title: What Factors Are Associated With Failure of Compressive Osseointegration Fixation?
abstract: BACKGROUND
  Compressive osseointegration is as an alternative to traditional intramedullary fixation. Two- to 10-year survivorship and modes of failure have been reported; however, as a result of relatively small numbers, these studies are limited in their ability to identify risk factors for failure.
  
  
  OBJECTIVE
  (1) What is survivorship free from aseptic mechanical and survivorship free from overall failure of compressive osseointegration fixation? (2) What patient factors (age, sex, body mass index [BMI], anatomic location of reconstruction, indication for reconstruction, radiation, chemotherapy) are associated with increased risk of failure?
  
  
  METHODS
  Between 2006 and 2014, surgeons at one center treated 116 patients with 137 Compress®implants for lower extremity oncologic reconstructions, revision arthroplasty, and fracture nonunion or malunion. One hundred sixteen implants were available for review with a minimum of 2-year followup (mean, 4 years; range, 2-9 years). Kaplan-Meier survival plots were produced to examine survivorship and Cox regression modeling was used to generate hazard ratios (HRs) for potential risk factors for failure. Patient factors (age, sex, BMI, anatomic location of reconstruction, indication for reconstruction, radiation, chemotherapy) were obtained from chart review and an institutional database.
  
  
  RESULTS
  Survivorship free from aseptic mechanical failure was 95% (95% confidence interval [CI], 91%-99%) at 18 months and 93% (95% CI, 86%-99%) at 4 years. Survivorship free from overall failure was 82% (95% CI, 75%-89%) at 18 months and 75% (95% CI, 66%-84%) at 4 years. Risk of overall failure was increased with reconstruction of the proximal tibia (HR, 4.42; 95% CI 0.98-19.9) and distal femur (HR, 1.74; 95% CI, 0.50-6.09) compared to the proximal femur (HR, 1; referent; p = 0.049). Risk of aseptic mechanical failure was increased with reconstruction of the proximal tibia (HR, 1; referent) and distal femur (HR, 0.37; 95% CI, 0.08-1.77) compared with the proximal femur (HR, 0, p = 0.048). Radiation was associated with increased risk of overall failure (HR, 3.85; 95% CI, 1.84-8.02; p < 0.003), but not aseptic mechanical failure. Age, sex, BMI, chemotherapy, and surgical indication were not associated with increased risk of aseptic or overall failure.
  
  
  CONCLUSIONS
  This study questions the use of age as a contraindication for the use of this technology and suggests this technology may be considered in proximal femoral reconstruction and for patients with indications other than primary oncologic reconstructions. Future research should establish long-term survivorship data to compare this approach with conventional intramedullary stems and to evaluate the potential benefits of preventing stress shielding and preserving bone stock in revision situations.
  
  
  METHODS
  Level III, therapeutic study.
authors.affiliation: Department of Orthopaedics & Rehabilitation, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Mail Code OP-31, Portland, OR, 97239, USA. Kagan@ohsu.edu.
authors.forename: Ryland
authors.initials: R
authors.lastname: Kagan
authors.affiliation: Department of Orthopaedics & Rehabilitation, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Mail Code OP-31, Portland, OR, 97239, USA.
authors.forename: Jacob
authors.initials: J
authors.lastname: Adams
authors.affiliation: Department of Orthopaedics & Rehabilitation, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Mail Code OP-31, Portland, OR, 97239, USA.
authors.forename: Caroline
authors.initials: C
authors.lastname: Schulman
authors.affiliation: Department of Orthopaedics & Rehabilitation, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Mail Code OP-31, Portland, OR, 97239, USA.
authors.forename: Rachel
authors.initials: R
authors.lastname: Laursen
authors.affiliation: Department of Orthopaedics & Rehabilitation, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Mail Code OP-31, Portland, OR, 97239, USA.
authors.forename: Karina
authors.initials: K
authors.lastname: Espana
authors.affiliation: Department of Orthopaedics & Rehabilitation, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Mail Code OP-31, Portland, OR, 97239, USA.
authors.forename: Jung
authors.initials: J
authors.lastname: Yoo
authors.affiliation: Department of Orthopaedics & Rehabilitation, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Mail Code OP-31, Portland, OR, 97239, USA.
authors.forename: Yee-Cheen
authors.initials: YC
authors.lastname: Doung
authors.affiliation: Department of Orthopaedics & Rehabilitation, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Mail Code OP-31, Portland, OR, 97239, USA.
authors.forename: James
authors.initials: J
authors.lastname: Hayden
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000295:instrumentation*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000295:instrumentation*; D016208:Databases, Factual; D018572:Disease-Free Survival; D005260:Female; D005264:Femoral Fractures / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D005266:Femoral Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D017102:Fracture Healing; D017759:Fractures, Malunited / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D005599:Fractures, Ununited / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D062785:Hemiarthroplasty / Q000009:adverse effects / Q000295:instrumentation*; D006622:Hip Prosthesis; D006801:Humans; D053208:Kaplan-Meier Estimate; D007720:Knee Prosthesis; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D009922:Oregon; D016348:Osseointegration; D010027:Osteotomy; D016016:Proportional Hazards Models; D011474:Prosthesis Design; D012086:Reoperation; D012307:Risk Factors; D013977:Tibia / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D013978:Tibial Fractures / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D017211:Treatment Failure