Perioperative complications and learning curve of the Mobility Total Ankle System

Only 2 articles related to the recently developed Mobility Total Ankle System (Johnson & Johnson Medical/DePuy International, Leeds, UK) have been published to date. The purpose of this study was to determine the perioperative complications associated with the Mobility Total Ankle System and whether a learning curve exists for this system.

We recruited 60 consecutive patients undergoing total ankle arthroplasty using the Mobility Total Ankle System for advanced osteoarthritis and rheumatoid arthritis between May 2008 and June 2010. Group A included the initial 30 patients who underwent surgery, and group B included the next 30 patients. Reporting of adverse perioperative events, including wound healing problems, fracture, aseptic loosening, tendinitis, component malposition, neuroma, and bony impingement, was limited to the first 3 months after the surgery.

Eleven of the 30 patients in group A developed complications (36.7%), and 1 died of an unknown cause 6 months after leaving the hospital. The complications in this group included medial malleolar fracture in 6 patients, lateral malleolar fracture in 1, wound healing problems in 2, and varus deformity in 2. Five of the 30 patients in group B developed complications (16.7%). The complications in this group included medial malleolar fracture in 1 patient, medial impingement in 2, Achilles tendon rupture in 1, and wound problems in 1. There was no statistically significant difference (P = .08) between the 2 groups in the incidence of complications after total ankle replacement arthroplasty. There was also no significant difference between the 2 groups in the types of complications seen.

Perioperative complications associated with total ankle replacement arthroplasty using the Mobility Total Ankle System were seen in 16 of 60 patients. Group A had a higher incidence of perioperative complications than did group B. However, the difference was not statistically significant. Either the expertise of the surgeon or the simplicity of the total ankle system can affect the learning curve, although these things were not specifically quantified in this study.

Level III, comparative case series.