title: The Role of Highly Selective Implant Retention in the Infected Hip Arthroplasty.
abstract: BACKGROUND
  There is debate around how to treat patients with periprosthetic joint infection of the hip. When there is an ingrown component on one side of the arthroplasty and a loose component on the other, treatment is typically revision of the entire construct. There is an argument to retain an ingrown implant in instances in which removal would result in severe bone damage. However, little has been reported on the likelihood of success with this approach.
  
  
  OBJECTIVE
  Among carefully selected patients presenting with an infected total hip arthroplasty (THA) who were treated with joint débridement and at least partial implant retention: (1) What proportion remained apparently free of infection at a minimum of 5 years of followup? (2) What were the Harris hip scores of patients thus treated?
  
  
  METHODS
  Between January 2000 and December 2010, a total of 293 patients were treated surgically at one hospital for a periprosthetic joint infection of the hip. Of these, 18 (2.9%) were treated with an approach that retained either the femoral component or the acetabular component (the removed component was exchanged at this same single-stage procedure). During that time, the general indications for this approach were patients who had complex THAs with ingrown femoral stems or complex acetabular components that were well fixed with no evidence of loosening on radiographs and CT. Patients had to be free from chronic debilitating diseases, had not developed a tracking sinus, and had a positive microbial growth from the hip aspirate. In 12 of these patients, the ingrown cementless femoral component was kept in situ and the femoral head and acetabular component were exchanged. In six patients, complex acetabular reconstructions including augments and/or cages were left in situ, and femoral revision with liner exchange was performed. The technique included removal of the loose component, thorough débridement, synovectomy, and extensive lavage. The ingrown component, be it femoral or acetabular, was thoroughly cleaned, lavaged, and scrubbed. Once there was a clear field, redraping was carried out and new instruments were used to reimplant the other side. In all patients, intravenous antibiotics were used postoperatively for a minimum of 5 days and oral antibiotics for a minimum of 6 weeks based on serology, wound healing, and nutritional markers. None of the patients were lost to followup. Minimum followup was 5 years; median followup was 7.1 years (range, 5-9.9 years).
  
  
  RESULTS
  Reinfection occurred in three patients at 3, 9, and 10 months; all were treated by two-stage revision. No reinfection was noted in the other cases. At latest followup, the mean Harris hip score was 78 (range, 46-89).
  
  
  CONCLUSIONS
  In some patients, staged revision of large and well-fixed components will result in bone damage and compromised function. These results suggest that partial implant retention and joint débridement may be an alternative for those patients who have complex well-fixed acetabular or femoral components, are not immunocompromised, have not developed sinus formation, and we were able to obtain a positive hip aspirate. We caution this technique should not be applied when patients have chronic illness such as diabetes or rheumatoid disease, have a negative hip aspirate for microorganisms, or show any signs of loosening on radiography, CT, or on intraoperative assessment. These results at a minimum of 5 years are reassuring in this small single-center series, but we suggest that the technique not be widely adopted until or unless larger groups of patients with longer term data have been studied.
  
  
  METHODS
  Level IV, therapeutic study.
authors.affiliation: Department of Orthopaedics and Trauma, University College London Hospitals, 235 Euston Road, London, NW1 2BU, UK. moatazelhusseiny@gmail.com.
authors.forename: Moataz
authors.initials: M
authors.lastname: El-Husseiny
authors.affiliation: Department of Orthopaedics and Trauma, University College London Hospitals, 235 Euston Road, London, NW1 2BU, UK.
authors.forename: Fares S
authors.initials: FS
authors.lastname: Haddad
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000295:instrumentation*; D001696:Biomechanical Phenomena; D003646:Debridement; D020878:Device Removal / Q000009:adverse effects; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000382:microbiology / Q000503:physiopathology / Q000601:surgery*; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008131:London; D008297:Male; D008875:Middle Aged; D016459:Prosthesis-Related Infections / Q000000981:diagnostic imaging / Q000382:microbiology / Q000503:physiopathology / Q000601:surgery*; D020127:Recovery of Function; D012008:Recurrence; D012086:Reoperation / Q000009:adverse effects; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome