Fig. 3

A case of SPR. A Standing anteroposterior and lateral radiographs of the left knee reveal narrowing of the medial compartment, characteristic of OA changes. B Post-TKA anteroposterior and lateral radiographs of the left knee demonstrate a well-positioned prosthesis with normal alignment. C Post-TKA axial radiograph confirms the prosthetic alignment. D Triple-phase bone scan highlights radioactive concentration within the left knee joint. E SPECT/CT imaging identifies focal radionuclide concentration on the lateral articular surface of the patella. F Intraoperative findings include impingement between the lateral articular surface of the left patella and the lateral condyle of the femoral prosthesis, along with cartilage defects and metal debris attachment. G Standing anteroposterior and lateral radiographs following SPR. H Axial radiograph post-SPR. I Full-length radiograph in functional position after SPR. J standing anteroposterior and lateral radiographs post-SPR at a two-year follow-up