INCREASED RATE OF SEPTIC REOPERATIONS AFTER PRIMARY KNEE REPLACEMENT WITH CEMENTLESS FIXATION OF THE TIBIAL COMPONENT

Abstract

Antibiotic-impregnated cement is frequently used for fixation of total knee prostheses as a measure to prevent postoperative infection. In recent years, more cementless knee prostheses have been implanted especially for younger patients.

In 1997 to June 2004, 35044 primary total knee arthroplasties for primary or secondary osteoarthritis were performed in Finland and registered in nationwide arthroplasty register. The patients aged 70 years (range 21–96) on average, and 71.7% were women.

During the median follow-up of 39 months (range 0–104), 978 (2.8%) knees were revised. There were 188 (0.58%), 21 (1.09%) and 10 (1.18%) reoperations due to infection after cemented, hybrid and cementless arthroplasties, respectively (p=0.003). In hybrid arthroplasties with cemented tibial component, the septic reoperation rate did not significantly differ from cemented arthroplasties. Instead, the higher number of infections after hybrid arthroplasty was related to use of cementless tibial components (5.3% vs. 0.9%, p< 0.008). In Cox regression model adjusted for age, gender and diagnosis, the hazard ratio for septic reoperation after knee replacement with cementless tibial component was 2.4 (95% CI 1.4–4.1) compared to the cemented alternative. The fixation method did not affect the rate of septic reoperations occurring after the first postoperative year.

Cementless fixation of tibial component in primary total knee arthroplasty may associate with an increased risk of early septic reoperation. Until this finding is confirmed in other materials, cementless fixation in primary knee arthroplasty should be used cautiously in patients with increased risk for infection.