title: Comparative study of navigated versus freehand osteochondral graft transplantation of the knee.
abstract: BACKGROUND
  Osteochondral lesions are a common sports-related injury for which osteochondral grafting, including mosaicplasty, is an established treatment. Computer navigation has been gaining popularity in orthopaedic surgery to improve accuracy and precision.
  
  
  OBJECTIVE
  Navigation improves angle and depth matching during harvest and placement of osteochondral grafts compared with conventional freehand open technique.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Three cadaveric knees were used. Reference markers were attached to the femur, tibia, and donor/recipient site guides. Fifteen osteochondral grafts were harvested and inserted into recipient sites with computer navigation, and 15 similar grafts were inserted freehand. The angles of graft removal and placement as well as surface congruity (graft depth) were calculated for each surgical group.
  
  
  RESULTS
  The mean harvesting angle at the donor site using navigation was 4 degrees (standard deviation, 2.3 degrees ; range, 1 degrees -9 degrees ) versus 12 degrees (standard deviation, 5.5 degrees ; range, 5 degrees -24 degrees ) using freehand technique (P < .0001). The recipient plug removal angle using the navigated technique was 3.3 degrees (standard deviation, 2.1 degrees ; range, 0 degrees -9 degrees ) versus 10.7 degrees (standard deviation, 4.9 degrees ; range, 2 degrees -17 degrees ) in freehand (P < .0001). The mean navigated recipient plug placement angle was 3.6 degrees (standard deviation, 2.0 degrees ; range, 1 degrees -9 degrees ) versus 10.6 degrees (standard deviation, 4.4 degrees ; range, 3 degrees -17 degrees ) with freehand technique (P = .0001). The mean height of plug protrusion under navigation was 0.3 mm (standard deviation, 0.2 mm; range, 0-0.6 mm) versus 0.5 mm (standard deviation, 0.3 mm; range, 0.2-1.1 mm) using a freehand technique (P = .0034).
  
  
  CONCLUSIONS
  Significantly greater accuracy and precision were observed in harvesting and placement of the osteochondral grafts in the navigated procedures. Clinical studies are needed to establish a benefit in vivo.
  
  
  CONCLUSIONS
  Improvement in the osteochondral harvest and placement is desirable to optimize clinical outcomes. Navigation shows great potential to improve both harvest and placement precision and accuracy, thus optimizing ultimate surface congruity.
authors.affiliation: Orthopaedic Department, Hospital for Special Surgery, New York, New York, USA.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Koulalis
authors.forename: Paolo
authors.initials: P
authors.lastname: Di Benedetto
authors.forename: Mustafa
authors.initials: M
authors.lastname: Citak
authors.forename: Padhraig
authors.initials: P
authors.lastname: O'Loughlin
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Pearle
authors.forename: Daniel O
authors.initials: DO
authors.lastname: Kendoff
mesh_terms: D054544:Arthroplasty, Subchondral / Q000379:methods*; D016025:Bone Transplantation / Q000379:methods*; D006801:Humans; D007719:Knee Joint / Q000601:surgery; D025321:Surgery, Computer-Assisted