Tibial tray augmentation with modular metal wedges for tibial bone stock deficiency.

ABSTRACT

Peripheral defects in the proximal tibia can be difficult to treat during total knee arthroplasty. Attempts can be made to solve the problem with cement, cement with screws, bone grafts, metal wedges, and custom components. In vitro testing has shown that a custom-augmented prosthesis with a built-up metal wedge is mechanically superior in resisting deflections when loaded. Using modular metal wedges, the tibial tray can be customized at the time of surgery. In vitro testing has also shown the wedge to be superior to the use of cement alone or cement reinforced by screws. The authors report on modular metal wedges to augment tibial bone stock deficiency. Twenty-two knees (20 patients) were followed for a minimum of two years with an average follow-up time of 37 months. The average age of the patients at the time of surgery was 70 years. There have been no failures of this technique and no loosening of tibial components. The incidence of nonprogressive radiolucent lines was 27%. All but one patient was pain-free, and this patient's discomfort was not related to the tibial component fixation. No patient has had subsequent revision surgery. This technique should be considered in the treatment of severe peripheral tibial deficiencies in the elderly, low-demand patient.