Long-Term Evaluation Of Allografts Unicondylar Replacement Around The Knee Joint Tumor

Knee joint is composed of distal part of femur, proximal part of tibia, which are the major sites for aggressive benign, like giant cell tumor, and malignant bone tumors. Surgical resection is the major therapeutic measures, while it often creates large bone defects, so joint reconstruction is imperative. For tumors only occur in medial or lateral condyles, the mainly operative methods include allogeneic or autologous bone graft transplantation, artificial joint reconstruction and compose reconstruction with allografts and artificial joint. Artificial joint and composite reconstructions have the defects of bigger damage, biomechanical change and late revision. Bicondylar allografts provide the opportunity to support mechanical loads, while sacrificing the contralateral condyle as the price. For these reasons, unicondylar allografts may be a more acceptable option.Purposes:Evaluate the replacement of allografts unicondyle around the knee joint. Analyze the postoperative function and radiological evaluation of bone tumor. Summarize the major complications and matters need attention.Methods:We retrospectively reviewed the results of 11 unicondylar allografts around the knee joint from 1991.1 to 2014.10. Preoperative imaging studies confirm all the tumors invasion no more than 1/2 transverse section, no break through the articular surface.8 males and 3 females.8 giant cell tumor,2 malignant fibrous histiocytoma, and 1 benign fibrous histiocytoma.6 giant cell tumor Campanacci grade II, the others grade Ⅲ. All the malignant bone tumors are stage ⅡA.9 allografts are femoral transplants and include 2 medial and 7 lateral condyles, the other 2 are tibial medial condyles. The average age is 35.3(22～46).1 case of giant cell tumor is recurrent and surgery again, the remaining 12 cases are first surgery. All the patients underwent X ray, CT and MRI pre-operation, determing the scope of the lesions, preparing the unicondylar allografts. During operation, edge resection for benign tumor, malignant tumor wide excision. Using Musculoskeletal Tumor Society(MSTS) Lower limb function scoring system, and the International Society of Limb Salvage (ISOLS) imaging scoring system, to analyse the, to evaluate the prognosis of unicondylar allografts replacement systematically.Results:All operations are completed as expected. The average time of postoperative follow-up 148.6 months (9～288 months). One patient of malignant giant cell tumor died from lung metastasis 5 years after operation. One patient of giant cell tumor local recurrence after 2 years, and make knee prosthesis replacement. The remaining 9 patients long-term disease-free survival, the graft normal position. Four cases express obvious joint degeneration, one bone ununion, six reasorption. MSTS score is 25.6 (17～30), ISOLS score is 85.5%(69.4%～97.2%).Conclusion:Allografts unicondylar replacement have advantages to maintain knee joint function, bone form and reduce local recurrence. It might be a reliable method for patients reconstruction for unicondylar tumor of the femur or the tibia.