title: [A case of spontaneous osteonecrosis of the grossly depressed medial tibial plateau].
abstract: The patient of this case was a 64 year-old woman who visited our hospital with a complaint of arthralgia in the left knee lasting from nearly seven months ago. The radiogram taken at the first visit revealed no abnormalities in the knee, but she had persistent arthralgia, and so prednisolone was intraarticularly injected at a dose of 25 mg twice with an one-week interval. One month later, varus deformity rapidly progressed, resulting to cause gait disturbance. Since comminution and depression of the tibial plateau were revealed by radiography, steroid arthropathy was suspected. Histological examination showed normal articular cartilage and osteonecrosis in the subchondral bone. In addition, new bone formation was observed in the region around the tibial intercondylar eminence apart from the necrotic area, indicating extensive bone remodeling. On these findings, the patient was diagnosed as the spontaneous osteonecrosis. At that time unicompartmental knee arthroplasty (UKA) was done. Thereafter five years have passed and a revision TKA with bone graft was made because of the loosening of the prosthesis. Though the postoperative course is satisfactory, osteonecrosis developed in the contralateral medial femoral condyle, so that she is receiving a conservative treatment.
authors.affiliation: Department of Orthopedic Surgery, Shiso General Hospital, Hyogo.
authors.forename: M
authors.initials: M
authors.lastname: Kobayashi
mesh_terms: D019645:Arthroplasty, Replacement, Knee; D005260:Female; D006801:Humans; D007719:Knee Joint; D008875:Middle Aged; D010020:Osteonecrosis / Q000473:pathology* / Q000601:surgery; D013977:Tibia / Q000473:pathology*