Prospective Study of Patient Outcomes Following Scandinavian Total Ankle Replacement (STAR) Implantation

Background: The complexity of the ankle joint has resulted in total ankle replacement procedures only recently showing comparable outcomes to ankle arthrodesis and therefore increasing in popularity. Initial first-generation prostheses had poor outcomes and high failure rates. The two component, semi-constrained, cementless design of second generation prostheses resulted in minimal bone resection and improved outcomes and even further improvements are now being seen with the 3rd generation 3 component designs.

Methods: Between 2004 and 2016, 75 consecutive Scandanavian Total Ankle Replacement (STAR) procedures were carried out at Sunderland Royal Hospital by a single surgeon. Patients were assessed using The American Orthopaedic Foot and Ankle Society Score (AOFAS) and scored pre-operatively, post operatively, at 3 months, at 6 months then yearly.

Results: A total of 75 ankle replacements were carried out; 63 males, 12 females. Mean follow up was 63 months. 72 (95.9%) of procedures were successful. 3 (4.1%) failed; 2 (2.7%) required revision to arthrodesis and 1 (1.4%) required tibial component revision and PE (polyethylene) liner replacement. The overall failure rate at 5 year follow up was 5.12%. The commonest complications were PE liner replacement in 9 patients (12.2%), symptomatic foot deformity in 5 (6.7%) and chronic pain in 4 (5.4%). The mean increase in AOFAS scores from baseline to final statistically significant follow up was 22.6 for total scores, 25.6 for pain, 14.6 for function and 3.5 for alignment.

Conclusions: STAR Ankle Replacement is associated with significant improvements in pain and function. The senior authors function and pain outcomes are comparable to other publications.

Keywords: Ankle replacement, Total ankle replacement, STAR system, outcomes, complications.