OPEN VERSUS ARTHROSCOPIC ANKLE FUSION: A LONG-TERM PROSPECTIVE COMPARATIVE MULTICENTRE STUDY

Introduction: This multi-centre study aimed to compare complication rates, reoperation rates, and patient-reported outcome measures (PROMs) between open ankle arthrodesis (OAA) and arthroscopic ankle arthrodesis (AAA) in treating end-stage ankle arthritis. Method: Prospectively collected data from three medical centres in the (blinded) database in a retrospective study. Patients who underwent primary ankle arthrodesis for the treatment of end-stage arthritis with a minimum of 2 years follow up and valid patient-reported outcome measures (PROMs) scores were included. Preoperative COFAS ankle arthritis type, validated PROMs including the Ankle Osteoarthritis Scale (AOS), Short Form-36 (SF-36) with 2 components (the Physical Component Summary (PCS) and Mental Component Summary (MCS)), as well as major complications including malunion, non-union, infection, amputations, and reoperations related to the arthrodesis were evaluated using CROCS (Canadian Reoperation Coding System). Results: 447 primary ankle arthrodeses were included (178 AAA, 269 OAA) with 1-15 years of follow up (average 7.13 yrs +/- 3.8). There was no difference between the two groups with respect to demographics except there were more cases of type-1 and type-4 COFAS arthritis in the OAA group, and a higher BMI in the open group. There was a 6.9% (31 cases) incidence of major complications including 3.79% (17) related operations around the ankle, 0.67% (3) deep infection, 1.78% (8) revisions due to non-union or malunion, and 0.67% (3) amputations. The arthroscopic ankle arthrodesis cohort had a better outcome score at 2 years (AOS score 22.9 +/- 19.3 vs 29.3 +/- 29.3 +/- 20.7) and 4 years (23.3 +/- 19.5 vs 34.3 +/- 22.4). From 5 to 15 years there was no difference. Conclusion: This study shows better outcomes for the arthroscopic cohort. However, differences may be less after correction for confounding factors such as surgeon, site, and COFAS grade. Revision surgery is rare in both groups.