Warner J J, Micheli L J, Arslanian L E, Kennedy J, Kennedy R
Division of Sports Medicine, Children's Hospital, Harvard Medical School, Boston, Massachusetts.
Am J Sports Med. 1990 Jul-Aug;18(4):366-75. doi: 10.1177/036354659001800406.
Imbalance of the internal and external rotator musculature of the shoulder, excess capsular laxity, and loss of capsular flexibility, have all been implicated as etiologic factors in glenohumeral instability and impingement syndrome; however, these assertions are based largely on qualitative clinical observations. In order to quantitatively define the requirements of adequate protective synergy of the internal and external rotator musculature, as well as the primary capsulolabral restraints, we prospectively evaluated 53 subjects: 15 asymptomatic volunteers, 28 patients with glenohumeral instability, and 10 patients with impingement syndrome. Range of motion was evaluated by goniometric technique in all patients with glenohumeral instability and impingement. Laxity assessment was performed and anterior, posterior, and inferior humeral head translation was graded on a scale of 0 to 3+. Isokinetic strength assessment was performed in a modified abducted position using the Biodex Clinical Data Station with test speeds of 90 and 180 deg/sec. Internal and external rotator ratios and internal and external rotator strength deficits were calculated for both peak torque and total work. Patients with impingement demonstrated marked limitation of shoulder motion and minimal laxity on drawer testing. Both anterior and multidirectional instability patients had excessive external rotation as well as increased capsular laxity in all directions. Sixty-eight percent of the patients with instability had significant impingement signs in addition to apprehension and capsular laxity. Isokinetic testing of asymptomatic subjects demonstrated a 30% greater internal rotator strength in the dominant shoulder. Comparison of all three experimental groups demonstrated a significant difference between internal and external rotator ratios for both peak torque and total work. Conclusions are that there appears to be a dominance tendency with regard to internal rotator strength in asymptomatic individuals. Impingement syndrome and anterior instability have significant differences in both strength patterns of the rotator muscles and flexibility and laxity of the shoulder. Isokinetic testing potentially may be helpful in diagnostically differentiating between these two groups in cases where there is clinical overlap of signs and symptoms.
肩部内外旋肌系统失衡、关节囊过度松弛以及关节囊灵活性丧失，均被认为是肩肱关节不稳和撞击综合征的病因；然而，这些论断很大程度上基于定性的临床观察。为了定量界定肩部内外旋肌系统以及主要关节盂唇限制结构的充分保护性协同作用的要求，我们前瞻性地评估了53名受试者：15名无症状志愿者、28名肩肱关节不稳患者以及10名撞击综合征患者。采用角度测量技术对所有肩肱关节不稳和撞击患者进行活动范围评估。进行松弛度评估，并对肱骨头向前、向后和向下移位进行0至3+级评分。使用Biodex临床数据站在改良外展位置进行等速肌力评估，测试速度为90和180度/秒。计算峰值扭矩和总功的内外旋比率以及内外旋肌力不足。撞击综合征患者表现出明显的肩部活动受限，抽屉试验时松弛度最小。前方和多方向不稳患者均存在外旋过度以及各方向关节囊松弛增加的情况。68%的不稳患者除了有恐惧和关节囊松弛外，还有明显的撞击体征。对无症状受试者的等速测试表明，优势肩的内旋肌力比非优势肩大30%。对所有三个实验组的比较表明，峰值扭矩和总功的内外旋比率均存在显著差异。结论是，无症状个体的内旋肌力似乎存在优势倾向。撞击综合征和前方不稳在旋转肌的力量模式以及肩部的灵活性和松弛度方面均存在显著差异。在体征和症状存在临床重叠的情况下，等速测试可能有助于对这两组进行诊断性区分。
