Repair of an Osteochondral Defect With Minced Cartilage Embedded in Atelocollagen Gel: A Rabbit Model.

BACKGROUND: Autologous chondrocyte implantation (ACI) is often performed for large cartilage defects. Because this technique has several disadvantages, including the need for second-stage surgery, cartilage repair using minced cartilage has been suggested. However, this technique could be improved using 3-dimensional scaffolds. PURPOSE: To examine the ability of chondrocyte migration and proliferation from minced cartilage in atelocollagen gel in vitro and evaluate the repairable potential of minced cartilage embedded in atelocollagen gel covered with a periosteal flap in a rabbit model. STUDY DESIGN: Controlled laboratory study. METHODS: Minced cartilage or isolated chondrocytes from rabbits were embedded in atelocollagen gel and cultured for 3 weeks. Chondrocyte proliferation and matrix production were evaluated in vitro. An osteochondral defect at the trochlear groove was created in 56 rabbits, which were divided into 4 groups. The defect was left empty (defect group), filled with allogenic minced cartilage (minced cartilage group), filled with isolated allogenic chondrocytes embedded in atelocollagen gel (ACI group), or filled with atelocollagen gel (atelocollagen with periosteal flap group). At 4, 12, and 24 weeks after surgery, repair of the defect was evaluated in these 4 groups. RESULTS: In vitro, the number of chondrocytes and abundant matrix on the surface of the gel significantly increased in the minced cartilage group compared with the ACI group (P < .05). In vivo, the minced cartilage and ACI groups showed good cartilage repair compared with the empty defect and atelocollagen/periosteal flap groups (P < .05); there was no significant difference in the Pineda score between the minced cartilage and ACI groups. CONCLUSION: Minced cartilage in atelocollagen gel had good chondrocyte migration and proliferation abilities in vitro, and osteochondral defects were well repaired by implanting minced cartilage embedded in the atelocollagen gel in vivo. Implantation of minced cartilage embedded in atelocollagen gel showed good cartilage repair equivalent to ACI. CLINICAL RELEVANCE: Implantation of minced cartilage embedded in atelocollagen gel as a 1-step procedure has outcomes similar to those of ACI but is cheaper and more convenient than ACI.