Kikukawa Kenshi, Ide Junji, Terakawa Yusuke, Takada Koji, Morita Makoto, Hashimoto Kenzo, Mizuta Hiroshi
Department of Orthopaedic Surgery, Kumamoto General Hospital, Japan Community Healthcare Organization, Yatsushiro, Kumamoto, Japan.
Department of Advanced Joint Reconstructive Surgery, Kumamoto University Hospital, Kumamoto University, Kumamoto, Japan.
J Shoulder Elbow Surg. 2016 Nov;25(11):1882-1888. doi: 10.1016/j.jse.2016.04.016. Epub 2016 Jun 30.
In posterosuperior rotator cuff tears (PS-RCT), the progression of infraspinatus (ISP) muscle atrophy seems to induce compensatory hypertrophy of the teres minor (TM) muscles. However, the effect of these changes on shoulder strength and range of external rotation (ER) remains unclear. This study determined the strength and range of ER in patients with PS-RCT with atrophic ISP and hypertrophic TM and compared this with patients with PS-RCT and normal or deficient TM.
We investigated 35 patients with PS-RCT and atrophic ISP. TM muscles were classified as hypertrophic (type A) in 17, normal (type B) in 10, or deficient (type C) in 8. The strength ratio of the affected shoulder to the healthy contralateral shoulder was calculated, and the active range of motion was measured for both shoulders.
The strength ratios of ER in types A, B, and C were 60%, 33%, and 7% (P < .01) with the patient's arm at the side and were 60%, 35%, and 5% (P < .001) at 90° abduction, respectively. The average ranges of ER in types A, B, and C were 22.6°, 15.0°, and -12.5° (P < .001) with the patient's arm at the side and were 71.6°, 44.5°, and 21.9° at 90° abduction (P < .01), respectively. The differences between shoulder types in other measures of strength or ER range were not significant.
In patients with PS-RCT and atrophic ISP, shoulders with compensatory hypertrophy of the TM had greater strength and range of ER than shoulders with normal or atrophic TM.
在肩袖后上撕裂（PS-RCT）中，冈下肌（ISP）萎缩的进展似乎会导致小圆肌（TM）的代偿性肥大。然而，这些变化对肩部力量和外旋（ER）范围的影响仍不清楚。本研究测定了PS-RCT伴ISP萎缩和TM肥大患者的ER力量和范围，并将其与PS-RCT伴TM正常或发育不良的患者进行比较。
我们调查了35例PS-RCT伴ISP萎缩的患者。TM肌肉分为肥大（A型）17例、正常（B型）10例或发育不良（C型）8例。计算患侧肩部与健侧对侧肩部的力量比值，并测量双肩的主动活动范围。
患者手臂位于身体一侧时，A型、B型和C型的ER力量比值分别为60%、33%和7%（P＜0.01），外展90°时分别为60%、35%和5%（P＜0.001）。患者手臂位于身体一侧时，A型、B型和C型的平均ER范围分别为22.6°、15.0°和-12.5°（P＜0.001），外展90°时分别为71.6°、44.5°和21.9°（P＜0.01）。在其他力量或ER范围测量指标上，肩部类型之间的差异不显著。
在PS-RCT伴ISP萎缩的患者中，TM有代偿性肥大的肩部比TM正常或萎缩的肩部具有更大的力量和ER范围。
