McGarry Michelle H, Nguyen Michael L, Quigley Ryan J, Hanypsiak Bryan, Gupta Ranjan, Lee Thay Q
Orthopaedic Biomechanics Laboratory, VA Long Beach Healthcare System (09/151), 5901 East 7th. Street, Long Beach, CA, 90822, USA.
Department of Orthopaedic Surgery, Mount Sinai Hospital, New York, NY, USA.
Knee Surg Sports Traumatol Arthrosc. 2016 Jun;24(6):1979-87. doi: 10.1007/s00167-014-3318-5. Epub 2014 Sep 26.
To evaluate the effect of loading the long and short heads of the biceps on glenohumeral range of motion and humeral head position.
Eight cadaveric shoulders were tested in 60° abduction in the scapula and coronal plane. Muscle loading was applied based on cross-sectional area ratios. The short and long head of the biceps were loaded individually followed by combined loading. Range of motion was measured with 2.2 Nm torque, and the humeral head apex position was measured using a MicroScribe. A paired t test with Bonferroni correction was used for statistics.
Long head loading decreased internal rotation in both the scapular (17.9 %) and coronal planes (5.7 %) and external rotation in the scapular plane (2.6 %) (P < 0.04). With only short head loading, maximum internal rotation was significantly increased in the scapular and coronal plane. Long head and short head loading shifted the humeral head apex posteriorly in maximum internal rotation in both planes with the long head shift being significantly greater than the short head. Long head loading also shifted the humeral apex inferiorly in internal rotation and inferiorly posteriorly in neutral rotation in the scapular plane. With the long head unloaded, there was a significant superior shift with short head loading in both planes.
Loading the long head of the biceps had a much greater effect on glenohumeral range of motion and humeral head shift than the short head of the biceps; however, in the absence of long head loading, with the short head loaded, maximum internal rotation increases and the humeral head shifts superiorly, which may contribute to impingement following tenodesis of the long head of the biceps. These small changes in rotational range of motion and humeral head position with biceps tenodesis may not lead to pathologic conditions in low-demand patients; however, in throwers, biceps tenodesis may lead to increased contact pressures in late-cocking and deceleration that will likely translate to decreased performance therefore every effort should be made to preserve the biceps-labral complex.
评估肱二头肌长头和短头负荷对盂肱关节活动范围及肱骨头位置的影响。
对8具尸体肩部在肩胛面和冠状面60°外展位进行测试。根据横截面积比施加肌肉负荷。分别对肱二头肌短头和长头进行负荷，随后进行联合负荷。用2.2牛米的扭矩测量活动范围，并用MicroScribe测量肱骨头顶点位置。采用经Bonferroni校正的配对t检验进行统计学分析。
长头负荷使肩胛面（17.9%）和冠状面（5.7%）的内旋减少，肩胛面的外旋减少（2.6%）（P<0.04）。仅短头负荷时，肩胛面和冠状面的最大内旋显著增加。长头和短头负荷在两个平面的最大内旋时均使肱骨头顶点向后移位，但长头移位明显大于短头移位。长头负荷还使肩胛面内旋时肱骨头顶点向下移位，中立位旋转时向下向后移位。在长头卸载的情况下，短头负荷在两个平面均使肱骨头显著向上移位。
与肱二头肌短头相比，肱二头肌长头负荷对盂肱关节活动范围和肱骨头移位的影响要大得多；然而，在长头未负荷而短头负荷的情况下，最大内旋增加且肱骨头向上移位可能会导致肱二头肌长头腱固定术后的撞击。肱二头肌腱固定时旋转活动范围及肱骨头位置上的这些微小变化可能不会导致低需求患者出现病理状况；然而，对于投掷运动员，肱二头肌腱固定可能会导致在晚举臂过肩和减速阶段接触压力增加，这可能会导致表现下降，因此应尽一切努力保留肱二头肌-盂唇复合体。
