High tibial osteotomy for proximal tibial osteonecrosis with medial tibial plateau fracture in a patient with prior knee arthroscopy: a case report

High tibial osteotomy (HTO) is a well-established joint-preserving procedure for unloading the medial compartment of the knee. It has been applied in selected cases of spontaneous osteonecrosis or subchondral insufficiency fracture of the knee. However, the coexistence of proximal tibial osteonecrosis, medial tibial plateau fracture, femoral condylar bone infarction, and subchondral bone cyst in a patient with prior knee arthroscopy is extremely rare. The role of HTO as a joint-preserving strategy in this setting has rarely been described. A 50-year-old man presented with a 2-year history of right knee pain and limitation of motion. He had undergone arthroscopic surgery at another hospital in May 2022, after which the pain recurred and progressively worsened. However, the operative details and immediate postoperative course could not be independently verified. Preoperative imaging demonstrated varus malalignment of the right lower limb, a fracture of the medial tibial plateau, proximal tibial osteonecrosis, bone infarction of the lateral femoral condyle, and a bone cyst in the medial femoral condyle. Clinical examination showed medial joint line tenderness, a range of motion of 0–90°, a visual analogue scale (VAS) pain score of 6, and a Lysholm score of 67. Arthroscopy confirmed intact cartilage in the lateral compartment. The articular surface at the tibial plateau fracture site remained relatively congruent. Histopathology of the resected bone from the osteotomy site confirmed focal osteonecrosis. The osteotomy was created distal to the articular fracture line and gradually opened to 15 mm. Proximal fixed-angle screws were directed subchondrally to bridge and support the medial plateau lesion. At 1 year, the patient was pain-free, had returned to normal daily activities and work, and could stand on the operated leg without pain. The VAS score improved from 6 to 0, the Lysholm score improved from 67 to 97, and postoperative radiographs showed satisfactory correction, with the mechanical axis passing through the lateral intercondylar eminence region of the tibial plateau. In this rare case, arthroscopic assessment combined with HTO achieved favorable short-term clinical and radiographic outcomes. HTO may be considered a joint-preserving option for carefully selected middle-aged and active patients with malalignment when the lateral articular surface remains intact. Longer follow-up is required, particularly to determine how the lateral compartment tolerates load transfer and whether arthroplasty is ultimately required.