ENDOPROSTHESES WITH CURVED STEMS FOR RECONSTRUCTION OF THE FEMUR AFTER EXCISION OF BONE SARCOMA

Abstract

Our centre has used a specially designed custom-made endoprostheses with curved stems to reconstruct femoral defects in patients with residual short proximal femur after excision of primary bone sarcoma over the last 18 years. Two designs of endoprostheses with curved intramedullary stems were used: the rhinohorn stem type and the bifid stem type. We report the safety, survival and functional outcome of this form of reconstruction.

Twenty six patients who had these special endoprosthesis reconstruction were studied. The median age was 16 years (range 7 to 60 years). Prostheses with rhino horn stems were used in 15 patients and bifid-stem in 1 1 patients. Twenty patients had the prostheses inserted as a primary procedure after excision of primary bone sarcoma, and in six patients the prostheses were inserted after revision surgery of failed distal femur endoprostheses. Seventeen patients (65%) were alive and free of disease at a median follow-up of 98 months (12 to 203 months) and nine patients had died of metastatic disease. Local recurrence developed in two patients (1 0%) out of the 20 patients. Surgical complications occurred in five patients (191/o). Deep infections occurred in two patients (8%) requiring revision surgery in one patient. Prosthetic failure, occurred in nine patients (35%). The cumulative survival of prostheses was 69% at five years and 43% at 10 years. Musculoskeletal Tumour Society mean functional score was 83% (53% to 97%).

In conclusion, preservation of a short segment of the proximal femur and the use of endoprostheses with curved stems for reconstruction of the femur is technically possible. There is an increased risk of fracture of the prostheses decreasing the survival rate. Functional outcome of patients with this form of reconstruction is not significantly different from the functional outcome of patients who have proximal femur or total femur endoprosthetic reconstruction. This operation is particularly desirable in skeletally immature patients and allows normal development of the acetabulum.