Malige Ajith, Thomas Stephen, Fraipont Genevieve, Hung Victor T, McGarry Michelle H, Paul Ryan W, Gupta Richa, Ciccotti Michael G, Kelly John D, Kibler W Ben, Lee Thay Q
Advanced Orthopaedics and Sports Medicine, San Francisco, CA, USA.
Ronson Health and Applied Science Center, Thomas Jefferson University, Philadelphia, PA, USA.
J Shoulder Elbow Surg. 2025 Sep;34(9):2246-2257. doi: 10.1016/j.jse.2024.12.023. Epub 2025 Jan 30.
Combined posterior and posterior-superior (PPS) injuries (6:30-12:00; right shoulder) have a much higher incidence than isolated superior labral anterior to posterior (SLAP) injuries (11:00-1:00; right shoulder). However, it is unclear how PPS injuries affect glenohumeral (GH) biomechanics and how they should be treated. This study evaluated if (1) PPS injuries alter GH kinematics and joint characteristics, (2) standard repair techniques restore GH kinematics and contact characteristics toward their intact state, and (3) there are differences between repair techniques.
Ten fresh frozen male cadaveric shoulders (61.4 ± 5.7 years) without pre-existing shoulder pathology were evaluated using a custom shoulder testing system. After a PPS injury was created, a posterior repair technique reattached the labrum from 6:30 to 10:00, whereas a subsequent posterior-superior repair technique included an additional anchor at 11:00. The shoulder was placed in 90° of abduction and tested in the scapular plane at 10°, 20°, 30°, and 40° of horizontal adduction in the scapular plane at both 30° and 60° of external rotation using a deceleration load and 2 posteriorly directed unbalanced muscle loading conditions. These positions were chosen as they would occur during the deceleration and follow-through phases of pitching. All measurements were performed for the following conditions: intact, PPS injury, posterior repair, and posterior-superior repair. Humeral head (HH) position, GH translation, and GH contact area and pressure were measured.
PPS injuries alter GH kinematics and GH joint contact characteristics. There was significant posterior translation of the HH in multiple positions of horizontal adduction in the scapular plane and GH rotation in both muscle imbalance conditions, significant decreases in joint contact area, and increases in joint contact pressure. Repair of PPS injuries by both repair techniques resulted in HH anterior and superior translation toward the intact state in multiple positions of horizontal adduction and GH rotation, increased joint contact area, and decreased joint contact pressure. Compared with posterior repairs, posterior-superior repairs resulted in significantly increased nonphysiologic anterior and inferior HH translation in relation to the intact state.
The PPS injury produces alterations in GH kinematics with implications for GH joint instability, increased GH joint loading, and potential joint damage. The posterior labral repair restores HH kinematics closer to intact, whereas the addition of a posterior-superior repair induces significantly increased nonphysiologic anterior and inferior HH translation at multiple positions of adduction and IR.
合并的后方及后上方（PPS）损伤（6:30 - 12:00；右肩）的发生率远高于孤立的上盂唇从前到后的（SLAP）损伤（11:00 - 1:00；右肩）。然而，目前尚不清楚PPS损伤如何影响盂肱（GH）生物力学以及应如何治疗。本研究评估了：（1）PPS损伤是否改变GH运动学和关节特征；（2）标准修复技术能否将GH运动学和接触特征恢复至完整状态；（3）修复技术之间是否存在差异。
使用定制的肩部测试系统对10具无肩部既往病变的新鲜冷冻男性尸体肩部（61.4 ± 5.7岁）进行评估。在制造PPS损伤后，一种后方修复技术将盂唇从6:30重新附着至10:00，而随后的后上方修复技术在11:00处增加了一个锚钉。将肩部外展90°，并在肩胛平面分别于30°和60°外旋时，在肩胛平面内10°、20°、30°和40°水平内收位使用减速负荷以及两种向后的不平衡肌肉负荷条件进行测试。选择这些位置是因为它们会在投球的减速和随挥阶段出现。对以下情况进行所有测量：完整状态、PPS损伤、后方修复和后上方修复。测量肱骨头（HH）位置、GH平移以及GH接触面积和压力。
PPS损伤改变了GH运动学和GH关节接触特征。在肩胛平面内多个水平内收位以及两种肌肉失衡情况下的GH旋转中，HH均有明显的向后平移，关节接触面积显著减小，关节接触压力增加。两种修复技术对PPS损伤的修复均使HH在多个水平内收位和GH旋转位向前和向上平移至接近完整状态，关节接触面积增加，关节接触压力降低。与后方修复相比，后上方修复导致HH相对于完整状态出现明显增加的非生理性向前和向下平移。
PPS损伤会导致GH运动学改变，这对GH关节不稳定、GH关节负荷增加及潜在的关节损伤具有影响。后方盂唇修复使HH运动学更接近完整状态，而后上方修复的添加在多个内收位和内旋位导致明显增加的非生理性HH向前和向下平移。
