Biceps Augmentation Outperforms Tear Completion Repair or In Situ Repair for Bursal-Sided Partial-Thickness Rotator Cuff Tears in a Rabbit Model

Abstract

Background: There is an ongoing debate on the treatment of bursal-sided partial-thickness rotator cuff tears (PTRCTs), including ideal repair techniques. Augmentation using a collagen patch has been introduced as a new surgical approach to treat PTRCTs, while the effect of autogenous biceps augmentation (BA) has not been investigated. Purpose: To analyze the effects of BA on bursal-sided PTRCTs and compare its histological and biomechanical results with those of tear completion followed by repair and in situ repair (ISR). Study Design: Controlled laboratory study. Methods: Unilateral chronic PTRCTs were created in 96 mature New Zealand White rabbits, which were randomly divided into 4 groups: no repair, tear completion repair (TCR), ISR, and BA. A new bicipital groove was fabricated in BA for the biceps tendon that was transferred to augment the bursal-sided PTRCT repair. In each group, we sacrificed 6 rabbits for biomechanical testing of the whole tendon-to-bone complex (WTBC) and 6 for histological evaluation of bursal- and articular-sided layers at 6 and 12 weeks postoperatively. Healing responses between the biceps and new bicipital groove in the BA group were determined using histological analysis, and final groove morphologies were evaluated using micro–computed tomography. Results: The remaining tendon and enthesis in bursal-sided PTRCTs progressively degenerated over time. WTBCs of ISR exhibited a larger failure load than those of TCR, although better healing properties in the bursal-sided repaired site were achieved using TCR based on histological scores and superior articular-sided histological scores were observed using ISR. However, WTBCs of BA displayed the best biomechanical results and superior histological scores for bursal- and articular-sided regions. The new bicipital groove in BA remodeled over time and formed similar morphologies to a native groove, which provided a mature bone bed for transferred biceps tendon healing to augment bursal-sided PTRCTs. Conclusion: BA achieved better biomechanical and histological results for repairing bursal-sided PTRCTs as compared with TCR and ISR. When compared with that of TCR, the WTBC of ISR exhibited a higher failure load, showing histological superiority in the articular-sided repair and inferiority in the bursal-sided repair. Clinical Relevance: BA may be an approach to improve bursal-sided PTRCT repair in humans, which warrants further clinical investigation.

An Arthroscopy-Assisted Mini-Invasive Technique to Create a Chronic Rabbit Model With Massive and Retracted Supraspinatus Rotator Cuff Tears

“…In recent rabbit studies on rotator cuff diseases, the chronic RCT model has been highlighted and described in detail to simulate the chronic inflammatory status with degenerative tissues in humans as much as possible. 6 , 11 , 14 However, the open surgery for generating chronic RCT model, especially for massive tears, inevitably results in additional injuries of adjacent anatomical structures when establishing both a longer surgical incision and a larger surgical approach. 20 , 21 In this context, the undue acute inflammatory responses, local tissue infections, subsequent excessive tissue adhesion, long-term postoperative pain, and shoulder movement disorder can be caused by open surgery.…”

“… 5 , 6 , 7 , 8 , 9 Numerous basic studies have used rabbit models to investigate rotator cuff diseases and healing capacities after rotator cuff repair. 10 , 11 , 12 , 13 , 14 , 15 , 16 The rabbit model of RCT is important because it is a reasonable and reliable animal model, and findings from such studies may accurately reflect the chronic and degenerative status of RCTs in humans. However, in these studies, rotator cuff repairs were performed using an acute tear model or a chronic tear model created by an open surgery.…”

Biomechanical and Histological Results of Dual-Suspensory Reconstruction Using Banded Tendon Graft to Bridge Massive Rotator Cuff Tears in a Chronic Rabbit Model

“…Then the partial distal tendon (~3 to 4 mm long; medial-lateral direction) of the detached supraspinatus was resected so that a full-thickness, U-shaped defect was created (see Appendix Figure A1, a-c, available in the online version of this article). 51,55 The remaining tendon end was braided for free retraction to prevent spontaneous healing, followed by routine incision closure.…”

“…The humeral shaft was rigidly potted into a polyvinyl chloride (PVC) cylinder with plaster, and the distal supraspinatus was covered with polyester cloth and braided using a whipstitch technique to ensure a strong fixation by a custom clamp (Figure 3, inset). 37,43,51 The PVC cylinder was rigidly clamped in a custom jig and secured by a K-wire. The tensile tension of the supraspinatus was tested in a direction parallel to the longitudinal axis of the humerus.…”

The Plug-Type Patch Results in Immediate and Postoperative Advantages in Graft-to-Bone Integration for Bridging Massive Rotator Cuff Tears in a Chronic Rabbit Model

“…Moreover, inflammatory tissues were identified as the light yellow, shiny, and loose tissues with oozing bright fluid exudated. 50,57,58 All complexes for postoperative biomechanical analysis were tested using the same method, with the same parameters noted.…”