Factors associated with Trochanteric Bursitis and Gluteal Tendinopathy.

The hypothesis of this study was that age and weakness of the Gluteus Medius are the main factors associated with trochanteric bursitis and gluteal tendinopathy. The study aims to relate the factors associated with TB and GT, evaluating BMI, age and strength of GMed muscle. The results of this study demonstrated that muscle strength (Kgf) and electrical activity (RMS-%) were similar between the group with trochanteric bursitis and gluteal tendinopathy and the control group; there was no significant difference in relation to BMI. However, in relation to the Trendelenburg test, there was a significant difference between the groups. The age variable presented as a factor associated with trochanteric bursitis and gluteal tendinopathy, being in agreement with the literature. In the present study, there was no significant relationship between BMI and Trochanteric Bursitis and Gluteal Tendinopathy, but the literature presents contradictory evidence. To date, no studies have been found that relate muscle strength (Kgf), MSR (%) and Trendelenburg test as factors associated with TB and GT. In the present study, we chose to evaluate the strength of the GM muscle in lateral decubitus, differently from authors who evaluated in dorsal decubitus and found weakness in the abductor group in gluteal tendinopathy. However, this difference in position is important because it interferes in the production of muscular strength. In this study, the Trendelenburg test was also used to evaluate it as a predictor of the associated factor for trochanteric bursitis and gluteal tendinopathy. The result showed that young adults with Trendelenburg positive had a higher prevalence for TB and GT. Based on the biomechanical analysis of the Balance of Pauwels and the concepts of classical physics on the Vector System and the application of force, we identify the non-correlation between the muscle strength test performed in lateral decubitus and the Trendelenburg test. Considering that one of the main complaints of patients is the difficulty to walk and often with falsehood and lameness, the Trendelenburg test presents as an important predictor of TB and GT. The limitations of the study are mainly due to the cross-sectional design, since it is not known if the weakness of the hip abductors, specifically GMed, is a result or cause of Greater Trochanteric Pain Syndrome, which may be an important factor associated . Another aspect turns to the relation to the time factor of disease development, since it is not evident if in the group without TB the patients will develop the disease in the future. In addition, there are methodological differences between the studies. The present study identified that the factors associated with trochanteric bursitis and gluteal tendinopathy are related to age (more frequent in young adults - 25-59 years), females and GMed muscle weakness, which was evidenced by the test of positive modified Trendelenburg

本研究的假说为：臀中肌（Gluteus Medius）力量减弱与年龄是转子滑囊炎（trochanteric bursitis）及臀肌腱病（gluteal tendinopathy）的主要相关危险因素。本研究旨在明确与转子滑囊炎和臀肌腱病相关的影响因素，评估体质量指数（BMI）、年龄以及臀中肌肌力水平。
本研究结果显示，转子滑囊炎与臀肌腱病患者组与对照组的肌肉力量（千克力，Kgf）及肌电活动（均方根百分比，RMS-%）无显著组间差异；体质量指数也未表现出统计学意义上的组间差异。然而，特伦德伦伯试验（Trendelenburg test）结果在两组间存在显著差异。年龄作为相关因素与转子滑囊炎和臀肌腱病显著相关，这与既往文献结论一致。本研究未发现体质量指数与转子滑囊炎、臀肌腱病存在显著关联，但现有文献对此结论存在分歧。
截至目前，尚未有研究将肌肉力量（Kgf）、肌电均方根百分比（RMS-%）以及特伦德伦伯试验作为转子滑囊炎和臀肌腱病的相关影响因素进行联合分析。本研究选择侧卧位（lateral decubitus）评估臀中肌肌力，与既往采用仰卧位（dorsal decubitus）评估并发现臀肌腱病患者外展肌群（abductor group）力量减弱的研究有所不同。但测试体位的差异至关重要，因其会对肌肉力量的产生造成干扰。
本研究同时采用特伦德伦伯试验作为转子滑囊炎和臀肌腱病相关危险因素的预测指标。结果显示，特伦德伦伯试验阳性的青年群体患转子滑囊炎和臀肌腱病的患病率更高。基于鲍威尔平衡（Balance of Pauwels）的生物力学分析、经典物理学的矢量系统（Vector System）概念及力的应用原理，本研究发现侧卧位肌力测试结果与特伦德伦伯试验结果无相关性。
考虑到患者最主要的主诉为行走困难，常伴随跛行，特伦德伦伯试验可作为转子滑囊炎和臀肌腱病的重要预测指标。本研究的局限性主要源于横断面研究设计：目前尚无法明确髋外展肌群（尤其是臀中肌）力量减弱是大转子疼痛综合征（Greater Trochanteric Pain Syndrome）的病因还是结果，这可能是重要的相关影响因素。此外，本研究未明确疾病发生的时间维度，无法判断无转子滑囊炎的受试者未来是否会罹患该病。同时，不同研究间存在方法学差异。
本研究证实，与转子滑囊炎和臀肌腱病相关的影响因素包括年龄（25~59岁青年群体发病率更高）、女性性别以及臀中肌肌力减弱，该指标可通过改良特伦德伦伯试验阳性得以证实。