Total ankle replacement with INBONE-II prosthesis: A short-to- medium-term follow-up study in China

Total ankle replacement (TAR) is a viable option for the treatment of end-stage ankle arthritis. In China, the INBONE-II implant is the only total ankle prosthesis approved since 2016. The purpose of this study is to report a large sample of findings for the TAR with INBONE-II prosthesis.

A total of 64 patients with end-stage ankle arthritis, who underwent primary TAR using INBONE-II by the same surgeon from 2016 to 2019, at a single institution were included in this retrospective, single-center study. Clinical data, radiographic findings, survival rate, and complications were recorded and assessed pre-operatively and at the most recent follow-up.

A total of 64 patients were available for follow-up at least 2 years after surgery; the mean follow-up duration for clinical outcomes was 37.9 months (24-59 months), and for radiographic findings was 22.8 months (12-59 months). There were significant improvements ( P  < 0.01) in the American Orthopedic Foot and Ankle Society hindfoot scale, the visual analog scale for pain, and the Short Form-36. There were statistically significant differences between pre-operative and post-operative comparisons of the talar tilt angle (TT) and the tibial lateral surface angle (TLS) in the radiographic findings (TT from 4.7 ± 4.3° to 1.3 ± 1.3°, TLS from 80.4 ± 7.7° to 87.4 ± 2.3°, P  < 0.01). There was no statistically significant difference in improvement of the tibial anterior surface angle ( P  = 0.14). Ten complications (all low grade) were recorded according to the Glazebrook classification system. The survivorship of the prosthesis was 100% (64/64).

Patients who underwent TAR with INBONE-II prosthesis demonstrated significant improvements in all measures of pain and function as well as in radiographic findings. High survival and a low incidence of complications were observed in this study.