Bursal Acromial Reconstruction (BAR) Using an Acellular Dermal Allograft for Massive, Irreparable Posterosuperior Rotator Cuff Tears: A Dynamic Biomechanical Investigation

To investigate the effect of bursal acromial reconstruction (BAR) using an acellular dermal allograft on glenohumeral joint kinematics including maximum abduction angle, glenohumeral superior translation, cumulative deltoid force, and subacromial contact pressure. In this dynamic biomechanical cadaveric shoulder study, 8 fresh-frozen cadaveric shoulders (age 53.4 ± 14.2 years, mean ± standard deviation) were tested using a dynamic shoulder testing system. Maximum abduction angle (MAA), glenohumeral superior translation (ghST), maximum cumulative deltoid force (cDF), and subacromial peak contact pressure (sCP) were compared across 3 conditions: (1) intact shoulder; (2) massive retracted irreparable posterosuperior rotator cuff tear (psRCT) according to Patte III; and (3) BAR. Additionally, humeral head containment was measured using contact pressure. Compared with the simulated psRCT, BAR significantly increased mean MAA and significantly decreased ghST (P < .001, respectively) and cDF (P = .017) Additionally, BAR was found to significantly decrease sCP compared with psRCT (P = .024). In a dynamic biomechanical cadaveric shoulder simulator, resurfacing the undersurface of the acromion using the BAR technique leads to significantly improved ghST, MAA, cDF, and sCP compared with the irreparable rotator cuff tear. With the BAR technique, native humeral containment may be restored, which can potentially delay progressive subacromial and glenoidal abrasive wear and improve overall shoulder function. As such, the proposed BAR technique can be considered as a technically feasible and potentially cost- and timesaving procedure, as no bone anchors are needed, glenoidal or humeral side graft ruptures can be avoided, and postoperative rehabilitation can be started immediately. However, future clinical studies are needed.