Comparison of Generic, Musculoskeletal-Specific, and Foot and Ankle–Specific Outcome Measures Over Time in Tibial Plafond Fractures

Abstract

Background: This study performed a psychometric analysis assessing and comparing the responsiveness of the relevant components of a generic (Short Form–36 [SF36]), a musculoskeletal-specific (Short Musculoskeletal Functional Assessment [SMFA]), and a foot and ankle–specific (Foot and Ankle Outcome Score [FAOS]) outcome score when evaluating surgically treated tibial plafond fractures over time. Methods: Fifty-one patients were followed for 12 months after their tibial plafond fracture. Responsiveness, or the ability to detect clinical change in a disease, was evaluated through the standardized response mean (SRM), the proportion meeting a minimal clinically important difference (MCID), and floor and ceiling effects. Results: The SRM of the SF36–Physical Component Summary (PCS) was significantly greater than the SMFA–dysfunction index (DI) ( P < .01) and FAOS–Activities of Daily Living (ADL) ( P = .01) between baseline and 6 months, whereas the SRMs of only SF36-PCS and FAOS-ADL differed ( P = .01) between 6 and 12 months. The proportion of patients achieving an MCID for SF36-PCS was higher than FAOS-ADL ( P = .03) between baseline and 6 months and higher than SMFA-DI ( P = .04) between 6 and 12 months. The FAOS-ADL showed substantial ceiling effects at baseline (88.2%) but much less at 6 months (5.9%) and 12 months (9.8%). Smaller ceiling effects were observed for the SMFA-DI (11.8%) at baseline, whereas none were observed for the SF36-PCS. Conclusions: This study found that the SF36-PCS had greater responsiveness in assessing tibial plafond fractures compared to the SMFA-DI and FAOS-ADL, particularly in the first 6 months after surgery. In addition, limitations were revealed in the SMFA-DI and FAOS-ADL. This study illustrates the necessary diligence required for selection of outcome measures, as musculoskeletal and anatomy specific scores are not necessarily superior. Level of Evidence: Level II, prospective cohort study.