Abstract
Introduction: Total ankle replacement is proving a reliable procedure for ankle arthrosis. Some authors have recommended that significant hindfoot deformity should be a contraindication. This study aims to provide guidance on the management of this difficult problem.
Methods: 170 consecutive total ankle replacements were performed in 147 patients, aged 32–83 (mean 65) between 1999 and 2006 by a single surgeon. All surviving patients (5 deaths) were followed up prospectively on an annual basis, for a mean of 3 years (1–8 years). Comparison was made between Group A (45 ankles with a hindfoot deformity of > 10° varus or valgus) and Group B (the remaining 120 ankles).
Results: There was no statistical difference between the 2 groups for age, sex or indication for surgery (osteoarthritis in 81%). Group A comprised 8 valgus and 36 varus ankles. 23/36 varus ankles had a deformity of > 20°.
6 revisions (13%) were performed in Group A (5 of these related to instability – all preoperatively varus of > 20 degrees). 10 revisions (8%) were performed in Group B (2 related to instability).
6 ankles underwent intra-operative deltoid release and 6 had pre or post-operative calcaneal osteotomy. Only one of these required revision for instability. 4 ankles underwent post-operative lateral ligament reconstruction. These ankles all failed due to instability.
The mean postoperative American Foot and Ankle Society score in Group A was 85, compared to 78 in Group B.
Discussion: Our study reveals that patients with significant hindfoot deformity may benefit from total ankle replacement. However, the risk of revision due to instability and need for further surgery is higher, especially with a varus deformity of > 20°. Almost a quarter of these ankles required revision. Potential solutions may be to correct the deformity with additional calcaneal osteotomy or medial release, whereas lateral ligament reconstruction alone is inadequate.
Correspondence should be addressed to: D. Singh, BOFAS, c/o BOA, The Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PE.
