Early outcomes of revision total ankle arthoplasty using the INBONE II and INVISION systems

T. Batten, N. Talbot, I. Sharpe

Introduction: Revision options for a failed Total ankle arthroplasty (TAA) have historically been limited to complex hindfoot fusions, bespoke ankle arthroplasty revision or amputation. The patient outcomes of these procedures has been felt to be poor. The introduction of the INBONE-II and INVISION ankle arthroplasty revision systems has created a range of revision arthroplasty options, with the possibility of improved patient outcomes.

Methods: We aim to report on the early results of 20 sequential revision TAA. All patients undergoing revision TAA with INBONE-II or INVISION had prospective collection of pre-operative and post-operative MOx-FQ and EQ-5D scores. Between September 2013 and June 2019 23 patients underwent revision TAA with mean time from implantation of 35 months (6 to 74). Those with greater than 1 year follow-up had scores included. Other outcomes included radiographic assessment for loosening and revision.

Results: 13 patients had INBONE-II and 10 INVISION. None required revision at the time of review. Pre-operative MOx-FQ averaged 40.6 (13.4 pain, 21 walking, 6.2 social). Post-operative MOx-FQ averaged 17.4 (6.2 pain, 8.1 walking, 3.1 social). Average EQ-5D improved from 8 to 6.6 and average EQ-VAS from 60 to 80. On radiograph review one patient had radiolucent lines around their INBONE-II stem evident at 1 year. This had not progressed by 4 years total follow-up. Another patient had uncoupling of part of the stem of her INBONE-II but had not required revision. This was attributed to surgeon error.

Conclusions: Revision TAA using the INBONE-II and INVISION systems shows promising early results relating to loosening and revision and good maintained improvement in MOx-FQ and EQ-5D scores. This provides further evidence that patients with a failed TAA can safely have revision rather than having to commit to complex ankle/hindfoot fusion. This provides surgeons with flexibility particularly in those patients with other hindfoot arthritis or arthrodesis.