title: Cylindrical press-fit osteochondral allografts for resurfacing the equine metatarsophalangeal joint.
abstract: OBJECTIVE
  To investigate the feasibility of resurfacing the equine fetlock joint using cylindrical, orthotopic, press-fit, osteochondral allografts.
  
  
  METHODS
  Experimental study.
  
  
  METHODS
  Ten mature, mixed-breed horses.
  
  
  METHODS
  Cylindrical, osteochondral grafts (6.5-mm diameter) were harvested aseptically from cadaveric equine metatarsophalangeal joints. Allografts were transplanted into 6 horses; 4 horses were sham operated. The surgical approach involved creation of a bone block at the origin of the medial collateral ligament and luxation of the metatarsophalangeal joint. Grafts were placed into the medial and lateral metatarsal condyles. Radiographs were taken at 8 and 25 weeks, and lameness was evaluated at 25 weeks. Horses were killed at 25 weeks. Analyses included gross evaluation, microradiography, paravital staining, light microscopy, and cartilage biochemistry.
  
  
  RESULTS
  No complications occurred that could be attributed to the surgical procedure. Graft congruency with the surrounding articular cartilage was fair to excellent. Two horses were sound at 25 weeks. Most grafts had more than 90% articular cartilage coverage, and histologic and microradiographic analysis revealed good graft incorporation and articular cartilage survival. Sulphated glycosaminoglycan concentration was decreased in grafted tissue.
  
  
  CONCLUSIONS
  We attribute the viability of osteochondral allografts in the equine fetlock to adequate congruency, stable graft fixation, and the use of orthotopic tissue. Host response to the allograft bone tissue did not affect cartilage viability.
  
  
  CONCLUSIONS
  Before clinical use, improvements to instrumentation are required that would decrease damage to grafts and minimize technique-associated incongruencies of the articular surface at the time of grafting. Larger grafts would also likely be required to resurface a greater surface area.
authors.affiliation: Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Simon G
authors.initials: SG
authors.lastname: Pearce
authors.forename: Mark B
authors.initials: MB
authors.lastname: Hurtig
authors.forename: Ludovic P
authors.initials: LP
authors.lastname: Boure
authors.forename: Rolfe M
authors.initials: RM
authors.lastname: Radcliffe
authors.forename: Dean W
authors.initials: DW
authors.lastname: Richardson
mesh_terms: D000818:Animals; D016025:Bone Transplantation / Q000662:veterinary*; D002358:Cartilage, Articular / Q000637:transplantation*; D005260:Female; D006085:Graft Survival; D006736:Horses / Q000601:surgery*; D008297:Male; D008683:Metatarsophalangeal Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D011859:Radiography; D014184:Transplantation, Homologous / Q000662:veterinary*