Stiff Knee Gait Research Articles

Between-limb difference in peak knee flexion angle can identify persons post-stroke with Stiff-Knee gait

BackgroundStiff-Knee gait affects 25–75 % of individuals with post-stroke gait impairment and is typically defined as reduced swing phase knee flexion. Different studies use various measures to identify Stiff-Knee gait, such as peak swing knee flexion angle, timing of peak knee flexion, knee range of motion, and ankle push-off acceleration, leading to inconsistent results. MethodsThis study used univariate cluster analysis to examine the independence, consistency, validity, and accuracy of different definitions in 50 post-stroke individuals (24 with and 26 without Stiff-Knee gait), as determined by a physiatrist. Spearman's rank correlation was used for correlation analysis, and five clustering techniques along with clinician evaluations were used for validity analysis. FindingsCorrelation analysis showed that peak knee flexion timing and knee hyperextension are poorly correlated with reduced swing-phase knee flexion angle (ρ = −0.09 and ρ = −0.26 respectively). Validity analysis indicated that the between-limb difference in peak swing knee flexion angle and peak swing knee flexion angle at self-selected gait speeds were the most valid differentiators. At the fastest comfortable gait speed, the between-limb difference of peak knee flexion angle had the highest sensitivity, lowest specificity, and highest F1 scores. InterpretationWe determined thresholds of less than 44.3° for peak swing knee flexion angle and greater than 17.0° for the between-limb difference of peak knee flexion angle identify Stiff-Knee gait during self-selected walking. We recommend using the difference in peak swing knee flexion angle between limbs to diagnose post-stroke Stiff-Knee gait due to its robustness to changes in gait speed.

Altered muscle synergy structure in patients with poststroke stiff knee gait

Stiff knee gait (SKG) occurrence after a stroke is associated with various abnormal muscle activities; however, the interactions among these muscles are unclear. This study aimed to elucidate the muscle synergy characteristics during walking in patients with SKG after a stroke. This cross-sectional study included 20 patients with poststroke SKG (SKG group), 16 patients without poststroke SKG (non-SKG group), and 15 healthy adults (control group). Participants walked a 10-m distance at a comfortable speed, and electromyographic data were recorded from six lower-limb muscles. Non-negative matrix factorization was employed to derive time-varying activity (C), muscle weights (W), and the percentage of total variance accounted for (tVAF) for muscle synergies. The SKG group showed a higher tVAF than the control group. The initial stance module (including knee extensors) showed increased activity during the swing phase. The initial swing module (including hip flexors and ankle dorsiflexors) exhibited a higher activity during the single-support phase but a lower activity during the swing phase. The synergy structure in patients with SKG after stroke was simplified, with specific abnormalities in synergy activities. SKG may arise from several synergy alterations involving multiple muscles, indicating that approaches focused on controlling individual muscle activities are unsuitable.

The effect of rectus femoris transfer on kinematics and functional outcomes in adult stroke patients walking with a stiff knee gait

BackgroundStiff knee gait is characterized by a reduced peak knee flexion during swing. Overactivity of the rectus femoris is often cited as a main cause for stiff knee gait. Little is known about the effect of an isolated rectus femoris transfer treatment on kinematic and functional outcomes in a group of stroke survivors. ObjectiveTo perform an experimental study to evaluate the effect of an isolated rectus femoris transfer on knee and hip kinematics and functional outcomes in adult stroke patients walking with a stiff knee gait. MethodIn this experimental study, 10 stroke survivors were included. During the surgical procedure, the distal rectus femoris tendon of the affected side was transferred to the medial knee flexors to improve knee flexion during swing. Knee and hip kinematics and a variety of functional outcomes were measured within 3 weeks before surgery and between 6 and 7 months after the surgery. ResultsWe found a statistically significant improvements in peak knee flexion during swing and knee range of motion of 10.6° (sd 4.7, p=0.000) and 10.5° (sd 6.2, p=0.001) post-surgery, respectively. Hip kinematics showed no significant differences.In addition, we found statistically significant improvements on the 6-minute walk test (42.5, sd 36.7, p=0.008), 10-meter walk test (1.26, sd 1.4, p=0.030), Timed up-and-go test (1.34, sd 1.18, p=0.009), L-test (2.97 sd 2.85, p=0.014) and on a subjective BORG scoring of foot clearance (1.8, sd 0.6, p=0.006). No significant differences were found on other measured functional outcomes. ConclusionsRectus femoris transfer is a valuable treatment option for stroke patients walking with a stiff knee gait to improve knee kinematics and a selection of functional outcomes. There are no detrimental side effects on hip kinematics.

Residual gait deviations in children treated by medial open reduction for developmental dysplasia of the hip at long-term follow-up: a comparison with healthy controls.

This study aimed to analyze and compare gait patterns and deviations at long-term follow-up in children who received medial open reduction (MOR) before 18months for unilateral or bilateral hip developmental dysplasia (DDH). A retrospective chart review was conducted on children who underwent MOR. The study population was divided into two groups: the unilateral group, including unilateral (five children with unilateral) and bilateral (five children with bilateral DDH). Ten healthy children were recruited for the control group. Spatiotemporal, kinematic, stiff-knee gait (SKG), and kinetic gait characteristics were analyzed. Stance time was significantly shorter in both the unilateral (median [IQR]; 590ms, [560.0-612.5] and bilateral (575ms, [550-637.5]) groups than in the control group (650, [602.5-677.5]) (p < 0.001), whereas swing time did not differ substantially (p = 0.065) There was no considerable difference in the mean knee flexion at swing between the unilateral (31.6°, [30-36]) and control (30.11°, [27.8-33.6] groups (p > 0.05), but the bilateral group (28.5°, [24.9-32.1]) showed the lower values than the other groups (p < 0.001 for bilateral vs unilateral group; p = 0.008 bilateral vs unilateral group). All the SKG parameters significantly differed among the groups in multi-group comparisons (p < 0.001 for each parameter). Three children had borderline SKG, and two had not-stiff limbs in the unilateral group. In the bilateral group, four children had stiff limbs, and one had borderline SKG. Most kinetic gait parameters were not statistically different between groups (p > 0.05). This study has revealed notable deviations in gait patterns of children with DDH treated by MOR at long-term follow-up compared to healthy children's gait. MOR could negatively affect pelvic motion during gait due to impaired functions of the iliopsoas and adductor muscles, and SKG can be encountered secondary to iliopsoas weakness.

Multiple sclerosis and spasticity: the role of anaesthetic nerve blocks on rectus femoris muscle. When should stiff knee be treated with botulinum toxin?

To compare the effect of rectus femoris diagnostic motor nerve blocks (DNB) with anaesthetics and rectus femoris muscle botulinum toxin (BoNT-A) injection in multiple sclerosis patients with unilateral stiff-knee gait. Prospective observational study Subjects/Patients: Multiple sclerosis patients in stable condition. Patients underwent evaluation before and 1 hour after the anaesthetic block, and 1 month after the botulinum injection. Assessment included a 10-m walking test, a 6-minute walking test, a timed-up-and-go (TUG) test, and a Baseline Expanded Disability Status Scale (EDSS). Post-DNB and post-BoNT-A satisfaction was measured with the global assessment of efficacy scale. Fourteen patients with unilateral stiff-knee gait due to multiple sclerosis underwent a DNB, among whom 13 received botulinum injections in the rectus femoris muscle after a satisfying test result. Positive post-DNB results correlated with significant functional improvements after BoNT-A. Higher EDSS and longer time from diagnosis correlated with poorer post-DNB and post-BoNT-A absolute outcomes. DNB showed predictive value for BoNT-A outcomes, especially in the case of worse functional status. It effectively predicted endurance and walking speed improvement, while TUG showed greater improvement after botulinum. In cases of uncertain therapeutic benefit, nerve blocks may provide a valuable diagnostic support, particularly in patients with lower functional status.

Ankle-foot orthosis in stroke survivors: status of the issue

This paper presents an analysis of information regarding the peculiarity of ankle joint orthosis in cerebral stroke survivors. Gait research methods used to assess gait changes in patients who had suffered a cerebral stroke were briefly reviewed. The three most common patterns of gait impairment after a stroke, namely, stiff-knee gait, “dropped foot,” and gait with knee joint hyperextension, were described. A brief review of the main functional types of ankle joint orthoses, namely, static and dynamic, considering their strengths and weaknesses, was presented. Changes in temporal, spatial, and kinematic parameters of gait in cerebral stroke survivors using orthoses were reported. Changes in gait parameters when using ankle joint orthoses depending on the initial pattern of gait disturbance were assessed. The effect of orthotics on the angles of flexion in the ankle, knee, and hip joints at various gait phases as well as their effect on the speed, rhythm, and length of the step were described. Data on the effect of ankle orthosis on patient’s ability to maintain balance were also presented. The effects of orthosis on gait biomechanics and balance function in stroke survivors are debatable. Thus, our findings in this study allow us to raise the question regarding the optimal timing of the use of ankle joint orthoses during the recovery period of a stroke. Possible reasons for these ambiguous results were considered. The necessity for further research into the effectiveness of ankle–foot orthoses regarding various pathological gait patterns in stroke survivors is justified.

Abnormal gait pattern in downhill hiking is related to muscular deficits of the knee flexors and extensors in active patients with total knee arthroplasty

BackgroundTo assess the in-field walking mechanics during downhill hiking of patients with total knee arthroplasty five to 14 months after surgery and an age-matched healthy control group and relate them to the knee flexor and extensor muscle strength. MethodsParticipants walked on a predetermined hiking trail at a self-selected, comfortable pace wearing an inertial sensor system for recording the whole-body 3D kinematics. Sagittal plane hip, knee, and ankle joint angles were evaluated over the gait cycle at level walking and two different negative slopes. The concentric and eccentric lower extremity muscle strength of the knee flexors and extensors isokinetically at 50 and 120°/s were measured. FindingsLess knee flexion angles during stance have been measured in patients in the operated limb compared to healthy controls in all conditions (level walking, moderate downhill, steep downhill). The differences increased with steepness. Muscle strength was lower in patients for both muscle groups and all measured conditions. The functional hamstrings to quadriceps ratio at 120°/sec correlated with knee angle during level and downhill walking at the moderate slope in patients, showing higher ratios with lower peak knee flexion angles. InterpretationThe study shows that even if rehabilitation has been completed successfully and complication-free, five to 14 months after surgery, the muscular condition was still insufficient to display a normal gait pattern during downhill hiking. The muscle balance between quadriceps and hamstring muscles seems related to the persistence of a stiff knee gait pattern after knee arthroplasty. LoE: III.

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

Materials and Manufacturing for Ankle–Foot Orthoses: A Review

Ankle–foot orthoses (AFOs) assist patients with gait impairment by correcting ankle and foot deformities, restoring mobility, reducing pain, and providing protection and immobilization. AFOs can effectively manage various types of gait pathologies, including foot drop, crouch gait, equinus gait, and stiff knee gait. AFOs are available in prefabricated or custom‐made forms in various designs. The selection criteria for the fabrication of an AFO are the duration of usage, the amount of applied force, the degree of axial loading, the patient's skin condition, and the cost. The accessibility of diverse materials in the last century has significantly improved orthoses. Ideal orthotic materials must be light, stiff, and strong, and can be made of plastics, metals, polymer‐based composites, leather, or a hybrid of different materials. A deeper understanding of the materials employed in the fabrication of AFOs holds the potential for more advanced and efficient orthoses, which can improve patients’ ability to ambulate in the real world. The present review provides insight into the various materials utilized for the fabrication of AFOs and describes the benefits and challenges associated with the materials. An attempt has also been made to highlight typical gait pathologies and design concepts in response to them.

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

AbstractIntroduction/PurposeTo determine the location of the rectus femoris (RF) motor branch nerve, as well as its coordinates with reference to anatomical and ultrasound landmarks.MethodsThirty 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.ResultsThe 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.ConclusionThe 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.

Self-modulation of rectus femoris reflex excitability in humans

Hyperreflexia is common after neurological injury such as stroke, yet clinical interventions have had mixed success. Our previous research has shown that hyperreflexia of the rectus femoris (RF) during pre-swing is closely associated with reduced swing phase knee flexion in those with post-stroke Stiff-Knee gait (SKG). Thus, reduction of RF hyperreflexia may improve walking function in those with post-stroke SKG. A non-pharmacological procedure for reducing hyperreflexia has emerged based on operant conditioning of H-reflex, an electrical analog of the spinal stretch reflex. It is currently unknown whether operant conditioning can be applied to the RF. This feasibility study trained 7 participants (5 neurologically intact, 2 post-stroke) to down-condition the RF H-reflex using visual feedback. We found an overall decrease in average RF H-reflex amplitude among all 7 participants (44% drop, p < 0.001, paired t-test), of which the post-stroke individuals contributed (49% drop). We observed a generalized training effect across quadriceps muscles. Post-stroke individuals exhibited improvements in peak knee-flexion velocity, reflex excitability during walking, and clinical measures of spasticity. These outcomes provide promising initial results that operant RF H-reflex conditioning is feasible, encouraging expansion to post-stroke individuals. This procedure could provide a targeted alternative in spasticity management.

Hip and Knee Joint Kinematics Predict Quadriceps Hyperreflexia in People with Post-stroke Stiff-Knee Gait.

Wearable assistive technology for the lower extremities has shown great promise towards improving gait function in people with neuromuscular injuries. But common secondary impairments, such as hypersensitive stretch reflexes or hyperreflexia, have been often neglected. Incorporation of biomechanics into the control loop could improve individualization and avoid hyperreflexia. However, adding hyperreflexia prediction to the control loop would require expensive or complex measurement of muscle fiber characteristics. In this study, we explore a clinically accessible biomechanical predictor set that can accurately predict rectus femoris (RF) reaction after knee flexion assistance in pre-swing by a powered orthosis. We examined a total of 14 gait parameters based on gait kinematic, kinetic, and simulated muscle-tendon states from 8 post-stroke individuals with Stiff-Knee gait (SKG) wearing a knee exoskeleton robot. We independently performed both parametric and non-parametric variable selection approaches using machine learning regression techniques. Both models revealed the same four kinematic variables relevant to knee and hip joint motions were sufficient to effectively predict RF hyperreflexia. These results suggest that control of knee and hip kinematics may be a more practical method of incorporating quadriceps hyperreflexia into the exoskeleton control loop than the more complex acquisition of muscle fiber properties.

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.

Gait classification in a population of adults with hereditary spastic paresis.

Classification of gait in adults with hereditary spastic paresis is limited. Our aim was to use a previously established system to classify gait. Forty-nine participants were retrospectively recruited and grouped into existing classifications based on sagittal plane knee joint kinematic data extracted from a 3D analysis. Waveform analysis was used to compare the grouped data to determine if and where differences in the subjective classifications appeared. Classification of gait patterns in adults with hereditary spastic paresis is successful. Differences between groups in line with the classification system were confirmed by statistical analysis. Crouch gait is illustrated by a flexed knee throughout stance phase. Recurvatum gait is dominated by knee hyperextension in mid-late stance. Stiff-knee gait demonstrates limited knee range of motion in stance and jump-knee gait is characterised by less knee flexion in early and mid-stance phase than all groups. Sagittal plane hip and ankle kinematics compliment group differences at the knee joint. The jump-knee group is more flexed at the hip than all groups during loading response phase and mid-stance; and the recurvatum group is more extended at the hip than the crouch, jump-knee, and stiff-knee groups during mid and late-stance phase. There is less ankle dorsiflexion throughout stance phase in the recurvatum group than in all other groups. Sagittal plane knee joint kinematic data can be subjectively used to classify gait features in adults with hereditary spastic paresis. Novel analysis show hip and ankle sagittal plane kinematics can be used to further assist classification.

Rectus femoris transfers with and without a hamstring lengthening will not change hip kinematics in children with cerebral palsy

BackgroundA rectus femoris transfer (RFT) surgery with and without a hamstring lengthening (HSL) is used to treat stiff-knee gait in children with cerebral palsy (CP). While current literature has reported that a RFT surgery improves the kinematics at the knee, little is known about the kinematic changes at the hip. Research questionDoes a RFT surgery change hip joint kinematics in children with CP? MethodsThis retrospective study included children (<18 years old) diagnosed with CP, who underwent a RFT procedure, and who were seen at our institution’s accredited clinical motion laboratory. Patients with both pre- and post-operative gait analysis were identified and comparison between those analyses were performed to identify kinematic differences at the hip and knee. A total of 66 legs from 46 children (mean age: 11.1 ± 3.6) met the inclusion criteria. ResultsOverall results revealed that a RFT did not change kinematics at the hip [p > 0.05], however, a RFT did increase the maximum knee flexion during the swing period [Mean Difference Post – Pre: 8.3°, 95% CI: 4.9–11.8, p < 0.0001]. Additionally, it was found that changes in hip extension during the terminal stance phase were significantly different between the combined RFT and HSL compared to solely an RFT. The results of this study also revealed that children whose stiff-knee gait did not improve, tended to have increased hip external rotation during terminal stance and swing and greater hip extension during terminal stance, compared to children whose stiff-knee gait did improve. SignificanceOverall, a RFT with and without a HSL surgery improves hip and knee kinematics in the sagittal plane, however, improvements at the hip were not clinically significant. As a result, a RFT or a combined RFT with HSL should not be used to change hip kinematics in children with CP.

Quadriceps Avoidance After Total Knee Arthroplasty: Descriptive Study

Background: Quadriceps avoidance is a reflex deficit disorder of quadriceps activation after total knee arthroplasty (TKA) that can lead to abnormal gait kinematics. It is patient apprehension due to pain, to prevent quadriceps activation that induces deforming forces at the knee joint. Aim: To describe the frequency of ‘quadriceps avoidance’ among patients after total knee arthroplasty. Study Design: Descriptive case series. Methodology: The study sample size comprised of 55 post-TKA patients (Male: 16; Female: 39), who were the ages of 40-80 years. Participants were recruited who had undergone unilateral total knee replacement and attended an outpatient physiotherapy clinic of Ghurki trust teaching hospital and Surgimed hospital Lahore. Participants were undergone ‘quadriceps avoidance gait’ testing at approximately 02 weeks and 01 month postoperatively by using a diagnostic observational questionnaire, designed according to the observational gait analysis. Data was evaluated by using SPSS version 23. All qualitative data was presented in frequency form and quantitative data was in the form of mean±SD. Results: Mean age of patients was 58.98 with range minimum of 40 years to a maximum of 80 years. Out of a sample size of 55, 25 (45.5%) patients were diagnosed with quadriceps avoidance after TKA, 11(20%) were male patients out of 16 and 14 (25.5%) were female patients out of 39 which showed ‘stiff knee gait’ pattern. Conclusion: It was concluded that quadriceps avoidance after total knee arthroplasty was one of major complication of abnormal gait pattern which can lead to knee joint deformities if left uncorrected. Keywords: Total knee arthroplasty, Quadriceps avoidance, Gait kinematics, Gait kinetic

Classification of Stiff-Knee Gait Kinematic Severity after Stroke Using Retrospective k-Means Clustering Algorithm.

Nowadays, a classification system for unilateral stiff-knee gait (SKG) kinematic severity in hemiparetic adult patients after stroke does not exist. However, such classification would be useful to the clinicians. We proposed the use of the k-means method in order to define unilateral SKG severity clusters in hemiparetic adults after stroke. A retrospective k-means cluster analysis was applied to five selected knee kinematic parameters collected during gait in 96 hemiparetic adults and 19 healthy adults from our clinical gait analysis database. A total of five discrete knee kinematic clusters were determined. Three clusters of SKG were identified, based on which a three-level severity classification was defined: unbend-knee gait, braked-knee gait, and frozen-limb gait. Preliminary construct validity of the classification was obtained. All selected knee kinematic parameters defining the five clusters and the majority of usual kinematic parameters of the lower limbs showed statistically significant differences between the different clusters. We recommend diagnosing SKG for values strictly below 40° of knee flexion during the swing phase. Clinicians and researchers are now able to specify the level of kinematic severity of SKG in order to optimize treatment choices and future clinical trial eligibility criteria.

Количественные параметры кинетики и кинематики ятрогенного crouch паттерна

The pattern of pathological crouch gait in patients with spastic paralysis is characteristic of diplegic forms and in natural development manifests itself usually after the age of 10-12 years. This pathological gait may develop earlier after early surgical interventions that weaken the triceps of the lower leg, especially the soleus muscle. The heterogeneity of the crouch gait pattern is diverse. Qualitative assessment of the difference in the decompensated crouch pattern, especially associated with stiff-knee gait, according to the graphs of kinematics and kinetics of the joints can be difficult, and quantitative criteria for differentiation have not been reflected in the literature. The purpose of the study was to conduct a comparative analysis of the quantitative parameters of the compensated, decompensated and associated stiff-knee gait crouch pattern. Materials and methods The assessment of the locomotor profile by 3D gait analysis (3DGA) was carried out in stationary conditions in 27 children (54 limbs) with spastic diplegia, who had previously undergone percutaneous fibromyotomy according to the Ulzibat method, or open lengthening of the Achilles tendon. The mean age at the time of the survey was 13.0 (8–17) years. Control group: 19 children without orthopedic pathology (38 limbs) of the same age. Three groups of changes within the crouch gait pattern, recorded on separate limbs, were distinguished: I – model of the crouch pattern of the “compensated” type (n = 30); II – model of the crouch pattern of the "decompensated" type (n = 14); III – models of crouch pattern of the "stiff-knee" type (n = 10). Results An analysis of the evaluation of the models of compensated, decompensated, and stiff-knee patterns of crouch gait revealed criteria for their differentiation in terms of quantitative indicators of kinematics and kinetics. GPS: compensated and decompensated crouch gait up to 25.0, stiff-knee gait – more than 25.0. The angle of maximum dorsiflexion of the foot in the stance phase: compensated and decompensated crouch pattern up to 35.0°, stiff-knee crouch pattern – more than 35.0°. Knee joint extension range: compensated crouch over 11.0°, stiff-knee gait up to 6.0°. Flexion knee joint range: compensated crouch more than 11.0°, stiff-knee gait – up to 6.0°. The strength of the leg extensor muscles during the formation of the support push: compensated and decompensated crouch less than 1.0 H*m/kg, stiff-knee – more than 1.0 N*m/kg. The strength of the leg flexor muscles in the midstance period: compensated crouch less than 0.25 H*m/kg, stiff-knee – more than 0.75 N*m/kg. Absorption power (negative) of the knee joint: compensated and decompensated crouch more than 0.9 W/kg, stiff-knee less than -0.9 W/kg. Useful peak power of the joints: compensated and decompensated crouch patterns – more than 0.40 W/kg, stiff‑knee gait – less than 0.40 W/kg. Conclusions The development of the crouch gait pattern in the absence of a tertiary compensatory deviation (torso tilt) can be formed with or without a decrease in the power of the joints. The decompensated and compensated types of the crouch pattern have a significant difference in the kinematics of the knee joint and in the duration of the internal moment of extension, while the power parameters of the joints do not have significant differences. Stiff-knee associated crouch pattern is the most severe type in which all the power parameters of the joints are decreased. The manifestation of the severity of this pathological pattern may vary between the right and left limbs of the individual.

Differences in causes of stiff knee gait in knee extensor activity or ankle kinematics: A cross-sectional study

BackgroundStiff knee gait (SKG), a common occurrence after the onset of stroke, is caused by hyperactivity of the rectus femoris during the swing phase. Another cause of SKG is the weakness of push-off in hemiparetic gait. Prior research did not consider the effect of the magnitude of knee extensors in their subjects. Research questionDoes the cause of SKG differ between patients with high and low knee extensor activities during the swing phase? MethodsWe examined 38 patients with chronic stroke hemiplegia who presented with SKG. After placing an inertia sensor and an electromyogram, patients walked 10 m at a comfortable speed. All patients were categorized per the sign of the principal component 2 (PC2) as a component with large factor loadings of knee extensors attained from the electromyographic amplitude during the early swing phase of the paretic limb. Then, the kinematic parameters of knee flexion and other gait parameters in each group were compared, and a correlation analysis was performed. ResultsIn the high PC2 group, the timing of peak knee flexion during the swing phase was early, and vastus lateralis activity during the preswing phase negatively correlated with the knee-flexion angle during the swing phase. In the low PC2 group, the angular velocity of ankle plantar flexion at the toe-off was slow, which positively correlated with the knee-flexion angle during the swing phase. SignificanceThe cause of SKG could be an inappropriate activity of the vastus lateralis rather than the rectus femoris in patients with high knee extensor activity and slow plantar-flexion velocity at toe-off in patients with low knee extensor activity. Not all causes of SKG in patients with hemiplegia are common, and different treatment strategies are needed per the individuality of spastic knee extensor activity.

Mid-Term Results of Distal Femoral Extension and Shortening Osteotomy in Treating Flexed Knee Gait in Children with Cerebral Palsy.

Background: Distal femoral extension and shortening osteotomy (DFESO) seems to be an effective method for the treatment of flexed knee gait in children with cerebral palsy. Nevertheless, studies investigating the mid- and long-term outcomes after such procedures are lacking in the literature. Therefore, the purpose of this study was to assess the mid-term outcomes regarding sagittal plane kinematics of the knee after DFESO with or without concomitant patella advancement. Furthermore, an evaluation of the postoperative course and possible recurrence of flexed knee gait was planned. Methods: In a prospective observational study, 19 patients (28 limbs; mean age 11.8 years (6.7–16.0 years)) were examined using 3-D gait analysis and clinical exam before (E0) and at a mean of 38 months (E2: 24–55 months) after surgery. Fifteen patients (22 limbs) had an additional first postoperative gait analysis (E1) after a mean of 14 (10–20) months after surgery. In these patients, the postoperative changes between the short-term and mid-term gait analyses were evaluated. Results: DFESO led to a significant decrease in flexed knee gait with an improvement in sagittal plane kinematics during the stance phase. In addition, a slightly increased anterior pelvic tilt was observed at E1, and we found a tendency towards stiff knee gait with a decrease in mean knee flexion in swing at E2. Conclusions: DFESO led to a significant improvement in flexed knee gait in children with cerebral palsy. The therapeutic effect seems to be lasting on mid-term follow-up with a slight overall tendency to recurrence.