Rotator Cuff Repair Using an Acellular Dermal Matrix Graft: An In Vivo Canine Study

Principal Investigator: Scott P. Steinman, M.D.
Project Coordinator: Mark E. Zobitz— zobitz.mark@mayo.edu

Figure 1: An intraoperative view of the acellular dermal matrix repair.

Large rotator cuff tears present a challenge to orthopedic surgeons. Because tissue may be insufficient or of inadequate quality to repair, a variety of materials have been used as an adjunct. Human dermal tissue may be processed to render it acellular, and thus less immunogenic, but with the extracellular matrix left intact, creating a collagen scaffold with favorable characteristics. Because of these traits, use of this material in rotator cuff repair was proposed.

A canine model for a full-thickness infraspinatus tendon tear was used. Tendon was excised from the bony interface to the myotendinous junction, and human acellular dermal matrix graft (experimental) or the autologous excised tendon (control) was used to bridge the defect (Fig. 20). Animals were sacrificed, and shoulders were evaluated histologically and biomechanically. At time = 0, strength of the control and experimental repairs were similar. At 6-weeks, the strength of experimental was half that of the control side. Strength of the control specimens remained the same at 6 and 12 weeks, but by 12 weeks, the strength of the experimental repair was equal to the control. Histologically, cells infiltrated the grafts by 6 weeks, with chronic inflammation consistent with surgery and repair. Use of human acellular dermal matrix as a patch is a viable option in this model of large rotator cuff defects. No failures were noted, and by six weeks, histological evidence of native cell infiltration and neotendon development was observed. By 12-weeks, the strength of the dermal matrix graft repair was equivalent to that of autologous tendon. Further studies are indicated to determine the role of this material in the treatment of full-thickness rotator cuff tears in humans.