Arthroscopic removal of impinging cement after unicompartmental knee arthroplasty.

Complications following unicompartmental knee arthroplasty (UKA) include aseptic loosening, polyethylene wear, arthritis progression and periprothetic fractures. We report on a patient with a firmly fixed, sizeable cement extrusion into the posteromedial aspect of the knee after a UKA causing impingement and pain in full extension. Cement extrusion is an extremely rare but potentially disabling complication that may occur despite care to remove all cement following implantation of the prosthesis. Removing a cement fragment, especially when this is firmly fixed to difficult-to-visualise and access parts of the prosthesis, is challenging. We believe the patient we report is the first one where a firmly fixed, sizeable cement extrusion was removed arthroscopically from the posterior aspect of the knee. This was achieved via an anterolateral portal with trans-notch view, combined with a posteromedial portal used both for viewing and instrument insertion. Arthroscopic removal of the impinging cement with the technique described above is a safe and effective option for the treatment of this difficult albeit rare problem.