Abstract
Summary: The SF-36, FFI, AOS and the AOFAS AHS were recorded pre and post-operatively in patients with end-stage ankle arthritis. Comparison of responsiveness shows the AOFAS score to be completely unresponsive.
Introduction: Outcome studies should include both general health and disease specific measures. The Short Form 36 (SF36) is validated and widely used in musculoskeletal disease. A number of disease specific scores are available for the foot and ankle but, at present there is no widely agreed and validated score used specifically in end-stage ankle arthritis (EAA).
Methods: 555 sets of pre and post-operative data on 239 EAA patients undergoing definitive treatment have been collected. The SF36 and three widely used Foot and Ankle scores (Foot Function Index (FFI), AOFAS Ankle Hindfoot Score (AHS) and Ankle Osteoarthritis Scale (AOS)) were recorded. We assessed the responsiveness (Standardized Response Mean (SRM) and Effect Size (ES)) and correlation (Spearman Rank Correlation) of each of the above scores.
Results: The SF36, FFI and AOS responded to change and correlated in sub-scale and total scores. The AHS did not respond to change in pain or total scores and did not correlate with any other score.
Using the three responsive scores there was a significant improvement in outcome with operative intervention (p< 0.0001) with each score. Using the SRM and the ES, the AOS showed the highest level of responsiveness. It also showed an increased response rate suggesting that patients find it more useable.
Conclusion: In future studies we would recommend the use of the SF36 and the AOS for assessment of patients with EAA. We would also discourage use of the AOFAS Ankle Hindfoot Score which we have demonstrated to be unresponsive to change.
Correspondence should be addressed to: D. Singh, BOFAS, c/o BOA, The Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PE.
