Authors: Laudermilch DJ, Fedorka CJ, Klatt BA, Crossett LS, Heyl A, Rao N, McGough RL, Pittsburgh, PA
Title: Outcomes Of Revision Total Knee Arthroplasty After Methicillin-Resistant Staphylococcus Aureus Infection
Purpose: The incidence of infection by methicillin-resistant Staphylococcus aureus (MRSA) in total knee arthroplasty (TKA) is becoming a more frequent concern. This study investigates the poorly understood outcome of TKA revision (TKA-R) after MRSA sepsis.
Methods: This is a single-institution, retrospective cohort study of 101 patients (103 knees) who underwent mobile bearing TKA-R from January 2003 to September 2006. Chart review was conducted for 103 knees (9 MRSA), and final follow-up was obtained at >2 years for 49 knees (6 MRSA) with the following indices: Western Ontario and McMaster University Osteoarthritis Index (WOMAC), Activities of Daily Living Score (ADLS), SF-36 and Knee Society Scores (KSS). Three groups of TKA-R were compared: MRSA infection, non-MRSA infection, and aseptic failure.
Results: The MRSA, non-MRSA, and aseptic groups had no significant differences in demographics or comorbidities. The MRSA group had longer operative times, with an average of 166 min, compared to 149 min (non-MRSA) and 121 min (aseptic) (p = 0.001). The three groups had no significant differences in 6 month range of motion (ROM) with available numbers. Patients who returned for 2 year follow-up were similar in demographics, comorbidities, and 6 month ROM to those patients without 2 year follow-up. With the sample size available, there were no significant differences in outcomes at 6 month and final ROM, WOMAC, ADLS, KSS, and SF-36. Power analysis revealed, that for >80% power to detect differences, between 35 (KSS) and 1000 (ADLS) MRSA patients were needed.
Discuassion and Conclusion: Based upon this data, the outcomes and motion in MRSA revisions were similar to revisions for other reasons, despite technical difficulty and longer operative times. Patients treated aggressively for MRSA septic TKA can expect similar results to revisions for other indications.