Unicompartmental knee arthroplasty has been reported to show good results as a method for treating severe osteoarthritis. However, appropriate surgical techniques are required since the operation is unilateral, and a high incidence of complications such as loosening, wear and sinking over time have been reported when the insertion has not been at the optimal site. In the present study, the causes for this were studied and a pathological examination of extirpated tissue was performed in two patients undergoing revision surgery. Both of them had unicompartmental osteoarthritis, and one received a Marmortype joint and the other a PCA-type joint.
