The Zenith total ankle replacement: early to mid-term results in 155 cases

R. Walter, W. Harries, S. Hepple, I. Winson

Introduction: The Zenith^TM total ankle replacement (Corin, Cirencester) is a mobile-bearing implant based on the Buechal Pappas design. Key features are the simple fully-jigged instrumentation aiming to improve accuracy and reproducibility of implant positioning, cementless calcium phosphate coated surfaces for improved early osseointegration, and titanium nitride-coated bearing surfaces to resist wear. We present early to mid-term survival data for 155 total ankle replacements implanted by three surgeons in our institute.

Methods: Case records of all patients undergoing Zenith^TM Total Ankle Replacement by three senior surgeons, including a member of the design team, between 2007 and 2014 were examined. Patients were examined clinically and radiographically annually after the early postoperative period. The primary outcome measure was implant survival. Secondary outcome measures included complication rates, parameters of radiographic alignment, and radiographic evidence of cysts and loosening.

Results: One hundred and fifty-five cases were performed for a mixture of primary pathologies, predominantly primary or posttraumatic arthrosis. Mean follow-up was 50 months. Implant survival was 99.0% at 3 years (n=103), 94.0% at 5 years (n=50), and 93.8% at 7 years (n=16). One patient was revised to arthrodesis for aseptic loosening, one arthrodesis was performed for periprosthetic infection with loosening, and one below-knee amputation was performed for chronic pain. Three cases underwent further surgery to address cysts, and 7 malleolar fractures were reported. Medial gutter pain was experienced by 9% of patients.

Conclusions: Overall, our data show excellent early and mid-term survivorship for the Zenith^TM Total Ankle Replacement. Simple fully-jigged instrumentation allows accurate and reproducible implant alignment.