Significance of operative cultures in total hip arthroplasty.

The significance of operative cultures to the development of deep infections in total hip arthroplasties performed for failures of previous surgeries was studied. Four hundred fifty conversion total hips were followed for three or more years. Twenty-nine percent had had more than one prior surgery. One hundred twenty-one organisms in 81 hips (18%) were found. Gram-positive cultures were increased in rheumatoid arthritis. Twenty (4.4%) of the hips became infected. Nine (11%) of the hips with positive cultures and 11 (3%) of the hips with no growth at conversion later developed infections. Failed total hip arthroplasties with a positive culture had a 40% rate of reinfection. Rheumatoid hips had a two-times higher infection rate, and 80% were caused by gram-negative organisms. Hips with a gram-negative growth at the time of conversion had a higher infection rate than hips infected with gram-positive organisms.