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

The Effect of Botulinum Neurotoxin-A (BoNT-A) on Muscle Strength in Adult-Onset Neurological Conditions with Focal Muscle Spasticity: A Systematic Review

Botulinum neurotoxin-A (BoNT-A) injections are effective for focal spasticity. However, the impact on muscle strength is not established. This study aimed to investigate the effect of BoNT-A injections on muscle strength in adult neurological conditions. Studies were included if they were Randomised Controlled Trials (RCTs), non-RCTs, or cohort studies (n ≥ 10) involving participants ≥18 years old receiving BoNT-A injection for spasticity in their upper and/or lower limbs. Eight databases (CINAHL, Cochrane, EMBASE, Google Scholar, Medline, PEDro, Pubmed, Web of Science) were searched in March 2024. The methodology followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was registered in the Prospective Register of Systematic Reviews (PROSPERO: CRD42022315241). Quality was assessed using the modified Downs and Black checklist and the PEDro scale. Pre-/post-injection agonist, antagonist, and global strength outcomes at short-, medium-, and long-term time points were extracted for analysis. Following duplicate removal, 8536 studies were identified; 54 met the inclusion criteria (3176 participants) and were rated as fair-quality. Twenty studies were analysed as they reported muscle strength specific to the muscle injected. No change in agonist strength after BoNT-A injection was reported in 74% of the results. Most studies' outcomes were within six weeks post-injection, with few long-term results (i.e., >three months). Overall, the impact of BoNT-A on muscle strength remains inconclusive.

Anatomical landmarks for ultrasound-guided rectus femoris diagnostic nerve block in post-stroke spasticity

Introduction/Purpose

To determine the location of the rectus femoris (RF) motor branch nerve, as well as its coordinates with reference to anatomical and ultrasound landmarks.

Methods

Thirty chronic stroke patients with stiff knee gait (SKG) and RF hyperactivity were included. The motor nerve branch to the RF muscle was identified medially to the vertical line from anterior superior iliac spine and the midpoint of the superior margin of the patella (line AP) and vertically to the horizontal line from the femoral pulse and its intersection point with the line AP (line F). The point of the motor branch (M) was located with ultrasound, and nerve depth and subcutaneous tissue thickness (ST) were calculated.

Results

The coordinates of the motor branch to the RF were 2.82 (0.47) cm medially to the line AP and 4.61 (0.83) cm vertically to the line F. Nerve depth and subcutaneous tissue thickness were 2.71 (0.62) cm and 1.12 (0.75) cm, respectively.

Conclusion

The use of specific coordinates may increase clinicians' confidence when performing RF motor nerve block. This could lead to better decision-making when assessing SKG in chronic stroke patients.

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.

Stiff Knee Gait Disorders as Neuromechanical Consequences of Spastic Hemiplegia in Chronic Stroke

Stiff knee gait (SKG) is defined as decreased knee flexion during the swing phase. It is one of the most common gait disorders following stroke. Knee extensor spasticity is commonly accepted as the primary cause. Clinical management has focused on the reduction in knee extensor spasticity. Recent advances in understanding of post-stroke hemiplegic gait suggest that SKG can present as mechanical consequences between muscle spasticity, weakness, and their interactions with ground reactions during walking. Various underlying mechanisms are presented through sample cases in this article. They include ankle plantar flexor spasticity, knee extensor spasticity, knee flexor and extensor coactivation, and hip flexor spasticity. Careful and thorough clinical assessment is advised to determine the primary cause for each patient. Understanding of these various presentations of SKG is helpful to guide clinical assessment and select appropriate target muscles for interventions.

Muscle contributions to pre-swing biomechanical tasks influence swing leg mechanics in individuals post-stroke during walking

Background

Successful walking requires the execution of the pre-swing biomechanical tasks of body propulsion and leg swing initiation, which are often impaired post-stroke. While excess rectus femoris activity during swing is often associated with low knee flexion, previous work has suggested that deficits in propulsion and leg swing initiation may also contribute. The purpose of this study was to determine underlying causes of propulsion, leg swing initiation and knee flexion deficits in pre-swing and their link to stiff knee gait in individuals post-stroke.

Methods

Musculoskeletal models and forward dynamic simulations were developed for individuals post-stroke (n = 15) and healthy participants (n = 5). Linear regressions were used to evaluate the relationships between peak knee flexion, braking and propulsion symmetry, and individual muscle contributions to braking, propulsion, knee flexion in pre-swing, and leg swing initiation.

Results

Four out of fifteen of individuals post-stroke had higher plantarflexor contributions to propulsion and seven out of fifteen had higher vasti contributions to braking on their paretic leg relative to their nonparetic leg. Higher gastrocnemius contributions to propulsion predicted paretic propulsion symmetry (p = 0.005) while soleus contributions did not. Higher vasti contributions to braking in pre-swing predicted lower knee flexion (p = 0.022). The rectus femoris had minimal contributions to lower knee flexion acceleration in pre-swing compared to contributions from the vasti. However, for some individuals with low knee flexion, during pre-swing the rectus femoris absorbed more power and the iliopsoas contributed less power to the paretic leg. Total musculotendon work done on the paretic leg in pre-swing did not predict knee flexion during swing.

Conclusions

These results emphasize the multiple causes of propulsion asymmetry in individuals post-stroke, including low plantarflexor contributions to propulsion, increased vasti contributions to braking and reliance on compensatory mechanisms. The results also show that the rectus femoris is not a major contributor to knee flexion in pre-swing, but absorbs more power from the paretic leg in pre-swing in some individuals with stiff knee gait. These results highlight the need to identify individual causes of propulsion and knee flexion deficits to design more effective rehabilitation strategies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12984-022-01029-z.

The Use of Botulinum Toxin for Treatment of Spasticity

Spasticity is one component of the upper motor neuron (UMN) syndrome resulting from a multitude of neurologic conditions, such as stroke, brain injury, spinal cord injury, multiple sclerosis, and cerebral palsy. It is clinically recognized as a phenomenon of velocity-dependent increase in resistance, i.e., hypertonia. Recent advances in the pathophysiology of spasticity improve our understanding of mechanisms underlying this complex phenomenon and its relations to other components of UMN syndrome (weakness and disordered motor control), as well as the resultant clinical problems. This theoretical framework provides a foundation to set up treatment goals and to guide goal-oriented clinical assessment and treatment. Among a spectrum of treatment options, botulinum toxin (BoNT) therapy is the preferred treatment for focal spasticity. The evidence is very robust that BoNT therapy effectively reduces spasticity; however, it does not improve voluntary movement. In this chapter, we highlight a few issues on how to achieve the best clinical outcomes of BoNT therapy, such as dosing, dilution, guidance techniques, adjunctive therapies, early treatment, repeated injections, and central effects, as well as the ways to improve motor function in selected subgroups of patients with spasticity. We also discuss the reasons of poor responses to BoNT therapy and when not to use BoNT therapy.

Ankle-foot orthosis with dorsiflexion resistance using spring-cam mechanism increases knee flexion in the swing phase during walking in stroke patients with hemiplegia

BACKGROUND

Ankle-foot orthoses with plantarflexion resistance (AFO-Ps) improve knee flexion in the stance phase on the paretic side in patients with hemiparesis. However, AFO-Ps decrease ankle power generation in the late stance phase and do not improve the knee flexion in the swing phase based on insufficient push-off at the late stance, resulting in lower toe clearance.

RESEARCH QUESTION

This study sought to investigate the effect of an AFO with dorsiflexion resistance, which was implemented by our developed device with spring-cam mechanism attached to the AFO-P (Gait Solution; Pacific Supply Co., Ltd., Japan), on kinetics and kinematics in the lower limb during gait in patients with hemiparesis.

METHODS

Eleven patients with hemiparesis due to stroke walked on a 7-m walkway at a self-selected comfortable pace in the following conditions: (a) walking using the AFO-P with the proposed device with a spring-cam mechanism (AFO-PCAM), (b) walking using the AFO-P without our device (AFO-P), and (c) walking using no device (barefoot condition). Gait kinematics and kinetics were collected using a three-dimensional motion analysis system and four ground-reaction force plates. Changes in all parameters from the barefoot to AFO-PCAM and AFO-P conditions were compared using the Wilcoxon signed-rank test.

RESULTS

In the AFO-PCAM condition, decrease in the maximum ankle power generation in the late-stance phase was significantly smaller than that in the AFO-P condition (p = 0.041). We noted a significant higher change in knee flexion in the paretic swing phase in the AFO-PCAM condition relative to that in the AFO-P condition (p = 0.016). The effect size for the comparisons of change was large (r ≧ 0.5).

SIGNIFICANCE

Our device facilitated the realization of the ankle plantarflexion power in the late-stance phase because of dorsiflexion resistance, increasing the knee flexion angle during the swing phase.

The Effects of Botulinum Toxin Injections on Spasticity and Motor Performance in Chronic Stroke with Spastic Hemiplegia

Spastic muscles are weak muscles. It is known that muscle weakness is linked to poor motor performance. Botulinum neurotoxin (BoNT) injections are considered as the first-line treatment for focal spasticity. The purpose of this study was to quantitatively investigate the effects of BoNT injections on force control of spastic biceps brachii muscles in stroke survivors. Ten stroke survivors with spastic hemiplegia (51.7 ± 11.5 yrs; 5 men) who received 100 units of incobotulinumtoxinA or onabotulinumtoxinA to the biceps brachii muscles participated in this study. Spasticity assessment (Modified Ashworth Scale (MAS) and reflex torque) and muscle strength of elbow flexors, as well as motor performance assessment (force variability of submaximal elbow flexion) were performed within one week before (pre-injection) and 3~4 weeks (3-wk) after BoNT injections. As expected, BoNT injections reduced the MAS score and reflex torque, and elbow flexor strength on the spastic paretic side. However, motor performance remained within similar level before and after injections. There was no change in muscle strength or motor performance on the contralateral arm after BoNT injections. The results of this study provide evidence that BoNT injections can reduce spasticity and muscle strength, while motor performance of the weakened spastic muscle remains unchanged.

Long-term effects on body functions, activity and participation of hemiplegic patients in equino varus foot deformity surgical correction followed by immediate rehabilitation. A prospective observational study

Background: Functional surgery is an effective approach in the treatment of the rigid equinovarus foot deformity (EVFD). This must be associated with early rehabilitation treatments (ERTs) to prevent muscle rearrangements due to immobilization. Objectives: To assess the effects of EVFD surgical correction in adult stroke patients, when assessed according to the ICF domains. Methods: Variables from 24 adult chronic stroke survivors with EVFD surgical correction followed by ERT, age 55 ± 13 years, affected side 12L/12R, time from lesion 5 ± 4 years were analyzed. Body function domain: pain (NPRS), walking speed, clinical global impression of change (cGIC). Activity domain: Rivermead Mobility Index (RMI), FAC, and 6 min walking test (6MWT). Participation domain: Walking Handicap Scale (WHS). Patients were assessed before (T0), one (T1), three (T2) and twelve (T3) months after surgery by a single assessor. Results: All variables but the 6MWT significantly improved (Wilcoxon test, p < .05) at T1 or T2 and this remained until the 12-months mark. Since T1, all patients reached and maintained a supervised independent walking (FAC≥3) and all those wearing an AFO stopped using it. The median cGCI was "much improved" at T1, with a "further minimal improvement" at T3. This was not associated with the improvement measured by both FAC, and WHS (Chi-square test, p = .20 and p = .36, respectively). Conclusions: Functional surgery combined with ERT is effective in improving the patients' condition according to all ICF domains. Both subjective and objective assessments have to be used when assessing these patients.

Impact of instrumental analysis of stiff knee gait on treatment appropriateness and associated costs in stroke patients

BACKGROUND

Stiff Knee Gait (SKG) in stroke patients is typically treated by the inhibition of the rectus femoris (RF) with botulinum toxin (BoNT) after clinical evaluation, obtaining an average pooled recovery in knee flexion (KF) of 7 degrees.

PURPOSE

Our hypothesis is that this limited recovery after BoNT could depend on the inadequacy in the selection of patients to be treated. The aim of this study was to assess the percentage of inappropriate treatments (PIT) that can be avoided when instrumental gait analysis (GA) is used, and to estimate the associated cost savings.

METHODS

We retrospectively analyzed GA data from chronic stroke patients with SKG and clinically assessed knee extensors spasticity referred to our laboratory over a five-year period. Gait kinematics and dynamic electromyography data were used. Patients were considered unsuitable for RF inhibition when: their SKG was determined by inadequate ankle push-off (APO) rather than by a brake from knee extensors, based on a previously published algorithm using gait kinematics (PIT_KIN); when RF was not active during KF (PIT_EMG); and when a proximal braking mechanism was found, if this was not due to RF activity (PIT_GA).

RESULTS

160 patients, age 20-87 years, gait speed 9-77%height/s, KF peak -4-44 degrees, were included. Of these, in 119 cases poor APO was the main cause of SKG, thus leading to PIT_KIN = 74%. In 48 out of 107 non-obese subjects, RF spasticity was not involved in SKG, resulting in PIT_EMG = 45%. Finally, patients with a braking activity as the main cause and concurrent RF activity were 20/107 = 19%, resulting in PIT_GA = 81% SIGNIFICANCE: When treating SKG, proper use of GA can reduce the percentage of inappropriate treatments by BoNT at the RF up to 81%. Savings are in the order of €100k/year when considering centers treating 100 or more patients/year.

Lower Extremity Problem-Solving: Challenging Cases

Lower limb dysfunction associated with upper motor neuron syndrome can be complex due to interaction of muscle overactivity, weakness, impaired motor control, and contracture. Treatment should be goal-directed and address the patient's passive and active functional impairments in addition to their symptoms. Therefore, a comprehensive, multidisciplinary team approach tailored to each patient's unique needs and functional goals is warranted. This article reviews the evaluation and management of issues related to lower limb muscle overactivity and how this approach was applied to 3 challenging cases.

Post-stroke Hemiplegic Gait: New Perspective and Insights

Walking dysfunction occurs at a very high prevalence in stroke survivors. Human walking is a phenomenon often taken for granted, but it is mediated by complicated neural control mechanisms. The automatic process includes the brainstem descending pathways (RST and VST) and the intraspinal locomotor network. It is known that leg muscles are organized into modules to serve subtasks for body support, posture and locomotion. Major kinematic mechanisms are recognized to minimize the center of gravity (COG) displacement. Stroke leads to damage to motor cortices and their descending corticospinal tracts and subsequent muscle weakness. On the other hand, brainstem descending pathways and the intraspinal motor network are disinhibited and become hyperexcitable. Recent advances suggest that they mediate post-stroke spasticity and diffuse spastic synergistic activation. As a result of such changes, existing modules are simplified and merged, thus leading to poor body support and walking performance. The wide range and hierarchy of post-stroke hemiplegic gait impairments is a reflection of mechanical consequences of muscle weakness, spasticity, abnormal synergistic activation and their interactions. Given the role of brainstem descending pathways in body support and locomotion and post-stroke spasticity, a new perspective of understanding post-stroke hemiplegic gait is proposed. Its clinical implications for management of hemiplegic gait are discussed. Two cases are presented as clinical application examples.

Electromyographic activity of the vastus intermedius muscle in patients with stiff-knee gait after stroke. A retrospective observational study

Stiff-knee gait (SKG) in hemiplegic patients is often due to an inappropriate activity of the quadriceps femoris. However, there are no studies in literature addressing the vastus intermedius (VI) involvement in SKG. In this study, VI activity was analyzed in a sample of 46 chronic stroke patients with SKG, during spontaneous gait. VI activity was recorded by fine-wire electrodes inserted under ultrasound guidance then confirmed by electrical stimulation. The measured VI activity was compared to the normal reference pattern reported in literature and classified (e.g. premature, prolonged). The occurrences of abnormal activations during each sub-phase of the gait cycle were assessed. VI activity presented an abnormal timing in 96% of the sample. The most common pathological pattern (in 46% of the sample) was the combination of premature and prolonged VI activation. Nearly 20% of patients presented a continuous activity. A pathological activation in patients was found for 91% in mid stance, for more than 50% in terminal stance and pre-swing and for 37% and 70% in initial- and mid-swing. Results indicate that abnormal VI activity is frequent in patients with SKG. Hence, VI activity should be included in the assessment of SKG to assist in the clinical decision-making processes.

Neurotomy of the rectus femoris nerve: Short-term effectiveness for spastic stiff knee gait: Clinical assessment and quantitative gait analysis

BACKGROUND

Stiff knee gait is a troublesome gait disturbance related to spastic paresis, frequently associated with overactivity of the rectus femoris muscle in the swing phase of gait.

OBJECTIVE

The aim of this study was to assess the short-term effects of rectus femoris neurotomy for the treatment of spastic stiff-knee gait in patients with hemiparesis.

PATIENTS AND METHODS

An Intervention study (before-after trial) with an observational design was carried out in a university hospital. Seven ambulatory patients with hemiparesis of spinal or cerebral origin and spastic stiff-knee gait, which had previously been improved by botulinum toxin injections, were proposed a selective neurotomy of the rectus femoris muscle. A functional evaluation (Functional Ambulation Classification and maximal walking distance), clinical evaluation (spasticity - Ashworth scale and Duncan-Ely test, muscle strength - Medical Research Council scale), and quantitative gait analysis (spatiotemporal parameters, stiff knee gait-related kinematic and kinetic parameters, and dynamic electromyography of rectus femoris) were performed as outcome measures, before and 3 months after rectus femoris neurotomy.

RESULTS

Compared with preoperative values, there was a significant increase in maximal walking distance, gait speed, and stride length at 3 months. All kinematic parameters improved, and the average early swing phase knee extension moment decreased. The duration of the rectus femoris burst decreased post-op.

CONCLUSION

This study is the first to show that rectus femoris neurotomy helps to normalise muscle activity during gait, and results in improvements in kinetic, kinematic, and functional parameters in patients with spastic stiff knee gait.

Safety and efficacy of incobotulinumtoxinA as a potential treatment for poststroke spasticity

Spasticity is a common disabling symptom for several neurological conditions. Botulinum toxin type A injection represents the gold standard treatment for focal spasticity after stroke showing efficacy, reversibility, and low prevalence of complications. In recent years, incobotulinumtoxinA, a new Botulinum toxin type A free of complexing proteins, has been used for treating several movement disorders with safety and efficacy. IncobotulinumtoxinA is currently approved for treating spasticity of the upper limb in stroke survivors, even if several studies described the use also in lower limb muscles. In the present review article, we examine the safety and effectiveness of incobotulinumtoxinA for the treatment of spasticity after stroke.