title: Young age and wedge stem design are risk factors for periprosthetic fracture after arthroplasty due to hip fracture. A case-control study.
abstract: BACKGROUND
  It has been suggested that a hip fracture as a primary diagnosis for arthroplasty is a risk factor for periprosthetic fracture.
  
  
  METHODS
  We compared 16 patients with late periprosthetic fracture of the femur to 48 controls. The primary diagnosis for all patients was hip fracture. The date of operation for hip fracture was used to select the control group of patients, all of whom were operated at the same time and in the same hospital district. No other selection criteria were used. Complications at the time of index operation, type of prosthesis, age, sex, BMI, patient's diseases, medication, and surgeon's experience were compared using conditional logistic regression.
  
  
  RESULTS
  We found that low age at the time of the hip fracture operation increased the risk of periprosthetic fracture (OR = 4.9, CI = 1.2-20). The polished wedge type of prosthesis was associated with a higher risk of periprosthetic fracture than were other designs (OR = 11, CI = 1.2-97).
  
  
  CONCLUSIONS
  These findings of risk factors for periprosthetic fracture are new and should be confirmed by further studies using larger numbers of patients.
authors.affiliation: Jorvi Hospital, HUS, Turuntie 150, FI-02710, Espoo, Finland. sarvilinna@yahoo.com
authors.forename: Roope
authors.initials: R
authors.lastname: Sarvilinna
authors.forename: Heini
authors.initials: H
authors.lastname: Huhtala
authors.forename: Jorma
authors.initials: J
authors.lastname: Pajamäki
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000379:methods; D016022:Case-Control Studies; D005260:Female; D006620:Hip Fractures / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012042:Registries; D012086:Reoperation; D012307:Risk Factors