Limb salvage surgery for primary bone sarcoma of the lower extremities: long-term consequences of endoprosthetic reconstructions.

Background: Adjuvant chemotherapy and endoprosthetic replacement for bone sarcomas of the lower extremity is well established. The specific long-term consequences of these endoprosthetic reconstructions for the patient's affected limb are unknown.
Method: The oncologic results and the survival of the endoprostheses were reviewed in 32 patients with primary bone sarcoma of the femur or proximal tibia. There were 26 high-grade sarcomas, and 6 low-grade sarcomas. A proximal femoral endoprosthesis was used for reconstruction in 4 patients, a total or push-through femoral endoprosthesis in 11 patients, a distal femoral endoprosthesis in 15 patients, and a proximal tibial endoprosthesis in two patients.
Results: Median survival was 10 years (range, 1.1 to 18.9 years) for patients with high-grade sarcoma, and 8.1 years (range, 7.1 to 10 years) for patients with low-grade sarcomas. Distant metastases developed in seven patients (22%), all with stage IIB sarcoma, with concomitant local recurrence in 3 patients (9%). Five-year overall and disease-free survival rates for high-grade sarcomas were 81% and 73%, respectively. The overall endoprosthetic survival rate was 87% at 5 years, 80% at 10 years, and 56% at 15 years. Median follow-up of the original endoprostheses was 8.3 years (range, 0.6 to 18.7 years). Endoprosthesis-related complications occurred in 13 patients (41%); most complications were mechanical failures. The highest complication rate was found in distal femoral replacements (60%); amputation was necessary in both patients treated with a proximal tibial endoprosthesis. Five endoprostheses (16%) were revised. An amputation of the involved limb was performed in four patients (13%): in two patients because of local recurrence and in the other two patients because of infection. For patients alive at follow-up, the median functional Enneking evaluation score was 22 points (range, 12 to 28 points), with the highest functional scores in patients with a distal femoral endoprosthesis, and the lowest functional scores in patients with total or push-through femoral replacements.
Conclusion: Endoprosthetic reconstructions gave satisfying functional results in most patients after long-term survival. However, the proximal tibial and distal femoral endoprosthesis are particularly at risk for long-term endoprosthetic complications requiring additional surgical procedures.