Abstract
Introduction: Despite advances in limb-sparing techniques, the proximal tibia remains a difficult area in which to perform a wide resection of extensive bone tumors due to the intimate relationship to the nerves and blood vessels, inadequate soft-tissue coverage, and the need to reconstruct the extensor mechanism. The current long-term follow-up study, based on the experience with 55 patients who underwent proximal tibia endoprosthetic reconstruction emphasizes reconstruction of the extensor mechanism.
Materials and Methods: Between 1980 and 1997, 55 patients underwent proximal tibia resection with endoprosthetic reconstruction. There were 34 males and 21 females whose age ranged from 8 to 56 years (median, 27 years. Diagnoses were: primary bone sarcomas – 48, benign aggressive lesions – 6, and failure of previous osteoarticular allograft reconstruction – 1. Intra-articular resection with en bloc removal of the tibial tuberosity was performed in all cases. Endoprosthetic reconstruction was performed with 39 modular, 16 custom-made prostheses. Reconstruction of the extensor mechanism included reattachment of the patellar tendon to the prosthesis with a Dacron tape and reinforcement with a gastrocnemius flap and bone grafting of the patellar tendon-prosthesis interface. Rehabilitation emphasized prolonged immobilization of knee joint in full extension.
Results: All patients were followed for a minimum of 2 years (range 24–235 months, median – 75.5 months). Full extension to extension lag of 20° was achieved in 44 patients (78%), extension lag of 20° to 30° was found in 10 patients (19%), and extension lag of 40° was found in 1 patient (3%). Eight patients required an additional procedure which involved reinforcement of the patellar tendon with either combined quadriceps tendon and Goretex graft construct (seven patients) or simple plication of the tendon (one patient). Seven of these patients gained an extension lag of less than 20°. Overall, function was estimated to be good to excellent in 48 patients, fair in 6, and poor in one patient.
Discussion: Extension lag of up to 20° is considered compatible with activities of daily living. Emphasis on reattachment of the patellar tendon to the prosthesis and its reinforcement with a gastrocnemius flap and bone graft achieved that goal in the majority of the patients.
Secondary reinforcement of the patellar tendon is recommended for extension lag of more than 20°.
The abstracts were prepared by Orah Naor. Correspondence should be addressed to him at the Israel Orthopaedic Association, PO Box 7845, Haifa 31074, Israel.
