DISTAL TIBIAL REPLACEMENT COMBINED WITH ANKLE JOINT REPLACEMENT FOR BONE TUMOURS OF THE DISTAL TIBIA

Abstract

Introduction: Primary or secondary bone tumours of the distal tibia are uncommon. Before the development of endoprostheses in the 1970’s, the primary treatment for these was below knee amputation. Limb salvage is now possible without adversely affecting survival largely due to improvements in chemotherapy. We report the clinical and functional outcome of six patients who underwent limb salvage with endoprosthetic reconstruction of the distal tibia and ankle joint for malignancy.

Methods: Retrospective review of all patients who underwent limb salvage with endoprosthetic reconstruction of the distal tibia and ankle joint at our institution. Data was collected from the bone tumour database, medical records, imaging studies, clinic reviews and individual structured patient questionnaires. MSTS and TESS scores were used to assess functional outcome.

Results: Six patients underwent distal tibial replacement for malignant bone tumours of the distal tibia. There were 4 males and 2 females with a mean age of 31.2 years (range 13 to 68) and mean follow-up of 35 months (range 13 to 76). One patient died of non-neoplastic disease at 76 months. Two patients had Ewings sarcoma, two had osteosarcoma, one had malignant fibrous histiocytoma and one had adamantinoma.

No patient had metastases at presentation and no patient developed local recurrence or distant metastases post-operatively. Four patients developed infection, for which two required below knee amputation and two suppressive antibiotics. Hardware failure was seen in one patient with infection which was managed by below knee amputation. One patient required sub-talar fusion and calcaneal osteotomy for persistent ankle pain.

A child who underwent the procedure age 13 developed a 5 cm leg-length discrepancy once skeletally-mature. Mean MSTS and TESS scores for the three patients who still had a functioning endoprosthesis were 77% and 79% respectively.

Conclusion: Limb salvage with distal tibial combined with ankle joint replacement can be used as an alternative to below knee amputation in patients with bone tumours of the distal tibia. Due to the difficulties in achieving adequate soft tissue cover, patients should be counselled regarding the high potential complication rate which can lead to significant morbidity, functional deficit and further surgical intervention.