title: An original knee arthrodesis technique combining external fixator with Steinman pins direct fixation.
abstract: BACKGROUND
  Knee arthrodesis may be the last possible option for infected total knee arthroplasty (TKA) patients and in revision cases involving severe bone loss and/or extensor mechanism damages. Success in these situations depends on achieving good fixation assembly stability. We report bone fusion results using a fixation technique combining cross-pinning by two Steinman pins with a single-frame external fixator. Remission of infection at long-term follow-up was an additional criteria assessed for those cases initially treated for sepsis.
  
  
  OBJECTIVE
  This fixation modality improves fusion rates.
  
  
  METHODS
  In six of this series of eight patients (mean age: 59 years), surgery was performed in a context of infection: five cases of infected TKA, and one case of septic arthritis. In the other two cases, arthrodesis was respectively indicated for a severe post-traumatic stiffness compounded by extensor system rupture and for a fracture combined to a complete mechanical implant loosening. In three of the six infection cases, arthrodesis was performed as a single-stage procedure. All patients were operated on using the same technique: primary arthrodesis site stabilization by frontal cross-pinning with two Steinman pins, followed by installation of a sagittal external fixator frame. Results were assessed at a mean 8 year follow-up.
  
  
  RESULTS
  All the arthrodeses showed fusion at a mean 3.5 months (range: 2.5 to 6 months) postoperative delay without reintervention. Weight-bearing was resumed at 2 to 3 months. The external fixator was removed at a mean 5.2 months. No recurrence of infection was observed over a mean follow-up of 8.2 years (range: 1 to 15 years). Three complications occurred: one hematoma, managed surgically; one supracondylar fracture treated orthopedically; and one osteitis, managed by surgical curettage.
  
  
  CONCLUSIONS
  This knee arthrodesis technique proved effective, with no failures in this short series, especially in cases of primary infection. It is a reproducible means of osteosynthesis, with little subsequent morbidity. Fixation in two orthogonal planes seemed to provide the stability required to achieve bone fusion. This assembly avoids internal fixation, which is never risk-free in a context of primary sepsis.
  
  
  METHODS
  Level IV. Retrospective study.
authors.affiliation: Orthopedics and Traumatology Department, Bicêtre Hospital; Paris-XI-Sud University Medical School, 78, rue du Général-Leclerc, 94275 Le-Kremlin-Bicêtre cedex, France.
authors.forename: G
authors.initials: G
authors.lastname: Riouallon
authors.forename: V
authors.initials: V
authors.lastname: Molina
authors.forename: C
authors.initials: C
authors.lastname: Mansour
authors.forename: C
authors.initials: C
authors.lastname: Court
authors.forename: J-Y
authors.initials: JY
authors.lastname: Nordin
mesh_terms: D001170:Arthritis, Infectious / Q000601:surgery*; D001174:Arthrodesis / Q000379:methods*; D019645:Arthroplasty, Replacement, Knee; D001858:Bone Nails; D016267:External Fixators; D005260:Female; D005500:Follow-Up Studies; D006406:Hematoma / Q000601:surgery; D006620:Hip Fractures / Q000601:surgery; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D010000:Osteitis / Q000601:surgery; D011183:Postoperative Complications / Q000601:surgery*; D011475:Prosthesis Failure; D016459:Prosthesis-Related Infections / Q000601:surgery*; D016896:Treatment Outcome; D016474:Weight-Bearing