title: Do retained pediatric implants impact later total hip arthroplasty?
abstract: BACKGROUND
  It is debated whether all pediatric implants in the proximal femur should be removed in childhood. Hardware removal requires an additional surgical procedure and may put the child at risk for postoperative fracture. However, the impact of retained pediatric implants on future surgeries such as total hip arthroplasty (THA) is not well-understood. We undertook this case-control study to evaluate the effect of retained pediatric implants on surgical complexity and complications at the time of THA. This may offer insight as to whether pediatric proximal femoral implants should be removed in childhood.
  
  
  METHODS
  Case-control study. Between 1990 and 2007, 15,601 primary THAs were performed at a tertiary referral center. Of those, 31 hips had pediatric hardware that had been implanted at a mean of 31 years before the time of THA. Perioperative course and complications were compared with an age-matched, sex-matched, and BMI-matched cohort of 31 patients with no retained implants. Mean follow-up after arthroplasty was 7 years.
  
  
  RESULTS
  Operative time was significantly longer in the retained implant group compared with the control group (230 vs. 159 min; P<0.0001), as was the hospital stay (5.2 vs. 3.8 d; P=0.02). Four of the 14 patients with retained plates required a strut allograft at the time of primary THA. Revision femoral stems and bone grafting were more frequently required in the retained implant cohort. Estimated blood loss was also higher in the retained implant cohort (886 vs. 583 mL; P=0.031). Seven patients in the retained hardware group had a major complication, including intraoperative fracture (5), bleeding (1), and nerve injury (1), whereas no patients in the control group sustained major complications (P=0.017).
  
  
  CONCLUSIONS
  Retained pediatric implants removed at the time of THA were associated with increased operative time, length of stay, and risk of intraoperative fracture. This data supports routine removal of proximal femoral implants in pediatric patients with a high likelihood of future THA.
  
  
  METHODS
  III, case-control study.
authors.affiliation: Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Woodcock
authors.forename: A Noelle
authors.initials: AN
authors.lastname: Larson
authors.forename: Tad M
authors.initials: TM
authors.lastname: Mabry
authors.forename: Anthony A
authors.initials: AA
authors.lastname: Stans
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D020878:Device Removal / Q000009:adverse effects*; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology; D060489:Prosthesis Retention; D012189:Retrospective Studies; D013997:Time Factors; D055815:Young Adult