Jackson Timothy, Wright David, Long Charles, Truong Victor, Adamson Gregory, McGarry Michelle H, Lee Thay Q
Orthopaedic Biomechanics Laboratory, Congress Medical Foundation, Pasadena, California, U.S.A.
Arthrosc Sports Med Rehabil. 2023 Jun 14;5(4):100745. doi: 10.1016/j.asmr.2023.05.002. eCollection 2023 Aug.
To evaluate the effect of hip flexion and rotation on excursion of the gluteus medius (Gmed) and minimus (Gmin) myotendinous unit.
Seven hips from 4 cadaveric specimens (males, 68.5 ± 18.3 years old) were dissected to isolate the Gmed posterior and lateral insertions and the Gmin proximal and distal insertions. Sutures were placed from tendon insertions through origins created in the iliac fossa to simulate the myotendinous unit. A load of 10N was applied. Myotendinous excursion was measured at 10° hip extension and 0°, 45°, and 90° of hip flexion in neutral rotation, and from maximum internal and external rotation in 90° flexion. The amount of abduction and rotation was also measured at each flexion position with 20N applied to each tendon. Repeated-measures analysis of variance with Tukey post hoc was used for statistics.
Gmed-lateral excursion ranged from 2.4 ± 0.4 mm in 10° of hip extension to 23.0 ± 1.5 mm in 90° of flexion ( < .001), and Gmed-posterior excursion ranged from 0.92 ± 0.5 mm in 10° of extension to 38.1 ± 1.1 mm in 90° of flexion ( < .001). Gmin excursion shortened with hip flexion from 4.2 ± 0.3 mm in 10° of extension to -0.2 ± 1.5 mm in 90° of flexion (Gmin-prox: = .525, Gmin-distal: < .001). At 90° flexion from maximum internal to maximum external rotation, Gmin-distal and proximal demonstrated a 92.6% and 51.3% increase in excursion, respectively ( < .001). Gmed-lateral and Gmed-posterior demonstrated 49.4% and 23.1% increase in excursion with external rotation, respectively ( < .001).
The Gmed myotendinous unit undergoes significant excursion with hip flexion, whereas both Gmed and Gmin had significant excursion with femoral external rotation in 90° flexion.
It is important to understand whether active or passive hip flexion or rotation in the early postoperative period causes excessive strain to an abductor tendon repair. We found that consideration should be given to limit flexion after Gmed repair and external rotation after Gmed or Gmin repairs.
评估髋关节屈曲和旋转对臀中肌（Gmed）和臀小肌（Gmin）肌腱单位移动的影响。
对4具尸体标本（男性，68.5±18.3岁）的7个髋关节进行解剖，分离出Gmed的后外侧附着点以及Gmin的近端和远端附着点。将缝线从肌腱附着点穿过在髂窝处创建的起点，以模拟肌腱单位。施加10N的负荷。在髋关节中立旋转时，分别测量髋关节伸展10°以及屈曲0°、45°和90°时肌腱单位的移动情况，以及在屈曲90°时从最大内旋到最大外旋时的移动情况。在每个屈曲位置，对每条肌腱施加20N的力，同时测量外展和旋转的量。采用重复测量方差分析和Tukey事后检验进行统计学分析。
Gmed外侧移动范围从髋关节伸展10°时的2.4±0.4mm到屈曲90°时的23.0±1.5mm（P<0.001），Gmed后侧移动范围从伸展10°时的0.92±0.5mm到屈曲90°时的38.1±1.1mm（P<0.001）。Gmin移动随着髋关节屈曲而缩短，从伸展10°时的4.2±0.3mm到屈曲90°时的-0.2±1.5mm（Gmin近端：P = 0.525，Gmin远端：P<0.001）。在屈曲90°时从最大内旋到最大外旋，Gmin远端和近端的移动分别增加了92.6%和51.3%（P<0.001）。Gmed外侧和Gmed后侧在髋关节外旋时移动分别增加了49.4%和23.1%（P<0.001）。
Gmed肌腱单位在髋关节屈曲时会发生显著移动，而在屈曲90°时，Gmed和Gmin在股骨外旋时均有显著移动。
了解术后早期主动或被动的髋关节屈曲或旋转是否会对外展肌腱修复造成过度张力非常重要。我们发现，在Gmed修复后应考虑限制屈曲，在Gmed或Gmin修复后应考虑限制外旋。
