Outcome analysis of agility total ankle replacement with prior adjunctive procedures: two to six year followup.

Background: A retrospective case review of 65 agility total ankle replacements (64 patients) was done between April, 1998, and March, 2002. The purpose of this study was to more closely identify factors that may be predictive of a favorable outcome, including a comparison of outcome measures between patients who had preoperative corrective procedures and those patients who did not.

Methods: The outcomes of this series of patients were examined with post-operative Short Form (SF)-36 scores as well as chart and radiographic review. Endpoints for this study were amputation, arthrodesis, osteochondral allograft, total ankle revision, or revision of either or both components. The Kaplan-Meier survivorship curve also was estimated including the 95% confidence intervals.

Results: Patients with rheumatoid arthritis (RA) were found to have a statistically significant lower rate of failure. Use of a size 1 prosthesis was associated with subsidence and the highest rate of subsequent failure, but fell short of statistical significance (because of the limited power of the study). Smoking, diabetes, and methotrexate use were not associated with an adverse outcome either clinically or statistically, but the number of patients in each group was small. The age of the patient was not a factor in predicting failure of the prosthesis in the posttraumatic arthritis group; however it trended toward significance in the osteoarthritis group. The mean time to failure in patients with osteoarthritis was shorter than in the patients with post-traumatic arthritis but fell just short of statistical significance.

Conclusions: From this series we concluded that rheumatoid arthritis and use of a prosthesis larger than size 1 are predictive factors for better outcome.