The use of autologous adult, allogenic juvenile, and combined juvenile-adult cartilage fragments for the repair of chondral defects.

Abstract

The goal of the study was to evaluate the repair of chondral lesions treated with combined autologous adult/allogenic juvenile cartilage fragments, compared with isolated adult and isolated juvenile cartilage fragments. Fifty-eight adult (>16week old) and five juvenile (<6week old) New Zealand White female rabbits were used. A large osteochondral defect was created in the center of the femoral trochlea of adult rabbits. The rabbits were divided in four groups: Group 1=untreated defects (controls); Group 2=adult cartilage fragments; Group 3=juvenile cartilage fragments; and Group 4=adult+juvenile cartilage fragments. Killings were performed at 3 and 6months. The defects were evaluated with ICRS macroscopic score, modified O'Driscoll score, and Collagen type II immunostaining. At 3months, Group 4 performed better than Group 1, in terms of modified O'Driscoll score (p=0.001) and Collagen type II immunostaining (p=0.015). At 6months, Group 4 showed higher modified O'Driscoll score (p=0.003) and Collagen type II immunostaining score (p<0.001) than Group 1. Histologically, also Group 3 performed better than Group 1 (p=0.03), and Group 4 performed better than Group 2 (p=0.004). Mixing adult and juvenile cartilage fragments improved cartilage repair in a rabbit model. In the clinical setting, a new "one-stage" procedure combining the two cartilage sources can be hypothesized, with the advantages of improved chondral repair and large defect coverage, because of the use of an off-the-shelf juvenile allograft. Further studies on larger animals and clinical trials are required to confirm these results.