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Novel Diagnostics in Revision Arthroplasty: Implant Sonication and Multiplex Polymerase Chain Reaction
Published on: December 3, 2017
Outcomes of revision total knee arthroplasty after methicillin-resistant Staphylococcus aureus infection
Dann J Laudermilch1, Catherine J Fedorka, Alma Heyl
1University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
Background:
The incidence of infection by methicillin-resistant Staphylococcus aureus (MRSA) in total knee arthroplasty (TKA) is becoming a more frequent concern, as increased morbidity following TKA has been reported for infections by resistant organisms. This study investigates whether MRSA infections are associated with decreased functional scores.
Questions/Purposes:
We therefore compared the functional scores, operative times, and rates of reinfection of revision TKA following MRSA infection versus other indications for revision.
Methods:
We retrospectively reviewed charts of 101 patients (103 knees) who underwent mobile bearing TKA revision from January 2003 to September 2006, with a minimum clinical followup of 2 years in 45 knees (44%). We obtained the following indices: WOMAC, Activities of Daily Living Score (ADLS), SF-36, and Knee Society scores (KSS). Three groups of revisions were compared: MRSA infection (n = 6), non-MRSA infection (n = 9), and aseptic failure (n = 30). The three groups were similar in demographics and comorbidities.
Results:
The MRSA (166 minutes) and non-MRSA groups (149 minutes) had longer operative times than the aseptic group (121 minutes). With numbers available, there were no differences in ROM, WOMAC, ADLS, KSS, and SF-36, with MRSA separate or combined with all infections. Infection recurrence between MRSA-infected knees and non-MRSA-infected knees was similar.
Conclusions:
While our study was underpowered to detect functional differences between MRSA-infected knees and non-MRSA-infected knees it does add data to the literature. Knees revised for infection have longer operative times and more frequent infection after revision. The reason for increased operative times is unclear.
Level Of Evidence:
Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
Insights
Methicillin-resistant Staphylococcus aureus (MRSA) infections in total knee arthroplasty (TKA) revisions do not appear to decrease functional scores, but do increase operative times. Further research is needed to understand the reasons for longer procedures in MRSA cases.
Area of Science:
- Orthopedic Surgery
- Infectious Disease
- Biostatistics
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) infections are an increasing concern in total knee arthroplasty (TKA).
- MRSA infections may lead to increased morbidity following TKA.
- This study examines the impact of MRSA on functional outcomes after TKA revision.
Purpose of the Study:
- To compare functional scores, operative times, and reinfection rates in revision TKA.
- To specifically compare outcomes between MRSA infections and other revision indications.
Main Methods:
- Retrospective review of 101 patients (103 knees) undergoing mobile bearing TKA revision (2003-2006).
- Minimum 2-year follow-up for 45 knees.
- Comparison of three groups: MRSA infection (n=6), non-MRSA infection (n=9), and aseptic failure (n=30).
Main Results:
- Operative times were longer for MRSA (166 min) and non-MRSA (149 min) groups compared to aseptic failure (121 min).
- No significant differences were found in range of motion, WOMAC, ADLS, KSS, or SF-36 scores.
- Infection recurrence rates were similar between MRSA and non-MRSA infected knees.
Conclusions:
- While underpowered for definitive functional outcome differences, this study suggests MRSA TKA revisions have longer operative times.
- Revision for any infection, including MRSA, is associated with increased operative times and higher rates of post-revision infection.
- The underlying reasons for prolonged operative times in infected TKA revisions remain unclear.
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