Department of Biomedical Engineering, University of Melbourne, Parkville, Victoria, Australia.
Department of Orthopaedic Surgery, Epworth Healthcare, Richmond, Victoria, Australia.
J Shoulder Elbow Surg. 2018 Nov;27(11):2085-2092. doi: 10.1016/j.jse.2018.04.017. Epub 2018 Jun 25.
Rotator cuff tears following anatomic total shoulder arthroplasty increase with duration of follow-up. This study aimed to evaluate contact pressure between the rotator cuff tendons and prosthesis after anatomic total shoulder arthroplasty and compare these with the tendon-contact pressures in the native shoulder.
Eight entire upper extremities were mounted onto a testing apparatus, and simulated muscle loading was applied to each rotator cuff tendon with the shoulder positioned in abduction, internal rotation, and external rotation. Pressure-sensitive film placed between each tendon and bone was used to measure the resultant tendon contact pressures. Experiments were repeated after anatomic total shoulder arthroplasty using standardized implant sizes, and pressure-sensitive film was used to evaluate tendon-prosthesis contact pressure.
Both joint angle and shoulder joint replacement surgery had significant effects on the maximum contact pressure measured between the humeral head and all rotator cuff tendons (P < .05) except the teres minor. The supraspinatus demonstrated a significantly larger peak tendon contact pressure after surgery at 45° of abduction relative to that in the native shoulder (mean difference, 0.2 MPa; P = .031), while the subscapularis had a significantly larger maximum contact pressure at 10° of abduction (mean difference, 0.45 MPa; P = .032) and 90° of abduction (mean difference, 0.80 MPa; P = .008) postoperatively.
Anatomic total shoulder arthroplasty results in significantly larger tendon contact pressures relative to those in the native shoulder. High tendon contact pressures may ultimately predispose rotator cuff tendons to postoperative wear-induced damage and tearing.
解剖型全肩关节置换术后肩袖撕裂的发生率随随访时间的延长而增加。本研究旨在评估解剖型全肩关节置换术后肩袖肌腱与假体之间的接触压力，并将其与正常肩关节的肌腱接触压力进行比较。
将 8 个完整的上肢安装在测试装置上，使每个肩袖肌腱在肩关节外展、内旋和外旋位时模拟肌肉加载。在每个肌腱和骨之间放置压力敏感膜，以测量肌腱的接触压力。在解剖型全肩关节置换术后，使用标准化的植入物尺寸重复实验，并使用压力敏感膜评估肌腱-假体的接触压力。
关节角度和肩关节置换手术对肱骨头与所有肩袖肌腱之间测量的最大接触压力均有显著影响（P < .05），除了小圆肌。外展 45°时，术后肩袖的冈上肌肌腱接触压力明显大于正常肩（平均差异，0.2 MPa；P = .031），而肩胛下肌在 10°外展（平均差异，0.45 MPa；P = .032）和 90°外展（平均差异，0.80 MPa；P = .008）时的最大接触压力明显增大。
解剖型全肩关节置换术后，肌腱接触压力明显大于正常肩关节。高肌腱接触压力可能最终导致肩袖在术后易发生磨损诱导性损伤和撕裂。
