SF-36 Mental Component Summary (MCS) Score Does Not Predict Functional Outcome After Surgery for End-Stage Ankle Arthritis

Background: Mental health status has been shown to influence functional outcome in a number of orthopaedic disorders. The purpose of this retrospective cohort study was to assess whether a diminished baseline Mental Component Summary (MCS) score on the Short Form-36 (SF-36) is predictive of less improvement in the Ankle Osteoarthritis Scale (AOS) score at the time of midterm follow-up after arthroplasty or arthrodesis for end-stage ankle arthritis.

Methods: Preoperative and postoperative patient scores on the SF-36 MCS and AOS questionnaires were obtained from the Canadian Orthopaedic Foot and Ankle Society (COFAS) End-Stage Ankle Arthritis Database. The relationship between the preoperative MCS score and the change in the total AOS score at the time of final follow-up was summarized with use of a Pearson correlation coefficient (r). Subgroup analyses according to the type of treatment (ankle arthrodesis versus ankle arthroplasty) and preoperative MCS score (<50 versus ≥50) were conducted.

Results: Of an initial 372 ankles enrolled, 337 (91%, ninety-five arthrodeses and 242 arthroplasties) were reviewed after a mean duration of follow-up of 5.2 ± 1.3 years. Analysis revealed no correlation between the preoperative MCS score and the change in the AOS score, from the preoperative baseline to either a mean 5.2 years postoperatively or two years postoperatively (r < 0.1 in both analyses). There was no difference in the change in the AOS score between patients with a preoperative MCS score of <50 and those with a preoperative MCS score of ≥50.

Conclusions: In our study of patients with end-stage ankle arthritis treated with arthroplasty or arthrodesis, preoperative mental health status (as measured with the MCS score) did not predict functional outcome (as measured by the change in the AOS score) at the time of intermediate-term postoperative follow-up. AOS scores improved for all patients, regardless of the preoperative MCS score.

Level of Evidence: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.