Long-term results after triple arthrodesis: Influence of alignment on ankle osteoarthritis and clinical outcome

Pain, deformity and instability are the main reasons for fusion of the tarsal joints, a triple arthrodesis. The short and midterm results show that mobility, function and satisfaction increase postoperatively. However, osteoarthritis (OA) of the adjacent ankle joint is described as a long-term complication. Alignment of the foot could be an influencing factor. The aim of this study was to examine whether malalignment after triple arthrodesis leads to a higher grade of OA at long-term follow-up.

Between 1991 and 2002, 81 patients underwent a triple arthrodesis. Preoperatively, postoperatively, 3, 7.5 and 15 years after surgery, dorsoplantar (DP) and lateral X-rays were taken and used to evaluate the degree of OA and the geometry of the foot. The degree of OA was estimated using the Kellgren and Lawrence score. The geometry of the foot was assessed using Meary's angle; a Meary's angle exceeding 15° in DP and/or greater than -5 to 5° from the lateral view was defined as malalignment. In addition to the radiological evaluation, clinical scores (FFI and AOFAS) were recorded.

Thirty-five patients (40 feet) were available for analysis 15 years after surgery. In 19 cases there was an increase in ankle OA following the operation. Eight feet showed malalignment on the lateral view and 28 on the DP view. There was no difference in both an increase of ankle OA or clinical outcome between correct aligned feet and feet classified as malaligned. Thirty-three patients with 38 treated feet stated that they would decide to undergo the treatment again. Two patients would not want to undergo the same surgery again. The patients were satisfied with the result of surgery, clinical scores improved after surgery and remained stable in the long-term.

Triple arthrodesis is a salvage procedure in patients with a painful and deformed hindfoot and results in a clinically beneficial outcome, even 15 years after surgery. The present study did not show that malalignment after triple arthrodesis results in a higher grade of OA of the ankle joint in the long-term. The cause of the aggravation of OA is still not fully understood and needs further research. Nevertheless, clinical results are satisfying 15 years postoperatively.