PURPOSE: To develop a pelvic discomfort index (PDI) to evaluate outcome following fixation for pelvic ring injury.
METHODS: 29 female and 44 male consecutive patients (mean age, 36 years) underwent internal fixation for pelvic ring injury of type B1 (n=10), B2 (n=22), B3 (n=15), C1 (n=18), C2 (n=5), and C3 (n=3), based on the AO/OTA classification. At postoperative 6, 12, and 24 months, patients were asked to assess their discomfort in the pelvis using a 14-item questionnaire. Three questions were open-ended, and responses were categorised by a single assessor. The remaining 11 questions were closed-ended and had 6 ordinal options from 'no discomfort' (score=0) to 'extremely severe discomfort' (score=5). The content validity and relevance of the 11 closed-ended questions was determined. The 14-item questionnaire was compared with the 36-item Short Form Health Survey (SF-36).
RESULTS: Respectively at postoperative 6, 12, and 24 months, 78%, 71%, and 71% of the patients completed the 14-item questionnaire. Based on the factor analysis and responses to the open-ended questions, the number of items was reduced to 6 including pain, walking, mobility of the hips, loss of sensation in the legs, sexual life, and operation scar. Four factors could explain 96% of the total variance. The first factor involved the first 3 items (pain, walking, and hip motion) and addressed 'pelvis', whereas 3 factors involved the remaining items and each addressed peripheral neurology, sexual life, and operation scar. A PDI was developed using these 6 items. The PDI had high internal reliability (α=0.89), adequate content and criterion validity, and moderate correlation with the SF-36 total score or scores of physical function, bodily pain, and general health (r=0.50-0.77).
CONCLUSION: The PDI provides valid, specific, and relevant information to assess outcome following fixation for pelvic ring injury.