Revision total knee arthroplasty infection: incidence and predictors.

BACKGROUND

Deep infection remains one of the most devastating and costly complications after total knee arthroplasty (TKA). The risk of deep infection after revision TKA is reportedly greater than that for primary TKA; however, we do not know the exact incidence of infection after revision TKA.

QUESTIONS/PURPOSES: We determined the incidence of infection after revision, the type of microorganisms involved and TKA, and the potential risk factors for this infection.

METHODS

We retrospectively reviewed 475 patients (476 knees) with 499 TKA revisions performed between March 1998 and December 2005. Of the 476 knees, 91 (19%) were revised for infection and 385 (81%) were revised for aseptic failure. Preoperative history, results of physical examinations, laboratory and radiographic results, joint fluid aspiration results along with analysis of intraoperative findings were all considered to make an assessment of septic versus aseptic failure modes. Patients were followed for a minimum of 25 months (mean, 65 months; range, 25-159 months).

RESULTS

Deep infection developed in 44 of the 476 knees (9%). The infection rate was higher in patients undergoing revision for infection than in patients with aseptic revisions: 21% (23 of 91) and 5% (21 of 385), respectively. Revision for infection, higher Charlson index, and diagnosis other than osteoarthritis at the time of primary TKA predicted infection of the revision. The risk of infection for patients undergoing TKA revisions was 10-fold higher than for patients undergoing primary TKA at our institution.

CONCLUSIONS

Infection of primary TKA is the most important risk factor for subsequent infection of TKA revisions.

LEVEL OF EVIDENCE

Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.