Partial or total replacement of a unicompartmental knee prosthesis by another unicompartmental knee prosthesis: a reasonable option? About 22 cases.

Twenty-two patients who received primary unicompartmental knee arthroplasties (21 medial and 1 lateral) were reoperated between 2001 and 2010 for partial or total replacement of their implant without using a TKA. Of the 21 patients (1 bilateral) reoperated for PE insert wear (11), PE fracture (3), infection (2), and loosening or malposition (6), 3 patients died and 2 were lost to follow up. The remaining 17 cases had their clinical scores significantly improved. Only one re-revision occurred and consisted of a simple change of PE insert at 9 years, on a very heavy and very active patient. It therefore seems possible and reasonable for now to continue partial or total replacement of unicompartmental knee arthroplasty by another unicompartmental knee arthroplasty without using a TKA.