Effect of an Endoprosthetic Reconstruction Tube and Medial Gastrocnemius Flap on Extensor Mechanism Function After Oncologic Prosthesis Reconstruction of the Proximal Tibia.

BACKGROUND: Extensor mechanism reconstruction after the proximal tibial resection and implantation of a megaprosthesis is challenging. In this study, we evaluated the effectiveness of the Trevira tube and medial gastrocnemius flap in restoring extensor mechanism following the resection of proximal tibial tumor and implantation of megaprosthesis.

METHODS: Forty patients who underwent endoprosthetic implantation following the resection of proximal tibial tumor and patellar tendon reconstruction with the Trevira tube and medial gastrocnemius flap were included. The outcome measures were knee range of motion, extensor mechanism function, patellar position, and limb function subjectively evaluated through Toronto Extremity Salvage Score and objectively through Musculoskeletal Tumor Society score. The mean follow-up of the patients was 6.1 years.

RESULTS: The patellar position was normal in 28 (70%) patients, patella baja in 3 (7.5%) patients, and patella alta in 9 (22.5%) patients. The mean active knee range of motion was 98.9 ± 17° (range: 85°-125°). Extension lag was present in 7 (17.5%) patients (range: 5°-20°). The mean Toronto Extremity Salvage Score of patients was 92.1 ± 6.9% (range: 85-100). The mean Musculoskeletal Tumor Society score of the patients was 87.7 ± 13 (range: 73.3-100). Postoperative complications included aseptic wound dehiscence (2 patients), aseptic loosening of the tibial component (1 patient), periprosthetic fracture in the femur (2 patients), and wound infection (1 patient).

CONCLUSION: Trevira tube combined with gastrocnemius flap augmentation is a suitable procedure for restoring extensor mechanism after proximal tibial resection and megaprosthesis implantation.