Cooper Allison, Alghamdi Ghalib Abdulllah, Alghamdi Mohammed Abdulrahman, Altowaijri Abdulrahman, Richardson Susan
College of Human & Health Science, Swansea University, Swansea, UK.
Physiother Res Int. 2012 Sep;17(3):150-6. doi: 10.1002/pri.528. Epub 2011 Dec 7.
Despite the finding that 40% to 60% of stroke patients suffer from knee joint hyperextension during gait, there is a lack of agreement of the possible causes of this problem. The aim of this study was to determine whether there is a relationship between lower limb muscle weakness and knee joint hyperextension in hemiparetic stroke patients.
This is a cross-sectional observational comparison study. Twenty patients (mean age 66 years) who had suffered a single hemiparetic stroke and were ambulant with no major lower limb joint pathology participated. Muscle strength of the hip extensors, hip flexors, hip abductors, knee extensors, knee flexors, ankle plantarflexors and ankle dorsiflexors of both limbs was measured using a hand-held dynamometer. Computerized and visual gait analysis identified subjects with and without knee hyperextension in loading response and midstance. Subjects were categorized as having weakness of a particular muscle group if the difference in strength between the paretic and non-paretic muscle was greater than 50%. The Pearson's chi-squared test was used to evaluate the association between weakness and knee hyperextension.
A strong relationship was found between ankle plantarflexor weakness and knee hyperextension during midstance (p = 0.044). No relationship was found between lower limb muscle weakness and knee hyperextension during loading response (p > 0.05). No relationship was found between any other lower limb muscle groups and knee hyperextension in midstance (p > 0.05).
Weak ankle plantarflexors, in particular gastrocnemius, may have an important role in the presence of knee hyperextension. The results of this study did not support a role for weak hamstrings or quadriceps in knee hyperextension during gait. Further research is needed to clarify the role of gastrocnemius during the stance phase and to determine if strengthening weak gastrocnemius reduces knee hyperextension.
尽管有研究发现40%至60%的中风患者在步态中存在膝关节过度伸展的情况，但对于该问题的可能成因尚无定论。本研究的目的是确定偏瘫性中风患者下肢肌肉无力与膝关节过度伸展之间是否存在关联。
这是一项横断面观察性比较研究。20例（平均年龄66岁）单次发生偏瘫性中风且能行走、无主要下肢关节病变的患者参与了研究。使用手持测力计测量双下肢髋伸肌、髋屈肌、髋外展肌、膝伸肌、膝屈肌、踝跖屈肌和踝背屈肌的肌力。通过计算机化和视觉步态分析确定在负重反应和支撑中期有无膝关节过度伸展的受试者。如果患侧与非患侧肌肉力量差异大于50%，则将受试者归类为特定肌肉群无力。采用Pearson卡方检验评估无力与膝关节过度伸展之间的关联。
发现支撑中期踝跖屈肌无力与膝关节过度伸展之间存在密切关联（p = 0.044）。在负重反应期间，未发现下肢肌肉无力与膝关节过度伸展之间存在关联（p > ０.05）。在支撑中期，未发现其他任何下肢肌肉群与膝关节过度伸展之间存在关联（p > ０.05）。
无力的踝跖屈肌，尤其是腓肠肌，可能在膝关节过度伸展的发生中起重要作用。本研究结果不支持腘绳肌或股四头肌无力在步态中膝关节过度伸展中起作用的观点。需要进一步研究以阐明腓肠肌在站立期的作用，并确定加强无力腓肠肌是否能减少膝关节过度伸展。
