title: Prosthetic joint infection following hip fracture and degenerative hip disorder: a cohort study of three thousand, eight hundred and seven consecutive hip arthroplasties with a minimum follow-up of five years.
abstract: OBJECTIVE
  Prosthetic joint infections (PJIs) occur on a regular basis and with an increasing incidence. Under reporting of complications to national registries and unreliable ICD-10 coding increases the risk of under estimating the true rate of PJIs after hip arthroplasty. Also, the microbiology and final outcome is less well described, especially for hip-fracture patients operated upon with primary and secondary fracture prostheses. Our aim was to analyse re-operation rate, outcome and microbiology of PJIs following hip arthroplasty in patients operated upon due to hip fractures and degenerative hip disorders.
  
  
  METHODS
  This was a single-centre cohort study of 3807 consecutive hip arthroplasties performed between 1996 and 2005. The primary study outcome was to compare the incidence of PJIs. The secondary outcome was to analyse the microbiology and outcome of PJIs.
  
  
  RESULTS
  We identified 62 PJIs: seven surgical-site PJIs were found in patients operated upon for a degenerative hip disorder, 22 [hazard ratio (HR) 4.3] were found in patients operated upon for a primary fracture and prosthesis and 25 (HR 6.1) in patients operated upon with a secondary fracture and prosthesis. Outcome treatment was unfavourable for hip fracture patients with a high rate of Girdlestone operation performed (22 of 27). Staphylococcal infections dominated in the fracture group, whereas polybacterial infections were more common in patients with degenerative hip disorder.
  
  
  CONCLUSIONS
  Patients with a displaced femoral neck fracture treated primary or secondary with arthroplasties have a greater risk of PJIs and display worse outcomes compared with patients with a total hip replacement due to degenerative hip disorders.
authors.affiliation: Department of Clinical Science and Education, Karolinska Institutet, Stockholm, Sweden. richard.blomfeldt@ki.se.
authors.forename: Richard
authors.initials: R
authors.lastname: Blomfeldt
authors.affiliation: Department of Clinical Science and Education, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Piotr
authors.initials: P
authors.lastname: Kasina
authors.affiliation: Department of Clinical Science and Education, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Carin
authors.initials: C
authors.lastname: Ottosson
authors.affiliation: Department of Clinical Science and Education, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Enocson
authors.affiliation: Department of Clinical Science and Education, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Lasse J
authors.initials: LJ
authors.lastname: Lapidus
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006620:Hip Fractures / Q000601:surgery*; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000601:surgery*; D016459:Prosthesis-Related Infections / Q000453:epidemiology* / Q000382:microbiology; D012086:Reoperation / Q000706:statistics & numerical data; D016896:Treatment Outcome
keywords: Coagulase-negative staphylococci; Hip-fracture prosthesis; PJIs; Prosthetic joint infection; Secondary hip arthroplasty; Surgical-site infection