- This study evaluated the outcomes in patients who underwent two-stage revision total hip or knee arthroplasty as a salvage procedure for deep infection of periarticular fracture internal fixation (IF)
- The failure rate was significantly higher for the IF group than propensity score–matched controls who underwent two-stage revision for periprosthetic infection of the hip or knee after non-traumatic total joint arthroplasty (43% vs. 21%; P=0.03)
- Reinfection was the most common complication in the IF group, observed in 35% of patients vs. 11% of controls (P=0.005)
- Polymicrobial growth was encountered in 30% of the IF group and methicillin-resistant Staphylococcus aureus in 20%, emphasizing the need to identify causative pathogens for culture-guided antibiotic therapy
When patients develop a periprosthetic joint infection after total hip and knee joint arthroplasty for non-traumatic indications, two-stage revision is normally successful: (a) removal of all hardware, thorough irrigation and debridement, and antibiotic therapy (local and systemic); then (b) reimplantation after the infection is eradicated.
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In contrast, Massachusetts General Hospital researchers at the Bioengineering Laboratory recently detected poor outcomes when two-stage revision arthroplasty was used as a salvage procedure for deep infection of periarticular fracture fixation.
Janna van den Kieboom, MD, a research fellow in the Bioengineering Laboratory of the Department of Orthopaedic Surgery, Young-Min Kwon, MD, PhD, vice chair of the Department and director of the Lab, and colleagues report their findings in The Archives of Bone and Joint Surgery.
Patients and Propensity Matching
From a prospectively maintained database at Mass General, the team identified the following:
- 40 patients who underwent two-stage revision as a salvage procedure for deep infected internal fixation (IF) of a periarticular fracture of the acetabulum, femur, tibia, or patella ("IF patients"; 68% hips, 32% knees)
- 471 patients who underwent two-stage revision for periprosthetic infection of the hip or knee after non-traumatic total joint arthroplasty ("non-IF patients")
Propensity Score Matching
As the study wasn't randomized, the researchers used propensity score matching to reduce selection bias. They estimated a propensity score for each of the 40 IF patients and matched each one to two non-IF controls, for a total of 120 patients.
The two resulting groups were similar in age, gender, body mass index, joint, smoking status, cardiovascular disease, diabetes mellitus, and inflammatory disease. They were also similar to intervals between first- and second-stage revision surgery.
Overall Clinical Outcomes
Two-stage revision was defined as successful when:
- No clinical signs of infection were evident during follow-up
- No subsequent surgical interventions were necessary
- No amputation occurred
After an average follow-up of 4.5 years (range, 1.0–25.8):
- The failure rate was 43% for IF patients and 21% for non-IF patients (P=0.03)
- Reinfection was the most common indication for failure, occurring in 14 of the 40 IF patients (35%) and nine of the 80 non-IF patients (11%; P=0.005)
- Readmission and amputation rates did not differ significantly between the groups
Reinfection of Knee vs. Hip
The reinfection rates by joint were:
- Knee IF—46% (deep reinfection, 31%; superficial, 15%)
- Hip IF—26% (deep, 19%; superficial, 7%)
In the IF group, compared with the non-IF group, there were significantly higher rates of:
- Polymicrobial growth—30% vs. 11% (P=0.01)
- Methicillin-resistant Staphylococcus aureus—20% vs. 8% (P=0.04)
- Gram-positive organisms—8% vs. 0% (P=0.04)
Among patients who developed a recurrent infection, patients in the IF group had significantly higher rates of MRSA, Staphylococcus species, and polymicrobial growth.
The incidence of high-virulence pathogens highlights the need to identify causative pathogens for culture-guided antibiotic therapy before second-stage surgery.
Salvage two-stage revision arthroplasty for infected internal fixation of periarticular fractures was associated with poor outcomes. The overall post-operative complications after salvage two-stage revision for infected internal fixation of peri-articular fractures was high, with 35% reinfection rates associated with the presence of mixed and resistant pathogens.
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