2- to 9-year outcome of stemmed total knee arthroplasty. Similar failure rates in patients when used primary or as a revision.

BACKGROUND AND PURPOSE: There is an increase in demand for primary and revision total knee joint procedures. We studied implant survival and functional outcome of patients operated with a constrained condylar knee (CCK) or a rotating hinge implant (RH) as a primary or a revision total knee arthoplasty (TKA).

PATIENTS AND METHODS: We evaluated clinically and radiographically 65 surgical procedures with a mean follow-up time of 5 (2-9) years (40 CCK and 25 RH). There were 24 primary TKAs-due to instability-and 41 revision TKAs, mostly due to aseptic loosening. Mean age at the index operation was 68 (31-88) years.

RESULTS: Overall, there were 12 failures, including 8 reoperations due to deep infection. The overall 5-year survival rate with reoperation as the endpoint was 82% (95% CI: 72-99). Radiolucent lines on either the femoral or the tibial side were seen in 36 cases. When comparing the cases that were operated as a primary TKA or as a revision TKA, function, health-related quality of life, and survival were similar. However, after primary TKA the patients generally had less pain and a higher proportion of patients were very satisfied or satisfied.

INTERPRETATION: Although a high rate of severe complications was observed, most patients improved in function after surgery regardless of whether it was a primary or a revision TKA. We found narrow radiolucent lines-mainly on the tibial side-in nearly half of the cases, but none of the implants were loose radiographically. Overall patient satisfaction and health-related quality of life were high, and a minority had problems with persistent pain.