title: Minimally invasive fixation of type B and C interprosthetic femoral fractures.
abstract: BACKGROUND
  Interprosthetic femoral fractures are rare and raise unresolved treatment issues such as the length of the fixation material that best prevents secondary fractures. Awareness of the advantages of locked-plate fixation via a minimally invasive approach remains limited, despite the potential of this method for improving success rates.
  
  
  OBJECTIVE
  Femur-spanning (from the trochanters to the condyles) locked-plate fixation via a minimally invasive approach provides high healing rates with no secondary fractures.
  
  
  METHODS
  From January 2004 to May 2011, all eight patients seen for interprosthetic fractures were treated with minimally invasive locked-plate fixation. Mean time since hip arthroplasty was 47.5 months and mean time since knee arthroplasty was 72.6 months. There were 12 standard primary prostheses and four revision prostheses; 11 prostheses were cemented and a single prosthesis showed femoral loosening. Classification about the hip prostheses was Vancouver B in one patient and Vancouver C in seven patients; about the knee prosthesis, the fracture was SoFCOT B in three patients and SOFCOT C in five patients, and a single fracture was SoFCOT D. Minimally invasive locking-plate fixation was performed in all eight patients, with installation on a traction table in seven patients.
  
  
  RESULTS
  Healing was obtained in all eight patients, after a mean of 14 weeks (range, 12-16 weeks). One patient had malalignment with more than 5° of varus. There were no general or infectious complications. One patient died, 32 months after surgery. The mean Parker-Palmer mobility score decreased from 6.2 pre-operatively to 2.5 at last follow-up. Early construct failure after 3 weeks in one patient required surgical revision. There was no change in implant fixation at last follow-up. No secondary fractures were recorded.
  
  
  CONCLUSIONS
  In patients with type B or C interprosthetic fractures, femur-spanning fixation not only avoids complications related to altered bone stock and presence of prosthetic material, but also decreases the risk of secondary fractures by eliminating stress riser zones. The minimally invasive option enhances healing by preserving the fracture haematoma. Thus, healing was obtained consistently in our patients, with no secondary fractures, although the construct failed in one patient.
  
  
  METHODS
  Level IV.
authors.affiliation: Department of Orthopaedics and Trauma Surgery De Hautepierre Hospital, Strasbourg University Hospital Group, 1, avenue Molière, 67098 Strasbourg cedex, France. Matthieu.ehlinger@chru-strasbourg.fr
authors.forename: M
authors.initials: M
authors.lastname: Ehlinger
authors.forename: J
authors.initials: J
authors.lastname: Czekaj
authors.forename: P
authors.initials: P
authors.lastname: Adam
authors.forename: D
authors.initials: D
authors.lastname: Brinkert
authors.forename: G
authors.initials: G
authors.lastname: Ducrot
authors.forename: F
authors.initials: F
authors.lastname: Bonnomet
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000379:methods; D001843:Bone Cements; D001860:Bone Plates; D015331:Cohort Studies; D005260:Female; D005264:Femoral Fractures / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D005593:Fracture Fixation, Internal / Q000295:instrumentation / Q000379:methods*; D017102:Fracture Healing / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods; D057068:Periprosthetic Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D011859:Radiography; D020127:Recovery of Function; D012086:Reoperation / Q000379:methods; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D016896:Treatment Outcome
chemical_list: D001843:Bone Cements
keywords: Femoral fracture; Internal fixation; Interprosthetic fracture; Locked-plate; Minimally invasive; Periprosthetic fracture