Safety and performance of contemporary press-fit titanium osseointegration implants in lower extremity amputation : a five-year follow-up study.

Abstract

Aims: Treatment using bone-anchored prostheses (BAPs) with press-fit femoral osseointegration implants (OIs) has been used in patients with lower limb amputations for more than two decades. The development of these OIs has enabled treatment in patients with a short transfemoral and a transtibial amputation. The aim of this follow-up study was to report the safety of this treatment at five years postoperatively, the prosthesis wearing time (PWT), and health-related quality of life (HRQoL).

Methods: All consecutive patients undergoing treatment between March 2015 and June 2018 using one of three different OIs were eligible for inclusion. A total of 90 patients were included, of whom 14 were lost to follow-up, leaving 76 available for analysis. The curved- or gamma-osseointegration femoral implant (OFI-C, OFI-Y) was used in patients with a mid-diaphyseal or short transfemoral amputation, respectively. The osseointegration tibial implant (OTI) was used in those with a transtibial amputation. The adverse events which were evaluated included infection (soft-tissue, bone, implant), stoma-related complications, aseptic loosening, implant breakage, periprosthetic fracture, and complications between surgical stages. The functional outcomes which were assessed included the Questionnaire for Persons with a Transfemoral Amputation (Q-TFA)-Prosthetic Use Score (PUS) and the Global Score (GS), for PWT and HRQoL, respectively.

Results: A 94.2% implant survival was achieved at five years (OFI-C = 93.8%, OFI-Y = 93.3%, OTI = 95.5%); five implants were removed. Overall, 27 patients (36%) had a total of 56 infections, 53 (95%) of which were infections of the soft-tissues. Septic loosening occurred in three patients (4%, OFI-C = 2, OTI = 1), resulting in removal of the implant in two. The infection/implant-year ratio was 0.09, 0.16, and 0.24 for OFI-C, OFI-Y and OTI, respectively. Periprosthetic fracture occurred in four patients (5%, all OFI-C); all were treated surgically, three with fixation, one with removal. One patient had asymptomatic radiological evidence of partial aseptic loosening; this was managed conservatively. Stoma-related problems required surgery on 26 occasions, mostly in patients treated with an OFI-Y. The implant was removed in two patients (2.6%) due to unexplained pain. Complications between surgical stages were mostly surgical site infections, requiring bringing forward stage 2 on seven occasions. Baseline Q-TFA-PUS and GS scores increased significantly in all patients, and also when stratified per type of implant with the passage of time.

Conclusion: Contemporary press-fit titanium OIs, when used in lower limb amputations, result in acceptable rates of survival and safety, with considerable improvements in functional outcomes.