College of Health Professions, Marshall University, Huntington, West Virginia, USA.
Department of Orthopedics, Joan C. Edwards School of Medicine, Marshall University, Huntington, West Virginia, USA.
J Ultrasound Med. 2019 Apr;38(4):959-966. doi: 10.1002/jum.14779. Epub 2018 Oct 2.
The medial elbow is stabilized during valgus loading by the ulnar collateral ligament, the flexor pronator mass (FPM), and the radial head. Impairment of the FPM can occur as a result of repeated wrist flexion activity. The purpose of this study was to determine the effect of repeated elbow flexion exercise on medial elbow stability.
Thirty volunteers were included in this study. Ultrasound images of the medial joint space of the nondominant elbow of the participants were collected during a valgus stress test. The images were collected before and immediately after a wrist flexion exercise protocol.
The wrist flexion strength measure decreased (7.5%) after the exercise protocol (t = 3.840; P = .001). The medial elbow width increased between unstressed (mean ± SD, 2.8 ± 0.1 mm) and stressed (3.6 ± 0.1 mm) conditions (P < .001). The stress-by-fatigue interaction was significant (P = .048). The medial elbow width increased after fatigue (0.9 ± 0.09 mm) while remaining unchanged in the unstressed condition.
This study found an effect of repeated wrist flexion exercise on decreasing the stability of the medial elbow. Future research needs to explore the mechanisms leading to the decrease in medial elbow stability and to identify the effect of FPM fatigue on the development of medial elbow pain associated with activities.
在外翻负荷下，尺侧副韧带、屈肌旋前肌（FPM）和桡骨头稳定了内侧肘。由于反复的腕关节屈曲活动，可能会导致 FPM 受损。本研究旨在确定反复的肘部弯曲运动对内侧肘稳定性的影响。
本研究纳入了 30 名志愿者。在进行外翻压力测试时，采集了参与者非优势侧肘部内侧关节间隙的超声图像。在腕关节弯曲运动方案之前和之后立即采集图像。
运动方案后，腕关节弯曲力量测量值下降（7.5%）（t=3.840；P=.001）。在无应力（平均±标准差，2.8±0.1mm）和受力（3.6±0.1mm）条件下，内侧肘宽度增加（P<.001）。疲劳与压力的相互作用具有统计学意义（P=.048）。在疲劳后，内侧肘宽度增加（0.9±0.09mm），而在无应力状态下保持不变。
本研究发现，反复的腕关节弯曲运动对内侧肘稳定性产生了影响。未来的研究需要探索导致内侧肘稳定性下降的机制，并确定 FPM 疲劳对与活动相关的内侧肘疼痛发展的影响。
