title: The use of a multiplanar, multi-axis external fixator to achieve knee arthrodesis in a worst case scenario: a case series.
abstract: BACKGROUND
  One of the most catastrophic outcomes following total knee arthroplasty (TKA) is a chronic periprosthetic infection with concomitant failure of the knee extensor mechanism. This study retrospectively reviewed the clinical records of 7 patients who were treated with a 6 axis circular external fixation frame (Taylor Spatial Frame (TSF)) for this condition. Fusion was achieved in 5 of 7 patients (71%) at an average of 8.4 months after surgery. Complications occurred in the treatment of 5 of 7 patients (71%). Infection was controlled in all cases. The TSF presents another valuable tool, which the orthopaedic surgeon should consider when treating these difficult cases.
  
  
  OBJECTIVE
  To evaluate the use of the Taylor Spatial Frame (TSF) to achieve knee arthrodesis in patients with chronically infected total knee arthroplasties (TKAs) with concomitant failure of the knee extensor mechanism.
  
  
  METHODS
  We retrospectively evaluated the clinical records of 7 patients who were referred to our tertiary care orthopaedic medical center with multiple failed knee arthroplasties, chronic draining infection and complete loss of the extensor mechanism. All patients were treated with a similar protocol including, debridement and bony stabilization with an adjustable, 6 axis circular external fixation frame (TSF). Hospital charts were reviewed for sociodemographic information, surgical details, hospital course and complications. Radiographs were reviewed for healing and alignment. Follow up included clinical examination and radiographs.
  
  
  RESULTS
  The mean age of the patients was 70.9 years (range, 59 - 83 years) at the time of application of the TSF. There were 3 men and 4 women. The average time between TKA and diagnosis of infection was 30.7 months (range, 2.6 - 67.0 months). The 7 patients had undergone an average of 3.3 prior surgical procedures (range, 2-4 procedures) on the ipsilateral extremity. Fusion was achieved in 5 of 7 patients (71%) at an average of 8.4 months after surgery (range, 6 - 10.5 months). Complications occurred in the treatment of 5 of 7 patients (71%) and included infection at the site of the pin tracks (5 patients), antibiotic- induced acute renal failure (1 patient), wound breakdown requiring flap closure (1 patient), and femur fracture secondary to a fall after placement of the antibiotic spacer but before application of the TSF (1 patient). The 2 patients in whom failure of fusion occurred returned to ambulation with an assistive device. Infection was controlled in all cases.
  
  
  CONCLUSIONS
  Fusion and complication rates in this cohort are comparable to those reported in previous studies using other techniques to achieve external fixation. The TSF is a versatile external fixator that offers another tool, which the orthopaedic surgeon should consider when treating these difficult cases.
authors.affiliation: SUNY Downstate College of Medicine , Brooklyn , NY ; Department of Orthopaedic Surgery NYU Hospital for Joint Diseases , New York , NY.
authors.forename: Dima
authors.initials: D
authors.lastname: Raskolnikov
authors.forename: James D
authors.initials: JD
authors.lastname: Slover
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Egol
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001174:Arthrodesis / Q000295:instrumentation*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects; D016267:External Fixators; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D007720:Knee Prosthesis / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D016459:Prosthesis-Related Infections / Q000209:etiology / Q000601:surgery*; D012189:Retrospective Studies; D016896:Treatment Outcome
keywords: Taylor Spatial Frame; knee arthrodesis; peri-prosthetic infection; total knee arthroplasty
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