title: Osseous Integration after Fresh Osteochondral Allograft Transplantation to the Distal Femur: A Prospective Evaluation Using Computed Tomography.
abstract: OBJECTIVE
  Fresh osteochondral allograft transplantation (OCA) is an increasingly available option for patients with damage to the bone-cartilage complex of the distal femur. This study prospectively assesses osseous integration and early clinical results following fresh OCA with single or multiple cylindrical grafts to the femoral condyle.
  
  
  METHODS
  Patients with grade 4 International Cartilage Repair Society (ICRS) defects of the distal femur were treated with OCA. Outcome measures were collected preoperatively and postoperatively at 6, 12, and 24 months. Computed tomography (CT) scans obtained at 6 months were used to assess degree of osseous incorporation regionally.
  
  
  RESULTS
  Thirty-four patients, with a mean age of 34.5 years (range, 15-61), with a mean femoral osteochondral lesion of 5.7 cm(2) (range, 1.5-15.0) due to focal osteoarthritis, osteochondritis dissecans, and avascular necrosis, are reported. Statistically significant (P < 0.05) mean improvement in outcome scores at 2 years included Knee Injury and Osteoarthritis Outcomes Score (KOOS) pain, sports and recreation, quality of life, and International Knee Documentation Committee (IKDC). CT imaging indicated grafts implanted to direct weightbearing regions had >75% incorporation (20/26 grafts) compared to <50% incorporation in the indirect weightbearing regions (8/14 grafts). A greater degree of incorporation and earlier outcome improvement were found after single (n = 23) compared to multiple (n = 11) grafts.
  
  
  CONCLUSIONS
  CT scans were used to assess osseous incorporation of fresh osteochondral allografts in a cohort that showed significant improvements after 2 years. Single-graft implantation is associated with stable incorporation of a greater percentage of the graft. Lesser incorporation appears more frequently with grafts in posterior indirect weightbearing regions of the condyle and multiple contiguous grafts.
authors.affiliation: Department of Orthopaedics and Rehabilitation, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Dawson
authors.initials: D
authors.lastname: Brown
authors.affiliation: Department of Orthopaedics and Rehabilitation, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Khalid
authors.initials: K
authors.lastname: Shirzad
authors.affiliation: Department of Orthopaedics and Rehabilitation, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Lavigne
authors.affiliation: Department of Orthopaedics and Rehabilitation, Oregon Health & Science University, Portland, OR, USA.
authors.forename: Dennis C
authors.initials: DC
authors.lastname: Crawford
keywords: allograft; articular cartilage; bone; knee