Extensive osteolytic cystlike area associated with polyethylene wear debris adjacent to an aseptic, stable, uncemented unicompartmental knee prosthesis: case report

We present the case of a patient who after uncemented unicompartmental knee arthroplasty developed a large osteolytic cystlike area in the lateral aspect of the tibial metaphysis, contralateral to a well-fixed tibial component at revision surgery. The lesion contained fibrotic soft tissue, evidence of a foreign-body giant cell reaction and polyethylene particles, but no metal wear debris, infection, or malignancy. This case demonstrates that there is a direct communication between the joint cavity and the cyst.