1. The Biomechanical Relevance of Anterior Rotator Cuff Cable Tears in a Cadaveric Shoulder Model
by Mena M. Mesiha, Kathleen A. Derwin, Scott C. Sibole, Ahmet Erdemir, and Jesse A. McCarron
J Bone Joint Surg Am
Volume 95(20):
October 16, 2013
©2013 by The Journal of Bone and Joint Surgery, Inc.

2. Fig. 1-A Articular side of the supraspinatus showing the silk marking sutures that were passed from the articular to the bursal side of the tendon.
Fig. 1-A Articular side of the supraspinatus showing the silk marking sutures that were passed from the articular to the bursal side of the tendon. Fig. 1-B Bursal side of the supraspinatus tendon showing the location of the corresponding suture knots used for tracking displacements. The positions of the actual suture markers are masked with colored dots to help indicate the anatomic substructures. The dotted lines demarcate the medial outer border and the lateral inner border of the rotator cuff cable.
Mena M. Mesiha et al. J Bone Joint Surg Am 2013;95:
©2013 by The Journal of Bone and Joint Surgery, Inc.

3. Mechanical testing setup.
Mechanical testing setup. Humeri were fixed in aluminum pots and attached to a uniaxial testing machine. The infraspinatus and subscapularis muscle bellies were each clamped and statically loaded with 70 N along their approximated anatomical axes of pull. The supraspinatus muscle belly was gripped with a custom cryoclamp, aligned at approximately 135° with respect to the long axis of the humerus, and cyclically loaded from 10 N to 180 N at 30 mm/min. (Reproduced with permission of the Cleveland Clinic Center for Medical Art & Photography © All rights reserved.)‏
Mena M. Mesiha et al. J Bone Joint Surg Am 2013;95:
©2013 by The Journal of Bone and Joint Surgery, Inc.

4. Schematic of tear protocol.
Schematic of tear protocol. Tears were created with use of a number-11 scalpel blade and a standard ruler. For each specimen, small full-thickness tears were created to match half the measured anteroposterior width of its crescent insertion, and large tears were created to match the total anteroposterior width of its crescent insertion. Small crescent tears were centered on the midpoint of the crescent and were extended anteriorly and posteriorly to create large tears involving the entire crescent footprint. Small cable tears were initiated at the posterior border of the anterior cable insertion and were extended anteriorly to create large tears. The large cable tears always involved the entire cable footprint and, in cases in which the crescent was larger than the cable, also extended through the transverse humeral ligament into the bicipital groove. The asterisk corresponds with the posterior border of the anterior cable insertion. (Reproduced with permission of the Cleveland Clinic Center for Medical Art & Photography © All rights reserved.)‏
Mena M. Mesiha et al. J Bone Joint Surg Am 2013;95:
©2013 by The Journal of Bone and Joint Surgery, Inc.

5. Bursal side of the supraspinatus tendon.
Bursal side of the supraspinatus tendon. Fig. 4-A The tear gap distance was defined as the distance between markers (circled in red) spanning a tear region at 180 N minus the distance between the same markers in the intact condition at 180 N. Fig. 4-B Tendon stiffness was defined as the peak force during cyclic loading (180 N) divided by the average displacement of the three musculotendinous junction markers (orange dots) with respect to the average position of the four bone markers (black dots). Fig. 4-C Von Mises strain was reported for nine elements as they were deformed by a 180-N force (referenced from the 10-N intact condition). The value calculated for the middle of the rotator cuff cable was an area-weighted average of three triangular elements. The colored dots and shapes in these images denote the anatomic substructures and regions.
Mena M. Mesiha et al. J Bone Joint Surg Am 2013;95:
©2013 by The Journal of Bone and Joint Surgery, Inc.

6. Von Mises strains of the nine tendon elements deformed by 180 N of force in the intact and tear conditions.
Von Mises strains of the nine tendon elements deformed by 180 N of force in the intact and tear conditions. Fig. 5-A Regional strains in the loaded, intact supraspinatus tendons prior to creation of the tear were in the expected physiologic range (1% to 6%) and did not differ significantly between the cable and crescent specimens in any region (nine regions: median, p = 0.644). Figs. 5-B and 5-C Regional strains in tendons with crescent tears of either size closely matched the strain distributions and magnitudes of the intact tendons. In contrast, small and large cable tears resulted in an asymmetric strain distribution with strains that were significantly increased compared with that in the intact condition in several regions. The asterisks indicate p values of <0.10, and the red color indicates p values of <0.05 compared with the intact condition.
Mena M. Mesiha et al. J Bone Joint Surg Am 2013;95:
©2013 by The Journal of Bone and Joint Surgery, Inc.