Giant cell tumor of bone sometimes is an aggressive benign skeletal tumor. Historically, curettage and bone grafting have a high recurrence with satisfactory function whereas wide resection has a reduced recurrence rate with compromise of limb function. Thus, maintaining joint function and achieving adequately wide resection introduces contradictory surgical goals. We developed a method for achieving both goals for giant cell tumors located in only one lateral plateau of the proximal tibia. We reconstructed 13 knees preserving the meniscus and reconstructing the tibial plateau with an iliac plate autograft after resection of a giant cell tumor involving one tibial plateau. Four patients had primary tumors and nine had recurrences after curettage. The minimum followup was 5 years (mean, 9.1 years; range, 5–12.75 years). We used the system of Enneking et al. to evaluate function. One patient had recurrence and underwent prosthesis replacement. No patient experienced collapse, instability, or pain, and knee function was restored to near normal. The mean functional score was 95%. While resecting the tumor, the normal anatomic structures of the knee can be preserved or restored in many patients. This method can be used in selected patients to reconstruct the knee after resection of tumors involving one tibial plateau.