OSSEOINTEGRATED IMPLANTS FOR TRANSTIBIAL AMPUTEES: EARLY OUTCOMES FROM A PROSPECTIVE COHORT STUDY

To evaluate early outcomes following OI for transtibial amputees with significant socket issues, focusing on functional improvements, implant survival and complications. The study involves the analysis of prospectively collected data from the Montreal Osteointegration (OI) Clinic's Redcap database between March 2019 and April 2025. All provided informed consent and IRB authorization was given. The study includes patients with a minimum of six months of follow-up and involves data collection on various clinical parameters, including complications, and functional tests (2MWT, 6MWT, Prosthetic use score, ICL, AMPPRO, L -test and TUG). There were 22 patients (23 implantations) all with custom designed implants. One patient with bilateral below knee amputation got OI in the same setting. The follow-up averaged 2.9 years (0.5–5.6 yrs). Minor intraoperative fractures occurred in 5 (22%) during implant insertion. Only one needed fixation with 1 cerclage wire. Postoperative infections were classified according to the Al Muderis grading system. Eleven patients (50%) developed at least one infection. Nine were Grade 1A infections, one patient a Grade 2A, and another one was Grade 2B. Additionally, one patient with congenital insensitivity to pain, who had undergone bilateral tibial OI, sustained bilateral Charcot's tibial plateau fractures at 1 year, which were successfully managed with TKA. No OI implants failed, required revision or led to chronic osteomyelitis. No other complication or additional surgery were recorded. Functional tests were available for 18 pts at 1 year and 13 at 2 yrs. The 2MWT mean score improved from 118.5m pre-OI to 150.2m at 1-year (p = 0.038) and from 126.4m pre-OI to 145.7m (p = 0.033) at 2 yrs. Similarly, the 6MWT improvement with the mean distance going from 291.6m pre-OI to 435m at the 1 yr (p = 0.012) and from 302.2m pre-OI to 423.9m (p = 0.036) at 2 yrs. The AMPPRO remained of similar values at 1 yr with a mean scores of 43.3 and 44.5 (p = 0.13). However, for the 2 yrs group, there was significant improvement from a mean of 43 pre-OI to 44.4 (p = 0.044). The TUG Test showed no significant improvements at either the 1-year or 2-year. The mean score was 8.6 pre-OI and 9.32 at 1 year (p = 0.53), while at 2 years, it went from 10 pre-OI to 10.4 (p = 0.7). We found no difference between the 1-year and 2-year the functional tests results. Our study highlights osseointegration as an effective and advantageous option for transtibial amputees who have struggled with socket prostheses. The procedure significantly improved functional outcomes, and complications were minor and manageable without implant revision or removal. Although infections were frequent, they remained manageable. This research provides valuable insights into the short-term sustainability and effectiveness of osseointegration for transtibial amputees.