The Effect of Botulinum Toxin Type A Injection in the Rectus Femoris in Stroke Patients Walking With a Stiff Knee Gait: A Randomized Controlled Trial.

BACKGROUND: Over activity of the rectus femoris is often cited as a main cause for stiff knee gait (SKG). Botulinum toxin (BoNT) can be used to reduce this over activity. Inconsistent results for the effect of BoNT injections were found in literature which can possibly be explained by the study design as these were uncontrolled or non-randomized studies. OBJECTIVE: To conduct a randomized controlled trial (RCT) to investigate the effect of botulinum toxin type A (BoNT-A) injections in the rectus femoris on gait kinematics and functional outcome in adult stroke patients. METHODS: Twenty-six participants were included in this triple-blind cross-over RCT. The intervention consisted of an injection with BoNT-A. Placebo is an injection with saline. Besides knee and hip kinematics, functional outcomes were measured. RESULTS: Comparison of the effect of BoNT-A injection to placebo injection showed a significant increase in peak knee flexion and knee range of motion of 6.7° and 4.8° respectively. There was no difference in hip kinematics. In functional outcomes, only the 6 Minute Walking Test showed a significant increase of 18.3 m. CONCLUSIONS: BoNT-A injections in the rectus femoris is a valuable treatment option for stroke patients walking with a SKG to improve knee kinematics. To study the effect on functional outcome more research is necessary with different functional outcome measures that can capture the effect in kinematics. It is important to use kinematic measurements to demonstrate effects in quality of movement that are not captured by commonly used functional outcome measurements post stroke.Clinical Trial Registration: https://trialsearch.who.int/Trial2.aspx?TrialID=NTR2169.

Does the Duncan-Ely test predict abnormal activity of the rectus femoris in stroke survivors with a stiff knee gait?

OBJECTIVE: To determine the diagnostic value of the Duncan-Ely test in predicting abnormal rectus femoris activity during gait in stroke survivors walking with a stiff knee gait. DESIGN: Cross-sectional diagnostic study. SUBJECTS: A total of 95 patients with chronic stroke. METHODS: During physical examination, the Duncan-Ely test was performed and scored. Surface electromyography of the rectus femoris was then recorded during dynamic gait. To determine the diagnostic value, the results of the Duncan-Ely test and surface electromyography recordings (gold standard) were compared. RESULTS: The Duncan-Ely test had a sensitivity of 73%, a specificity of 29%, a positive predictive value of 60%, and a negative predictive value of 42%. The area under the curve was 0.488 ([AQ1] CI 0.355-0.621, p = 0.862), showing that the Duncan-Ely test is not better than random guessing. CONCLUSION: The Duncan-Ely test has no predictive value for determining abnormal activity of the rectus femoris during gait. Using this test can lead to incorrect identification of abnormal rectus femoris activity, which might hamper the selection of optimal treatment options. We recommend stopping use of the Duncan-Ely test to predict rectus femoris overactivity during swing, and instead use surface electromyography.

Influence of functional electrical stimulation of the hamstrings on knee kinematics in stroke survivors walking with stiff knee gait.

OBJECTIVE: To explore whether functional electrical stimulation of the hamstrings results in improved knee kinematics in chronic stroke survivors walking with a stiff knee gait. DESIGN: Quasi-experimental. SUBJECTS: Sixteen adult chronic stroke survivors. METHODS: Survivors received functional electrical stimulation of the hamstrings, 3 times a week for 1 h during a period of 5 weeks. 3D kinematics was calculated before the training period and after 5 weeks of training. Knee kinematics of walking without stimulation before the training period was compared with walking with stimulation after 5 weeks of training. (intervention effect). In addition, knee kinematics of walking without stimulation before the training period was compared with walking without stimulation after the training period (therapeutic effect). RESULTS: The intervention effect showed a significant increase, of mean 8.7° (standard deviation (SD) 8.3, p = 0.001), in peak knee flexion. The therapeutic effect showed a significant increase in peak knee flexion, of mean 3.1° (SD 4.7, p = 0.021) Conclusion: The results of this exploratory study suggest an increase in knee kinematics in swing after functional electrical stimulation of the hamstrings in stroke survivors walking with a stiff knee gait. The largest improvement in peak knee flexion in swing was seen when participants walked with hamstring stimulation. Participants with low neurological impairment responded better to hamstring stimulation, and there are indications that the effect of hamstring stimulation can be predicted during a single session. The effect of functional electrical stimulation is comparable to that of more invasive treatment options, such as botulinum toxin or soft-tissue surgery. This makes functional electrical stimulation a feasible treatment option for daily clinical practice.

Effect of chemodenervation of the rectus femoris muscle in adults with a stiff knee gait due to spastic paresis: a systematic review with a meta-analysis in patients with stroke.

OBJECTIVE: To determine the effect of motor branch block (MBB) or neuromuscular block (NMB) of the rectus femoris on knee kinematics during swing, functional outcome, and energy cost in adults with spastic paresis presenting a stiff knee gait. DATA SOURCES: PubMed, Embase, CINAHL, and Cochrane Library were searched. Studies were collected up to February 26, 2013. Reference lists were additionally scrutinized. STUDY SELECTION: No restrictions were applied regarding study design. Patients were adults suffering from a central neurological disorder. Interventions had to include MBB or NMB. Outcome measures had to include knee kinematics during the swing phase. Study selection was independently performed by 2 reviewers. DATA EXTRACTION: Two reviewers independently assessed the methodological quality of included studies. Data on kinematics, functional outcome, and energy cost from patients with stroke were extracted from the total population and when possible pooled. DATA SYNTHESIS: A total of 9 articles describing 12 different studies were included. Knee kinematics (peak knee flexion or knee range) during swing improved significantly in all the included studies. The average increase in peak knee flexion varied from 1.9° to 15.4°. Data pooling of peak knee flexion in patients with stroke showed a significant improvement of 7.37° (P=.000) in NMB studies and of 9.35° (P=.002) in MBB studies. Data pooling of knee velocity at toe-off showed a significant improvement of 53.01°/s in NMB studies. In MBB studies, this improvement was not significant. Data pooling of knee range of motion, functional outcomes, and energy cost showed no significant difference. CONCLUSIONS: According to this review, chemodenervation of the rectus femoris shows a significant improvement in peak knee flexion during swing. The effect on functional outcomes and energy cost is still unclear.

Effects of an implantable two-channel peroneal nerve stimulator versus conventional walking device on spatiotemporal parameters and kinematics of hemiparetic gait.

OBJECTIVE: The aims of this study were: (i) to compare the neuro-prosthetic effect of implantable peroneal nerve stimulation to the orthotic effect of a standard of care intervention (no device, shoe or ankle foot orthosis) on walking, as assessed by spatiotemporal parameters; and (ii) to examine whether there is evidence of an enhanced lower-limb flexion reflex with peroneal nerve stimulation and compare the kinematic effect of an implantable peroneal nerve stimulation device vs standard of care intervention on initial loading response of the paretic limb, as assessed by hip, knee and ankle kinematics. DESIGN: Randomized controlled trial. SUBJECTS: A total of 23 chronic stroke survivors with drop foot. METHODS: The intervention group received an implantable 2-channel peroneal nerve stimulator for correction of drop foot. The control group continued using a conventional walking device. Spatiotemporal parameters and hip, knee and ankle kinematics were measured while subjects walked with the device on using a 3-dimensional video camera system during baseline and after a follow-up period of 26 weeks. RESULTS: Peroneal nerve stimulation normalized stance and double support of the paretic limb and single support of the non-paretic limb, in comparison with using a conventional walking device. In addition, peroneal nerve stimulation is more effective to provide ankle dorsiflexion during swing and resulted in a normalized initial loading response. CONCLUSION: Although peroneal nerve stimulation and ankle foot orthosis are both prescribed to correct a drop foot in the same patient population, spatiotemporal parameters, dorsiflexion during swing and loading response are influenced in a functionally different way.

The effect of FES of the tibial nerve on physiological activation of leg muscles during gait.

The effects of surface functional electrical stimulation (FES) of the tibial nerve of healthy subjects were evaluated. The FES was applied at three different times during gait: early, mid and late stances. The purpose of this work is to understand the effect of unilateral stimulation on the bilateral activation patterns of leg muscles, because FES is used in practice to improve gait, while associated neuromuscular change is not often measured. The experimental protocol presented here will be transferred to stroke subjects, who could benefit from improved push-off during gait. Results show that FES of the tibial nerve changes the offset timing of the tibialis anterior muscle on the stimulated side and the on- and offset timings of the tibialis anterior muscle of the leg contralateral to stimulation. Additionally, activity levels of the semitendinosus ipsilateral and tibialis anterior contralateral to the stimulated leg significantly decreased, with respect to the non-stimulated condition. For the semitendinosus, this was a difference of 6-7microV, with p<0.05. For the tibialis anterior, this was a difference of 7-15microV, with a significance of p=0.00, respectively. This information is important for future applications of stimulation as it means that stimulation not only affects the stimulated muscle but also the physiological motor control by the CNS.

Therapeutic effect of an implantable peroneal nerve stimulator in subjects with chronic stroke and footdrop: a randomized controlled trial.

BACKGROUND AND PURPOSE: Footdrop, characterized by a person's inability to raise the foot at the ankle, is a common problem in patients with stroke. A randomized controlled trial was performed to determine the therapeutic effect of using a new implantable, 2-channel peroneal nerve stimulator for 6 months versus an ankle-foot orthosis (AFO). SUBJECTS: Twenty-nine patients with chronic stroke and footdrop participated in the study. The mean time from stroke was 7.3 years (SD=7.3), and all subjects were community ambulators. METHODS: The study used a randomized controlled trial design. The functional electrical stimulation (FES) group received the implantable stimulation system for correction of their footdrop. The control group continued using their conventional walking device (ie, AFO, orthopedic shoes, or no walking device). All subjects were measured at baseline and at weeks 4, 8, 12, and 26 in the gait laboratory. The therapeutic effect of FES on the maximum value of the root mean square (RMSmax) of the tibialis anterior (TA) muscle with both flexed and extended knees and walking speed were selected as the primary outcome measures. The RMSmax of the peroneus longus (PL), gastrocnemius (GS), and soleus (SL) muscles with both flexed and extended knees and muscle activity of the TA muscle of the affected leg during the swing phase of gait were selected as secondary outcome measures. RESULTS: A significantly higher RMSmax of the TA muscle with extended knee was found after using FES. No change in walking speed was found when the stimulator was not switched on. A significantly increased RMSmax of the GS muscle with both flexed and extended knees was found after using FES. DISCUSSION AND CONCLUSION: Functionally, no therapeutic effect of implantable peroneal nerve stimulation was found. However, the significantly increased voluntary muscle output of the TA and GS muscles after the use of FES suggests that there was a certain extent of plasticity in the subjects in this study.

Interaction of artificial and physiological activation of the gastrocnemius during gait.

Objectives. The purpose of this research was to understand the effects of surface functional electrical stimulation (FES) of the tibial nerve on the activation of the gastrocnemius medialis of the stimulated side. Methods. FES was carried out on six healthy subjects, initiated at three different times during gait: early, mid, and late stance. Each stimulation burst consisted of 15 pulses, applied for 300 msec, at 50 Hz stimulation frequency. Mixed model statistical analysis was carried out on the median onset and offset times of the gastrocnemius medialis and the root mean square of the interpulse interval responses. Results. Results indicate that the electromyography response to FES is dependent on the time of application. The most prominent effects found in the intervals between the stimulation pulses (interpulse intervals) were found when stimulation was applied early in the stance phase. This study revealed that the only statistically significant effect on burst timing was a delay in offset timing due to mid-timed stimulation. Conclusions. We conclude that additional activation may have been compensated, at least in part, by blocking of the physiological activation during the stimulation burst.

A randomized controlled trial of an implantable 2-channel peroneal nerve stimulator on walking speed and activity in poststroke hemiplegia.

OBJECTIVE: To determine the effect of a new implantable 2-channel peroneal nerve stimulator on walking speed and daily activities, in comparison with the usual treatment in chronic stroke survivors with a drop foot. DESIGN: Randomized controlled trial. SETTING: All subjects were measured 5 times in the gait laboratory. PARTICIPANTS: Twenty-nine stroke survivors with chronic hemiplegia with drop foot who fulfill the predefined inclusion and exclusion criteria were included in the study. INTERVENTION: The intervention group received an implantable 2-channel peroneal nerve stimulator for correction of their drop foot. The control group continued using their conventional walking device, consisting of an ankle-foot orthosis, orthopedic shoes, or no device. MAIN OUTCOME MEASURES: Walking speed, assessed both by a six-minute walk test (6MWT) and by using a 10-m walkway, was selected as primary outcome measure and activity monitoring data, consisting of percentage time spent on stepping, standing, and sitting/lying were selected as secondary outcome measure. RESULTS: Functional electric stimulation (FES) resulted in a 23% improvement of walking speed measured with the 6MWT, whereas the improvement in the control group was only 3% (P=.010). Comfortable walking speed measured on a 10-m walkway was also significantly improved in favor of FES (P=.038). The percentage time spent on stepping deteriorated with 3% in the intervention and 0.8% in control group, which was not statistically significant between both groups (P=.13). CONCLUSIONS: The present study shows a clinically relevant effect of the implantable 2-channel peroneal nerve stimulator on walking speed in the sample of stroke survivors included in our study.

An implantable two channel drop foot stimulator: initial clinical results.

This article reports preliminary results of pilot studies of a new implantable two channel drop foot stimulator. The stimulator consists of an externally worn transmitter inductively coupled to an implanted receiver unit located in the lower leg, lateral and distal to the knee. The receiver is connected to electrodes located under the epineurium of the deep and the superficial peroneal nerves. Stimulation is triggered by detection of heel lift and terminated at heel strike in a manner similar to surface mounted systems. The location of the electrodes allows for a degree of selectivity over the resultant moment about the ankle joint that is not possible with surface stimulation of the common peroneal nerve. The two subjects used the stimulator on a regular basis and showed increases in walking speed of between 10% and 44% when compared to their baseline measurements. Isometric tests have demonstrated that the stimulator allows selective and repeatable stimulation of ankle joint muscles.