Shoulder Research

Principal Investigators: Scott P. Steinmann, M.D.
Project Coordinator: Mark Zobitz —

Large rotator cuff tears present a challenge to orthopedic surgeons. It is not possible for some rotator cuff tears to be repaired because of a large defect associated with muscle retraction. Because tissue may be insufficient or of inadequate quality to repair, a variety of materials have been used as an adjunct. Over the past year the Biomechanics Laboratory has been active is studying repair methods for massive rotator cuff tears.

In Vitro Analysis of Patch Graft for Rotator Cuff Tear
The purpose of this study was to investigate the use of a synthetic patch graft to restore abduction force transmission in the glenohumeral joint with a rotator cuff defect. Cadaver shoulders (n=10) were fixed in hanging arm and neutral rotation position and loading was applied to the rotator cuff tendons and middle deltoid. In cadaver shoulders a simulated supraspinatus tendon defect and retraction was created and a patch graft was inserted into the defect. The optimum grafting technique for abduction torque restoration occurred with a reduced size patch connected anteriorly to the subscapularis and sutured to the greater tuberosity.

In Vivo Repair of Rotator Cuff Using Acellular Dermal Matrix Graft
In collaboration with Wright Medical Technology ( Arlington, TN), we have undertaken a study to compare the use of an acellular dermal matrix tissue (GraftJacket) to an autologous tendon in a full-thickness infraspinatus tendon tear model in canine. Bilateral surgeries were performed on each dog so comparisons could be directly made between the two repairs. Animals were sacrificed, and shoulders were evaluated histologically and biomechanically at time 0, 6 weeks, 12 weeks, and 24 weeks. Testing and data analysis are currently ongoing.