Correlation of Physical Performance and Patient-Reported Outcomes Following Total Ankle Arthroplasty

Abstract

Background: Functional recovery following total ankle arthroplasty (TAA) is assessed with patient-reported metrics, but physical performance tests may allow for a more accurate assessment of patient function. We quantified correlations between patient-reported measures and physical performance tests in patients after TAA to determine the usefulness of physical performance tests in post-TAA assessment. Methods: In total, 140 patients with end-stage ankle osteoarthritis were assessed prior to TAA and again at 12 and 24 months postoperatively. At each time point, the visual analog scale (VAS), Foot and Ankle Disability Index (FADI), American Orthopaedic Foot & Ankle Society (AOFAS), Short Musculoskeletal Function Assessment (SMFA), and Short-Form 36 (SF-36) scores were collected, as well as walking speed, Four-Square Step Test (FSST) times, and Short Physical Performance Battery (SPPB) balance scores. Results: All but 1 (SF-36 general health component) of the patient-reported outcomes improved significantly from preoperative assessment to both 1 and 2 years postoperatively ( P < .001 in all cases). Walking speed, FSST times, and balance scores improved significantly across time ( P < .001 in all cases). Walking speed was moderately correlated with total SF-36 scores at both 1 and 2 years postoperatively ( P < .001 in both cases), both components of the SMFA at 1 year postoperatively ( P < .001 in both cases), and total AOFAS scores at 2 years postoperatively ( P = .001). Conclusion: The lack of strong correlations between the 2 sets of metrics indicates that they provide different information about a patient’s recovery following TAA. Therefore, it is important to include both sets of metrics in post-TAA assessments to better understand operative success and functional recovery. Level of Evidence: Level IV, cohort study.