Effectiveness of Adhering Adipose-Derived Stem Cells to Defective Cartilage in Promoting Cartilage Regeneration in a Rabbit Model

Purpose: To evaluate the therapeutic effect of using a local adherent technique to transplant adipose-derived stem cells (ADSCs) for cartilage regeneration in a rabbit model for patients with traumatic damage or osteochondritis dissecans. Methods: Cartilage defects were created in the trochlear groove of 60 adult white rabbit knees. The rabbits were either left untreated (control group), treated with intra-articularly injected ADSCs (injected group), or treated by adhering ADSCs (adherent group). The 3 groups were compared at 4, 12, and 24 weeks postoperatively using the International Cartilage Repair Society macroscopic scoring system and a modified Wakitani histologic grading system to quantitatively evaluate the regenerated cartilage. The degree of defect repair, integration to the border zone, macroscopic appearance, cell morphology, matrix staining, surface regularity, cartilage thickness, and integration of the donor with the host were evaluated. Results: The mean International Cartilage Repair Society scores in the control, injected, and adherent groups were 6.4 +/- 2.9, 7.6 +/- 0.8, and 7.6 +/- 1.4, respectively, at 4 weeks; 6.2 +/- 2.4, 8.2 +/- 1.5, and 9.6 +/- 1.0, respectively, at 8 weeks; and 7.6 +/- 1.0, 8.4 +/- 1.4, and 10.2 +/- 1.7, respectively, at 24 weeks. Although the scores were higher in the adherent group, no significant difference was noted. The mean modified Wakitani scores in the control, injected, and adherent groups were 3.8 +/- 2.0, 5.1 +/- 1.8, and 7.8 +/- 1.3, respectively, at 4 weeks (P = .041); 5.1 +/- 1.0, 5.4 +/- 2.7, and 9.6 +/- 1.4, respectively, at 12 weeks (P = .016); and 5.4 +/- 1.0, 5.9 +/- 1.5, and 9.8 +/- 1.8, respectively, at 24 weeks (P = .007). Conclusions: The histologic modified Wakitani scores showed that adhering ADSCs to osteochondral cartilage defects was more effective than intra-articular injection for promoting cartilage regeneration.