Allograft-prosthetic composite in the proximal tibia after bone tumor resection

Abstract

We consider an allograft-prosthesis composite in the proximal tibia one of the better reconstructive options in this site because it combines the mechanical stability of a prosthesis with the biologic reconstruction of the extensor mechanism. We retrospectively reviewed 62 patients who had proximal tibia reconstructions with allograft-prosthesis composites to ascertain the complications and functional outcomes. By combining an allograft with a prosthesis, placing cement in the graft, and press-fitting the prosthesis in the tibial diaphysis, we obtained satisfactory Musculoskeletal Tumor Society scores in 90.4% of patients, with a 5-year survival rate (73.4%) comparable to that of reconstruction with a modular prosthesis. However, we observed high infection rates (24.2%) and rotation of the medial gastrocnemius seemed not to reduce this complication. For this reason, we do not recommend using this reconstructive technique in patients who will receive postoperative chemotherapy or in patients in whom a previous reconstructive method failed. We believe the ideal candidate is the young patient with a benign aggressive or malignant low-grade tumor who has not undergone previous surgery.

Level of evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Fig. 1

An intraoperative image of the reconstruction technique shows the prosthesis cemented in the graft and implanted press-fit in the residual tibial diaphysis using a long revision stem.

Fig. 2A–B

(A) Anteroposterior and (B) lateral views of an APC implanted without the trochlear shield. In (B), the absence of the trochlear shield is clearly evident. In this type of prosthesis, the patellar-femoral joint is not involved in the reconstruction, whereas in prostheses with the trochlear shield, the design of the femoral component is prolonged anteriorly to completely substitute the trochlear groove of the femur (trochlear shield).

Fig. 3

An intraoperative image shows reinsertion of the patellar tendon by direct suture overlapping the autologous proximal part of the tendon onto the distal one provided by the graft.

Fig. 4

Kaplan-Meier analysis of the prosthetic general survivorship, including local recurrence, shows a survivorship rate at 60 months of 73.4% (95% confidence interval, 61.8%–85.0%). After 72 months, it is stable at 68% (95% confidence interval, 54.9%–81.1%).

Fig. 5

Kaplan-Meier analysis of the prosthesis survivorship rate, excluding local recurrence, shows a survivorship rate at 60 months of 78.8% (95% confidence interval, 68.0%–89.6%). After 72 months, it is stable at 73% (95% confidence interval, 60.0%–85.5%).