Abstract
Purpose of the study: Composite knee prostheses using a massive implant and an allograft is one option for joint reconstruction after extensive resection of the knee joint for bone tumor. Implant survival after resection of the proximal tibia is not well documented. We analyzed survival and complications in 26 composite knee prostheses.
Material and methods: A composite prosthesis was implanted in 26 patients after resection of a tumor of the proximal tibia. Median length of resection was 14 cm (range 9–20 cm). A GUEPAR massive implant was used in all cases. Allografts were sterilized with gamma radiation. Median length of the tibial stem was 30 cm (range 20–38 cm). The stem was cemented in the allograft and in the tibia.
Results: Median patient survival was 68 months. At last follow-up, 19 patients were living disease free. Among the 26 allografts, seven had fractured and five were partially resorbed. Seven allografts exhibited signs of fusion at the junction with the recipient bone. Seven reconstructions of the extensor system failed (rupture). Conversely, there were no ruptures in patients whose extensor system could be preserved (continuity) at tumor resection. Six composite prosthesis were infected, four early (< 2 months) and two late. There were four cases of local recurrence. Globally, 48 secondary procedures were required in 21 patients: 26 for mechanical defects, 13 for infection, 7 for local recurrence and 2 for postoperative complications (necrosis of the tibialis anterior in both). There were 14 revisions: 9 composite prostheses were replaced, fusion was performed in 2 patients, and 3 patients required amputation. Median survival of the reconstructions, considering all failures together, was 102 months (95%IC 64.3-Inf). Median survival, including all failures for local recurrence, was 105 months (95%IC 101-Inf).
Discussion: The rate of failure and of complications is high for massive knee prosthesis combined with a radiated allograft for reconstruction of the proximal tibia. There is no series reported in the literature. When possible, the extensor system should be preserved.
Conclusion: We currently use massive knee prostheses without allografts, reconstructing the extensor system with a vastus medialis flap.
Correspondence should be addressed to SOFCOT, 56 rue Boissonade, 75014 Paris, France.
