Ankle fusion after failed ankle replacement in rheumatic and non-rheumatic patients.

BACKGROUND: With longer follow-up, survival rate of total ankle replacements (TAR) diminishes. It is therefore important to have a reliable fall-back option in case of failed TAR. Revision arthroplasty is often impossible because of loss of bonestock or infection. Conversion to ankle fusion is then indicated. We investigated the clinical, radiographic and patient reported results for fusion after failed TAR in a consecutive group of patients. We concentrated on the influence of inflammatory joint disease (IJD) on union rate.

METHODS: Patient files and radiographic images of 46 consecutive patients (47 ankles) were reviewed. There were 22 patients with IJD. Fixation methods included; anterior plating, blade plate fixation, intramedullary nailing, compression screws and external fixation. Foot and Ankle Outcome Score (FAOS) and Foot and Ankle Ability Measure (FAAM) were used to determine patient related outcomes.

RESULTS: Forty out of 47 ankles (85%) Fused. Union rate in the non-IJD group (96%) was significantly higher compared to the IJD-group (73%, p=0.04). Revisions and complications were more frequent in the IJD group, but numbers were too small to detect a significant difference. Mean PROM scores were: FAOS-symptoms; 68.5, FAOS-pain; 70.3, FAOS-QoL; 43.7, FAOS-ADL; 68.1 and FAAM-ADL; 52.1, with no significant difference between IJD and non-IJD patients.

CONCLUSIONS: IJD-patients have a higher nonunion rate after ankle fusion for failed TAR. However, patient reported outcome is not significantly different between the two groups.

LEVEL OF EVIDENCE: IV, retrospective cohort.