Semi–Bone Tunnel Technique Using Double-Row Suture Bridge Combined With Platelet-Rich Plasma Hydrogel for Rotator Cuff Repair in a Rabbit Model

Background: The approach to managing the footprint area and reconstructing the tendon-bone interface (TBI) is critical for optimal healing. Purpose: To evaluate the outcomes of the semi–bone tunnel (SBT) technique using a double-row suture bridge combined with platelet-rich plasma (PRP) hydrogel for rotator cuff repair in a rabbit model. Study Design: Controlled laboratory study. Methods: A total of 48 New Zealand White rabbits were divided into 4 groups. The supraspinatus tendons were severed at the footprint to create a rotator cuff tear model in the surgical groups. Rabbits were treated with the traditional onto-surface repair (control group), SBT technique (SBT group), and SBT technique combined with PRP hydrogel implantation (SBT+PRP group). The rabbits without surgery were the normal group. At 8 weeks after surgery, macroscopic observation, magnetic resonance imaging (MRI) and micro–computed tomography (μCT) examinations, histological evaluations, and biomechanical tests were performed to assess the curative effects of the given treatments. Results: The MRI results showed that the repaired supraspinatus tendon presented a uniform signal, minimal inflammatory response, and the lowest signal-to-noise quotient value in the SBT+PRP group. The μCT results suggested that the SBT technique did not reduce the local bone mineral density in the TBI area compared with the onto-surface repair technique. The histological staining results showed that the regenerated TBI in the SBT+PRP group had a 4-layer structure similar to the natural tissue. The highest values for biomechanical properties were observed in the SBT+PRP group, and there was no significant difference between the SBT+PRP group and normal group. Conclusion: The SBT technique presented a better tendon-bone healing effect for rotator cuff tear in the rabbit model compared with the traditional onto-surface repair technique. The specimens in the SBT+PRP group had a similar TBI structure and biomechanical properties to the natural tissue. Clinical Relevance: The SBT technique can be an alternative surgical approach for rotator cuff repair, especially for moderate to large tears and cases requiring scaffold implantation.