Total ankle replacement: 6 year survivorship of 118 consecutive Zenith Ankle replacements from a non-designer centre

J. Ring, J. Davenport, M. Karski, R. Smith, H. Divercha, T. Clough

Introduction: Traditional treatment for end-stage ankle arthritis has been ankle arthrodesis, however ankle arthroplasty is becoming an accepted alternative. The Zenith Ankle (Corin, UK) is 3rd generation implant with a mobile bearing design. In the NJR 2016 report, the Zenith was the commonest ankle prosthesis implanted in the UK. However, compared to other ankle implants, there's little published data on its performance and survival. The aim of this study was to analyse outcome in a consecutive series from a non-designer centre.

Method: We conducted a retrospective review of a consecutive series of 118 Zenith Ankle replacements implanted in our Unit (December 2010 to May 2016). Data was collected from our National Joint Registry entries, research databases, patient notes, PACS and PROMS.

Results: Average age was 68.2 years (range 46-86 years; 75M:43F; 97 Osteoarthritis, 20 inflammatory arthritis, 1 haemophilia). Results show a 95.8% survivorship at average 3.5 years follow up (range 0.6-6.3 years). 5 patients (4.2%) required revision. Average pre- and post-op MOXFQ scores were 85.0/100 and 32/100 respectively with improvements in VAS from 7.0/10 to 3.6/10, with an average range of movement of 20.4 degrees. Overall satisfaction rate was 89%. There were 65 complications in 55 patients, but only 7.7% of these led to detrimental effects on the implant. The commonest were malleolar fracture (14.4%), wound problems (13.6%) and superficial infection (12.7%), medial gutter pain (10.2%). There were no cases of deep infection. Five patients required revision (all were revised to revision arthroplasty), for component loosening, or pain and stiffness.

Conclusions: This is largest non-designer centre series examining the outcomes of the Zenith implant. Survival figures for this implant are comparable to NJR averages (6.8% revision at 5 years), with high levels of patient functional outcome and satisfaction. The data highlights the risks associated with this procedure.