Endoscopic-Assisted Curettage of Posterior Proximal Tibia Chondroblastoma: A Case Report and Review of Literature.

Chondroblastoma is a benign cartilage-producing bone lesion that characteristically occurs in the epiphyseal region of long bones. The most typical locations are the proximal humerus, proximal femur, distal femur, and proximal tibia. There is no medical treatment for the disease; classically, it must be treated by intralesional curettage and bone grafting. A 15-year-old female patient presented with chronic knee pain with no antecedent history of trauma. Clinical examination showed deep tenderness on maximum flexion and 15 degrees extension lag with full knee flexion. Plain radiographs and knee MRI showed a lesion in the posterior part of the proximal tibia on the midline, highly suggestive of chondroblastoma. CAT-guided biopsy did not show any evidence of malignancy. Intralesional curettage assisted by endoscopic visualization was done using a small incision, and a bone graft substitute reconstructed the defect. Endoscopic-assisted curettage of benign bone lesions can be considered in challenging locations with good results.

Dislocation of Rotating Hinged Knee Prostheses in a Patient With Extensor Mechanism Dysfunction.

Rotating hinged knee replacements are used to restore knee stability when intrinsic stability is lost in the form of soft tissue compression. With medical engineering advancements and improvements in arthroplasty, intrinsic stability can be achieved by an implant post system. We present the case of a 44-year-old female who presented with post-traumatic right knee multi-ligamentous instability and advanced secondary osteoarthritis following a traumatic knee dislocation two years ago. The patient initially underwent a hinged total knee replacement. After five years, she got dislocation of hinged total knee replacement that affected her condition and necessitated emergency admission for open reduction and revision. Most reported cases of rotating hinge prosthesis dislocation occurred during the first year of follow-up. However, our case dislocated after five years of follow-up due to dislodgement from the tibial tray with the polyethylene channel in the form of fatigue failure of the anti-dislocation mechanism.