Objective: The aim of this study was to evaluate and compare the effects of injectable platelet-rich fibrin (I-PRF) and concentrated growth factor (CGF) on tendon-to-bone interface healing in a rabbit model of rotator cuff tear. Methods: A full-thickness supraspinatus tendon tear was surgically induced in both shoulders of 18 adult New Zealand White rabbits. The animals were randomly assigned into 3 groups: Group 1 received CGF, Group 2 received I-PRF, and Group 3 served as the control group with no biological augmentation. In Groups 1 and 2, CGF and I-PRF were applied to the repair site of the rotator cuff tendon following surgical reattachment. Six weeks postoperatively, all rabbits were sacrificed. The supraspinatus tendon along with the humeral head was harvested. Histological analysis was performed on specimens from the left shoulders, while biomechanical testing was conducted on those from the right shoulders. Biomechanical evaluation included measurements of failure load and elongation. Histological and immunohistochemical assessments were carried out using the Nourissat tendon–bone interface scoring system. Results: Biomechanical testing demonstrated that the CGF group exhibited significantly greater failure load compared to the other groups P = .001. Mean elongation values were 3.9 mm in the CGF group, 3.1 mm in the I-PRF group, and 2.5 mm in the control group, with a statistically significant difference favoring CGF P = .03. Although no significant differences were observed among the groups regarding cell density at the tendon-bone interface P = .237 or chondrocyte organization P = .327, the CGF group showed significantly higher scores for type 2 collagen content P = .0001, glycosaminoglycan content P = 0.001, and collagen fiber organization P = .004. Conclusion: The application of CGF significantly enhanced tendon-to-bone healing in a rabbit rotator cuff repair model when compared to I-PRF, as evidenced by superior biomechanical and histological outcomes. Cite this article as: Sözgen E, Önal MS, Yörükoğlu A.. Comparison of the effects of injectable platelet-rich fibrin (I-PRF) and concentrated growth factor (CGF) on tendon-bone interface healing in the rabbit rotator cuff tear model. Acta Orthop Traumatol Turc., 2026; 60(2), 0431, doi: 10.5152/j.aott.2026.25431.
Sözgen et al. (Sun,) studied this question.