ABSTRACT
BACKGROUND: The aim of this study was to investigate the effect of combining rhFGF18 or BMP-7 with a biphasic collagen/GAG osteochondral scaffold (Chondromimetic) on the repair of osteochondral defects in sheep. METHODS: Osteochondral defects (5.8x6mm) were created in the medial femoral condyle (MFC) and the lateral trochlea sulcus (LTS) of the stifle joint of 24 female sheep. Sheep were randomly assigned to four groups (n = 6); 1) empty defect, 2) scaffold only, 3) scaffold + rhFGF-18 (30 µg) and 4) scaffold + BMP-7 (100 µg). At 6 months the defects underwent non-destructive mechanical testing, gross assessment of repair tissue (ICRS score) and histological analysis (Modified O'Driscoll score). RESULTS: ICRS repair score: Defects treated with scaffold + rhFGF18 (mean 9.83, 95% CI 8.43-11.23) and scaffold + BMP-7 (10, 9.06-10.94) in the MFC had significantly improved ICRS scores compared to empty defects (4.2, 0-8.80) (p = 0.002). Mechanical properties: BMP-7 treated defects (mean 64.35, 95% CI 56.88-71.82) were significantly less stiff than both the rhFGF18 (mean 84.1, 95% CI 76.8-91.4) and empty defects in the LTS, compared to both contralateral limb (p = 0.003), and the perilesional articular cartilage (p < 0.001). HISTOLOGY: A statistically significant improvement in the modified O'Driscoll score was observed in the rhFGF18 treated group (mean 16.83, 95% CI 13.65-20.61) compared to the empty defects (mean 9, 95% CI 4.88-13.12) (p = 0.039) in the MFC. Excellent tissue fill, lateral integration and proteoglycan staining was observed. Only the rhFGF18 defects showed pericellular type VI collagen staining with positive type II collagen and reduced positive type I collagen staining. The majority of defects in the control and BMP-7 groups demonstrated fibrocartilagenous repair tissue. CONCLUSION: Statistically significant improvements in gross repair, mechanical properties and histological score were found over empty defects when Chondromimetic was combined with rhFGF18. These results suggest that rhFGF18 may play a significant role in articular cartilage repair applications.
ABSTRACT
OBJECTIVE: This study investigates the combination of platelet-rich plasma (PRP) or concentrated bone marrow aspirate (CBMA) with a biphasic collagen/glycosaminoglycan (GAG) osteochondral scaffold for the treatment of osteochondral defects in sheep. DESIGN: Acute osteochondral defects were created in the medial femoral condyle (MFC) and the lateral trochlea sulcus (LTS) of 24 sheep (n = 6). Defects were left empty or filled with a 6 × 6-mm scaffold, either on its own or in combination with PRP or CBMA. Outcome measures at 6 months included mechanical testing, International Cartilage Repair Society (ICRS) repair score, modified O'Driscoll histology score, qualitative histology, and immunohistochemistry for type I, II, and VI collagen. RESULTS: No differences in mechanical properties, ICRS repair score, or modified O'Driscoll score were detected between the 4 groups. However, qualitative assessments of the histological architecture, Safranin O content, and collagen immunohistochemistry indicated that in the PRP/scaffold groups, there was a more hyaline cartilage-like tissue repair. In addition, the addition of CBMA and PRP to the scaffold reduced cyst formation in the subchondral bone of healed lesions. CONCLUSION: There was more hyaline cartilage-like tissue formed in the PRP/scaffold group and less subchondral cystic lesion formation in the CBMA and PRP/scaffold groups, although there were no quantitative differences in the repair tissue formed.
