Arthroscopy after dysfunctional total knee arthroplasty: two cases with peg fracture of the polyethylene insert.

Arthroscopy may be indicated in patients with painful dysfunction of the knee joint following total joint replacement. Arthrofibrosis, impacted soft tissue, patellar malalignment, synovialitis, and intra-articular foreign bodies can be treated with the promise of a good outcome. Two cases of peg fracture of the polyethylene insert of a semiconstrained knee prosthesis are presented. In relation to fracture position, instability and locking-up of the joint were clinically manifest. When arthroscopy is used judiciously, its merits are found in ensuring the proper diagnosis and in the reliable planning of treatment. When the patient reports locking-up of the joint, the rare complication of a polyethylene peg fracture must be considered.