs) are defined as terminally differentiated B cells that secrete large amounts of immunoglobulin (Ig). PCs that reside in the bone marrow (BM) are responsible for maintaining long-term antibody (Ab) responses after infection and vaccination, while PCs present in the blood are generally short-lived. In rhesus macaques, a species frequently used for the evaluation of human vaccines, B cells resemble those found in humans. However, a detailed characterization of BM-resident rhesus PC phenotype and function is lacking. Here, we examined Ig secretion of distinct rhesus CD138+ populations by B cell ELISpot analysis to couple phenotype with function. We demonstrate that the CD20low/-CD138+CD31+ BM population was highly enriched for antibody-secreting cells with IgG being the predominant isotype (60%), followed by IgA (33%) and IgM (7%). Transmission electron microscopy analysis confirmed PC enrichment in the CD20low/-CD138+CD31+ population with cells containing nuclei with "spokes of a wheel" chromatin structure and prominent rough endoplasmic reticulum. This panel also stained human BM PCs and allowed a clear distinction between BM PCs and short-lived peripheral PCs, providing an improved strategy to isolate PCs from rhesus BM for further analysis.

  • 16.
    Mikhail, W. E.
    et al.
    Department of Orthopaedic Biomedical Engineering Research, and Department of Orthopaedic Surgery Medical College of Ohio, Toledo, Ohio, USA.
    Weidenhielm, L. R.
    Department of Orthopaedic Surgery, Karolinska Hospital, Stockholm, Sweden.
    Wretenberg, Per
    Department of Orthopaedic Surgery, Karolinska Hospital, Stockholm, Sweden.
    Mikhail, N.
    Mayo Medical School, Rochester, Minnesota, USA.
    Bauer, T. W.
    Department of Pathology, Cleveland Clinic, Cleveland, Ohio, USA.
    Femoral bone regeneration subsequent to impaction grafting during hip revision: histologic analysis of a human biopsy specimen1999In: The Journal of Arthroplasty, ISSN 0883-5403, E-ISSN 1532-8406, Vol. 14, no 7, p. 849-953Article in journal (Refereed)
    Abstract [en]

    Cemented revision with impaction grafting shows encouraging early clinical results; postoperative biopsy specimens taken from the proximal femur in humans have demonstrated viable trabecular and cortical bone. Human radiographic studies also illustrate density changes within the proximal femur, consistent with remodeling of bone-graft. In an animal experiment, bone incorporation was shown in the proximal femur, but graft lysis was reported around the distal portion of the implant. We report on a patient who sustained a traumatic femoral fracture at the level of the tip of the femoral component 27 months after revision with impaction grafting and a collarless polished taper stem. At the time of open reduction and internal fixation of the fracture, we obtained circumferential biopsy specimens from the fracture site. Three distinct zones could be identified histologically: i) an inner zone consisting of bone-cement, fibrous tissue, and partially necrotic trabeculae with evidence of bone remodeling; ii) a middle zone consisting of viable trabecular bone and probable neocortex formation with fewer particles of bone-cement; and iii) an outer zone with viable cortex. Fibrous tissue was present around some of the incorporating bone-graft fragments, but no continuous fibrous membrane was present. Cement particles were identified, but no polyethylene debris was found by light microscopy. Biopsy specimens from the distal aspect of the prosthesis may not reflect changes seen proximally, but based on the available tissue, this case illustrated histological evidence of bone-graft remodeling after impaction grafting. These results are consistent with our expectations based on radiographic findings and clinical results.

  • 17.
    Mikhail, W. E.
    et al.
    Department of Orthopaedic Surgery, Karolinska Hospital, Stockholm, Sweden; Div. Total Jt. and Reconstr. Surg., Medical College of Ohio, Toledo, OH, United States .
    Wretenberg, Per
    Department of Orthopaedic Surgery, Karolinska Hospital, Stockholm, Sweden .
    Weidenhielm, L. R.
    Department of Orthopaedic Surgery, Karolinska Hospital, Stockholm, Sweden .
    Mikhail, M. N.
    Mayo Medical School, Rochester, MN, United States .
    Complex cemented revision using polished stem and morselized allograft. Minimum 5-years' follow-up1999In: Archives of Orthopaedic and Trauma Surgery, ISSN 0936-8051, E-ISSN 1434-3916, Vol. 119, no 5-6, p. 288-291Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to evaluate the results of complex hip revision using a cemented, collarless and polished femoral stem design (CPT, Zimmer, Warsaw, In.) within a tightly impacted morselized allograft. We have now been using the impaction grafting technique in combination with the CPT stem (Zimmer) for 10 years in complex cases of severe bone loss. In this study we have elected to report only those patients who have been revised at least once before revision using the impaction grafting technique. All the patients in the study group have a minimum follow-up of 5 years after the impaction grafting revision. In total, 43 consecutive hips in 40 patients, 22 men and 18 women, with a follow-up time of between 5 and 7 years are included in the study. The complications related to the revised hip consist of three early dislocations managed by closed reduction. Two patients suffered from periprosthetic fracture, both managed with plate osteosynthesis. Two cementless sockets were revised due to aseptic socket loosening. The Endoklinik rating of preoperative bone loss for the revised hips was 2 in 13 hips, 3 in 23 hips, and 4 in 7 hips. During the first year 29 stems subsided 2-4 mm within the cement mantle. In 8 cases, a subsidence of 5-9 mm was measured. The subsidence was nonprogressive, and no subsidence occurred after the 1st year. The Charnley, D'Aubigne, Postel scoring (maximum 6 points) for pain improved from 2.2 points preoperatively to 4.4 postoperatively, function from 2.3 to 4.3, and movement from 2.3 to 4.1. In conclusion, the concept of impaction grafting in THR revision in our study has so far proven to be successful with good clinical results at 5 years despite the relatively high early subsidence of the femoral component.

  • 18.
    Naili, Josefine E.
    et al.
    Department of Women’s and Children’s Health, Karolinska Institutet, MotorikLab, Q2:07, Karolinska University Hospital, Stockholm, Sweden.
    Wretenberg, Per
    Örebro University, School of Medical Sciences. Örebro University Hospital. Department of Orthopedics, School of Medical Sciences, Örebro University, Örebro University Hospital, Örebro, Sweden.
    Lindgren, Viktor
    Department of Molecular Medicine and Surgery, Karolinska Institutet, L1:00, Karolinska University Hospital, Stockholm, Sweden.
    Iversen, Maura D.
    Department of Women’s and Children’s Health, Karolinska Institutet, MotorikLab, Q2:07, Karolinska University Hospital, Stockholm, Sweden; Department of Physical Therapy, Movement & Rehabilitation Sciences, Bouve College of Health Sciences, Northeastern University, 360 Huntington Avenue, Boston MA, United States; Division of Rheumatology, Immunology, and Allergy, Brigham and Women’s Hospital, Harvard Medical School, Boston MA, United States.
    Hedström, Margareta
    Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Karolinska University Hospital, K54, Stockholm, Sweden.
    Broström, Eva W.
    Department of Women’s and Children’s Health, Karolinska Institutet, MotorikLab, Q2:07, Karolinska University Hospital, Stockholm, Sweden.
    Improved knee biomechanics among patients reporting a good outcome in knee-related quality of life one year after total knee arthroplasty2017In: BMC Musculoskeletal Disorders, ISSN 1471-2474, E-ISSN 1471-2474, Vol. 18, article id 122Article in journal (Refereed)
    Abstract [en]

    Background: It is not well understood why one in five patients report poor outcomes following knee arthroplasty. This study evaluated changes in knee biomechanics, and perceived pain among patients reporting either a good or a poor outcome in knee-related quality of life after total knee arthroplasty.

    Methods: Twenty-eight patients (mean age 66 (SD 7) years) were included in this prospective study. Within one month of knee arthroplasty and one year after surgery, patients underwent three-dimensional (3D) gait analysis, completed the Knee Injury and Osteoarthritis Outcome Score (KOOS), and rated perceived pain using a visual analogue scale. A "good outcome" was defined as a change greater than the minimally detectable change in the KOOS knee-related quality of life, and a "poor outcome" was defined as change below the minimally detectable change. Nineteen patients (68%) were classified as having a good outcome. Groups were analyzed separately and knee biomechanics were compared using a two-way repeated measures ANOVA. Differences in pain between groups were evaluated using Mann Whitney U test.

    Results: Patients classified as having a good outcome improved significantly in most knee gait biomechanical outcomes including increased knee flexion-extension range, reduced peak varus angle, increased peak flexion moment, and reduced peak valgus moment. The good outcome group also displayed a significant increase in walking speed, a reduction (normalization) of stance phase duration (% of gait cycle) and increased passive knee extension. Whereas, the only change in knee biomechanics, one year after surgery, for patients classified as having a poor outcome was a significant reduction in peak varus angle. No differences in pain postoperatively were found between groups.

    Conclusion: Patients reporting a good outcome in knee-related quality of life improved in knee biomechanics during gait, while patients reporting a poor outcome, despite similar reduction in pain, remained unchanged in knee biomechanics one year after total knee arthroplasty. With regards to surgeon-controlled biomechanical factors, surgery may most successfully address frontal plane knee alignment. However, achieving a good outcome in patient-reported knee-related quality of life may be related to dynamic improvements in the sagittal plane.

  • 19.
    Ramsey, D. K.
    et al.
    School of Human Kinetics, University of Ottawa, Ottawa, Canada; Department of Surgical Sciences, Section for Orthopaedics, Karolinska Institute, Stockholm, Sweden.
    Lamontagne, M.
    University of Ottawa, Ottawa, Canada.
    Wretenberg, Per
    Örebro University, School of Medical Sciences. Department of Orthopaedics, Karolinska Hospital, Stockholm, Sweden.
    Valentin, A.
    Department of Orthopaedics, Karolinska Hospital, Stockholm, Sweden.
    Engström, B.
    Department of Orthopaedics, Karolinska Hospital, Stockholm, Sweden.
    Németh, G.
    Department of Orthopaedics, Karolinska Hospital, Stockholm, Sweden.
    Assessment of functional knee bracing: an in vivo three-dimensional kinematic analysis of the anterior cruciate deficient knee2001In: Clinical Biomechanics, ISSN 0268-0033, E-ISSN 1879-1271, Vol. 16, no 1, p. 61-70Article in journal (Refereed)
    Abstract [en]

    Objective: To describe three-dimensional tibial and femoral movements in vivo and examine the effect of a brace on knee kinematics during moderate to intense activity.

    Design: Skeletal kinematics of anterior cruciate ligament deficient knees was measured with and without braces during moderate to intense activity.

    Background: Invasive markers implanted into the tibia and femur are the most accurate means to directly measure skeletal motion and may provide a more sensitive measure of the differences between brace conditions.

    Methods: Steinmann traction pins were implanted into the femur and tibia of four subjects having a partial or complete anterior cruciate ligament rupture. Non-braced and braced conditions were randomly assigned and subjects jumped for maximal horizontal distance to sufficiently stress the anterior cruciate ligament.

    Results: Intra-subject peak vertical force and posterior shear force were generally consistent between conditions. Intra-subject kinematics was repeatable but linear displacements between brace conditions were small. Differences in angular and linear skeletal motion were observed across subjects. Bracing the anterior cruciate ligament deficient knee resulted in only minor kinematic changes in tibiofemoral joint motion.

    Conclusion: In this study, no consistent reductions in anterior tibial translations were observed as a function of the knee brace tested. Relevance. Investigations have reported that knee braces fail when high loads are encountered or when load is applied in an unpredictable manner. Questions remain regarding tibiofemoral joint motion, in particular linear displacements. The pin technique is a means for direct skeletal measurement and may provide a more sensitive measure of the differences between brace conditions.

  • 20.
    Ramsey, D. K.
    et al.
    Department of Orthopaedic Surgery, Karolinska Hospital, Stockholm, Sweden.
    Wretenberg, Per
    Department of Orthopaedic Surgery, Karolinska Hospital, Stockholm, Sweden.
    Biomechanics of the knee: methodological considerations in the in vivo kinematic analysis of the tibiofemoral and patellofemoral joint1999In: Clinical Biomechanics, ISSN 0268-0033, E-ISSN 1879-1271, Vol. 14, no 9, p. 595-611Article in journal (Refereed)
    Abstract [en]

    The purpose of this review article is twofold: to report on the use of intracortical pins to measure three-dimensional tibiofemoral and patellofemoral joint kinematics and highlight methodological concerns associated with this procedure. Tibiofemoral and patellofemoral kinematics has been extensively investigated using reflective markers attached to the surrounding soft tissue of the calf and thigh. However, surface markers may not adequately represent true anatomical locations and skin movement artefacts present the most critical source of measurement error. Consequently, knowledge about skeletal tibiofemoral kinematics is limited, in particular abduction-adduction and internal-external rotations. Considerable questions remain regarding what constitutes normal motion of the knee. A way to avoid the problem of surface markers is use invasive markers to directly measure skeletal motion. To date, many co-ordinate systems have been used to describe three-dimensional skeletal kinematics of the lower limb in vivo. They include helical axes, finite helical axes, instantaneous helical axes, and the joint co-ordinate system based on local anatomic landmarks. Although each method accurately describes the relative motion in 6 d. of f., the differences in how the motion is partitioned may account for the differences across investigations. Additionally, the problem of defining the anatomical co-ordinate system makes comparisons across subjects and studies difficult since subtle differences may be caused by small deviations in the anatomical reference alignment. Cross talk is also a primarily a concern. For joints that articulate principally about one axis, the primary flexion/extension that is registered will be cross-talked into ab/adduction and internal/external rotations.

  • 21.
    Ramsey, D. K.
    et al.
    Astrid Lindgren Children’s Hospital, Karolinska Hospital, Stockholm, Sweden; Institution for Surgical Sciences, Section for Orthopedics, Karolinska Institute, Stockholm, Sweden.
    Wretenberg, Per
    Institution for Surgical Sciences, Section for Orthopedics, Karolinska Institute, Stockholm, Sweden; Department of Orthopedics, Karolinska Hospital, Stockholm, Sweden.
    Benoit, D. L.
    Institution for Surgical Sciences, Section for Sports Medicine, Department of Orthopedics, Karolinska Institute, Stockholm, Sweden.
    Lamontagne, M.
    University of Ottawa, Ottawa, Canada.
    Németh, G.
    Institution for Surgical Sciences, Section for Orthopedics, Karolinska Institute, Stockholm, Sweden; Department of Orthopedics, Karolinska Hospital, Stockholm, Sweden.
    Methodological concerns using intra-cortical pins to measure tibiofemoral kinematics2003In: Knee Surgery, Sports Traumatology, Arthroscopy, ISSN 0942-2056, E-ISSN 1433-7347, Vol. 11, no 5, p. 344-349Article in journal (Refereed)
    Abstract [en]

    The complexity of human tibiofemoral joint motion is now better understood with the advancement of new methodologies to measure tibiofemoral kinematics in vivo. Marker clusters anchored to stainless steel bone pins inserted directly into the femur and tibia provide the most sensitive and accurate means for directly measuring skeletal tibiofemoral joint motion. Despite its invasiveness, this technique has been successful, although complications have been reported with the femoral pin and its insertion site. The purpose of this technical report is twofold: to review the difficulties with the femoral pin and its insertion site from a historical perspective, and to identify the load force required from biological tissue to permanently deform the pin. In addition, proposals in the advancement of this method are discussed in the context of reducing impingement with the femoral pin and the Iliotibial band. Because stainless steel exhibits plastic behaviour with no sharp yield point, Apex self-drilling/self-tapping bone pins underwent incremental loading on an Instron materials testing machine. Loads were transmitted perpendicular to the pin with the threads partially exposed and fully secured in vice. Since the accuracy of our combined stereophotogrammetry and Optoelectric motion analysis was less than 0.4 mm, it was decided that plastic deformation occurred after deflections of 0.4 mm. With exposed threads, deflections larger than 0.4 mm were observed at 150 N and 100 N when loads were applied at 15 mm and 20 mm from the vice (representative of where the tissue came in contact with the pin). Loads greater than 200 N produced deflections less than 0.2 mm when threads were fully inserted. The 90 Hz resonant frequency for the marker cluster-bone pin complex is beyond the spectrum of human movement and can be lowpass filtered. To reduce impingement and pin bending, one solution may be to implant pins with a shorter threaded section. By completely penetrating the bone, only the smooth surface of the pin is exposed which is more resistant to bending. Otherwise pins with larger diameters and longer longitudinal incisions about the femoral insertion site are an alternative. Lengthening the longitudinal incisions about the insertion site, and correctly aligning and inserting the femoral pin between the Iliotibial band and quadriceps tendon may diminish impingement. Performing dynamic open chain flexion and extension movements while on the operating table may aid in aligning the pin at the incision site. This may stretch the IT band and quadriceps tendon and may guide the femoral pin into a more optimal position prior to it being inserted into the cortex of the bone.

  • 22.
    Ramsey, Dan K.
    et al.
    Department of Orthopaedic Surgery, Karolinska Hospital, Institution for Surgical Sciences, Karolinska Institute, Stockholm, Sweden.
    Wretenberg, Per
    Department of Orthopaedic Surgery, Karolinska Hospital, Institution for Surgical Sciences, Karolinska Institute, Stockholm, Sweden.
    Lamontagne, Mario
    University of Ottawa, Ottawa, Canada.
    Németh, Gunnar
    Department of Orthopaedic Surgery, Karolinska Hospital, Institution for Surgical Sciences, Karolinska Institute, Stockholm, Sweden.
    Electromyographic and biomechanic analysis of anterior cruciate ligament deficiency and functional knee bracing2003In: Clinical Biomechanics, ISSN 0268-0033, E-ISSN 1879-1271, Vol. 18, no 1, p. 28-34Article in journal (Refereed)
    Abstract [en]

    Objective: Examine the neuromuscular response to functional knee bracing relative to anterior tibial translations in vivo.

    Design: During randomised brace conditions, electromyographic data with simultaneous skeletal tibiofemoral kinematics were recorded from four anterior cruciate ligament deficient subjects to investigate the effect of the DonJoy Legend functional brace during activity.

    Background: Knee braces do not increase knee stability but may influence afferent inputs from proprioception and therefore one might expect changes in muscle firing patterns, amplitude and timing.

    Methods: Hoffman bone pins affixed with markers were implanted into the tibia and femur for kinematic measurement. The EMG data from the rectus femoris, semitendinosus, biceps femoris, and lateral head of the gastrocnemius were integrated for each subject in three separate time periods: 250 ms preceding footstrike and two consecutive 125 ms time intervals following footstrike.

    Results: With brace, semitendinosus activity significantly decreased 17% prior to footstrike whereas bicep femoris significantly decreased 44% during A2, (P<0.05). Rectus femoris activity significantly increased 21% in A2 (P<0.05). No consistent reductions in anterior translations were evident.

    Conclusion: Our preliminary findings, based on a limited number of subjects, indicate joint stability may result from proprioceptive feedback rather than the mechanical stabilising effect of the brace. Despite a significant increase in rectus femoris activity upon landing, only one subject demonstrated an increase in anterior tibial drawer.

    Relevance: Studies have shown functional braces do not mechanically stabilise the anterior cruciate ligament deficient knee. Perhaps bracing alters proprioceptive feedback. It has been shown that bracing the anterior cruciate ligament deficient knee may affect hamstring and quadriceps activity. Our findings stresses the importance of functional knee bracing combined with proprioceptive and muscular coordination training in order to increase joint stability.

  • 23.
    Sayed-Noor, Arkan S.
    et al.
    Department of Orthopedics, Sundsvall Hospital, Sundsvall, Sweden.
    Agren, Per-Henrik
    Wretenberg, Per
    Interobserver reliability and intraobserver reproducibility of three radiological classification systems for intra-articular calcaneal fractures2011In: Foot & ankle international, ISSN 1071-1007, E-ISSN 1944-7876, Vol. 32, no 9, p. 861-866Article in journal (Refereed)
    Abstract [en]

    Background: The management of intra-articular calcaneal fractures is difficult. One aspect for successful management is the use of a reliable and reproducible fracture classification system (FCS). The purpose of this study was to evaluate the interobserver reliability and intraobserver reproducibility of Letournel, Sanders, and Zwipp classification systems on CT scan and the Bohler's angle measurement on plain X-ray. Furthermore, we studied if the addition of a CT scan to the plain X-ray influenced the evaluation of fracture extension to the calcaneocuboid joint.

    Methods: The CT scan and plain X-ray images of 51 intra-articular calcaneal fractures were evaluated two times by three observers (two radiologists and one orthopedic surgeon) within a 5-month interval. The interobserver reliability was measured using the Fleiss kappa while the intraobserver reproducibility was measured using the Cohen's kappa.

    Results: The mean kappa values for the interobserver reliability and intraobserver reproducibility of the Sanders classification were 0.25 and 0.39, respectively, of Zwipp classification were 0.24 and 0.16, respectively, while those of the Letournel classification were 0.50 and 0.42, respectively. For the Böhler's angle, the mean kappa values for the interobserver reliability and intraobserver reproducibility were 0.34 and 0.32, respectively. The addition of CT scan images to plain X-ray found a higher incidence of calcaneocuboid joint involvement.

    Conclusion: Clinicians should be aware of the limitation regarding the interobserver reliability and intraobserver reproducibility of the Letournel, Sanders and Zwipp classification systems for calcaneal fractures. Future studies should attempt to improve the present classification systems.

  • 24.
    Sayed-Noor, Arkan S.
    et al.
    Department of Orthopaedic Surgery, Sundsvall Hospital, Sundsvall, Sweden.
    Englund, Erling
    Department of Research and Development, Sundsvall Hospital, Sundsvall, Sweden .
    Wretenberg, Per
    Department of Orthopaedic Surgery, Karolinska University Hospital, Stockholm, Sweden; Department of Molecular Medicine and Surgery, Karolinska Institute, Solna, Stockholm, Sweden.
    Sjödén, Göran O.
    Department of Orthopaedic Surgery, Sundsvall Hospital, Sundsvall, Sweden; Department of Surgical and Perioperative Sciences, Norrland University Hospital, Umeå, Sweden .
    Pressure-pain threshold algometric measurement in patients with greater trochanteric pain after total hip arthroplasty2008In: The Clinical Journal of Pain, ISSN 0749-8047, E-ISSN 1536-5409, Vol. 24, no 3, p. 232-236Article in journal (Refereed)
    Abstract [en]

    Background: The evaluation of tenderness associated with greater trochanteric pain (GTP) syndrome is amenable to bias and depends on the examiner's experience. In this study, we tested whether the use of an electronic pressure algometer enhanced the reliability of this evaluation.

    Patients and methods: Pressure-pain threshold (PPT) was measured with an electronic algometer in 18 patients who developed GTP after total hip arthroplasty and in matched controls. Both groups were evaluated with visual analog scale.

    Results: The PPT measurements showed large interindividual variability across patients. The correspondence of the PPT measurements in asymptomatic patients was good. We found good validity for the algometer used. The PPT ratio of 0.8 (affected vs. unaffected side) can be used as a cut-off ratio. The PPT measurements at the greater trochanter (local pain) were significantly lower than at the ilio-tibial band (radiated pain). There was no correlation between PPT measurements and visual analog scales. Despite the acceptable sensitivity and specificity of pressure algometer, because of low positive predictive value and large interindividual variability, pressure algometer has a limited value as a screening test.

    Conclusions: The examination of tenderness associated with GTP is facilitated by the used algometer. It is the intraindividual body-side PPT differences that yield the most sensitive measurement for the assessment of deep pain. A cut-off value of 0.8 can be used for diagnostic purposes. Interindividual differences might be considerable and could mask pathologic diagnostic findings.

  • 25.
    Sayed-Noor, Arkan S.
    et al.
    Department of Orthopaedic Surgery, Sundsvall Hospital, Sundsvall, Sweden.
    Hugo, Anders
    Karolinska Department of Orthopaedic Surgery, Karolinska University Hospital, Stockholm, Sweden.
    Sjödén, Göran O.
    Department of Orthopaedic Surgery, Sundsvall Hospital, Sundsvall, Sweden.
    Wretenberg, Per
    Karolinska Department of Orthopaedic Surgery, Karolinska University Hospital, Stockholm, Sweden; Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden.
    Leg length discrepancy in total hip arthroplasty: comparison of two methods of measurement2009In: International Orthopaedics, ISSN 0341-2695, E-ISSN 1432-5195, Vol. 33, no 5, p. 1189-1193Article in journal (Refereed)
    Abstract [en]

    Measurement of leg length discrepancy is an important part in planning a successful total hip arthroplasty (THA). Many clinical and radiological methods with variable degrees of accuracy have been advocated to carry out this measurement. We studied the accuracy of a commonly used clinical method by comparing it to a well-known and reliable radiological method. A total of 139 patients aged 44-89 (mean: 67.5 years) scheduled to undergo THA were examined for clinical and radiological leg length discrepancy measurements before and after the operation by the same observers. There was a poor correlation between the clinical and radiological methods preoperatively [r = 0.21, intra-class correlation coefficient (ICC) = 0.33]. The correlation was better postoperatively (r = 0.45, ICC = 0.62). The clinical method used is not recommended for leg length discrepancy measurement preoperatively. Caution should even be taken when using this method postoperatively. The authors recommend using the radiological method when measuring leg length discrepancy as a part of planning for THA.

  • 26.
    Sayed-Noor, Arkan S.
    et al.
    Department of Orthopaedic Surgery, Sundsvall Hospital, Sundsvall, Sweden; Department of Surgical and Perioperative Sciences, Norrland University Hospital, Umeå, Sweden.
    Pedersen, Eskild
    Department of Orthopaedic Surgery, Sundsvall Hospital, Sundsvall, Sweden.
    Wretenberg, Per
    Department of Orthopaedic Surgery, Karolinska University Hospital, Stockholm, Sweden; Department of Molecular Medicine and Surgery, Karolinska Institute, Solna, Stockholm, Sweden.
    Sjödén, Göran O.
    Department of Orthopaedic Surgery, Sundsvall Hospital, Sundsvall, Sweden; Department of Surgical and Perioperative Sciences, Norrland University Hospital, Umeå, Sweden.
    Distal lengthening of ilio-tibial band by Z-plasty for treating refractory greater trochanteric pain after total hip arthroplasty (Pedersen-Noor operation)2009In: Archives of Orthopaedic and Trauma Surgery, ISSN 0936-8051, E-ISSN 1434-3916, Vol. 129, no 5, p. 597-602Article in journal (Refereed)
    Abstract [en]

    Introduction: The development of greater trochanteric pain (GTP) after total hip arthroplasty (THA) represents a special category. Despite that treatment is mainly conservative, some patients show poor response and surgical intervention should be considered. We propose a new method consisting of distal lengthening of ilio-tibial band (ITB) by Z-plasty.

    Material and methods: Between March 2004 and June 2006, 12 women with refractory GTP after THA were operated on using distal ITB lengthening. The procedure was done under local anaesthesia on an outpatient basis. The patients were followed up 3-4 months postoperatively by phone interview and at 1-3 years by EQ-5D questionnaire and clinical examination including tenderness evaluation with algometer.

    Results: All patients improved significantly (EQ-5D = 0.26 preoperatively vs. 0.67 postoperatively; P < 0.005) except one patient who experienced no change in GTP symptoms. No postoperative complications were reported.

    Conclusions: We believe that treating patients with GTP after THA by the technique described offers a simple, safe and reliable method.

  • 27.
    Svedmark, Per
    et al.
    Department of Orthopaedics, Karolinska Sjukhuset, Stockholm, Sweden.
    Wretenberg, Per
    Department of Orthopaedics, Karolinska Sjukhuset, Stockholm, Sweden.
    Stark, Andre
    Department of Orthopaedics, Karolinska Sjukhuset, Stockholm, Sweden.
    Broken wings: common with the Hardinger plug2002In: Acta Orthopaedica Scandinavica, ISSN 0001-6470, Vol. 73, no 4, p. 407-408Article in journal (Refereed)
    Abstract [en]

    We used the Hardinger occluder plug in 51 consecutive total hip arthroplasties. In 34 hips, 1 or more of the 12 polyethylene wings fractured and could be washed out from the canal. As many as 7 wings were loose in 2 arthroplasties. Although numerous wings were broken, no failure occurred in occlusion. The placement of loose wings in the femoral canal was studied by cementing a Charnley prosthesis in a saw-bone prepared with loose wings. The model was cut into slices. We found that the plastic wings could come into contact with both the bone and prosthesis.

  • 28.
    Thur, Charlotte K.
    et al.
    Department of Molecular Medicine and Surgery, Section of Orthopaedics and Sports Medicine, Karolinska Institutet, Stockholm, Sweden; Karolinska University Hospital, Stockholm, Sweden.
    Edgren, Gustaf
    Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden; and Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA.
    Jansson, Karl-Åke
    Department of Molecular Medicine and Surgery, Section of Orthopaedics and Sports Medicine, Karolinska Institutet, Stockholm, Sweden; Karolinska University Hospital, Stockhlm, Sweden.
    Wretenberg, Per
    Department of Molecular Medicine and Surgery, Section of Orthopaedics and Sports Medicine, Karolinska Institutet, stockholm, Sweden; Karolinska University Hospital, Stockhlm, Sweden.
    Epidemiology of adult ankle fractures in Sweden between 1987 and 2004: a population-based study of 91,410 Swedish inpatients2012In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 83, no 3, p. 276-281Article in journal (Refereed)
    Abstract [en]

    Background and purpse: Previous national epidemiological data on the characteristics and trends of patients with ankle fractures have been limited. We therefore analyzed data on Swedish inpatients with ankle fractures in this nationwide population study, based on data from 1987 through 2004.

    Patients and methods: Data on all inpatients aged 15 years and older with ankle fracture were extracted from the Swedish National Patient Register for the period 1987-2004.

    Results: We identified 91,410 hospital admissions with ankle fracture, corresponding to an annual incidence rate of 71 per 10(5) person-years. During the study period, the number of hospital admissions increased by 0.2% annually, mainly from increase in fracture incidence in the elderly women. Mean age at admission was 45 (SD 19) years for men and 58 (18) for women. The major mechanism of injury was falling at the same level (64%).

    Interpretation: This nationwide study of inpatients with ankle fractures showed an increase in fracture incidence, particularly in elderly women.

  • 29.
    Wang, Ruoli
    et al.
    Department of Mechanics, Royal Institute of Technology, Stockholm, Sweden.
    Thur, Charlotte K.
    Department of Molecular Medicine and Surgery, Section of Orthopaedics and Sports Medicine, Karolinska Institutet, Stockholm, Sweden.
    Gutierrez-Farewik, Elena M.
    Department of Mechanics, Royal Institute of Technology, Stockholm, Sweden; Department of Women’s and Children’s Health, Karolinska Institutet, Stockholm, Sweden.
    Wretenberg, Per
    Department of Molecular Medicine and Surgery, Section of Orthopaedics and Sports Medicine, Karolinska Institute, Solna, Stockholm, Sweden.
    Broström, Eva
    Department of Women’s and Children’s Health, Karolinska Institutet, Stockholm, Sweden.
    One year follow-up after operative ankle fractures: a prospective gait analysis study with a multi-segment foot model2010In: Gait & Posture, ISSN 0966-6362, E-ISSN 1879-2219, Vol. 31, no 2, p. 234-240Article in journal (Refereed)
    Abstract [en]

    Ankle fractures are one of the most common lower limb traumas. Several studies reported short- and long-term post-operative results, mainly determined by radiographic and subjective functional evaluations. Three-dimensional gait analysis with a multi-segment foot model was used in the current study to quantify the inter-segment foot motions in 18 patients 1 year after surgically treated ankle fractures. Data were compared to that from gender- and age-matched healthy controls. The correlations between Olerud/Molander ankle score and kinematics were also evaluated. Patients with ankle fractures showed less plantarflexion and smaller range of motion in the injured talocrural joint, which were believed to be a sign of residual joint stiffness after surgery and immobilization. Moreover, the forefoot segment had smaller sagittal and transverse ranges of motion, less plantarflexion and the hallux segment had less dorsiflexion and smaller sagittal range of motion. The deviations found in the forefoot segment may contribute to the compensation mechanisms of the injured ankle joint. Findings of our study show that gait analysis with a multi-segment foot model provides a quantitative and objective way to perform the dynamic assessment of post-operative ankle fractures, and makes it possible to better understand not only how the injured joint is affected, but also the surrounding joints.

  • 30.
    Weidenhielm, L. R.
    et al.
    Departments of Orthopaedic Surgery, Karolinska Hospital, Stockholm, Sweden.
    Mikhail, W E
    Departments of Orthopaedic Biomedical Engineering Research and Orthopaedic Surgery, Medical College of Ohio, Toledo, Ohio, USA.
    Wretenberg, Per
    Departments of Orthopaedic Surgery, Karolinska Hospital, Stockholm, Sweden.
    Fow, J.
    Departments of Orthopaedic Biomedical Engineering Research and Orthopaedic Surgery, Medical College of Ohio, Toledo, Ohio, USA.
    Simpson, J.
    Departments of Cumberland Orthopaedics, Crossville, USA.
    Bauer, T. W.
    Pathology and Orthopaedic Surgery, The Cleveland Clinic Foundation, Cleveland, Ohio, USA.
    Analysis of the retrieved hip after revision with impaction grafting2001In: Acta Orthopaedica Scandinavica, ISSN 0001-6470, Vol. 72, no 6, p. 609-614Article in journal (Refereed)
  • 31.
    Weiss, R. J.
    et al.
    Department of Molecular Medicine and Surgery, Section of Orthopaedics and Sports Medicine, Karolinska Institutet, Stockholm, Sweden.
    Broström, E.
    Department of Women and Child Health, Karolinska Institutet, Stockholm, Sweden.
    Stark, A.
    Department of Molecular Medicine and Surgery, Section of Orthopaedics and Sports Medicine, Karolinska Institutet, Stockholm, Sweden.
    Wick, M. C.
    Department of Medicine, Section of Rheumatology, Karolinska Institutet, Stockholm, Sweden.
    Wretenberg, Per
    Department of Molecular Medicine and Surgery, Section of Orthopaedics and Sports Medicine, Karolinska Institutet, Stockholm, Sweden.
    Ankle/hindfoot arthrodesis in rheumatoid arthritis improves kinematics and kinetics of the knee and hip: a prospective gait analysis study2007In: Rheumatology, ISSN 1462-0324, E-ISSN 1462-0332, Vol. 46, no 6, p. 1024-1028Article in journal (Refereed)
    Abstract [en]

    Objectives: To evaluate the effects of ankle/hindfoot arthrodesis in rheumatoid arthritis (RA) patients on gait pattern of the knee and hip.

    Methods: In this prospective follow-up study, 14 RA patients scheduled for ankle/hindfoot arthrodesis (talo-calcaneal, talo-navicular, calcaneo-cuboid and/or talo-crural joints) and 14 age- and sex-matched healthy controls were included. Three-dimensional gait analyses of joint angles, moments and work were performed at the index operation and after 13 months of follow-up. Each patient underwent clinical assessments of pain while walking, overall evaluation of disease activity, Health Related Quality of Life Questionnaire (EQ-5D), activity limitations, maximum walking distance, difficulty with walking surface and gait abnormality. For comparisons of pre- vs post-operative conditions, Wilcoxon's matched pairs test and Friedman ANOVA by rank test were used.

    Results: At follow-up after ankle/hindfoot fusion surgery, RA patients demonstrated a statistically significant improvement in mean range of joint motions, moments and work in the overlying joints such as the knee and hip. Moreover, there was significantly less pain, disease activity, activity limitation, difficulty with walking surface and gait abnormality. EQ-5D and maximum walking distance were also significantly improved at follow-up.

    Conclusions: Our results demonstrate that ankle/hindfoot arthrodesis in RA is an effective intervention to reduce pain and to improve Health Related Quality of Life and functional ability. Moreover, the overlying leg joints experience an improvement in joint motion, muscle-generated joint moments and work during walking. Three-dimensional gait analysis may assist future investigations of the effects of orthopaedic surgery on functional mobility in RA to prevent irreversible disablement.

  • 32. Weiss, R. J.
    et al.
    Ehlin, A.
    Montgomery, Scott M.
    Örebro University, School of Health and Medical Sciences.
    Wick, M. C.
    Stark, A.
    Wretenberg, Per
    Decrease of RA-related orthopaedic surgery of the upper limbs between 1998 and 2004: data from 54,579 Swedish RA inpatients2008In: Rheumatology, ISSN 1462-0332, Vol. 47, no 4, p. 491-494Article in journal (Refereed)
    Abstract [en]

    Objectives. To describe the overall use and temporal trends in orthopaedic upper limb surgery associated with RA on a nation wide basis in Sweden between 1998 and 2004.

    Methods. Data for all inpatient visits during 1998–2004 for patients older than 18 yrs with RA-related diagnoses were extracted from the Swedish National Hospital Discharge Registry (SNHDR). The SNHDR prospectively collects data on all hospital admissions in Sweden according to the International Classification of Diseases (ICD). Data were analysed with respect to orthopaedic surgery of the hand, elbow and shoulder.

    Results. During the study period, 54 579 individual RA patients were admitted to a Swedish hospital and 9% of these underwent RA-related surgery of the upper limbs. The RA patient cohort underwent a total of 8251 RA-related upper limb surgical procedures. The hand (77%) was most frequently operated on, followed by the shoulder (13%) and the elbow (10%). There was a statistically significant decrease of 31% for all admissions associated with RA-related upper limb surgery during 1998–2004 (P = 0.001). Some 10% of all RA-related upper limb surgery was due to total joint arthroplasties (TJAs), mostly for the elbow (59%). During 1998–2004, all TJAs, elbow-TJAs and shoulder-TJAs had a stable occurrence. In contrast, the overall numbers of hand-TJAs significantly increased (P = 0.009).

    Conclusions. Rates of RA-related upper limb surgery decreased and TJAs had a stable occurrence in Sweden during 1998–2004. The findings of this study may reflect trends in disease management and health outcomes of RA patients in Sweden.

  • 33.
    Weiss, R. J.
    et al.
    Department of Orthopaedic Surgery, Karolinska University Hospital, Stockholm, Sweden.
    Stark, A.
    Department of Orthopaedic Surgery, Karolinska University Hospital, Stockholm, Sweden.
    Wick, M. C.
    Department of Rheumatology, Karolinska University Hospital, Stockholm, Sweden.
    Ehlin, A.
    Department of Medicine, Unit of Clinical Epidemiology, Karolinska University Hospital, Stockholm, Sweden.
    Palmblad, K.
    Department of Rheumatology, Astrid Lindgren Children’s Hospital, Stockholm, Sweden.
    Wretenberg, Per
    Örebro University, School of Medical Sciences. Department of Orthopaedic Surgery, Karolinska University Hospital, Stockholm, Sweden.
    Orthopaedic surgery of the lower limbs in 49,802 rheumatoid arthritis patients: results from the Swedish National Inpatient Registry during 1987 to 20012006In: Annals of the Rheumatic Diseases, ISSN 0003-4967, E-ISSN 1468-2060, Vol. 65, no 3, p. 335-341Article in journal (Refereed)
    Abstract [en]

    Objectives: To analyse changes in the rates of hospital admission and use of orthopaedic surgery to the lower limbs in Swedish patients with rheumatoid arthritis between 1987 and 2001.

    Methods: Data for all rheumatoid patients admitted to hospital between 1987 and 2001 were abstracted from the Swedish National Hospital Discharge Register (SNHDR). The data in the register are collected prospectively, recording all inpatient admissions throughout Sweden. The SNHDR uses the codes for diagnoses at discharge and surgical procedures according to the Swedish version of the International Classification of Diseases (ICD).

    Results: In all, 49,802 individual patients with rheumatoid arthritis were identified, accounting for 159,888 inpatient visits. Hospital admissions for rheumatoid arthritis decreased by 42% (p<0.001) during the period 1987 to 2001. Twelve per cent of all admissions were for a rheumatoid arthritis related surgical procedure to the lower limbs; those admissions decreased markedly (by 16%) between 1987 and 1996, and by 12% between 1997 and 2001, as did the overall number of rheumatoid arthritis related surgical procedures to the lower limbs during both time periods. Between 1997 and 2001, 47% of all rheumatoid arthritis related surgical procedures were total joint arthroplasties. There was an overall trend towards reduced length of hospital stay after orthopaedic surgery to the lower limbs during the study period.

    Conclusions: Rates of hospital admission and rheumatoid arthritis related surgical procedures to the lower limbs in Swedish patients with rheumatoid arthritis decreased between 1987 and 2001. This may reflect trends in disease severity, management, and health outcomes of this disease in Sweden.

  • 34.
    Weiss, Rüdiger J.
    et al.
    Department of Molecular Medicine and Surgery, Section of Orthopaedics and Sports Medicine, Karolinska Institutet, Stockholm, Sweden.
    Wretenberg, Per
    Department of Molecular Medicine and Surgery, Section of Orthopaedics and Sports Medicine, Karolinska Institute, Solna, Stockholm, Sweden.
    Stark, André
    Department of Molecular Medicine and Surgery, Section of Orthopaedics and Sports Medicine, Karolinska Institutet, Stockholm, Sweden.
    Palmblad, Karin
    Department of Women and Child Health, Karolinska Institutet, Stockholm, Sweden.
    Larsson, Per
    Department of Medicine, Section of Rheumatology, Karolinska Institutet, Stockholm, Sweden.
    Gröndal, Lollo
    Department of Molecular Medicine and Surgery, Section of Orthopaedics and Sports Medicine, Karolinska Institutet, Stockholm, Sweden.
    Broström, Eva
    Department of Women and Child Health, Karolinska Institutet, Stockholm, Sweden.
    Gait pattern in rheumatoid arthritis2008In: Gait & Posture, ISSN 0966-6362, E-ISSN 1879-2219, Vol. 28, no 2, p. 229-234Article in journal (Refereed)
    Abstract [en]

    The purpose of this study was to analyse kinematic and kinetic gait changes in rheumatoid arthritis (RA) patients in comparison to healthy controls and to examine whether levels of functional disability (Health Assessment Questionnaire (HAQ)-scores) were associated with gait parameters. Using a three-dimensional motion analysis system, kinematic and kinetic gait parameters were measured in 50 RA patients and 37 healthy controls. There was a significant reduction in joint motions, joint moments and work in the RA cohort compared with healthy controls. The following joint motions were decreased: hip flexion-extension range (Delta6 degrees ), hip abduction (Delta4 degrees ), knee flexion-extension range (Delta8 degrees ) and ankle plantarflexion (Delta10 degrees ). The following joint moments were reduced: hip extensor (Delta0.30Nm/kg) and flexor (Delta0.20Nm/kg), knee extensor (Delta0.11Nm/kg) and flexor (Delta0.13Nm/kg), and ankle plantarflexor (Delta0.44Nm/kg). Work was lower in hip positive work (Delta0.07J/kg), knee negative work (Delta0.08J/kg) and ankle positive work (Delta0.15J/kg). Correlations were fair although significant between HAQ and hip flexion-extension range, hip abduction, knee flexion-extension range, hip abductor moment, stride length, step length and single support (r=-0.30 to -0.38, p<0.05). Our findings suggest that RA patients have overall less joint movement and specifically restricted joint moments and work across the large joints of the lower limbs during walking than healthy controls. There were only fair associations between levels of functional disability and gait parameters. The findings of this study help to improve the understanding how RA affects gait changes in the lower limbs.

  • 35.
    Wretenberg, Per
    Department of Molecular Medicine and Surgery, Section of Orthopaedics), Karolinska Institute, Solna, Stockholm, Sweden.
    Good function but very high concentrations of cobalt and chromium ions in blood 37 years after metal-on-metal total hip arthroplasy2008In: Medical Devices: Evidence and Research, ISSN 1179-1470, Vol. 1, p. 31-32Article in journal (Refereed)
    Abstract [en]

    This case report describes a patient who had a metal-on-metal hip prosthesis implanted 37 years ago. The hip function and X-ray are presented. The levels of cobalt and chromium ions in blood are analyzed and found to be about 40 times higher than normal. Consequences are discussed.

  • 36.
    Wretenberg, Per
    et al.
    Örebro University, School of Medical Sciences. Kinesiology Research Group, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden .
    Arborelius, U. P.
    Kinesiology Research Group, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
    Power and work produced in different leg muscle groups when rising from a chair1994In: European Journal of Applied Physiology and Occupational Physiology, ISSN 0301-5548, E-ISSN 1432-1025, Vol. 68, no 5, p. 413-417Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to determine the power output and work done by different muscle groups at the hip and knee joints during a rising movement, to be able to tell the degree of activation of the muscle groups and the relationship between concentric and eccentric work. Nine healthy male subjects rose from a chair with the seat at knee level. The moments of force about the hip and knee joints were calculated semidynamically. The power output (P) and work in the different muscle groups surrounding the joints was calculated as moment of force times joint angular velocity. Work was calculated as: work = integral of P dt. The mean peak concentric power output was for the hip extensors 49.9 W, hip flexors 7.9 W and knee extensor 89.5 W. This power output corresponded to a net concentric work of 20.7 J, 1.0 J and 55.6 J, respectively. There was no concentric power output from the knee flexor muscles. Energy absorption through eccentric muscle action was produced by the hip extensors and hip flexors with a mean peak power output of 4.8 W and 7.4 W, respectively. It was concluded that during rising, the hip and knee muscles mainly worked concentrically and that the greatest power output and work were produced during concentric contraction of the knee and hip extensor muscles. There was however also a demand for eccentric work by the hip extensors as well as both concentric and eccentric work by the hip flexors. The knee flexor muscles were unloaded.

  • 37.
    Wretenberg, Per
    et al.
    Kinesiology Research Group, Department of Anatomy, Karolinska Institute, Stockholm, Sweden.
    Arborelius, U. P.
    Kinesiology Research Group, Department of Anatomy, Karolinska Institute, Stockholm, Sweden.
    Lindberg, F.
    Kinesiology Research Group, Department of Anatomy, Karolinska Institute, Stockholm, Sweden; Department of Surgery, Skellefteȧ Hospital, Skellefteȧ, Sweden.
    The effects of a pneumatic stool and a one-legged stool on lower limb joint load and muscular activity during sitting and rising1993In: Ergonomics, ISSN 0014-0139, E-ISSN 1366-5847, Vol. 36, no 5, p. 519-535Article in journal (Refereed)
    Abstract [en]

    Nine healthy male subjects rose from four different stools. The 'ordinary' stool (K) was set at normal chair height, approximately 50 cm, and the 'low ordinary' stool (O), the one-legged stool (T), and the pneumatically-sprung stool (S) were all approximately 32 cm high. The moments of force in the hip, knee, and ankle joints were calculated with a semidynamic technique using a Kistler force plate and video. EMG in four leg muscles was recorded. The part of bodyweight carried by the different stools when the subjects were sitting was measured, and the subjects estimated the effort of rising, using the Borg scale. The low ordinary stool gave higher knee and hip moments than the ordinary stool. Use of the pneumatic stool reduced the knee and hip moments to a level comparable with that of the ordinary stool. The reduction in moment compared with the one-legged stool (T) and the low ordinary stool (O) was significant, both in the knee (p < 0.005) and the hip (p < 0.001). Rising from the three low stools gave no significant differences in mean maximum muscle activity in any of the muscles investigated. The subjects estimated that the pneumatic stool and the ordinary stool were the easiest to rise from. The part of bodyweight carried by the ordinary stool and the low ordinary stool, both around 80% when sitting, was significantly higher than for the two other stools (p < 0.005). It was concluded that a pneumatic stool can be a useful device to workers who work in low positions and rise frequently.

  • 38.
    Wretenberg, Per
    et al.
    Department of Anatomy, Karolinska Institute, St. Göran's Hospital, Stockholm, Sweden .
    Arborelius, U. P.
    Department of Anatomy, Karolinska Institute, St. Göran's Hospital, Stockholm, Sweden .
    Weidenhielm, L.
    Department of Anatomy, Karolinska Institute, St. Göran's Hospital, Stockholm, Sweden .
    Lindberg, F.
    Department of Anatomy, Karolinska Institute, St. Göran's Hospital, Stockholm, Sweden .
    Rising from a chair by a spring-loaded flap seat: a biomechanical analysis1993In: Scandinavian Journal of Rehabilitation Medicine, ISSN 0036-5505, E-ISSN 1940-2228, Vol. 25, no 4, p. 153-159Article in journal (Refereed)
    Abstract [en]

    Nine healthy male subjects and 8 patients with unilateral knee osteoarthrosis were studied while rising from a chair with and without the aid of a spring-loaded flap seat. The seat force started at 216 N and decreased with increasing seat angle. Ground reaction forces and motion were recorded using a force plate and video. EMG of the left vastus lateralis muscle was recorded. The effort when rising was estimated by the Borg scale. The use of the flap seat reduced the mean peak knee moment for the healthy subjects from 73 to 41 Nm and for the patients from 55 to 33 Nm. The decreases were significant at a p < 0.001 level. The patients also reduced their hip moment significantly from 50 to 35 Nm (p < 0.005). The muscle activity in the vastus lateralis was also significantly lower when the flap seat was used (p < 0.005). When the theoretically maximal friction force between seat and subject was added, the effective seat force decreased more slowly, and the relation between its horizontal and vertical force components was more advantageous. The patients estimated greater effort reduction than the healthy subjects comparing the ordinary chair and the flap seat.

    Conclusion: a spring-loaded flap seat can reduce knee and hip load and can thus be useful for people with knee osteoarthrosis.

  • 39.
    Wretenberg, Per
    et al.
    Department of Orthopaedic Surgery, Karolinska Hospital, Stockholm, Sweden.
    Ekelund, A.
    Shoulder Service, Department of Orthopaedic Surgery, St. Göran's Hospital, Stockholm, Sweden .
    Acute hemiarthroplasty after proximal humerus fracture in old patients. A retrospective evaluation of 18 patients followed for 2-7 years1997In: Acta Orthopaedica Scandinavica, ISSN 0001-6470, Vol. 68, no 2, p. 121-123Article in journal (Refereed)
    Abstract [en]

    We evaluated the outcome of acute shoulder hemiarthroplasty in 18 patients following displaced three- and four-part fractures of the proximal humerus. The mean age of the patients was 82 (70-92) years and the average follow-up time was 3.5 (2-7) years. No revision due to loosening was performed. All patients were evaluated concerning activities of daily living, degree of pain (VAS-scale, 0-100 mm) and range of motion. The patients had a low functional level, but were able to sleep on the operated side and keep up their hobby. 11 patients were painfree and the worst pain recorded was 28 mm. Range of motion for all movements, except extension, was statistically significant lower than for the non-operated side. We conclude that in elderly patients acute hemiarthroplasty following three- or four-part fractures of the proximal humerus results in good pain relief, but a more limited range of motion than that reported for younger patients.

  • 40.
    Wretenberg, Per
    et al.
    Department of Orthopaedics, Karolinska University Hospital, Stockholm, Sweden.
    Ericson, Anne
    Department of Orthopaedics, Karolinska University Hospital, Stockholm, Sweden.
    Stark, André
    Department of Orthopaedics, Karolinska University Hospital, Stockholm, Sweden.
    Radial head prosthesis after fracture of radial head with associated elbow instability2006In: Archives of Orthopaedic and Trauma Surgery, ISSN 0936-8051, E-ISSN 1434-3916, Vol. 126, no 3, p. 145-149Article in journal (Refereed)
    Abstract [en]

    Introduction: Fractures of the radial head and associated elbow instability can be treated with operation with radial head prosthesis. In this study, we evaluate function 1-7 years after implantation and also function after removal of five prostheses.

    Material and methods: Eighteen patients with radial head fracture and associated elbow instability were evaluated 3.7 years (1-7) after implantation of a radial head prosthesis. Pain at rest and during activity was measured with a visual analogue scale (VAS). Test of stability and neurological examination was done manually as well as measurement of the range of motion, using a goniometer. Activity of daily living (ADL) was estimated using five questions where the answers were graded between 1 and 3. The patients were asked to grade their general satisfaction according to the following scale; very satisfied, satisfied, not satisfied, disappointed. Plain X-rays were taken and 14 patients agreed to have their elbow strength evaluated using the validated BTE work simulator.

    Results: Five prostheses had been extracted due to poor range of motion. All these patients improved after extraction. All elbows were stable. No patient with extracted prosthesis had VAS score >2. The mean extension defect for this group was 15 degrees (5-25) compared to the mean extension defect for the 13 patients with the prosthesis still in place 15 degrees (0-40). The highest VAS score for the patients with prosthesis was five but the mean as low as 0.8. In the whole group, 13 patients were pain free. ADL function was good in general. The X-rays of the prostheses, still in place, showed radiolucent lines in 7 of the 13 patients. In the whole group, there was a significant decrease in supination, flexion and extension strength (P<0.01, P<0.01, P<0.05).

    Discussion: Radial head prosthesis works as a spacer after fracture of the radial head and associated instability. If range of motion is much restricted post-operatively, the prosthesis can be removed with improved function as result.

  • 41.
    Wretenberg, Per
    et al.
    Kinesiology Research Group, Department of Neuroscience, Karolinska Institute, Stockholm, Sweden.
    Feng, Y.
    Kinesiology Research Group, Department of Neuroscience, Karolinska Institute, Stockholm, Sweden.
    Arborelius, U. P.
    Kinesiology Research Group, Department of Neuroscience, Karolinska Institute, Stockholm, Sweden.
    High- and low-bar squatting techniques during weight-training1996In: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 28, no 2, p. 218-224Article in journal (Refereed)
    Abstract [en]

    Eight Swedish national class weightlifters performed "high-bar" squats and six national class powerlifters performed "low-bar" squats, with a barbell weight of 65% of their 1 RM, and to parallel- and a deep-squatting depth. Ground reaction forces were measured with a Kistler piezo-electric force platform and motion was analyzed from a video record of the squats. A computer program based on free-body mechanics was designed to calculate moments of force about the hip and knee joints. EMG from vastus lateralis, rectus femoris, and biceps femoris was recorded and normalized. The peak moments of force were flexing both for the hip and the knee. The mean peak moments of force at the hip were for the weightlifters 230 Nm (deep) and 216 Nm (parallel), and for the powerlifters 324 Nm (deep), and 309 Nm (parallel). At the knee the mean peak moments for the weightlifters were 191 Nm (deep) and 131 Nm (parallel), and for the powerlifters 139 Nm (deep) and 92 Nm (parallel). The weightlifters had the load more equally distributed between hip and knee, whereas the powerlifters put relatively more load on the hip joint. The thigh muscular activity was slightly higher for the powerlifters.

  • 42.
    Wretenberg, Per
    et al.
    Örebro University, School of Medical Sciences. Department of Molecular Medicine and Surgery, Section of Orthopaedics), Karolinska Institute, Stockholm, Sweden.
    Hugo, Anders
    Department of Molecular Medicine and Surgery, Section of Orthopaedics), Karolinska Institute, Stockholm, Sweden.
    Broström, Eva
    Department of Women and Child Health, Karolinska Institute, Stockholm, Sweden.
    Hip joint load in relation to leg length discrepancy2008In: Medical Devices: Evidence and Research, ISSN 1179-1470, E-ISSN 1179-1470, Vol. 1, p. 13-18Article in journal (Refereed)
    Abstract [en]

    Objective: Leg length discrepancy is common both in healthy subjects and after total hip arthroplasty (THA). Studies that evaluated leg length following THA have demonstrated a notable inconsistency in restoring leg length. The effects concerning joint load during gait is however not well known. The purpose of this study was to use three-dimensional (3D) gait analysis to evaluate joint load during gait with a simulated leg length discrepancy of 2 and 4 cm. Nine healthy subjects without any history of hip injury participated.

    Method: A 3D gait analysis (Vicon, Motion System, Oxford, England) was performed with 6 cameras and 2 force palates using a standard biomechanical gait model. Hip joint moments of force were calculated for all three degrees of motion freedom. ANOVA for repeated measurements was used for statistical calculations.

    Results: Abduction peak moment was significantly increased at the short side (P < 0.05) but unaffected on the long side. The adduction moment decreased on the long side between 0 and 4 cm (P < 0.01) but was unaffected on the short side. The internal hip rotation moments were unchanged for both the long and the short side. The external rotation moment was unchanged on the short side and decreased between bare foot and 4 cm on the long side (P < 0.05).

    Conclusion: A leg length discrepancy of 2 cm or more creates biomechanical changes concerning hip joint load both on the long and the short side and that the effects are larger on the short side. The increased stress may cause problems in the long run.

  • 43.
    Wretenberg, Per
    et al.
    Kinesiology Research Group, Department of Anatomy, Karolinska Institute, Stockholm, Sweden.
    Lindberg, F.
    Kinesiology Research Group, Department of Anatomy, Karolinska Institute, Stockholm, Sweden.
    Arborelius, U. P.
    Kinesiology Research Group, Department of Anatomy, Karolinska Institute, Stockholm, Sweden.
    Effect of armrests and different ways of using them on hip and knee load during rising1993In: Clinical Biomechanics, ISSN 0268-0033, E-ISSN 1879-1271, Vol. 8, no 2, p. 95-101Article in journal (Refereed)
    Abstract [en]

    The loading moments of force about the hip and knee joints of ten healthy male subjects were calculated using recorded forces from a force plate and static contribution from body segments. The subjects rose from a chair while using armrests in ten different ways, and, as a reference, without arm aid. The influence of different armrest heights, hand placements and arm forces was studied. Horizontal and vertical forces on the armrests were measured. Irrespective of armrest height and hand placement, the use of armrests significantly reduced the hip and knee moments compared to rising without arm aid (P < 0.001). However, there were no statistically significant differences between different armrest heights or hand placements. High arm force reduced both hip and knee moments. The greatest reduction occurred for high armrests and high arm force, which reduced the mean peak hip moment from 39 to 17 N m and the knee moment from 83 to 28 N m. Calculation of patellofemoral compressive force and the force on the femoral head due to extensor muscle activity demonstrated that local hip and knee forces were reduced when armrests were used. Horizontal forces applied to the armrests were small. Subjectively 'doubled' arm force resulted in nearly double force on the armrests.

  • 44.
    Wretenberg, Per
    et al.
    Department of Neuroscience, Karolinska Institute, Stockholm, Sweden; Department of Orthopaedics, St Görans Hospital, Stockholm, Sweden.
    Németh, G.
    Department of Orthopaedics, Karolinska Hospital, Stockholm, Sweden.
    Lamontagne, M.
    Department of Radiology, Karolinska Hospital, Stockholm, Sweden.
    Lundin, B.
    School of Human Kinetics and Department of Anatomy and Neurobiology, University of Ottawa, Canada.
    Passive knee muscle moment arms measured in vivo with MRI1996In: Clinical Biomechanics, ISSN 0268-0033, E-ISSN 1879-1271, Vol. 11, no 8, p. 439-446Article in journal (Refereed)
    Abstract [en]

    Objective: To determine moment arm lengths from seven knee muscles and the patellar tendon. The knee muscles were the biceps femoris, semitendinosus, semimembranosus, gracilis, sartorius, and the lateral and medial gastrocnemius muscles.

    Design: The moment arms were calculated based on MRI measurements.

    Background: Moment arm lengths of different muscles with respect to the joint centre of rotation (CR) or the centre of the contact point between joint surfaces are necessary basic data for biomechanical models predicting joint load.

    Methods: Ten male and seven female subjects participated. Using a 1.5 Tesla magnetic resonance imaging system, 3-dimensional coordinates of relevant points were recorded from a 3-D volume reconstruction of the right knee at knee flexion angles of 0, 30 and 60 degrees. Muscular moment arms were calculated in both the sagittal and frontal planes. The recordings were all made during passive mode, which means that no muscular contraction was performed.

    Results: All muscles except the lateral gastrocnemius showed statistically significant differences (P<0.05) of moment arm lengths between gender in the frontal plane. All muscles except biceps femoris and sartorius showed significant differences (P<0.05) of moment arm lengths between gender in the sagittal plane. Most muscles also showed a linear or quadratic trend of changing moment arms with varying knee angle. CONCLUSIONS: Our results indicate that for most biomechanical analyses involving knee muscles, gender- and angle-specific moment arms should be used.

  • 45.
    Wretenberg, Per
    et al.
    Örebro University, School of Medical Sciences. Department of Orthopaedic Surgery, Karolinska Hospital, Stockholm, Sweden; Department of Surgical Sciences, Section for Orthopaedics, Karolinska Institute, Stockholm, Sweden.
    Ramsey, Dan K
    Department of Orthopaedic Surgery, Karolinska Hospital, Stockholm, Sweden.
    Németh, Gunnar
    Department of Orthopaedic Surgery, Karolinska Hospital, Stockholm, Sweden; Department of Surgical Sciences, Section for Orthopaedics, Karolinska Institute, Stockholm, Sweden.
    Tibiofemoral contact points relative to flexion angle measured with MRI2002In: Clinical Biomechanics, ISSN 0268-0033, E-ISSN 1879-1271, Vol. 17, no 6, p. 477-485Article in journal (Refereed)
    Abstract [en]

    Objective: To determine whether knee flexion influenced bony contact movements during flexion.

    Design: Accurate three-dimensional (3D) measurements of tibiofemoral bony contact points in vivo was performed using magnetic resonance imaging technology at 0 degrees, 30 degrees and 60 degrees of flexion.

    Background: Magnetic resonance imaging is an accurate non-invasive tool for visualizing muscles, tendons, and bone, and provides precise 3D co-ordinates.

    Methods: Magnetic resonance imaging recordings were made from the right knee of 16 subjects with no history of knee dysfunction at 0 degrees, 30 degrees and 60 degrees of flexion. Joint contact movements were reported as changes of the contact point's position on the medial and lateral tibial condyle with respect to a fixed reference point for each flexion angle.

    Results: The dominant motion of the centroid of the contact area was posterior with a concomitant inferior and lateral displacement when flexing from 0-30 degrees. Increased flexion to 60 degrees the contact points moved slightly anterior, superior and continued laterally. Comparing movements between the medial and lateral compartments, larger displacement magnitudes were observed laterally. Additionally, tibial rotations of 3-5 degrees were noted relative to the femur.

    Conclusion: Based on magnetic resonance imaging co-ordinates and the rotated anatomical reference frame, the geometric equations to derive the contact point between the tibiofemoral articulating surfaces is a viable means to investigate tibiofemoral bony contact movement.

    Reslevance: Contact areas and pressure distributions have been reported using cadaveric specimens but interpretation of the results is limited. Other investigations have been restricted to sagittal plane movement. Using kinematic magnetic resonance imaging, accurate non-invasive 3D recordings of the normal knee at increments of flexion are possible. The normative baseline date can be compared against that of the pathological knee, such as cruciate ligament injury or the status of post-operative meniscectomy in order to examine skeletal joint motion and stability.

  • 46.
    Ågren, Per-Henrik
    et al.
    Stockholm Fotkirurgklinik, Sofiahemmet, Stockholm, Sweden.
    Mukka, Sebastian
    Department of Surgical and Perioperative Sciences (Orthopaedics-Sundsvall), Umeå University, Umeå, Sweden.
    Tullberg, Tycho
    Stockholm Spine Center, Stockholm, Sweden.
    Wretenberg, Per
    Örebro University Hospital. Department of Molecular Medicine and Surgery (Orthopaedics), Karolinska Institute, Stockholm, Sweden.
    Sayed-Noor, Arkan S
    Department of Surgical and Perioperative Sciences (Orthopaedics-Sundsvall), Umeå University, Umeå, Sweden.
    Factors affecting long-term treatment results of displaced intraarticular calcaneal fractures: a post hoc analysis of a prospective, randomized, controlled multicenter trial2014In: Journal of Orthopaedic Trauma, ISSN 0890-5339, E-ISSN 1531-2291, Vol. 28, no 10, p. 564-568Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: To study the factors affecting long-term treatment results of displaced intraarticular calcaneal fractures (DIACFs).

    DESIGN: A post hoc analysis.

    SETTINGS: Tertiary care teaching hospitals.

    PATIENTS: Eight to twelve years of results from a randomized controlled multicenter trial of operative versus nonoperative treatment (n = 56) were divided into 2 groups: the superior 50% results (n = 28) and the inferior 50% results (n = 28), regardless of the treatment given. The determinant of this division was a visual analog score for pain and function.

    INTERVENTIONS: The operative treatment consists of open reduction and internal fixation, whereas the nonoperative treatment consists of nonweight bearing and early range of motion exercise.

    MAIN OUTCOME MEASUREMENTS: A visual analog score for pain and function, the short-form 36 (SF-36) general health outcome questionnaire, the American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot scale, and Olerud-Molander score. We compared age, sex, fracture type (Sanders classification), treatment given, Böhler angle, residual articular surface step-off at healing, type of occupation, and injury insurance between the 2 groups.

    RESULTS: Patients of the superior group had higher physical SF-36, AOFAS, and Olerud-Molander score than in the inferior group. Operative treatment, better Böhler angle and articular surface restoration, light labor/retirement, and absence of injury insurance were more common in the superior group. Age, sex, pretreatment Böhler angle, and fracture type were comparable in the superior and inferior groups.

    CONCLUSIONS: The decision making for definitive treatment of intraarticular calcaneal fractures is multifactorial with a spectrum of results and trends such as patient demographic features that should be considered in choosing the best treatment option.

    LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

  • 47.
    Ågren, Per-Henrik
    et al.
    Stockholms Fotkirurgklinik, Sophiahemmet, Stockholm, Sweden.
    Tullberg, Tycho
    Stockholm Spine Center, Stockholm, Sweden.
    Mukka, Sebastian
    Department of Surgical and Perioperative Sciences (Orthopaedics), Umeå University, Umeå , Sweden.
    Wretenberg, Per
    Örebro University, School of Medical Sciences. Department of Molecular Medicine and Surgery (Orthopaedics), Karolinska Institute, Solna, Stockholm, Sweden.
    Sayed-Noor, Arkan S
    Department of Surgical and Perioperative Sciences (Orthopaedics), Umeå University, Umeå , Sweden.
    Post-traumatic in situ fusion after calcaneal fractures: a retrospective study with 7-28 years follow-up2015In: Foot and Ankle Surgery, ISSN 1268-7731, E-ISSN 1460-9584, Vol. 21, no 1, p. 56-59Article in journal (Refereed)
    Abstract [en]

    Background In situ fusion as salvage operation after calcaneal fractures has been used. In this retrospective investigation, a group of in situ fused patients is analyzed with long-term follow-up.

    Methods: Twenty-nine patients with in situ single or multiple fusions performed between 1970 and 1990 were included. In 1998 these patients were examined with plain radiographs and computerized tomography (CT) scan of the affected foot. Also, a visual analogue score (VAS) for calcaneal fractures, short form health survey (SF-36), Olerud Molander score and American Orthopaedic Foot and Ankle society (AOFAS) hindfoot score were evaluated.

    Results: The plain radiographs and CT scan showed severe remaining deformities in these patients. The outcome parameters were generally poor and correlated to the degree of remaining deformity.

    Conclusions: Simple in situ fusion, without consideration of the deformity at hand, after a calcaneal fracture is not an adequate treatment and generally associated with poor outcome.

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