A new approach to superior capsular reconstruction with hamstring allograft for irreparable posterosuperior rotator cuff tears: a dynamic biomechanical evaluation

Abstract

Background: Superior capsular reconstruction (SCR) treatment of massive, symptomatic, irreparable rotator cuff tears (RCTs) has become a more recently used procedure. However, there is a lack of consensus surrounding optimal graft choice for the SCR technique, and current dermal grafts have increased cost and are technically challenging because of a need for multiple implants. The purpose of this study was to biomechanically investigate a biological lower-cost alternative as a support for the superior capsule reconstruction concept: an isolated semitendinosus tendon (STT) allograft and a combination graft with the long head of the biceps tendon (LHBT) in an established massive posterosuperior RCT cadaver model. Methods: Ten fresh-frozen cadaveric shoulders (53.3 AE 12.4 years: range: 26-65) were tested on an established dynamic shoulder simulator using dynamic muscle loading. Cumulative deltoid forces, maximum abduction angle, and superior humeral head translation were compared across 4 testing conditions: (1) intact state, (2) massively retracted (Patte III), irreparable posterosuperior RCT, (3) SCR repair using an STT allograft, and (4) SCR repair using a combined STT-LHBT repair. Results: Intact shoulders required a mean deltoid force of 154.2 AE 20.41 N to achieve maximum glenohumeral abduction (55.3 AE 2.3 ). Compared with native shoulders, the maximum abduction angle decreased following a massively retracted posterosuperior RCT by 52% (28.3 AE 8.4 ; P < .001), whereas the cumulative deltoid forces increased by 48% (205.3 AE 40.9 N; P ¼ .001). The STT repair and the STT-LHBT repair improved shoulder function compared with the tear state, with a mean maximum abduction angle of 30.6 AE 9.0 and 31.8 AE 7.7 and a mean deltoid force of 205.3 AE 40.9 N and 201.0 AE 34.0 N, respectively, but this was not statistically significant (P > .05). The STT-LHBT repair significantly improved the range of motion with respect to the tear state (P ¼ .04). Conclusions: In a dynamic shoulder simulator model, both the STT and the STT-LHBT repair techniques improved glenohumeral joint kinematics in an amount similar to previously reported ''traditional'' SCR techniques for treatment of an irreparable posterosuperior RCT.Ethical approval was obtained via Human Research Determination Form to the institutional review board (IRB) of the University of Connecticut, and it was documented that no IRB approval was required (deidentified specimen do not constitute human subjects research).

Anterior Latissimus Dorsi Transfer for Irreparable Subscapularis Tears Improves Shoulder Kinematics in a Dynamic Biomechanical Cadaveric Shoulder Model

“…Biomechanically, there is a substantial body of evidence that insufficiency of the rotator cuff leads to a disruption of the complex interactions between the rotator cuff and the deltoid muscles, with a subsequent increase in deltoid forces to compensate for loss of abduction. 1,[3][4][5]10,11,26 As such, based on the results of the present study, the aLDT allows not only for a rebalancing of glenohumeral abduction motion, but also for a reduction of compensatory deltoid forces. This is of clinical importance, as postoperative deltoid fatigue with subsequent pain and loss of glenohumeral abduction motion may be prevented.…”

“…Biomechanically, there is a substantial body of evidence that insufficiency of the rotator cuff leads to a disruption of the complex interactions between the rotator cuff and the deltoid muscles, with a subsequent increase in deltoid forces to compensate for loss of abduction. 1,3-5,10,11,26…”

Arthroscopic superior capsule reconstruction augmentation using a semitendinosus autograft in massive reparable rotator cuff tears

“…For patients with irreparable rotator cuff tears, structural augmentation, such as SCR using the fascia lata, LHBT, and acellular human dermal matrix, provides promising clinical and biomechanical outcomes. 3 , 8 , 16 , 31 , 39 , 41 , 43 , 51 …”

“…Recent studies demonstrated the biomechanical and technical feasibility of using the semitendinosus tendon in SCR for irreparable rotator cuff tears. 3 , 9 , 13 , 17 , 47 The semitendinosus tendon has potential advantages, including simple manipulation and management for secure and anatomical repair because of its cord-like morphology. A graft long enough to be folded can be designed based on the size and location of rotator cuff tears.…”

Physiological Tensioning During Lower Trapezius Transfer for Irreparable Posterosuperior Rotator Cuff Tears May Be Important for Improvement in Shoulder Kinematics

“…2,26,34 After being tested in the native state, an irreparable PSRCT was created by sharply dissecting the footprint of the supraspinatus muscle and cranial part of the infraspinatus muscle on the greater humeral tuberosity. [4][5][6]21 The supraspinatus muscle belly was detached from the supraspinous fossa to create an irreparably retracted tear (Figure 2A). Subsequently, LTT was performed using an Achilles tendon allograft, as previously described by Elhassan et al 12 (Figure 2B).…”