Bio-integrative screws versus metallic screws for calcaneus osteotomies: A non-inferiority randomized clinical trial

Potential advantages of bio-integrative implants, such as lower removal rates, and superior bone interaction, have been advocated. While many biomechanical and histological reports sustain its structural and biological properties, few clinical studies have supported its use. This trial aimed to determine the bio-integrative screws' capacity to achieve non-inferior clinical outcomes as metallic screws in calcaneal osteotomies. Our main hypothesis was that both implants would not differ in healing or complications.

This was a single-center, parallel-group, randomized non-inferiority clinical trial (NCT05018130) with patients undergoing a calcaneal osteotomy from September 2021 to March 2023. Patients were randomized in a 1:1 ratio to the metallic or bio-integrative groups, and allocation was performed after anaesthesia. Surgeries were performed with the same technique and two canulated 4 mm screws, either titanium or ossiofiber. The primary outcome was determined by bone healing at 6 weeks. Secondary outcomes included minor and major complications, patient-reported-outcomes (PROs) and healing at the 12th, 24th, 48th and 96th weeks of follow-up.

After 29 patients were evaluated, 24 feet were included in the study. Groups were similar demographically (ps>0.111), with 12 allocated to the bio-integrative and 12 to the metallic groups. Follow-up was 2 years, with no losses to endpoints. Considering bone healing at 6 weeks, the bio (83.3%) and the metallic (66.7%) groups had similar rates (p = 0.640), which was maintained at 12 weeks (100% vs. 91.7%; p = 1) and 96 weeks (100% vs. 100%; p = 1). Minor complications (16.7% vs. 16.7%; p = 1) and PROs (ps>0.059) were equivalent. No major complications or secondary surgeries were observed.

Bio-integrative screws have shown non-inferior results to metallic screws in calcaneal osteotomies regarding bone healing and complications. This non-inferiority clinical trial adds to the literature on the use of bio-integrative implants. Larger and longer trials are needed to determine whether any implant is superior and to assess its global effect on surgical care.