Pastor M-F, Ferle M, Hagenah J, Ellwein A, Wellmann M, Smith T
Department of Orthopaedic Surgery, Medical School Hannover, Hannover, Germany.
Laboratory of Biomechanics and Biomaterials, Medical School Hannover, Germany.
Clin Biomech (Bristol). 2019 Mar;63:179-184. doi: 10.1016/j.clinbiomech.2019.03.009. Epub 2019 Mar 13.
Numerous factors determine stability of reverse total shoulder arthroplasty. The effect of the conjoint tendon in relation to stability remains unknown. In this biomechanical study, we evaluated the influence of the conjoint tendon on the anterior stability of reverse total shoulder arthroplasty with a hemispherical glenosphere and a glenosphere with 9 mm lateralisation.
A reverse total shoulder arthroplasty was implanted in 6 human cadaveric shoulders. The anterior stability was evaluated using a shoulder simulator. Two conditions, intact and dissected conjoint tendon, and 2 component configurations, a hemispherical glenosphere and a glenosphere with 9 mm lateralisation, were tested in each specimen. Testing of anterior stability was performed in 30° and 60° of abduction, with 0° and 30° of external rotation in the glenohumeral joint.
The conjoint tendon showed a significant influence on the anterior stability with a hemispherical glenosphere in 30° and 60° with neutral rotation (p = 0.028) as well as 30° abduction with 30° (p = 0.028) external rotation. The 9 mm lateralised glenosphere stabilized significantly reverse total shoulder arthroplasty with resected conjoint tendon compared to the hemispherical glenosphere with resected conjoint tendon (p = 0.028).
In a biomechanical setting the conjoint tendon has a stabilizing influence on the anterior stability of the reverse total shoulder arthroplasty with a hemispherical glenosphere in an abducted arm position, but this stabilizing effect was not seen with the lateralised glenosphere. The single influence of the lateralisation of the glenosphere on anterior stability was shown in cases of resected conjoint tendon.
多种因素决定了反式全肩关节置换术的稳定性。联合肌腱对稳定性的影响尚不清楚。在这项生物力学研究中，我们评估了联合肌腱对采用半球形关节盂假体和关节盂假体外侧移位9毫米的反式全肩关节置换术前稳定性的影响。
在6具人类尸体肩部植入反式全肩关节置换假体。使用肩部模拟器评估前稳定性。在每个标本中测试两种情况，即联合肌腱完整和联合肌腱切断，以及两种假体配置，半球形关节盂假体和关节盂假体外侧移位9毫米。在肩关节外展30°和60°、肱骨头外旋0°和30°的情况下进行前稳定性测试。
联合肌腱对采用半球形关节盂假体在中立旋转30°和60°（p = 0.028）以及外展30°伴外旋30°（p = 0.028）时的前稳定性有显著影响。与联合肌腱切断的半球形关节盂假体相比，联合肌腱切断时，9毫米外侧移位的关节盂假体显著稳定了反式全肩关节置换术（p = 0.028）。
在生物力学环境中，联合肌腱对处于外展手臂位置的采用半球形关节盂假体的反式全肩关节置换术的前稳定性有稳定作用，但外侧移位的关节盂假体未见这种稳定效果。在联合肌腱切断的情况下，显示了关节盂假体外侧移位对前稳定性的单一影响。
