Osteochondral autograft transplantation in the porcine knee.
BACKGROUND
Knee articular cartilage defects are not an uncommon problem. Because articular cartilage is limited in its ability to heal, these defects are difficult to manage.


OBJECTIVE
Osteochondral autografts will provide less of a cavitary defect and more viable hyaline articular cartilage than will control knees.


METHODS
Controlled laboratory study.


METHODS
Osteochondral autografts were grossly and microscopically evaluated in the porcine knee and compared with a control at 6 weeks, 3 months, and 6 months. In 18 porcine specimens, a 1-stage surgical procedure was performed to harvest an osteochondral graft from a nonweightbearing articular cartilage surface, and the graft was transplanted into a defect created in the weight-bearing region of the medial femoral condyle. In the opposite control knee, a similar defect was created in the medial femoral condyle; an osteochondral transplant was not performed. Six pigs each were sacrificed at 6 weeks, 3 months, and 6 months.


RESULTS
Gross inspection of the control knees showed a cavitary defect. The defect grossly decreased in size with fibrous ingrowth seen on microscopic analysis. An increasing amount of fibrous tissue and fibrocartilage was present at the 3 time periods. Gross inspection of the graft knee showed a healed osteochondral plug with no obvious displacement, cavitary defects, or surrounding necrotic tissue at each time interval. Microscopic analysis revealed the graft knee contained viable hyaline cartilage and healed viable subchondral bone. At all time intervals, 75% to 100% of the hyaline cartilage was viable in all specimens. In 6-month specimens, bridging cartilage at the autograft-host junction was incomplete in 50%, partial in 33%, and complete in 17%.


CONCLUSIONS
Osteochondral autografts in the porcine knee resulted in viable hyaline cartilage for up to 6 months; there was inconsistent bridging hyaline cartilage at the periphery. Grafts appeared to heal into existing subchondral bone without displacement or evidence of necrosis.


CONCLUSIONS
This type of osteochondral transplant can be used as a reliable reconstructive alternative for osteochondral defects.
Harman
Bradley D
BD
Department of Orthopaedic Surgery and Rehabilitation, Texas Tech University Health Science Center, 3601 4th Street STOP 9436, Lubbock, Texas 79430, USA. bcole@ortho4.pro.rpslmc.edu
Weeden
Steven H
SH
Lichota
Derek K
DK
Brindley
George W
GW
D000818:Animals; D002358:Cartilage, Articular / Q000473:pathology / Q000637:transplantation*; D007719:Knee Joint / Q000473:pathology / Q000601:surgery*; D013552:Swine; D014182:Transplantation, Autologous / Q000473:pathology