Conversion of painful ankle arthrodesis to total ankle arthroplasty.

BACKGROUND: Pain following an ankle arthrodesis continues to be a challenging clinical problem. Recent reports on semiconstrained two-component ankle implants have demonstrated the feasibility of reversing a problematic ankle fusion and converting it to a total ankle arthroplasty. However, the failure rate is high. The objective of the present prospective study was to evaluate the intermediate-term outcome associated with the use of an unconstrained three-component ankle implant after taking down an ankle arthrodesis.

METHODS: Thirty painful ankles in twenty-eight patients (average age, 58.2 years) who were managed with takedown of a fusion and total ankle arthroplasty were followed for a minimum of thirty-six months (average, 55.6 months). The outcome was assessed on the basis of clinical and radiographic evaluations.

RESULTS: In twenty-nine ankles in twenty-seven patients, the American Orthopaedic Foot and Ankle Society hindfoot score increased from 34.1 preoperatively to 70.6 at the time of the latest follow-up. Twenty-four patients (82.7%) were satisfied with the results. While five ankles were completely pain-free, twenty-one ankles were moderately painful, and three remained painful. The average clinically measured range of motion of 24.3 degrees amounted to 55.1% of that of the contralateral, unaffected ankle. Radiographically, the tibial component was stable in all ankles but one. The talar component was found to have migrated in four ankles but was asymptomatic in two of them. One ankle had to be revised to a tibiocalcaneal arthrodesis because of persistent pain and loosening of the talar component.

CONCLUSIONS: For patients with pain at the site of a failed ankle arthrodesis, conversion to total ankle arthroplasty with the use of a three-component ankle implant is a viable treatment option that provides reliable intermediate-term results. Key factors for the success of this procedure may be the intrinsic coronal plane stability provided by the ankle implants and the use of wider talar implants.