title: Influence of basal support and early loading on bone cartilage healing in press-fitted osteochondral autografts.
abstract: OBJECTIVE
  The influence of basal graft support combined to early loading following an osteochondral autograft procedure is unclear. It was hypothesized that bottomed grafts may allow for early mobilization by preventing graft subsidence and leading to better healing.
  
  
  METHODS
  Osteochondral autografts were press fitted in the femoral condyles of 24 sheep (one graft per animal). In the unbottomed group (n = 12), a gap of 2 mm was created between graft and recipient bone base. In the bottomed group (n = 12), the graft firmly rested on recipient bone. Animals were allowed immediate postoperative weightbearing. Healing times were 3 and 6 months per group (n = 6 per subgroup). After killing, histological and histomorphometric analyses were performed.
  
  
  RESULTS
  Unbottomed grafts at 3 months showed significantly more graft subsidence (P = 0.024), significantly less mineralized bone (P = 0.028) and significantly worse cartilage and subchondral bone plate healing (P = 0.034) when compared to bottomed grafts. At 6 months, no differences were seen. Compared to the native situation, unbottomed grafts showed significantly more graft subsidence (P = 0.024), whereas bottomed grafts did not. Cystic lesions were seen in both groups. Osteoclasts were closely related to the degree of bone remodelling.
  
  
  CONCLUSIONS
  In the animal model, in the case of early loading, bottomed osteochondral autografts have less chance of graft subsidence. Evident subsidence negatively influences the histological healing process. In the osteochondral autograft procedure, full graft support should be aimed for. This may allow for early mobilization, diminish graft subsidence and improve long-term integration.
authors.affiliation: Julius Wolff Institute and Center for Musculoskeletal Surgery and Berlin-Brandenburg Center for Regenerative Therapies, Charité Universitätsmedizin Berlin, Augustenburger Platz 1, Forum 4, Postbox 24, 13353, Berlin, Germany, t.nosewicz@gmail.com.
authors.forename: Tomasz L
authors.initials: TL
authors.lastname: Nosewicz
authors.forename: Mikel L
authors.initials: ML
authors.lastname: Reilingh
authors.forename: Martin
authors.initials: M
authors.lastname: Wolny
authors.forename: C Niek
authors.initials: CN
authors.lastname: van Dijk
authors.forename: Georg N
authors.initials: GN
authors.lastname: Duda
authors.forename: Hanna
authors.initials: H
authors.lastname: Schell
mesh_terms: D000818:Animals; D064592:Autografts; D016025:Bone Transplantation; D001842:Bone and Bones / Q000601:surgery; D002356:Cartilage / Q000637:transplantation; D002358:Cartilage, Articular / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D005269:Femur / Q000601:surgery; D007719:Knee Joint / Q000601:surgery; D023421:Models, Animal; D011897:Random Allocation; D012756:Sheep; D016474:Weight-Bearing / Q000502:physiology*; D014945:Wound Healing / Q000502:physiology