Causes of failure in total knee arthroplasty.

BACKGROUND The number of primary total knee replacement procedures has rapidly increased worldwide because of the high success rates. The incidence of failure of total knee replacements has concurrently increased. Determining the causes of failure is very important for devising treatment and plan for future prevention strategies. MATERIAL AND METHOD A retrospective study was done with patients who underwent revised total knee replacements in Siriraj Hospital between September 2003 and March 2009. Patient demographic data, laboratory tests, radiographic studies, and intra-operative findings were used to categorize the causes of failure. RESULTS One hundred eighty nine patients (31 male, 158 female) were included in the present study. The average age was 70.8 years. The average survival time after surgery was 6.42 years (ranging from 1 month to 22 years). The major causes of failure included aseptic loosening (52%), polyethylene wear (43%), and infection (31%). Infection (61%) was found in more than half the cases of early failure (< 3 years). Most cases of late failure (> 3 years) were due to aseptic loosening (74%), polyethylene wear (68%), and infection (14%). Male sex and early failure were strongly associated with failure secondary to infection, with odds ratios 4.5 and 8.8, respectively. CONCLUSION There are different causes of early and late failure. The major cause of early failure was infection, while aseptic loosening and polyethylene wear played major roles in late failure. The number of failures due to infection was higher than observed from previous studies. Identification of the causes of failure of total knee replacement surgery from the same country or region will be useful for devising plans to manage and prevent failure in future surgeries.