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.