Konrad Gerhard G, Sudkamp Norbert P, Kreuz Peter C, Jolly John T, McMahon Patrick J, Debski Richard E
Department of Orthopaedic and Trauma Surgery, University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany.
J Bone Joint Surg Am. 2007 Nov;89(11):2477-84. doi: 10.2106/JBJS.F.00811.
Different operative techniques for transfer of the pectoralis major tendon have been proposed for the treatment of irreparable ruptures of the subscapularis tendon. The objective of this study was to compare the effects of two techniques of transferring the pectoralis major tendon (above or underneath the conjoint tendon) on glenohumeral kinematics during active abduction in a biomechanical model of a subscapularis-deficient shoulder.
Six shoulder specimens were tested with a custom dynamic shoulder testing apparatus. After the kinematics of the intact shoulder were recorded, a complete tear of the subscapularis tendon was simulated surgically. A transfer of the clavicular portion of the pectoralis major muscle to the lesser tuberosity was then performed with the transferred tendon placed either above (tendon-transfer 1) or underneath (tendon-transfer 2) the conjoint tendon. For each condition, the maximum abduction angle as well as the external rotation angle and the superoinferior and anteroposterior humeral translations at the maximum abduction angle were recorded.
With the rotator cuff intact, the mean maximum glenohumeral abduction angle (and standard error of the mean) was 86.3 degrees +/- 2.1 degrees and the mean amount of external rotation at the maximum abduction angle was 5.5 degrees +/- 7.6 degrees . A complete tear of the subscapularis tendon decreased the mean maximum abduction angle to 40.8 degrees +/- 2.4 degrees (p < 0.001) and increased the mean external rotation to 91.8 degrees +/- 4.8 degrees (p < 0.001). The mean humeral translations in the anterior and superior directions (+3.4 +/- 0.5 and +6.3 +/- 0.3 mm, respectively) at the maximum abduction angle were also increased (p < 0.01 and p < 0.001) when compared with those in the intact shoulder. Significant differences were found in the mean maximum abduction angle as well as the mean external rotation angle and humeral translations (anterior and superior) at maximum abduction between the tendon-transfer-1 condition (63.2 degrees +/- 13.5 degrees , 82.4 degrees +/- 6.6 degrees , 4.0 +/- 1.8 mm, and 3.3 +/- 1.9 mm, respectively) and tendon-transfer-2 condition (89.5 degrees +/- 12.3 degrees , 45.7 degrees +/- 22.5 degrees , -0.6 +/- 2.0 mm, and 0.5 +/- 2.3 mm, respectively). The tendon-transfer-2 condition restored glenohumeral kinematics that were closer to those in the intact shoulder than were those resulting from the tendon-transfer-1 condition.
Transfer of the pectoralis major tendon in subscapularis-deficient shoulders partially restored the glenohumeral kinematics of the intact shoulder. One possible explanation for the superior effect of the tendon-transfer-2 condition is that, with a pectoralis major tendon transfer underneath the conjoint tendon, the line of action of the transferred tendon is closer to that of the subscapularis muscle.
对于肩胛下肌腱不可修复的断裂，已提出不同的胸大肌腱转移手术技术。本研究的目的是在肩胛下肌缺失的肩部生物力学模型中，比较两种胸大肌腱转移技术（联合腱上方或下方）在主动外展过程中对盂肱关节运动学的影响。
使用定制的动态肩部测试装置对六个肩部标本进行测试。记录完整肩部的运动学数据后，手术模拟肩胛下肌腱的完全撕裂。然后将胸大肌锁骨部转移至小结节，转移的肌腱置于联合腱上方（肌腱转移1）或下方（肌腱转移2）。对于每种情况，记录最大外展角度以及最大外展角度时的外旋角度和肱骨头上下及前后移位情况。
在肩袖完整时，平均最大盂肱关节外展角度（及平均标准误差）为86.3度±2.1度，最大外展角度时的平均外旋角度为5.5度±7.6度。肩胛下肌腱完全撕裂使平均最大外展角度降至40.8度±2.4度（p<0.001），平均外旋角度增至91.8度±4.8度（p<0.001）。与完整肩部相比，最大外展角度时肱骨头向前和向上方向的平均移位（分别为+3.4±0.5和+6.3±0.3 mm）也增加（p<0.01和p<0.001）。在肌腱转移1组（分别为63.2度±13.5度、82.4度±6.6度、4.0±1.8 mm和3.3±1.9 mm）和肌腱转移2组（分别为89.5度±12.3度、45.7度±22.5度、-0.6±2.0 mm和0.5±2.3 mm）之间，最大外展角度时的平均最大外展角度、平均外旋角度及肱骨头移位（向前和向上）存在显著差异。肌腱转移2组恢复的盂肱关节运动学比肌腱转移1组更接近完整肩部。
在肩胛下肌缺失的肩部转移胸大肌腱可部分恢复完整肩部的盂肱关节运动学。肌腱转移2组效果更佳的一个可能解释是，当胸大肌腱转移至联合腱下方时，转移肌腱的作用线更接近肩胛下肌的作用线。
