Paccot Daniel, Fleet Cole T, Johnson James A, Athwal George S
Roth | McFarlane Hand and Upper Limb Centre, St Joseph's Health Care, London, ON, Canada.
Roth | McFarlane Hand and Upper Limb Centre, St Joseph's Health Care, London, ON, Canada; Department of Mechanical and Materials Engineering, Western University, London, ON, Canada.
J Shoulder Elbow Surg. 2025 Mar;34(3):688-698. doi: 10.1016/j.jse.2024.07.007. Epub 2024 Aug 15.
Massive irreparable rotator cuff tears (MIRCTs) treated with superior capsular reconstruction (SCR) using the long head of the biceps tendon have shown satisfactory early results. Different techniques and positions for biceps tenodesis have been described. This study aimed to evaluate the effect of tenodesis location and glenohumeral fixation angle for graft tensioning on the biomechanics of an SCR using a single-strand biceps technique.
Eight cadaveric shoulders were mounted onto a custom biomechanical simulator that used static tone loads to the deltoid and rotator cuff muscles. All cadavers were first tested in the intact condition, and then in the simulated MIRCT condition by sectioning the tendinous insertions of the supraspinatus and upper border of the infraspinatus. SCR using the long head of the biceps tendon was then evaluated. Three biceps tenodesis locations relative to the greater tuberosity (anterior, middle, and posterior) and 2 glenohumeral fixation angles (0° and 30°) for graft tensioning were tested. An optical tracking system was used to quantify superior-inferior and anterior-posterior humeral head translation relative to the glenoid, whereas the functional abduction force was quantified using a load sensor. All tests were conducted at 0°, 30°, and 60° of glenohumeral abduction in a randomized fashion.
When assessing isolated superior humeral head migration, all biceps tenodesis locations were effective at decreasing superior migration, with no tenodesis location significantly better than the other (P = .213). However, biceps grafts tensioned at 30° of glenohumeral abduction were significantly better at reducing proximal humeral migration as compared to graft tensioning at 0° abduction (P = .008). Posterior humeral head translation observed in the MIRCT condition was significantly reduced when tensioning the biceps tendon at 30° of glenohumeral abduction compared with 0° for all tenodesis locations (P ≤ .043). The tenodesis location also significantly influenced posterior humeral head translation (P = .001), with the middle and posterior positions restoring near normal humeral head position when fixed at 30° glenohumeral abduction. All SCR techniques using the biceps tendon improved the functional abduction force relative to the MIRCT condition, although no statistically significant differences were observed relative to the intact condition (P ≥ .448).
SCR using the long head of the biceps tendon is biomechanically effective in reducing posterosuperior translation of the humeral head in the setting of an MIRCT. Graft tensioning and fixation at 30° of glenohumeral abduction combined with either a middle or posterior tenodesis location on the greater tuberosity most effectively restores near normal time-zero humeral head kinematics.
采用肱二头肌长头进行上盂唇重建（SCR）治疗巨大不可修复性肩袖撕裂（MIRCT）已取得令人满意的早期效果。已有多种肱二头肌固定术的技术和位置被描述。本研究旨在评估使用单股肱二头肌技术进行上盂唇重建时，固定位置和盂肱关节固定角度对移植物张紧的生物力学影响。
将8具尸体肩部安装到定制的生物力学模拟器上，该模拟器对三角肌和肩袖肌肉施加静态张力负荷。所有尸体首先在完整状态下进行测试，然后通过切断冈上肌腱止点和冈下肌上缘模拟MIRCT状态。随后评估使用肱二头肌长头进行的上盂唇重建。测试了相对于大结节的三个肱二头肌固定位置（前、中、后）以及用于移植物张紧的两个盂肱关节固定角度（0°和30°）。使用光学跟踪系统量化肱骨头相对于关节盂的上下和前后平移，而使用负荷传感器量化功能性外展力。所有测试均在0°、30°和60°的盂肱关节外展角度下随机进行。
在评估孤立的肱骨头向上移位时，所有肱二头肌固定位置在减少向上移位方面均有效，没有一个固定位置明显优于其他位置（P = 0.213）。然而，与在0°外展时张紧移植物相比，在30°盂肱关节外展时张紧肱二头肌移植物在减少肱骨头近端移位方面明显更好（P = 0.008）。与在0°盂肱关节外展时相比，在所有固定位置，当在30°盂肱关节外展时张紧肱二头肌肌腱，MIRCT状态下观察到的肱骨头向后平移明显减少（P≤0.043）。固定位置也显著影响肱骨头向后平移（P = 0.001），当在30°盂肱关节外展时固定，中间和后部位置可使肱骨头位置恢复到接近正常。相对于MIRCT状态，所有使用肱二头肌肌腱的上盂唇重建技术均改善了功能性外展力，尽管相对于完整状态未观察到统计学显著差异（P≥0.448）。
在MIRCT情况下，使用肱二头肌长头进行上盂唇重建在生物力学上可有效减少肱骨头的后上平移。在30°盂肱关节外展时进行移植物张紧和固定，结合大结节上的中间或后部固定位置，最有效地恢复接近正常的零时肱骨头运动学。
