Prosthetic reconstruction in limb salvage surgery of the lower limb: preliminary results of a new modular system

Goals: Prosthetic replacement of articular bone loss is considered a reliable reconstructive technique in limb salvage surgery. In 2001, a new modular prosthetic system was introduced for reconstruction of the lower limb by Waldemar Link. The system was designed to replace the proximal femur, the distal femur, the total femur and the proximal tibia and for intercalary reconstructions of the femur and arthrodesis of the knee. The same modular system allowed the assembling of an allograft as allograft-prosthesis composite in proximal femur and proximal tibia replacements. The authors present a review of 190 consecutive cases of prosthetic reconstruction performed during the last five years with the new modular system. Methods: Between june 2001 and february 2007, 190 patients underwent prosthetic reconstruction of the lower limb with the new modular system. There were 98 males and 92 females with an average age of 48 years (11-90). The diagnosis was a primary malignant bone tumor in 78 cases, a bone metastasis in 70 cases, an aggressive benign bone tumor in 13 cases, plasmocitoma in 2 cases and linfoma in 1 case. In 26 cases the prosthesis was implanted as revision of a failed periarticular osteosynthesis (15 cases) or of a failed prosthesis (11 cases). A proximal femur replacement was done in 100 cases, a distal femur in 63, a total femur in 12 and a proximal tibia in 6 cases. In 6 cases an extra-articular resection of the knee was performed and both the distal femur and the proximal tibia were replaced using an allograft-prosthesis composite with the extensor mechanism of the allograft. In 3 cases the prosthesis was employed to achieve a knee arthrodesis. Results: Twentyfive major complications were observed in 21 patients. The most frequent complication was infection of the implant which occurred in 14 cases (7.3%). The mechanical failure of the morse taper of the prosthetic body occurred in 6 cases (3.1%) requiring surgical revision and component replacement preserving the stem in place. Aseptic loosening was seen in 2 cases (1%) and prosthetic dislocation in 3 cases (1.5%). At final follow up, 75% of the evaluable patients presented a satisfactory functional result (excellent or good following MSTS-ISOLS classification). Conclusions: In conclusion, the new modular prosthetic system for the lower limb may be successfully employed for prosthetic reconstruction or for allograft-prosthesis composite assembling. The preliminary data of the presented series of patients showed satisfactory functional results which need to be confirmed by a long term follow up.