LAUSR

Large en-bloc resections of the proximal tibia result in loss of the extensor mechanism, and because the proximal tibia is a subcutaneous bone, the risk of infection is high in this anatomic location. Reconstructions following proximal tibial resections should reestablish an insertion site for the extensor mechanism with metal or bone, and create a soft-tissue attachment to that site. The bone loss associated with these resections can bemanagedwith osteoarticular allograft, allograft prosthetic composite, or a megaprosthesis [3, 11, 13]. In the latter option, reestablishing continuity of the extensor mechanism to metal in this situation can be performed via direct reattachment, augmentation with synthetic materials, augmentation with autologous bone grafts or substitutes, tendon augmentations or transfers, muscle flaps, and combinations of these techniques [4, 6-10, 12]. Researchers, withNIH support, have attempted to create viable ingrowth of soft tissue by direct reattachment into a modified metallic surface with variable results that have not gained widespread acceptance [7, 8]. Numerous synthetic materials, either alone or in combination with other techniques, have been used for this purpose, including Dacron (Deknatel, Falls River, Massachusetts), Trevira (Telos, Hungen-Obbornhofen, Germany), Gore-Tex (W. L. Gore & Associates, Newark, Delaware), GraftJacket (Wright Medical Technology, Arlington, Tennessee), Ligament Advanced Reinforcement System (LARS; Surgical Implants andDevices,Arc-surTille, France), Leeds-Kio (Xiros, Leeds, United Kingdom), and Vicryl (polyglactin 910) mesh (Ethicon, Somerville, New Jersey) [4, 6, 9, 10, 12]. Although these synthetic materials provide at least temporary strength, they tend to deteriorate over time. The gastrocnemius flap, however, accomplishes not only restoration of continuity of the extensor mechanism but also soft-tissue coverage of the reconstruction (whether allograft of metallic prosthesis) in this vulnerable anatomic location with little else beneath the skin as a barrier to breakdown and deep infection. In the current study, Cipriano and colleagues [5] evaluated 16 patients treated with gastrocnemius flap coverage and extensor mechanism reconstruction following endoprosthetic reconstruction for primary malignant bone tumors of the proximal tibia during a 13-year periodwith a 28-month minimum followup. The review focused on the functional results, technique, and complications of gastrocnemius muscle flap coverage and extensor mechanism reconstruction and demonstrated that (1) most complications related to the extensor mechanism reconstruction occur within the first 18 months and (2) extensor-related function continues to improve throughout many years.