Objective To assess the clinical outcome of thelimb salvage surgery and complications occurring in the lower extremities after a wide resection of sarcoma. 〖WTHZ〗Methods A total of 167 patients underwent a limb-sparing procedure by means of the implantation of a custom-made or modular tumor endoprosthesis from July 1997 to July 2004. Of the 167 patients, 100 were followed up, including 56 males and 44 females, with their ages ranging from 13 to 57 years at surgery.In 5 patients, a proximal femur prosthesis was implanted; in 57 patients, a distal femur prosthesis was implanted; and in 38 patients, a proximal tibia prosthesis was implanted. According to the Enneking staging, 3 patients were grouped in the stage of ⅡA, 85 in ⅡB, and 12 in Ⅲ. Seventy-one patients used a domestic prosthesis, and 29 patients used a prosthesis made in Link Company, Germany. For the reconstruction, 17 patients used an autograft prosthesis composite, 21 patients used the allograft prosthesis composite, and the remaining 62 patients used an artificial prosthesis. All the patients received chemotherapy for 1-2 courses and 3-5 courses before operation and after operation, respectively. After operation, The Musculoskeletal Tumor Society(MSTS) score was used to evaluate the recovery of their corresponding functions. Results According to the follow-up for 1-8 years, with a median of 3.5 years, and the assessment by the Kaplan-Meier estimate, the 3-year survival rate of the prostheses was 81.8%, and the 5year survival rate was 65%. As for the complications, prosthesis breakage occurred in 6 patients, periprosthesis infection in 13 patients, aseptic loosening in 2 patients, non-union between the host bone and graft bone in 5 patients, allograft absorption in 2 patients, prosthesis sinking in 2 patient, and periprosthesis fracture in 1 patient. Local recurrence developed in 7 patients within 6 months to 2 years after operation. Of the 7 patients, 4 had a recurrence of the softtissue tumor for which resection was performed; the other 3 patients underwent amputation of the diseased limb. The mean MSTS score was 23.30±5.17, with an excellent limb function in 62 patients, good in 27 patients, fair in 7 patients, and poor in 4 patients. The overall excellent and good function was obtained in 89% of the patients. Conclusion We conclude that tumor prostheses can give a satisfactory functional outcome after the tumor around the knee is removed; however, the tumor prostheses still need to be further improved because of a high complication rate.