Post-traumatic knee osteoarthritis with malunited regenerated distal femur and limb length discrepancy: A case report of computer-assisted navigation total knee arthroplasty.

This case report presents a challenging case of total knee arthroplasty (TKA) in a 65-year-old male with right knee tricompartmental post-traumatic osteoarthritis (OA), in a limb with a malunited regenerated distal femur reconstructed using Illizarov for segmental bone loss. The altered distal femoral anatomy poses a challenge for intramedullary rod referencing, necessitating the use of computer-assisted TKA. Through individualized preoperative planning and soft tissue-preserving techniques, accurate alignment, balanced gaps, and restoration of limb length were achieved without resorting to constrained implants and extra-articular osteotomy. Postoperative outcomes demonstrated a satisfactory range of motion, stable and well-aligned joint, complete pain relief, and full functional recovery. Radiographs confirmed the satisfactory limb alignment and component positioning. Despite the complexity of the case and altered anatomy, navigation enabled precise bone resections and balancing, emphasizing its role in complex primary TKA cases. To the best of our knowledge, this report is the first case to document TKA in a limb with a regenerated and malunited distal femur, providing insights into surgical planning and execution in such scenarios. Long-term follow-up is however necessary to evaluate the implant survival and complications such as periprosthetic fractures and infections.