The risk for fractures after curettage and cryosurgery around the knee

Curettage and cryosurgery have been used successfully for treatment of benign locally aggressive and some low-grade malignant bone tumors. After treating these lesions, we reconstruct residual bone defects around the knee with cement, intramedullary pins, and autogenous bone graft for subchondral augmentation and closure of cortical windows. We questioned the incidence of fractures and the rates of nonunion and malunion and asked whether patients at risk for fractures can be identified. We conducted chart and radio-graphic reviews of 60 consecutive patients who had curettage and cryosurgery of primary bone lesions in the distal femur or proximal tibia. Ten of the 60 patients (17%) sustained postoperative intraarticular fractures. Patients who sustained fractures had (1) more freeze-thaw cycles; (2) metaphyseal defect ratios greater than 0.6 and 0.8 on the anteroposterior and lateral projections, respectively; and (3) 4 mm or less proximity of the defect to the joint. Only one fracture united in good alignment. Radiographic measurements can assist in identifying patients at risk for fractures after curettage and cryosurgery around the knee. We expect the fracture rate to decline by reducing the number of freeze-thaw cycles and improving our reconstruction method.