Heterotopic ossifications in anterior and lateral approach total ankle replacement: A retrospective evaluation

Heterotopic periarticular ossifications (HO) are a frequent short to mid-term complication following Total Ankle Replacement (TAR). Historically two primary surgical approaches exist-Lateral Approach (LA) and Anterior Approach (AA)-each bound with different prosthetic designs. However, there is no consensus on the incidence, real clinical impact, or need for reintervention of HO between these approaches, nor on the necessity of prophylactic treatments. This retrospective, monocentric, comparative study (evidence level III) involved radiological classification of patients using the modified Brooker Classification System (mBCS) by two independent orthopedic surgeons. A total of 105 patients undergoing LA or AA TAR at the same center were included. Radiographic HO was observed in 84 patients (80 %). Of these, 19 (23 %) required surgical intervention due to symptomatic HO. In the AA group (62 patients, Vantage Exactech prosthesis), 45 (73 %) developed HO, with 10 having sufficient symptoms which were treated with arthrolysis. In the LA group (43 patients, Trabecular Metal Zimmer prosthesis), 39 (91 %) developed HO, with 9 requiring arthrolysis. HO was more prevalent in the LA group than in the AA group (91 % vs. 73 %). A direct correlation was found between clinical scores (FAAM and Pain Score) and HO severity. Prosthesis with LA more frequently develop HO than AA. In addition, young patients, delayed ankle mobilization and weightbearing can be accounted as risk factors in the development of HOs; conversely smoking, BMI, duration of surgery and post-traumatic arthritis were not found to have a significant impact.