Massive,irreparable rotator cuff tears (RCT) in patients without severe signs of osteoarthritis remains a major challenge for orthopaedic surgeons. However, conventional superior capsular reconstruction (SCR) is noted to be technically complex time-consuming and high-cost surgery, which may put this technique beyond the confidence of many shoulder surgeons. The Bursal Acromial Reconstruction (BAR) presents a technique using an acellular human dermal allograft to reconstruct the bursal layer, which is normally interposed between the humeral head and the acromion and provides a permanent inter-position graft preventing humeral acromial contact,which does not undergo rapid bio-degradation.
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.
Study Design: Controlled laboratory study
Eight fresh-frozen cadaveric shoulders (mean age: 53.4 ± 14.2 years) were tested using a dynamic shoulder testing system. Maximum abduction angle, glenohumeral superior translation, cumulative deltoid force, and subacromial contact pressure were compared across three conditions: (1) intact shoulder; (2) massively retracted irreparable posterosuperior rotator cuff tear (RCT); (3) BAR using an acellular dermal allograft. Additionally, humeral head containment was measured using pressure sensitive foils.
Compared to intact shoulders, the posterosuperior RCT significantly decreased maximum abduction angle (61% of intact; P<.001), while significantly increasing glenohumeral superior translation (159% of intact; P<.001), cumulative deltoid force (121% of intact; P<.001), and peak subacromial contact pressure (296% of intact; P<.001). Subsequently, the BAR technique significantly increased mean maximum glenohumeral abduction (P<.001), while significantly decreasing glenohumeral superior translation (P<.001), cumulative deltoid force (P=.017), and subacromial peak contact pressure (P=.024) when compared to the irreparable posterosuperior RCT.
In a dynamic biomechanical cadaveric shoulder simulator, resurfacing the undersurface of the acromion using the BAR technique significantly increased mean maximum glenohumeral abduction, while significantly decreasing glenohumeral superior translation, required compensatory deltoid forces, and subacromial contact pressure when compared to an irreparable posterosuperior RCT.
Clinical Relevance: By using the BAR technique, native humeral containment may be restored which can potentially delay progressive subacromial and glenoidal abrasive wear and improve overall shoulder function. 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, while allowing for immediately starting postoperative rehabilitation.
Key Terms: Rotator Cuff Tear; Irreparable Rotator Cuff Tear; BAR; Bursal Subacromial Reconstruction; Biomechanics