ADJACENT HINDFOOT JOINT PRESERVATION VERSUS FUSION IN PATIENTS WITH IPSILATERAL HINDFOOT AND ANKLE ARTHRITIS (COFAS TYPE 4) UNDERGOING TOTAL ANKLE ARTHROPLASTY: A PROSPECTIVE COMPARISON OF OUTCOMES

Introduction: Adjacent joint arthritis poses a dilemma in end stage ankle arthritis. The purpose of this study was to compare the outcomes of patients undergoing total ankle arthroplasty with or without surrounding joint fusion in COFAS type 4 cases. Method: Prospectively collected data was retrospectively reviewed on 148 ankles with type 4 COFAS arthritis undergoing total ankle arthroplasty by 7 different surgeons in three centres and analysed changes of their AOS and SF36 PCS scores post operatively. Patients with surrounding joint preservation (59 ankles) were compared to those with total ankle and surrounding joint fusion (89 ankles). Multivariant analyses was performed for potential demographic differences within the patient cohorts. Outcomes were measured using SF 36 physical component, and AOS pain and difficulty scores. Preoperative scores were compared with the most recent outcome score. Revision surgery data was collected and classified. Results: At an average of 5 years follow up both groups exhibit equivalent post operative pain and functional improvement. The average AOS in patient who had surrounding joint preservation improved from 57.47 to 24.52. Those with surrounding joint fusion improved from 55.86 to 23.67. SF36 PCS scores improved from 33.87 to 40.02 for preservation, and 38.86 to 42.27 for fusions. There was no significant difference in the preoperative score or demographics of both groups, no difference in postoperative score, and no difference in the change of score. Both groups were able to achieve their peak scores across all measurement scales at the 2-year post operative mark. Results from multivariant analyses showed no difference in patients’ AOS scores between the two different surgical cohorts. Both surgical cohorts had similar rates of revisions. Conclusion: In combined arthritis of the hindfoot (COFAS type 4) preserving the hindfoot joints with TAA yields comparative results to TAA and hindfoot fusion. The authors recommend surrounding joint preservation and fusion later on the rare occasion as needed.