Abstract

Introduction: Unicondylar knee arthroplasty (UKA) is a treatment option for pure medial tibiofemoral osteoarthrosis. The most common complication of UKA is anterior or medial polyethylene dislocation. We report a rare complication (posterior fixed polyethylene dislocation) of UKA.

Case: We present a case of 79-year-old man with bilateral medial compart man arthrosis underwent bilaterally medial UKA. He had posterior fixed intra-articular polyethylene dislocation which was missed by his first intervention. After three months of missed polyethylene dislocation the implants of UKA was totally loosen.

Conclusion: Diagnostic delay of polyethylene dislocation may result to loosening of component and it will lead to revision of UKA to TKA, which is technically challenging then primer total knee arthroplasty. The most common early complication of UKA is polyethylene dislocation. This should not be forgotten in a painful UKA with locking or without locking.