Tokish, John M.

Abstract Glenoid bone loss is a common sequela of recurrent anterior shoulder instability. When treated surgically, a bone augmentation procedure is more likely to provide a good outcome with a lower risk of recurrent instability compared with a soft‐tissue repair alone. There are several bone augmentation options to address glenoid bone loss, including coracoid transfer, iliac crest autograft, and distal tibial allograft (DTA). Both open and arthroscopic DTA techniques have been described using the lateral one‐third of the distal tibia oriented with the anterior aspect placed superiorly on the anterior glenoid. This graft orientation places its concavity in the superior‐to‐inferior direction. It may be preferred to have this concavity maximized toward the anterior direction so that it can further resist anterior displacement. The posterior one‐third of the distal tibia may provide a more optimal arc of resistance. However, no previous technique has used the posterior one‐third of the distal tibia to reconstruct the “half‐pipe” concavity of the anterior glenoid. We describe an all‐arthroscopic technique for a posterior third DTA oriented with the posterior tibial edge placed anteriorly on the glenoid, termed the “congruent‐arc DTA,” to address anterior shoulder instability with bone loss. Technique Video video See video under supplementary data.

Purpose To evaluate the effects of this graft preparation technique on histologic evidence of tenocyte mechanical damage. Methods A consecutive series of patients undergoing biceps tenodesis for shoulder pathology were evaluated. After suprapectoral tenodesis, 27 mm of the long head of the biceps was secured for compression into the patch. The remaining length of the residual tendon was longitudinally split, resulting in 2 equal lengths of remnant tendon from the same zone. One sample was sent to pathology with no preparation, and the other was prepared as a compressed biceps autograft patch according to the manufacturer’s recommendations. Both grafts were sent to pathology for evaluation of tenocyte morphology. Records were reviewed to determine if compression resulted in mechanical damage to the tenocytes at the time of biceps augmentation. Results Fifty‐five shoulder procedures and 110 samples were sent for pathology analysis. Forty‐two of the 55 (76%) specimens demonstrated morphologically normal tenocytes in both the compressed and noncompressed groups, and 7 (13%) cases showed evidence of tenocyte necrosis or mechanical damage in both groups. The difference in abnormal tenocyte morphology between the compressed and native groups was not statistically significant ( P = .625). Conclusions Autograft biceps compression into a point‐of‐care patch did not result in mechanical damage to tenocyte morphology at the time of insertion for augmentation of rotator cuff pathology. Clinical Relevance Free proximal biceps tendon compression can result in a patch that does not mechanically damage the tenocyte. The patch can be used as a biologic autograft to enhance shoulder rotator cuff repair, as well as subscapularis repair in the setting of shoulder arthroplasty.

Background: Irreparable posterosuperior rotator cuff (PSRC) tears have been shown to result in shoulder pain and loss of function. Purpose/Hypothesis: The purpose of this study was to determine the effect of the loss of active or passive function of the PSRC on compensatory muscle loads in the deltoid and the remaining rotator cuff. It was hypothesized that both deactivation and resection of the PSRC would result in load increases in the remaining muscles and that resection of the PSRC would result in even higher required compensatory forces than would mere deactivation. Study Design: Controlled laboratory study. Methods: A total of 7 cadaveric shoulders were tested using a biomechanical shoulder simulator with 10 independently controlled actuators for various muscles (anterior, middle, and posterior deltoid; inferior and superior subscapularis; latissimus dorsi; pectoralis major; teres minor; supraspinatus; and infraspinatus) and 3-dimensional motion tracking. The muscle loads representing the latissimus dorsi and pectoralis major were each held constant, and the remaining muscle actuator forces required to abduct the arm in the scapular plane were determined. The actuator forces corresponding with arm elevation from 20° to 65° were compared at 5° increments for 3 testing conditions: (1) intact, active PSRC; (2) intact, deactivated PSRC; and (3) resected PSRC and shoulder capsule. Results: In both the deactivated and resected states, the teres minor showed a significant increase in required muscle forces through nearly the entire tested range of arm elevation compared to the active state. This was also the case for the subscapularis but only at higher elevation angles. The deltoid demonstrated increased muscle forces of at least 1 of its subunits between 25° and 55° of elevation when comparing the deactivated state or resected state to the active state. However, through nearly the entire range of elevation, no statistically significant differences were found between the deactivated and resected states for any of the actuator loads representing muscle forces. Conclusion: The loss of active function of the PSRC led to compensatory loads on the remaining rotator cuff and deltoid, regardless of the passive presence of the PSRC as a supposed subacromial spacer. Clinical Relevance: The findings encourage the exploration of treatment procedures that mimic the active function of the PSRC when the rotator cuff itself is irreparable.