Psychometric analysis of measuring functional outcomes in tibial plateau fractures using the Short Form 36 (SF-36), Short Musculoskeletal Function Assessment (SMFA) and the Western Ontario McMaster Osteoarthritis (WOMAC) questionnaires.

Patients participating in a modern prospective orthopaedic trauma database may be asked to complete many functional outcome measures, adding to the burden of study participation. This prospective study assessed the utility and responsiveness of the generic Short Form 36 (SF-36) and the disease specific Short Musculoskeletal Function Assessment (SMFA) and the Western Ontario McMaster Osteoarthritis (WOMAC) questionnaires in 55 patients treated operatively for tibial plateau fractures with the goal of determining if there was clear benefit of using multiple measures in a lower extremity peri-articular fracture population. There was very good correlation between all three scores at 6 and 12 months, indicating they are measuring similar factors. Responsiveness was assessed using the standard response mean (SRM), proportion of patients attaining the minimal clinically important difference (MCID) between 6 and 12 months, and floor and ceiling effects. The SRM for the SF-36 was statistically higher than the SRM for the SMFA or the WOMAC. Significantly more patients were found to have a MCID between 6 and 12 months post-surgery based on the SF-36 than the other two functional scores. There was no floor effect found on any of the 3 functional scores evaluated; however, a significant ceiling effect was noted with the WOMAC but not with the SF-36 or the SMFA. These results, along with the usefulness of the SF-36 for comparing disease burden across populations, favour the SF-36 as the instrument of choice in assessing functional outcome in patients with tibial plateau fractures.