The routine of surgical management reduces failure after unicompartmental knee arthroplasty

A total of 10 474 unicompartmental knee arthroplasties was performed for me dial osteoarthritis in Sweden between 1986 and 1995. We sought to establish whether the number of operations performed in an orthopaedic unit affected the incidence of revision. Three different implants were analysed: one wit h a high revision rate, known to have unfavourable mechanical and design pr operties; a prosthesis which is technically demanding with a known increase d rate of revision; and the most commonly used unicompartmental device. Most of the units performed relatively few unicompartmental knee arthroplas ties per year and there was an association between the mean number carried out and the risk of later revision. The effect of the mean number of operat ions per year on the risk of revision varied, The technically demanding imp lant was most affected, that most commonly used less so, and the outcome of the unfavourable design was not influenced by the number of operations per formed. For unicompartmental arthroplasty, the long-term results are related to the number performed by the unit, probably expressing the standards of managem ent in selecting the patients and performing the operation.