A capsular incision leads to a fast osteoarthritic response, but also elevated levels of activated osteogenic protein-1 in rabbit knee joint cartilage.
We studied whether a small capsular incision alone, or combined with meniscectomy could induce early osteoarthritic changes in the rabbit knee. Thirty-one rabbits were operated on with a capsular incision in the left knee and meniscectomy in the right knee. Another 12 rabbits were used as controls. The rabbits were killed 3, 6 and 12 weeks after surgery. Osteoarthritic changes in the articular cartilage were evaluated by the modified Mankin score. The subchondral bone was evaluated by scintimetry ((99m)Tc-HDP) and semiquantitative grading of histological changes. Osteogenic protein (OP-1) in its mature and pro-form was examined by immunohistochemistry. Both a capsular incision and meniscectomy induced articular cartilage fibrillation and increased bone metabolic activity during the initial weeks after surgery. Capsular incision led to lesser changes than meniscectomy. Mature OP-1 was elevated, and its pro-form reduced, in meniscectomized knees. A similar pattern was observed in knees with capsular incision. Already 3 weeks after surgery, the articular cartilage and subchondral bone showed typical signs of early osteoarthritis (OA), and a reparative response was suggested by increased intensity of OP-1 staining. As these signs were also found in knees with capsular incision only, it appears that trauma-related factors such as increased bleeding and inflammation are critical for the development of OA.
Fahlgren
A
A
Division of Orthopaedics and Sports Medicine, Department of Neuroscience and Locomotion, Faculty of Health Sciences, Linköping University, Linköping, Sweden. Anna.Fahlgren@inr.liu.se
Chubinskaya
S
S
Messner
K
K
Aspenberg
P
P
D000818:Animals; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins / Q000378:metabolism*; D016723:Bone Remodeling; D002358:Cartilage, Articular / Q000378:metabolism* / Q000473:pathology; D005269:Femur / Q000473:pathology; D007150:Immunohistochemistry; D017746:Joint Capsule / Q000473:pathology / Q000601:surgery*; D007719:Knee Joint / Q000473:pathology / Q000601:surgery; D008592:Menisci, Tibial / Q000601:surgery; D020370:Osteoarthritis, Knee / Q000378:metabolism* / Q000473:pathology*; D011817:Rabbits; D019275:Radiopharmaceuticals; D013669:Technetium Tc 99m Medronate / Q000031:analogs & derivatives; D013977:Tibia / Q000473:pathology; D016212:Transforming Growth Factor beta / Q000378:metabolism*
D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins; D019275:Radiopharmaceuticals; D016212:Transforming Growth Factor beta; C024226:technetium Tc 99m hydroxymethylene diphosphonate; D013669:Technetium Tc 99m Medronate