4.P.04 SHORT-TERM FOLLOW UP OF JOINT SPARING PROXIMAL TIBIAL REPLACEMENTS

Abstract

The proximal tibia is the second most common site for primary bone tumours. As a result of simultaneous advances in chemotherapy, surgical and biomechanical techniques limb salvage is now a practical option. We report the clinical and functional outcomes of eight patients who underwent limb salvage with a new form of endoprosthetic proximal tibial replacement that allows preservation of the knee joint.

A retrospective, case series of 8 patients who underwent joint sparing proximal tibial replacement between 2004 and 2008. There were 2 males and 6 females with a mean age of 28.9 years (8–43) with overall mean follow up of 35 months (4–48). Functional outcomes were assessed using the Musculoskeletal Tumour Society (MSTS) rating score and revised Oxford Knee Score (OKS)

Five patients had osteosarcoma, one patient had malignant fibrous histiocytoma, another adamantinoma and the final patient had Ewing’s sarcoma. All patients had complete tumour excision, neoadjuvant chemotherapy and to date there have been no distant metastasis. One patient however required a below knee amputation through the prosthesis due to local recurrence at the distal bone/prosthesis interface. Another patient fell at postop day 8 and fractured through the tibial metaphyseal bone requiring ORIF; this healed in extension and ultimately required revision to a proximal tibial replacement 20 months later. Mean MSTS and OKS for the remaining 6 patients were 77% (57–90) and 40 (36–46) respectively.

Limb salvage preserving the knee joint is an effective alternative to a proximal tibial replacement when the metaphyseal bone is tumour free. The joint sparing prosthesis has a favourable functional result when compared to the joint sacrificing prostheses. Retaining the native joint improves functional outcomes and reduces the peak loads through the prosthesis. There was no short-term evidence of loosening. Further follow up is required to ascertain the long-term outcomes of this new prosthesis.