Palmieri-Smith Riann M, Hopkins J Ty, Brown Tyler N
School of Kinesiology, University of Michigan, 401 Washtenaw Avenue, Ann Arbor, MI 48109, USA.
Am J Sports Med. 2009 May;37(5):982-8. doi: 10.1177/0363546508330147. Epub 2009 Mar 6.
Functional ankle instability (FAI) may be prevalent in as many as 40% of patients after acute lateral ankle sprain. Altered afference resulting from damaged mechanoreceptors after an ankle sprain may lead to reflex inhibition of surrounding joint musculature. This activation deficit, referred to as arthrogenic muscle inhibition (AMI), may be the underlying cause of FAI. Incomplete activation could prevent adequate control of the ankle joint, leading to repeated episodes of instability.
Arthrogenic muscle inhibition is present in the peroneal musculature of functionally unstable ankles and is related to dynamic peroneal muscle activity.
Cross-sectional study; Level of evidence, 3.
Twenty-one (18 female, 3 male) patients with unilateral FAI and 21 (18 female, 3 male) uninjured, matched controls participated in this study. Peroneal maximum H-reflexes and M-waves were recorded bilaterally to establish the presence or absence of AMI, while electromyography (EMG) recorded as patients underwent a sudden ankle inversion perturbation during walking was used to quantify dynamic activation. The H:M ratio and average EMG amplitudes were calculated and used in data analyses. Two-way analyses of variance were used to compare limbs and groups. A regression analysis was conducted to examine the association between the H:M ratio and the EMG amplitudes.
The FAI patients had larger peroneal H:M ratios in their nonpathological ankle (0.399 +/- 0.185) than in their pathological ankle (0.323 +/- 0.161) (P = .036), while no differences were noted between the ankles of the controls (0.442 +/- 0.176 and 0.425 +/- 0.180). The FAI patients also exhibited lower EMG after inversion perturbation in their pathological ankle (1.7 +/- 1.3) than in their uninjured ankle (EMG, 3.3 +/- 3.1) (P < .001), while no differences between legs were noted for controls (P > .05). No significant relationship was found between the peroneal H:M ratio and peroneal EMG (P > .05).
Arthrogenic muscle inhibition is present in the peroneal musculature of persons with FAI but is not related to dynamic muscle activation as measured by peroneal EMG amplitude. Reversing AMI may not assist in protecting the ankle from further episodes of instability; however dynamic muscle activation (as measured by peroneal EMG amplitude) should be restored to maximize ankle stabilization. Dynamic peroneal activity is impaired in functionally unstable ankles, which may contribute to recurrent joint instability and may leave the ankle vulnerable to injurious loads.
功能性踝关节不稳（FAI）在急性外侧踝关节扭伤后的患者中患病率可能高达40%。踝关节扭伤后机械感受器受损导致的传入改变可能会引起周围关节肌肉组织的反射性抑制。这种激活不足，即关节源性肌肉抑制（AMI），可能是FAI的潜在原因。激活不完全可能会妨碍对踝关节的充分控制，导致反复出现不稳发作。
关节源性肌肉抑制存在于功能不稳踝关节的腓骨肌群中，且与腓骨肌动态活动有关。
横断面研究；证据等级，3级。
21例（18例女性，3例男性）单侧FAI患者和21例（18例女性，3例男性）未受伤的匹配对照者参与了本研究。双侧记录腓骨肌最大Hoffmann反射（H反射）和M波以确定AMI是否存在，同时在患者行走过程中进行突然的踝关节内翻扰动时记录肌电图（EMG）以量化动态激活。计算H:M比值和平均EMG幅度并用于数据分析。采用双向方差分析比较肢体和组间差异。进行回归分析以检验H:M比值与EMG幅度之间的关联。
FAI患者非病变踝关节的腓骨肌H:M比值（0.399±0.185）大于病变踝关节（0.323±0.161）（P = 0.036），而对照组双侧踝关节之间无差异（0.442±0.176和0.425±0.180）。FAI患者病变踝关节内翻扰动后的EMG也低于未受伤踝关节（EMG，1.7±1.3）（P < 0.001），而对照组双腿之间无差异（P > 0.05）。未发现腓骨肌H:M比值与腓骨肌EMG之间存在显著相关性（P > 0.05）。
关节源性肌肉抑制存在于FAI患者的腓骨肌群中，但与通过腓骨肌EMG幅度测量的动态肌肉激活无关。逆转AMI可能无助于保护踝关节避免进一步的不稳发作；然而，应恢复动态肌肉激活（通过腓骨肌EMG幅度测量）以最大限度地稳定踝关节。功能不稳踝关节的腓骨肌动态活动受损，这可能导致反复的关节不稳，并可能使踝关节易受损伤负荷的影响。
