Osseointegrated exoprosthesis system: a pilot preclinical study

Background. Traditional socket prostheses suffer from several limitations, including skin complications, unstable fixation, and restricted patient mobility. Osseointegrated exoprostheses represent a promising alternative as they attach to the human body via an implant surgically placed in the residual bone. This solution provides secure fixation and is particularly effective for patients with short or pathological residual limbs.

The aim of the study — to evaluate the biocompatibility and safety of a domestically developed osseointegration system for femoral exoprosthetics using a large animal model.

Methods. A customized titanium osseointegrated implant, adapted based on CT data, was placed in one sexually mature minipig using a two-stage surgical protocol. During the 3-month observation period, a comprehensive set of clinical, laboratory, and radiographic examinations was performed. The study also involved routine stoma care and bacteriological monitoring. At the end of the period, an implant pull-out test was conducted.

Results. The animal was able to endure weight-bearing on the prosthesis while standing and walking. Body weight increased by approximately 10 kg. The implant pull-out force was 400 N, indicating the formation of a mechanical bond with the bone. Manageable complications were noted during the observation, specifically the development of anemia and asymptomatic bacterial colonization of the stoma with Staphylococcus spp. at 10⁷ CFU/ml. There were no clinical signs of infection or systemic inflammatory response.

Conclusion. The study demonstrated the feasibility of the successful and safe application of the evaluated osseointegration system in a large animal model. The observed complications were not critical. The findings confirm the biocompatibility and functionality of the system, justifying the need for further expansive preclinical studies.