Muscle fatigue in arthritis total hip replacement

背景：美国每年进行超过12.4万例全髋关节置换(THR)手术，旨在提高髋关节炎、髋关节恶化或髋关节损伤患者的活动能力和舒适度。THR最常见的术前诊断是骨性关节炎。正如NIH全髋关节置换术共识会议所指出的，关于产生最佳长期结果的康复方法仍然存在问题。以前没有关于THR患者肌肉疲劳的影响的研究被确定。肌肉疲劳和耐力会显著影响患者的活动功能和继发性损伤的风险。目的/假设：本研究旨在评估接受全髋关节置换(THR)手术的关节炎患者的肌肉疲劳，以此作为评估康复状况的一种手段。我们研究的主要假设是，THR患者表现出更高的疲劳率和水平，使这一人群面临更高的跌倒、关节脱位和其他伤害的风险。如果这一假设被证明是确凿的，康复评估和训练策略应该扩展到解决耐力问题。方法：研究方法。肌电测量和关节运动分析的组合将被用于评估THR患者对轻度肌肉疲劳的反应。测试条件包括测功机、次最大负荷(80%MVC)、等长和等速练习。患者组接受手术的髋关节的反应将与未手术的髋关节以及对照组进行比较。THR受试者将在术后4至5个月内接受评估。身体和社会功能的自我评估也将使用MOSS-SF 36、HAQ和MAQ进行评估。初步结果/发现：我们的初步数据来自由西巴马州资助的一项试点研究(10个病例和10个对照)。关节炎基金会的一章指出，在肌肉疲劳/耐力以及自我评估身体和社会功能方面，病例和对照组之间存在差异。在所有生物力学指标中，THR患者的表现或结果较差。与髋关节屈曲、伸展和外展相关的等速运动能力在病例和对照组之间有统计学上的显著差异。在80%的MVC锻炼中，患者的肌肉疲劳程度也与对照组有显著差异，这是通过中位数弓步频率变化来衡量的。我们进一步观察到病例手术髋关节的等速性能比未手术髋关节低。髋关节屈曲时，手术与非手术的等速表现有显著差异。使用MOSS-SF36测量的THR病例的自我评估也一致低于对照组。

Background: More than 124,000 total hip replacement (THR) surgeries are performed annually in the US in an effort to increase mobility and comfort in those having arthritic, deteriorated or injured hips. The most common preoperative diagnosis for THR is osteoarthritis. As indicated in the NIH Total Hip Replacement Consensus Conference, questions remain concerning rehabilitation approaches which yield the best long-term outcomes. No previous investigations regarding the influence of muscle fatigue in THR patients have been identified. Muscle fatigue and endurance can significantly affect mobility1 function and the risk of secondary injury in this patient population. Aim/Hypothesis: This study seeks to evaluate muscle fatigue in arthritis patients who have undergone total hip replacement (THR) surgery as a means to assess rehabilitation status. The primary hypothesis of our study is that THR patients exhibit increased rates and levels of fatigue placing this population at higher risk for falls, joint dislocations and other injuries. Should this hypothesis prove conclusive, rehabilitation evaluation and training strategies should be expanded to address endurance. Methods. A combination of EMG measures and joint kinetic analysis will be utilized to assess THR patient response to mild muscle fatigue. Test conditions will include dynamometer submaximal (80% MVC) isometric and isokinetic exercises. Response of the patient group's operated hip will be compared to the unoperated hip, as well as to a control group. THR subjects will be assessed postoperatively between 4 and 5 months. Self-assessment of physical and social function will also be evaluated using the MOSS-SF 36, HAQ and MAQ. Preliminary Results/Findings: Our preliminary data from a pilot study (10 cases and 10 controls) funded by the Western Pa. Chapter of the Arthritis Foundation indicates that differences exist between cases and controls in muscle fatigue/endurance and self-assessed physical and social function. Across all biomechanical measures THR cases have lower performance or outcome. Statistically significant differences were found between cases and controls in isokinetic performance associated with hip flexion, extension and abduction. Cases also differed significantly from controls in the level of muscle fatigue associated with 80% MVC exercises as measured by median bower frequency shift. We further observed lower isokinetic performance in case operated hips than unoperated hips. Significant differences were found between operated and unoperated isokinetic performance in hip flexion. Self-assessment of THR cases as measured using the MOSS-SF36 was also consistent lower than that of control subjects.