Oslo Sports Trauma Research Center

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Information about project titled 'Optimal microenviroment for cartilage repair: vascular or avascular?'

Optimal microenviroment for cartilage repair: vascular or avascular?

Details about the project - category Details about the project - value
Project status: Published
Project manager: Asbjørn Årøen
Supervisor(s): Lars Engebretsen
Coworker(s): Jan Erik Madsen, Finn Reinholt, Stig Heir, Sverre Løken


Full thickness cartilage lesions of the knee which could be suitable for surgical treatment is found in 11 % of all arthroscopies of the knee. Often this injury is seen in young active patient and it is estimated to be associated with a considerable danger of later degenerative osteoarthritis.

Today two cell-based therapies for surgical treatment are commonly used in orthopedic practice. Microfracture is done arthroscopically by special designed awls to make penetration of the subchondral boneplate to provide access for bone marrow stamcells to migrate to the defect and later differentiate to cartilage like tissue both biological and biomechanical. An alternatively technique though rather expensive is to harvest cells from a non weightbearing area in the joint. These cells will be expanded in culture to be reimplanted a few weeks later under a periosteum flap attached by sutures and sealed with Tissel glue. This creates an avascular chamber, which facilitates the repair of hyaline like cartilage without any damage to the subchondral boneplate.


This study utilize a experimental model in rabbits using a standardized injury induced by a sharp 4 mm biopsy punch in patella. Two weeks later the defect is repaired under microscopy. The two week interval between injury and repair is to simulate clinical situation treating a chronic lesion. Both knees in every experimental animal are used so that each animal can be it's own control. One side gets a vascular technique where a handdriven drill is used to create four penetrations of the subchondral boneplate before a periostflap is sutured to the edges of the lesion and as an addition sealed by Tissel glue. The other side is treated equally except for the penetration of the subchondral boneplate to induce an avascular chamber.

Periosteum flap is harvested from the anterior proximal part of tibia. Synovial fluid is sampled before inducing cartilage injury, at time of repair and at end of experimental period. All rabbits are treated preoperatively with Vibramycin antibiotics and for five days postoperatively additional to painrelief with morphine (Temgesic). Only adult female rabbits age 20-22 weeks are used and one week after second operation they are set housed on the floor to induce normal activity and use of the knees. The rabbits are observed for 36 weeks after second operation to ensure complete maturation of the repair cartilage. At the sacrifice of the rabbits the defects are evaluated macroscopically, histological and biochemically.

This study evaluates a proposed main difference between the cell based cartilage repair methods. It will also facilitate the development of more proper biological handling of these challenging injuries.