AAOS Now

Published 4/1/2017
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Terry Stanton

Study: Study Probes Reimplantation Rates, Complications Following THA Infection

A Medicare database study reviewing outcomes for patients who underwent antibiotic spacer placement following removal of total hip arthroplasty (THA) due to infection found that only 60 percent of such patients underwent THA reimplantation. Approximately 6 percent of these patients died within 1 year following removal.

The study, presented during the AAOS Annual Meeting by Jourdan Cancienne, MD, of the University of Virginia, examined records for 7,146 patients who underwent hip arthroplasty prosthesis removal and cement spacer placement for infection. Within 1 year postoperatively, 464 patients (6.5 percent) died, 775 patients (10.8 percent) had a repeat débridement procedure, 404 patients (5.7 percent) had a resection arthroplasty, and 1,202 patients (16.8 percent) retained their spacers. The remaining 4,301 patients (60.2 percent) were reimplanted. Independent risk factors for death within 1 year included male gender (P = 0.018), age older than 85 years (P < 0.0001), diabetes (P = 0.016), congestive heart failure (P < 0.0001), chronic lung (P = 0.001) and liver diseases (P < 0.0001), and hemodialysis (P < 0.0001). Independent risk factors for repeat débridement include obesity, inflammatory arthritis, depression, hyperlipidemia, and chronic kidney and chronic liver diseases (all significant). Independent risk factors for no reimplantation within 1 year included age older than 85 years, female gender, diabetes, peripheral vascular disease, congestive heart failure, hemodialysis, and depression (all P < 0.0001). Reporting on reimplantation
The authors noted that recent studies have questioned the definition of success for two-stage procedures in the treatment of prosthetic joint infection (PJI) and have begun to examine outcomes other than reimplantation. “In order to provide a more complete picture of the overall clinical impact of PJI in total joint arthroplasty, both the successes and failures of two-stage revision arthroplasty need to be appropriately reported and described,” they write. “Currently, reports investigating the outcomes and clinical course of patients who do not undergo reimplantation have been limited institutional series with mixed knee and hip arthroplasty cohorts that have prohibited the identification of patient-specific risk factors for these outcomes.” Their study, which drew from a Medicare patient database, provides national perspective on outcomes at 1 year following explantation and antibiotic spacer placement.  “When reviewing our institutional data and the limited reports on staged reimplantation for the infected THA, we noted that the number of patients who do not undergo reimplantation following spacer placement is not inconsequential and might be higher than previously thought,” said Dr. Cancienne. “Furthermore, the majority of the literature available on the topic consists of relatively small institutional reviews and focuses solely on patients who undergo successful reimplantation. We wanted to gain a national perspective on the outcomes following implant removal and spacer placement for the infected THA and see if the results coincided with the data at our own institution and that present in the literature. A secondary objective was to determine if there were any patient-related risk factors for outcomes other than successful reimplantation in the interstage period.” Dr. Cancienne noted that the number of patients who had outcomes other than uneventful reimplantations might be considered surprising. “While staged revision for the infected THA is the gold standard for infection eradication, it is not always successful—as seen in the 16 percent of patients who retained their spacers and the more than 10 percent who had a repeat debridement procedure,” he said. “Furthermore, 1-year documented mortality rate of at least 6.5 percent was a sobering amount of attrition. And given the fact that the dataset may not have captured all deaths, it is likely that the mortality rate is even higher than we report. “Our study demonstrates and identifies certain patient specific characteristics that influence mortality: resection arthroplasty, and spacer retention at 1 year,” continued the authors. “These data help contribute to the growing body of research that helps to predict the likelihood of success of the proposed intervention based on patient-specific criteria. These risk factors will help to develop management algorithms that are evidence based and can be discussed prior to the initial procedure, helping to further balance both patient and surgeon expectations of this challenging complication. For example, if a patient's comorbidity profile makes them unlikely to undergo reimplantation at any point, different surgical techniques and spacers might be used.” “Our study should help guide the shared decision process between patients and arthroplasty surgeons for management of the chronically infected THA,” said Dr. Cancienne. “Not all patients who undergo implant removal and spacer placement have the same chance of success, and there are several independent patient-related risk factors identified in the study that are risk factors for outcomes other than successful reimplantation. Patients with such risk factors should be counseled accordingly, and multidisciplinary care should be utilized in an attempt to mitigate the effects of these comorbidities on patient outcomes.” Future research, he said, should aim to identify other factors associated with the success and failure of implant removal and spacer placement for the eradication of infection following THA. “Multicenter, prospective studies are needed to evaluate the complex interplay of how patient demographics, comorbidity profiles, and the infecting organism contribute to the variable outcomes observed following explantation and spacer placement,” Dr. Cancienne said. “We hope this study will encourage further research that will help to manage patient and surgeon expectations for outcomes at 1 year following implant removal and spacer placement for infection following THA.” Dr. Cancienne's coauthors of “Removal of an Infected Total Hip Arthroplasty: Risk Factors for Repeat Debridement, Long-term Spacer Retention, and Mortality,” are Brian C. Werner, MD, and James A. Browne, MD. Details of the authors' disclosures as submitted to the Orthopaedic Disclosure Program can be found in the Final Program; the most current disclosure information may be accessed electronically at www.aaos.org/disclosure Terry Stanton is the senior science writer for AAOS Now. He can be reached at tstanton@aaos.org

Bottom Line

  • The study examined results for 7,146 patients who underwent hip arthroplasty prosthesis removal and cement spacer placement for infection.
  • Only 60 percent of the patients underwent THA reimplantation, while approximately 6 percent died within 1 year following removal.
  • Risk factors for no reimplantation within 1 year included age older than 85 years, female gender, diabetes, peripheral vascular disease, congestive heart failure, hemodialysis, and depression.
  • The results may be used to help to predict the likelihood of success of the proposed intervention for implant complications based on patient-specific criteria.