Effectiveness of surgical and non-surgical management of crouch gait in cerebral palsy: A systematic review

A randomized cross-over study protocol to evaluate long-term gait training with a pediatric robotic exoskeleton outside the clinical setting in children with movement disorders

Individuals with neuromuscular disorders display a combination of motor control deficits and lower limb weakness contributing to knee extension deficiency characterized by exaggerated stance phase knee flexion. There is a lack of evidence for long-term improvement of knee extension deficiency with currently available clinical treatment programs. Our previous work testing a wearable robotic exoskeleton with precisely timed assistive torque applied at the knee showed immediate increases in knee extension during walking for children with cerebral palsy, which continued to improve over an acute practice period. When we applied interleaved assistance and resistance to knee extension, we observed improvements in knee extension and increased muscle activation indicating the potential for muscle strengthening when used over time. There is a need for additional, high-quality trials to assess the impact of dosage, intensity and volume of training necessary to see persistent improvement in lower limb function for these patient populations. This randomized crossover study (ClinicalTrials.gov: NCT05726591) was designed to determine whether 12 weeks of overground gait training with a robotic exoskeleton outside of the clinical setting, following an initial in clinic accommodation period, has a beneficial effect on walking ability, muscle activity and overall motor function. Participants will be randomized to either complete the exoskeleton intervention or continue their standard therapy for 12 weeks first, followed by a crossover to the other study component. The primary outcome measure is change in peak knee extension angle during walking; secondary outcome measures include gait speed, strength, and validated clinical scales of motor function and mobility. Assessments will be completed before and after the intervention and at 6 weeks post-intervention, and safety and compliance will be monitored throughout. We hypothesize that the 12-week exoskeleton intervention outside the clinical setting will show greater improvements in study outcome measures than the standard therapy.

The impact of hamstring lengthening on stance knee flexion at skeletal maturity in ambulatory cerebral palsy

This study reports the long-term outcomes of hamstring lengthening to treat flexed knee gait in children with ambulatory cerebral palsy (CP) after skeletal maturity. This retrospective longitudinal observational study used instrumented gait analysis (GA) <8 and >15 years old in children with bilateral CP. The primary variable was knee flexion in stance phase. Eighty children (160 limbs) were included; 49% were male, 51% female. Mean age at first GA was 6.0 (SD: 1.2) years and 19.6 (SD: 4.5) years at final GA. Mean follow-up was 13.7 (SD: 4.7) years. Children were classified as Gross Motor Function Classification System I-8, II-46 and III-26. Average Gross Motor Function Measure Dimension D was 72% (SD: 20%). Hamstring lengthenings occurred once in 82, twice in 54 and three times in 10 limbs. From initial to final GA, average knee flexion in stance was unchanged, 27.8° (SD: 14.8°) to final 27.0° (SD: 11.2°; P = 0.54). Knee flexion at foot contact was 39.6° (SD: 13.0°), improving to final GA of 30.7° (SD: 10.6°; P < 0.001). Initial gait deviation index was 65.8 (SD: 31.9), improving to final 78.9 (SD: 28.2; P < 0.001). Older age, males and concomitant plantar flexor lengthening predicted change toward more flexed knee gait. Hamstring lengthening did not lead to back-kneeing gait at maturity while maintaining childhood stance phase knee flexion. A subgroup still developed significant flexed knee gait posture and may have benefited from more aggressive treatment options. This outcome may also be impacted by diverse functional levels, etiologies and treatments of flexed knee gait.

Does patella lowering as part of multilevel surgery improve knee kinematics in children with cerebral palsy and crouch gait? A meta-analysis of comparative studies

Purpose

To evaluate differences in knee kinematic outcomes of patellar-lowering surgery, specifically patellar tendon advancement or patellar tendon shortening, compared with no-patellar-lowering surgery in multilevel surgery for children with cerebral palsy and crouch gait.

Methods

Four databases were searched to retrieve studies published from inception until 2023. Three reviewers independently screened for studies with observational or randomized control designs, comparing two groups of patients with cerebral palsy and crouch gait who underwent multilevel surgery (with patellar-lowering surgery versus no-patellar-lowering surgery), where various gait analysis outcomes were reported (CRD42023450692). The risk of bias was assessed with the Risk Of Bias In Non-randomised Studies - of Interventions (ROBINS-I) tool.

Results

Seven studies (249 patients and 368 limbs) met the eligibility criteria. Patients undergoing patellar-lowering surgery demonstrated statistically significant improvements in knee flexion at initial contact (mean difference = -6.39; 95% confidence interval = [-10.4, -2.75]; p = 0.0006; I2 = 84%), minimum knee flexion in stance (mean difference = -14.27; 95% confidence interval = [-18.31, -10.23]; p < 0.00001; I2 = 89%), and clinical knee flexion contracture (mean difference = -5.6; 95% confidence interval = [-9.59, -1.6]; p = 0.006; I2 = 95%), with a significant increase in anterior pelvic tilt (mean difference = 2.97; 95% confidence interval = [0.58, 5.36]; p = 0.01; I2 = 15%). However, improvements in gait deviation index and decrease in peak knee flexion in swing did not reach statistical significance. Subgroup analysis reduced heterogeneity and revealed (1) greater improvement using patellar tendon shortening versus patellar tendon advancement techniques; (2) lack of knee flexion contracture improvement in high-quality or longer-term studies; (3) longer-term improvement only in minimum knee flexion in stance, with a decrease in peak knee flexion in swing; and (4) an inability to assess the potential benefit of rectus femoris procedure and hamstring preservation.

Conclusions

Overall, the combination of patellar-lowering surgery with multilevel surgery demonstrated superior improvements in stance-phase knee kinematics compared with multilevel surgery alone, despite an increase in anterior pelvic tilt and a longer-term knee flexion reduction during the swing phase.

Level of evidence

Level III, Systematic review of level III studies.

Patellar tendon shortening surgery restores the knee extensor mechanism in flexed knee gait in children with cerebral palsy

BACKGROUND

This study evaluated a patellar tendon shortening (PTS) surgical procedure that uses an overlapping repair combined with an additional Tycron non-absorbable suture to support the shortening in children with Cerebral Palsy (CP). This study aimed to outline this surgical technique and to evaluate its effectiveness in restoring the knee extensor mechanism.

METHODS

The sagittal plane lower limb kinematics, peak knee extensor moment, gait deviation index (GDI), localised movement deviation profile (MDP), temporospatial parameters, passive knee extension ROM, quadriceps lag, and knee extensor strength were calculated pre- and postoperatively. To determine significant differences a robust linear regression model with high breakdown point and high efficiency was fitted to the data.

RESULTS

In this retrospective cohort study, a total of 41 patients with CP who were treated with unilateral or bilateral PTS in isolation or as part of single event multilevel surgery (SEMLS), with a mean age of 11.1 years were included. The knee extension angle improved at initial contact (p < 0.0001), and during stance phase (p < 0.0001). The peak internal knee extensor moment decreased during early (p = 0.0014) and late stance phase (p < 0.0001). The quadriceps lag decreased (p < 0.0001) and knee extensor strength increased (p < 0.0001). The GDI improved (p < 0.0001), as well as the localised MDP for sagittal angles (p < 0.0001) and moments (p = 0.0001). Walking speed (p = 1.0) remained unchanged, but the cadence decreased (p = 0.024) and step length increased (p = 0.0001).

CONCLUSIONS

The knee extension angle and moment during stance phase improved significantly. The children with CP in this study showed improvements in knee extensor strength and quadriceps lag. Thereby it can be concluded that the PTS procedure was able to restore the knee extensor mechanism effectively.

Clinical functional outcome measures for children with cerebral palsy after gait corrective orthopaedic surgery: A scoping review

AIM

To identify the most frequently reported non-instrumented measures of gait, activity, and participation in children with cerebral palsy (CP) after undergoing gait corrective orthopaedic surgery.

METHOD

Four databases were searched from database inception to the 9th December 2021 for studies that evaluated functional outcomes for children with CP under 18 years undergoing gait corrective orthopaedic surgery.

RESULTS

Of 547 citations, 44 publications (n = 3535 participants, n = 1789 males, mean age 10 years 5 months [SD = 3 years 3 months], Gross Motor Function Classification System levels I-III at the time of surgery) were eligible for inclusion. Fourteen different outcome measures were used: one measure of gait, 10 measures of activity, and three measures of participation. Gait was measured with the Edinburgh Visual Gait Scale (EVGS; 4 out of 44). The most common activity and participation measures were the Functional Mobility Scale (FMS; 15 out of 44) and Pediatric Outcomes Data Collection Instrument (11 out of 44) respectively. No studies reported a combination of gait, activity, and participation measures.

INTERPRETATION

The EVGS and FMS should be considered as core outcome measures in gait corrective orthopaedic surgery, while a measure of participation is unclear. Additional considerations for developing a comprehensive suite of outcomes include identifying a combination of clinical measures and performance-reflective questionnaires that are standardized for children with CP undergoing surgery and meaningful to clinicians and families.

Knee Flexion While Walking Exceeds Knee Flexion Contracture in Children with Spastic Cerebral Palsy

Flexed knee gait is commonly related to contractures in children with cerebral palsy (CP). Therefore, knee position while walking was compared with passive knee extension and explored with respect to functional mobility. Gait was assessed with 3D motion analysis in 30 children with bilateral spastic CP, Gross Motor Function Classification System (GMFCS) levels I-III, and in 22 typically developing (TD) children. Knee angle at initial contact (KneeAngleIC) was greater than knee flexion in stance (MinKneeFlexSt) in all groups. MinKneeFlexSt exceeded knee contractures at GMFCS levels II and III. Both KneeAngleIC and MinKneeFlexSt were greater at GMFCS II and III than at GMFCS I and the TD group. The excessive knee flexion while walking at GMFCS II and III could not be explained by knee joint contractures. Functional mobility measured with the timed-up-and-go test took longer in children at GMFCS level III compared to the other groups, assumed to be explained by the energy-requiring flexed knee gait and spatial insecurity. Discriminating between passive knee extension at the physical assessment and maximum knee extension while weight bearing may contribute to further understanding of flexed knee gait and its causes in ambulating children with spastic bilateral CP.

The Rehabilitation Interventions and Adaptive Technologies Used for Treating Patients With Cerebral Palsy

Cerebral palsy (CP) is one of the most common disorders in pediatric patients. The prevalence of CP is 2-3 in 1,000 live births, but various changes in some trends are seen in different groups. This article is a systematic review of multiple sources available for interventions and new adaptive techniques used for treating patients for their better lifestyles. With recent advancements, it is possible to diagnose a child who is below six months to two years. For achieving goals, proper interventions and techniques are necessary in the early stages of the disease. This article summarizes the rehabilitation and interventions available for treating these children with the best procedures.

A prospective assessment of gait kinematics and related clinical examination measures in cerebral palsy crouch gait

Background While prospectively assessed crouch gait in cerebral palsy (CP) does not necessarily progress, prospective changes in clinical examination measures have not been reported. This study prospectively examined the association between selected clinical examination variables and change in crouch gait in a cohort with bilateral CP. Methods Inclusion criteria were a diagnosis of ambulant bilateral CP, knee flexion at mid-stance >19 0 and a minimum of two-years between gait analyses. The change in kinematic variables was assessed using Statistical Parameter Mapping (SPM) and changes in clinical measures using appropriate paired tests. Linear regression examined the association between progression of crouch and clinical examination variables. Results There was no mean change in crouch in 27 participants over 3.29 years. However, there was significant variability within this group. Clinical hamstring tightness (60.00 0 to 70.48 0, p<0.01) and external knee rotation during stance (SPM analysis, p<0.001) increased but there was no association between changes in clinical examination variables and changes in crouch (p-values 0.06 - 0.89).    Conclusions This prospective study found no association between the changes in clinical examination variables and changes in crouch highlighting the likely multi-factorial aetiology of this gait pattern and the need for larger prospective studies. The variability crouch gait progression among the 27 participants highlights the pitfall of group mean values in such a heterogeneous population.

Design and Implementation of a Portable Knee Actuator for the Improvement of Crouch Gait in Children with Cerebral Palsy

Common manifestation of spastic Cerebral Palsy (CP) are abnormal gait pathologies. These conditions require greater energy expenditure to successfully ambulate and are linked with significant deterioration in joint health and childhood musculoskeletal development. Crouch gait presents with knee hyperflexion throughout stance due to extensor muscle weakness and spasticity in flexor muscles stemming from neurological damage. The goal of this study was to develop a wearable cable-driven robotic system that applies controlled perturbation to the knee joint during overground walking in children with CP. Two children with spastic CP were recruited in this pilot study. They were tested in two conditions, i.e., applying knee resistance vs. knee assistance during overground walking. Kinematic and EMG data were recorded during overground walking. Data indicated that it was feasible to apply controlled knee perturbation torque during overground walking in children with crouch and preliminary results showed an improvement in crouch gait pattern in children with CP after one session of walking with the robotic system.Clinical Relevance- This study might have a potential clinical significance modifying neuromuscular control of CP patients with Crouch Gait.

American Society of Biomechanics Clinical Biomechanics Award 2021: Redistribution of muscle-tendon work in children with cerebral palsy who walk in crouch

BACKGROUND

Previous study showed the triceps surae exhibits spring-like behavior about the ankle during walking in children with cerebral palsy. Thus, the work generated by the triceps surae is diminished relative to typically developing children. This study investigated whether the quadriceps offset the lack of triceps surae work production in children with cerebral palsy who walk in crouch.

METHODS

Seven children with cerebral palsy (8-16 yrs) and 14 typically developing controls (8-17 yrs) walked overground at their preferred speed in a motion analysis laboratory. Shear wave tensiometers were used to track patellar and Achilles tendon loading throughout the gait cycle. Tendon force measures were coupled with muscle-tendon kinematic estimates to characterize the net work generated by the quadriceps and triceps surae about the knee and ankle, respectively.

FINDINGS

Children with cerebral palsy generated significantly less triceps surae work when compared to controls (P < 0.001). The reverse was true at the knee. Children with cerebral palsy generated positive net work from the quadriceps about the knee, which exceeded the net quadriceps work generated by controls (P = 0.028).

INTERPRETATION

There was a marked difference in functional behavior of the triceps surae and quadriceps in children with cerebral palsy who walk in crouch. In particular, the triceps surae of children with cerebral palsy exhibited spring-like behavior about the ankle while the quadriceps exhibited more motor-like behavior about the knee. This redistribution in work could partly be associated with the elevated energetic cost of walking in children with cerebral palsy and is relevant to consider when planning treatments to correct crouch gait.

Relationship between kinematic gait quality and caregiver-reported everyday mobility in children and youth with spastic Cerebral Palsy

BACKGROUND

3D gait analysis (3DGA) is a common assessment in Cerebral Palsy (CP) to quantify the extent of movement abnormalities. Yet, 3DGA is performed in laboratories and may thus be of debatable significance to everyday life.

AIM

The aim was to assess the relationship between kinematic gait abnormality and everyday mobility in ambulatory children and youth with spastic CP.

METHODS

73 paediatric and juvenile patients with uni- or bilateral spastic CP (N = 21 USCP, N = 52, BSCP, age: 4-20 y, GMFCS I-III) underwent a 3DGA, while the MobQues47 Questionnaire quantified caregiver-reported mobility. We calculated the Gait Profile Score (GPS), a metric that summarizes how far the lower limb joint angles during walking deviate from those of matched controls.

RESULTS

The GPS correlated well with indoor and outdoor mobility (rho = -0.69 and -0.70, both p < 0.001) and the relationships were not significantly different for USCP and BSCP. Still, mobility was lower in BSCP (p < 0.001) and more compromised outdoors (p = 0.002). Indoor mobility could be predicted by walking speed, GPS and age (adj. R² = 0.62). Outdoor mobility was best predicted by walking speed and GPS (adj. R² = 0.60). The additive explained variance by the GPS was even higher outdoors than indoors (17.1% vs. 11.4%).

CONCLUSIONS

Measuring movement deviations with 3DGA seems equally meaningful in uni- and bilaterally affected children and has considerable relevance for real-life ambulation, particurlarly outdoors, where children with spastic CP typically face greater difficulties. Therapeutic strategies that achieve faster walking and reduction of kinematic deviations may increase outdoor mobility.

Treatment of spasticity

Spasticity is characterized by an enhanced size and reduced threshold for activation of stretch reflexes and is associated with "positive signs" such as clonus and spasms, as well as "negative features" such as paresis and a loss of automatic postural responses. Spasticity develops over time after a lesion and can be associated with reduced speed of movement, cocontraction, abnormal synergies, and pain. Spasticity is caused by a combination of damage to descending tracts, reductions in inhibitory activity within spinal cord circuits, and adaptive changes within motoneurons. Increased tone, hypertonia, can also be caused by changes in passive stiffness due to, for example, increase in connective tissue and reduction in muscle fascicle length. Understanding the cause of hypertonia is important for determining the management strategy as nonneural, passive causes of stiffness will be more amenable to physical rather than pharmacological interventions. The management of spasticity is determined by the views and goals of the patient, family, and carers, which should be integral to the multidisciplinary assessment. An assessment, and treatment, of trigger factors such as infection and skin breakdown should be made especially in people with a recent change in tone. The choice of management strategies for an individual will vary depending on the severity of spasticity, the distribution of spasticity (i.e., whether it affects multiple muscle groups or is more prominent in one or two groups), the type of lesion, and the potential for recovery. Management options include physical therapy, oral agents; focal therapies such as botulinum injections; and peripheral nerve blocks. Intrathecal baclofen can lead to a reduction in required oral antispasticity medications. When spasticity is severe intrathecal phenol may be an option. Surgical interventions, largely used in the pediatric population, include muscle transfers and lengthening and selective dorsal root rhizotomy.

The medium-term effects of selective dorsal rhizotomy on gait compared to a matched cerebral palsy non-SDR group: A follow-up study

BACKGROUND

Selective dorsal rhizotomy (SDR) has been shown to improve gait in the short-term in children with cerebral palsy (CP). Further study is needed to look at the trajectory of outcomes over the longer-term.

RESEARCH QUESTION

What are the medium-term effects of SDR on gait compared to a matched CP non-SDR group?

METHODS

Participants underwent SDR at mean age 6.3 years and completed baseline, 1-year and 5-year follow-up gait analyses. Non-SDR participants were matched at baseline. Differences were assessed within and between groups. Kinematic variables were analysed using Statistical non-Parametric Mapping (SnPM). Other gait and clinical data were analysed using Friedman's one-way repeated measure analysis of variance and a Mann-Whitney U-test.

RESULTS

The initial SDR group consisted of 29 participants, reducing to 22 at 5-year follow-up. Of these, 15 (68 %) had orthopaedic surgeries either concurrent with or in the intervening period since the SDR, mean 3.3 procedures per participant. The initial non- SDR group had 18 participants, reducing to 17 at 5-year follow-up. Of these, 13 (76 %) had orthopaedic surgeries, mean 5.7 procedures. At 1-year follow-up the SDR group had significantly improved knee extension, ankle dorsiflexion, foot progression, Gait Deviation Index, and normalised step length compared to baseline, p < 0.05, and outcomes were maintained at 5-years. At 1-year follow-up the non-SDR group kinematic patterns were unchanged, but at 5-year follow-up this group demonstrated significantly improved knee extension, ankle dorsiflexion and foot progression. There were no significant kinematic differences between the SDR and the non-SDR group at medium-term follow-up.

SIGNIFICANCE

We have documented the trajectory of gait outcomes post-SDR over 3 assessments and found that short-term gait changes endured in the medium-term. However, kinematic changes were similar to a non-SDR group undergoing routine and orthopaedic care. These outcomes are important to guide surgical decision making and to manage treatment goals and expectations.

Botulinum toxin type A for spasticity in cerebral palsy patients: Which impact on popliteal angle to hamstring length? A proof-of-concept study

BACKGROUND

Cerebral palsy (CP) is the most common physical disability in childhood. It is a heterogeneous condition in terms of etiology, motor type and severity of impairments. Clinical impairments, such as increased muscle tone (spasticity), muscle weakness and joint stiffness contribute to the abnormal development of functional activities, including gait.

OBJECTIVE

The objective of this study was to investigate the popliteal angle to hamstring length after ultrasound guided Incobotulinum toxin A injections for spasticity in CP patients.

METHODS

In this proof-of-concept study, we included outpatients with CP and crouch gait correlated to hamstrings spasticity referred to the Pediatric Rehabilitation outpatient clinic of Umberto I University Hospital, Sapienza University of Rome, in the period between February and October 2018.

METHODS

Modified Ashworth Scale (MAS) of hamstring muscles, Popliteal Angle and Modified Popliteal Angle, Passive Knee Extension and 10 Meter Walk Test (10MWT) were assessed at baseline (T0) and three weeks after ultrasound guided injection (T1) of Incobotulinum Toxin A (dose weight and site dependent).

RESULTS

Thirteen patients (5 male and 8 female), mean aged 9.91 ± 3.59, were included. The clinical evaluation at T0 showed hamstring muscles spasticity, with MAS of 2.4 ± 0.6, popliteal angle -51.7∘± 11.0∘, modified popliteal angle of -39.5∘± 11.0∘, passive knee extension of -14.0∘± 8.7∘ and 10MWT of 14.3 ± 4.6 seconds. At T1, hamstring muscles MAS mean value was 1.7 ± 0.6 (p< 0.01), popliteal angle 41.3∘± 7.0∘ (p< 0.001), modified popliteal angle -32.9∘± 10.4∘ (p< 0.001), passive knee extension -4.0∘± 4.2∘ (p< 0.05) and 10MWT 12.6 ± 4.8 seconds (p< 0.05). None of the treated patients reported any adverse event related to Incobotulinum Toxin A injection.

CONCLUSION

Incobotulinum toxin A treatment has been proven to be safe and effective for hamstring muscles spasticity management in CP patients. Further studies with larger samples and longer follow-up are warranted to assess the efficacy of this treatment on the popliteal angle.

A prospective assessment of gait kinematics and related clinical examination measures in cerebral palsy crouch gait

Background While prospectively assessed crouch gait in cerebral palsy (CP) does not necessarily progress, prospective changes in clinical examination measures have not been reported. This study prospectively examined the association between selected clinical examination variables and change in crouch gait in a cohort with bilateral CP. Methods Inclusion criteria were a diagnosis of ambulant bilateral CP, knee flexion at mid-stance >190 and a minimum of two-years between gait analyses. The change in kinematic variables was assessed using Statistical Parameter Mapping (SPM) and changes in clinical measures using appropriate paired tests. Linear regression examined the association between progression of crouch and clinical examination variables. Results There was no mean change in crouch in 27 participants over 3.29 years. However, there was significant variability within this group. Clinical hamstring tightness (60.000 to 70.480, p<0.01) and external knee rotation during stance (SPM analysis, p<0.001) increased but there was no association between changes in clinical examination variables and changes in crouch (p-values 0.06 - 0.89).    Conclusions The variability crouch gait progression highlights the pitfall of group mean values in such a heterogeneous population.  The lack of association between changes in clinical examination variables and changes in crouch highlights the multi-factorial aetiology of this gait pattern and the need for larger prospective studies.

Long-term outcome of hamstring lengthening versus transfer and the role of biceps femoris lengthening in patients with spastic diplegia and dynamic knee flexion in gait

BACKGROUND

Orthopedic treatment of flexed-knee gait consists of hamstring lengthening along with surgery at other levels. Transfer of the semitendinosus (hamstring transfer) was introduced to avoid increase of anterior pelvic tilt as well as reduce risk of recurrence.

METHODS

We retrospectively assessed children with spastic cerebral palsy and flexed-knee gait pre-operatively, 1 year post-operatively, and at a minimum of 7 years post-operatively.

RESULTS

The 39 patients were a mean 9.4 ± 3.4 years at the time of surgery, 20 subjects underwent hamstring transfer, and 19 subjects had hamstring lengthening with mean follow-up 9.1 years. Passive range of motion improved initially, but regressed at long term. Dynamic minimum knee flexion in stance decreased in both groups at the first post-operative study, and was maintained at final follow-up in 64-67% of patients. There was a small increase in anterior pelvic tilt at the 1-year follow-up which subsequently decreased to less than pre-operative in the hamstring lengthening group but remained mildly increased (5°) in the hamstring transfer group at final follow-up. Success in correcting stance knee flexion of the entire group was 69% of the Gross Motor Function Classification System grades I and II and 60% of the Gross Motor Function Classification System grade III subjects. Gait profile Score and sagittal knee Gait Variable Score both showed clinically important improvement after surgery and was mostly maintained long term for both groups. Lateral hamstring lengthening was beneficial in more severe patients, with minimal risk of adverse effects.

CONCLUSION

Hamstring surgery as part of single event multi-level surgery (SEMLS) is effective in correcting flexed-knee gait in 60%-70% of patients with minimal effect on anterior pelvic tilt. There was no added advantage to hamstring transfer. Biceps Femoris lengthening may be beneficial and without significant additional risk.

LEVEL OF EVIDENCE

level III.

Short-Term Outcome of Rehabilitation Program with Hybrid Assistive Limb after Tendon Lengthening in Patients with Cerebral Palsy

In this study, we aimed to evaluate the short-term outcomes of a rehabilitation program with the Hybrid Assistive Limb® after soft tissue lengthening in young patients with cerebral palsy. We assessed six patients with cerebral palsy who underwent soft tissue surgery followed by gait training using the Hybrid Assistive Limb®. Clinical assessments were conducted preoperatively, before, immediately after, and at 1, 2, and 3 months after gait training. Gross Motor Function Measure was improved 5.93 ± 6.11% (mean ± standard deviation, p < 0.05), Canadian Occupational Performance Measure performance was improved 3.12 ± 1.53 points, and satisfaction was improved 3.80 ± 2.14 points (p < 0.05). The knee extension strength on the operated side was changed 7.75 ± 4.97 Nm after the intervention (p = 0.07). In ambulatory patients, gait speed was changed 8.37 ± 1.72 m/min, stride length was changed 10 ± 6.16 cm, and 6 min walking distance was changed 52 ± 16 m after the intervention. Training with the Hybrid Assistive Limb® may improve walking ability and clinical outcomes in young patients with cerebral palsy after soft tissue lengthening.

Defining usual physiotherapy care in ambulant children with cerebral palsy in the United Kingdom: A mixed methods consensus study

BACKGROUND

Ambulant children with cerebral palsy (CP) undertake physiotherapy to improve balance and walking. However, there are no relevant clinical guidelines to standardize usual physiotherapy care in the United Kingdom. A consensus process can be used to define usual physiotherapy care for children with CP. The resulting usual care checklist can support the development of clinical guidelines and be used to measure fidelity to usual care in the control groups of trials for children with CP.

METHODS

Twelve expert physiotherapists were recruited. In Phase 1, statements on usual care were developed using a survey and two nominal groups. Phase 2 included a literature review to support usual physiotherapy interventions. Phase 3 used a confirmatory survey, which also captured changes to provision during the COVID-19 pandemic. Consensus was calculated by deriving the mean of the deviations from the median score (MDM). High consensus was deemed to be where MDM < 0.42.

RESULTS

Physiotherapists reached high consensus on five outcome measures (MDM range 0-0.375) and nine areas of assessment (MDM range 0-0.25). Physiotherapists reached moderate consensus on task-specific training (MDM = 0.75), delivered at weekly intensity for 4-6 weeks (MDM = 0.43). There was high consensus (MDM = 0) that children should participate in modified sport and fitness activities and that children with Gross Motor Function Classification System Level III should be monitored on long-term pathways (MDM = 0.29).

CONCLUSIONS

Physiotherapists reached consensus on two usual care interventions, and a checklist was developed to inform the control groups of future randomized controlled trials. Further consensus work is required to establish clinical guidelines to standardize usual physiotherapy care in the United Kingdom.

Interleaved Assistance and Resistance for Exoskeleton Mediated Gait Training: Validation, Feasibility and Effects

Strength and selective motor control are primary determinants of pathological gait in children with cerebral palsy (CP) and other neuromotor disorders. Emerging evidence suggests robotic application of task-specific resistance to functional movements may provide the opportunity to strengthen muscles and improve neuromuscular function during walking in children with CP. Such a strategy could be most beneficial to children who are more severely affected by the pathology but their ability to overcome such resistance and maintain functional ambulation remains unclear. The goal of this study was to design, validate and evaluate initial feasibility and effects of a novel exoskeleton strategy that provides interleaved assistance and resistance to knee extension during overground walking. One participant with CP (GMFCS III) was recruited and completed ten total visits, nine walking with the exoskeleton. Our results validated the controller's ability to parse the gait cycle into five discrete phases (mean accuracy 91%) and provide knee extension assistance during stance and resistance during swing. Following acclimation to the interleaved strategy, peak knee extension was significantly improved in both the left (mean 7.9 deg) and right (15.2 deg) limbs when walking with the exoskeleton. Knee extensor EMG during late swing phase increased to 2.7 (left leg) and 1.7 (right leg) times the activation level during baseline exoskeleton walking without resistance. These results indicate that this interleaved strategy warrants further investigation in a longitudinal intervention study, particularly in individuals who may be more severely affected such that they are unable to ambulate overground using an exoskeleton training strategy that only deploys targeted resistance to limb motion.

The change in sagittal plane gait patterns from childhood to maturity in bilateral cerebral palsy

BACKGROUND

The longitudinal stability of sagittal gait patterns in diplegic cerebral palsy (CP), stratified using the Rodda classification, is currently unknown.

RESEARCH QUESTION

What is the trajectory of sagittal plane gait deformities as defined by the Rodda classification in a large cohort treated with orthopedic surgery guided by gait analysis?

METHODS

A retrospective study utilized gait analysis to evaluate sagittal gait parameters before age 8 and after age 15 years. Individual limbs were categorized at each time point according to the Rodda classification based on mean sagittal plane knee and ankle angle during stance. Welch's t-tests compared gait variables from early childhood with maturity and examined changes associated with plantarflexor lengthening surgery.

RESULTS

100 youth with CP were evaluated twice: at a mean age of 5.49 ± 1.18 and 19.09 ± 4.32 years, respectively. Gross Motor Function Classification System distribution at maturity was I (10.5 %), II (55.2 %), III (28.6 %), and IV (5.7 %). At the initial visit, most limbs were in either true equinus (30 %) or jump-knee gait (26.5 %). At maturity, crouch gait (52.5 %) was the most common classification, of which 47.6 % were mild (1-3 standard deviations from age-matched norm; 21°-30°) and 52.4 % moderate or severe. For the entire cohort, at initial and final visits, respectively, mean knee flexion in stance was 26.8°±14.8° and 25.9°±11.4° (p = 0.320), ankle dorsiflexion in stance increased from -0.3°±11.5° to 9.0°±6.0° (p < 0.001), and passive knee flexion contracture was -2.3°±7.0° and -3.9°±8.0° (p = 0.043). In children who started in true equinus, apparent equinus, and crouch, there was no difference in stance phase knee flexion at maturity between those who underwent plantarflexor lengthenings versus those who did not (p > 0.18).

SIGNIFICANCE

The trend in this cohort was toward crouch with increased stance phase ankle dorsiflexion from early childhood to maturity. Plantarflexor lengthenings were not a significant factor in the progression of stance phase knee flexion.

Restoration of Heel-Toe Gait Patterns for the Prevention of Asymmetrical Hip Internal Rotation in Patients with Unilateral Spastic Cerebral Palsy

Forward modelling has indicated hip internal rotation as a secondary physical effect to plantar flexion under load. It could therefore be of interest to focus the treatment for patients with unilateral spastic cerebral palsy on achieving a heel-toe gait pattern, to prevent development of asymmetrical hip internal rotation. The aim of this preliminary retrospective cohort investigation was to evaluate the effect of restoring heel-toe gait, through use of functional orthoses, on passive hip internal rotation. In this study, the affected foot was kept in an anatomically correct position, aligned to the leg and the gait direction. In case of gastrosoleus shortness, a heel raise was attached to compensate for the equinus and yet to provide heel-floor contact (mean equinus = -2.6 degrees of dorsiflexion). Differences in passive hip internal rotation between the two sides were clinically assessed while the hip was extended. Two groups were formed according to the achieved correction of their gait patterns through orthotic care: patients with a heel-toe gait (with anterograde rocking) who wore the orthosis typically for at least eight hours per day for at least a year, or patients with toe-walking (with retrograde rocking) in spite of wearing the orthosis who used the orthosis less in most cases. A Student's t-test was used to compare the values of clinically assessed passive hip rotation (p < 0.05) between the groups and the effect size (Hedges' g) was estimated. Of the 70 study participants, 56 (mean age 11.5 y, majority GMFCS 1, similar severity of pathology) achieved a heel-toe gait, while 14 remained as toe-walkers. While patients with heel-toe gait patterns showed an almost symmetrical passive hip internal rotation (difference +1.5 degrees, standard deviation 9.6 degrees), patients who kept toe-walking had an increased asymmetrical passive hip internal rotation (difference +10.4 degrees, standard deviation 7.5 degrees; p = 0.001, Hedges's g = 0.931). Our clinical findings are in line with the indications from forward modelling that treating the biomechanical problem might prevent development of a secondary deformity. Further prospective studies are needed to verify the presented hypothesis.

Knee flexion contracture impacts functional mobility in children with cerebral palsy with various degree of involvement: a cross-sectional register study of 2,838 individuals

Background and purpose - The impact of knee flexion contracture (KFC) on function in cerebral palsy (CP) is not clear. We studied KFC, functional mobility, and their association in children with CP.Subjects and methods - From the Swedish national CP register, 2,838 children were defined into 3 groups: no (≤ 4°), mild (5-14°), and severe (≥ 15°) KFC on physical examination. The Functional Mobility Scale (FMS) levels were categorized: using wheelchair (level 1), using assistive devices (level 2-4), walking independently (level 5-6). Standing and transfer ability and Gross Motor Function Classification (GMFCS) were assessed.Results - Of the 2,838 children, 73% had no, 14% mild, and 13% severe KFC. KFC increased from 7% at GMFCS level I to 71% at level V. FMS assessment (n = 2,838) revealed around 2/3 were walking independently and 1/3 used a wheelchair. With mild KFC (no KFC as reference), the odds ratio for FMS level 1 versus FMS level 5-6 at distances of 5, 50, and 500 meters, was 9, 9, and 8 respectively. Correspondingly, with severe KFC, the odds ratio was 170, 260, and 217. In no, mild, and severe KFC 14%, 47%, and 77% could stand with support and 11%, 25%, and 33% could transfer with support.Interpretation - Knee flexion contracture is common in children with CP and the severity of KFC impacts function. The proportion of children with KFC rose with increased GMFCS level, reduced functional mobility, and decreased standing and transfer ability. Therefore, early identification and adequate treatment of progressive KFC is important.

A New Method for Postural Misalignment of a 6-Year-Old Girl With Cerebral Palsy: A Case Report

Objective

To demonstrate the effects of a newly designed postural alignment relearning system on postural control dysfunction in a typical patient with cerebral palsy (CP).

Design

Evaluation before and after 8 weeks of Constraint Standing Training 3-dimensional postural alignment relearning system.

Setting

Department of Rehabilitation Medicine.

Participant

A 6-year-old girl with CP and postural misalignment on Gross Motor Function Classification System level I.

Interventions

Constraint Standing Training for 8 weeks to correct postural misalignment.

Main Outcome Measures

Parameters of lateral plain radiographs in static standing, posturography measurements in standing and walking, motor ability (Gross Motor Function Measure-88 [GMFM-88] scores, manual muscle testing [MMT] scores, muscle architecture), and gait kinematic parameters (40 3-dimensional parameters of arms, trunk, waist, and lower limbs).

Results

Knee hyperextension angle in static standing; peaks of knee flexion angle (KFA) when walking, hip flexion angle and ankle flexion angle in dynamic standing; and the KFA at initial contact in gait cycle all decreased significantly (P<.01). Scores of GMFM-88 sections D and E and MMT of 5 core stability muscles improved (P<.01). The velocities and range of motion of the arms, the 3-dimensinoal range of motion of the trunk and waist, and most of the parameters of the lower limbs showed statistically significant change (P<.01). Bilateral muscle thickness did not change significantly after the treatment (P=.738 left, P=.978 right), but the gluteus maximus morphology was changed: the muscle fibers became rounder, the interfiber space decreased, and the border lines of the muscle fibers got clearer.

Conclusions

Postural alignment, motor ability, and gait may be homologous external manifestations of more fundamental core abilities, referring to correct standing posture cognition, muscle activation, and postural unconsciousness. Constraint Standing Training 3-dimensional postural alignment relearning system aimed to improve the static and dynamic standing control ability, may fix postural misalignment and improve motor ability and flexed-knee gait. Future work should use Constraint Standing Training with patients with different kinds of misalignment, choose sensitive indicators, observe the duration of each step, and reveal the mechanism causes postural misalignment.

Recurrence of knee flexion contracture after surgical correction in children with cerebral palsy

PURPOSE

Knee flexion contracture (FC) and crouch gait are challenging to treat in children with cerebral palsy (CCP), and recurrent knee FC after surgery is a severe complication. The aim was to identify factors associated with recurrent knee FC after surgery.

METHODS

The records of 62 CCP (age 10.6±2.6 years) who underwent surgery and were followed for > six months were reviewed. Knee FC was treated by hamstring lengthening, posterior knee capsulotomy, and femoral shortening/extension osteotomy until full extension was obtained. Kaplan-Meier analysis was used to estimate the probability of the correction being maintained. Cox proportional hazard modeling was used to compare parameters between patients with and without recurrent knee FC, with the time to recurrence as the endpoint. Potential confounding factors were included in the multivariate analysis.

RESULTS

In total, the procedure was performed on 122 knees. The average weight-for-age z score was -1.3±1.2. The average follow-up period was 5.4±4.2 years. Knee FC recurrence was observed in 37 knees (30%). The average recurrence-free time was 4.9 years, with most cases of recurrence (33 knees) occurring within six years after surgery. The factors associated with recurrence were age (HR, 1.19) and a required posterior knee capsulotomy procedure (HR, 4.53).

CONCLUSION

Recurrent knee FC after correction is associated with CCP who are older at the time of operation and when posterior knee capsulotomy is performed. The age at operation should be optimized. The sequence of procedures should be performed only as necessary to minimize the chance of post-operative muscle weakness and recurrence.

A Systematic Review of Recommendations of Long-Term Strategies for Researchers Using Data Science Techniques

The impact of the strategies that researchers follow to publish or produce scientific content can have a long-term impact. Identifying which strategies are most influential in the future has been attracting increasing attention in the literature. In this study, we present a systematic review of recommendations of long-term strategies in research analytics and their implementation methodologies. The objective is to present an overview from 2002 to 2018 on the development of this topic, including trends, and addressed contexts. The central objective is to identify data-oriented approaches to learn long-term research strategies, especially in process mining. We followed a protocol for systematic reviews for the engineering area in a structured and respectful manner. The results show the need for studies that generate more specific recommendations based on data mining. This outcome leaves open research opportunities from two particular perspectives—applying methodologies involving process mining for the context of research analytics and the feasibility study on long-term strategies using data science techniques.

Are there common walking gait characteristics in patients diagnosed with late-onset Pompe disease?

Late-onset Pompe disease (LOPD) is a rare disease, defined as a progressive accumulation of lysosomal glycogen resulting in muscle weakness and respiratory problems. Anecdotally, individuals often have difficulties walking, yet, there is no three-dimensional data supporting these claims. We aimed to assess walking patterns in individuals with LOPD and compare with healthy individuals. Kinematic, kinetic and spatiotemporal data were compared during walking at a self-selected speed between individuals with LOPD (n = 12) and healthy controls (n = 12). Gait profile scores and movement analysis profiles were also determined to indicate gait quality. In comparison with healthy individuals, the LOPD group demonstrated greater thoracic sway (96%), hip adduction angles (56%) and pelvic range of motion (77%) and reduced hip extensor moments (36%). Greater group variance for the LOPD group were also observed. Individuals with LOPD had a slower (15%) walking speed and reduced cadence (7%). Gait profile scores were 37% greater in the LOPD group compared to the healthy group. Proximal muscular weakness associated with LOPD disease is likely to have resulted in a myopathic gait pattern, slower selected walking speeds and deviations in gait patterns. Although individuals with LOPD presented with some common characteristics, greater variability in gait patterns is likely to be a result of wide variability in phenotype spectrum observed with LOPD. This is the first study to examine walking in individuals with LOPD using instrumented gait analysis and provides an understanding of LOPD on walking function which can help orientate physiotherapy treatment for individuals with LOPD.

Effectiveness comparison between carbon spring and hinged ankle-foot orthoses in crouch gait treatment of children with diplegic cerebral palsy: a randomized crossover trial

BACKGROUND

Children with cerebral palsy (CP) often present a loss of effectiveness of the plantarflexors/knee-extensors couple that leads to crouch gait. When treating a child with crouch gait by means of ankle foot orthoses, preserving or restoring push off power is a key issue.

AIM

To compare carbon-fiber spring (Carbon Ankle Seven® = CAFO) and hinged anklefoot orthoses (HAFO) effectiveness in improving functionality and walking ability in children with diplegic CP and crouch gait.

DESIGN

Randomized crossover trial.

SETTING

Hospital center.

POPULATION

Ten children with diplegic CP and crouch gait, 5 males and 5 females, aged 11 (4) years.

METHODS

The gait of each child was evaluated by means of instrumental gait analysis with both CAFO and HAFO, in a randomized order and after a 4-week adaptation period. The primary outcome measure was the change in ankle power generation. As secondary outcome measures, knee joint kinematics, stride length, walking speed, Observational Gait Scale, and preferred orthosis were considered.

RESULTS

The median of the energy produced in stance was superior with CAFO (+2.2 J/kg, IQR 4.7, p=0.006), and the energy absorbed inferior (-3.3 J/kg, IQR 4.3, p=0.011). No statistically significant difference was found for any other parameter. Preference of the children was equally distributed between the two orthoses.

CONCLUSIONS

No evident superiority of CAFO with respect to HAFO was found in improving gait performance of children with CP and crouch gait. Nevertheless, the results suggest the possibility that CAFO permits an energy saving and reduction of the more compromising deficits.

CLINICAL REHABILITATION IMPACT

The final choice of the participants indicates that CAFOs are preferred by older and heavier children, but the preference does not correlate with the performance of the orthoses during gait.

The association between gait analysis measures associated with crouch gait, functional health status and daily activity levels in cerebral palsy

PURPOSE

The aim of this study was to examine the relationship between gait analysis measures associated with crouch gait, functional health status and daily activity in ambulant cerebral palsy (CP).

METHODS

Three-dimensional gait analysis was carried out on 35 ambulant participants with bilateral CP crouch gait (knee flexion at mid-stance (KFMS) ⩾ 190). KFMS, knee-flexion at initial contact, gait speed and step-lengths were extracted for analysis. Steps/day and sedentary time/day were assessed using an ActivPAL accelerometer. Functional health status was assessed using the five relevant domains of the Pediatric Outcomes Data Collection Instrument (PODCI) questionnaire. Associations between variables were assessed with correlation coefficients and multivariable linear regression.

RESULTS

There were no significant correlations between KFMS and PODCI domains (ρ=-0.008-0.110) or daily activity (ρ=-0.297-0.237) variables. In contrast, multivariable analysis found that step-length was independently associated with the Sports and Physical Function (p= 0.030), Transfers and Basic Mobility (p= 0.041) and Global Function (< 0.001) domains of the PODCI assessment. Gait speed was independently associated with mean steps/day (p< 0.001).

CONCLUSIONS

Step length and gait speed are more strongly associated with functional health status and daily activity than knee flexion during stance in children and adolescents with CP crouch gait.

Gait characteristics of children with Williams syndrome with impaired visuospatial recognition: a three-dimensional gait analysis study

Williams syndrome (WS) is a genetically based neurodevelopmental disorder characterized by intellectual disability and impaired visuospatial recognition. The aim of this study was to analyze the gait characteristics of WS children with impaired visuospatial recognition using a three-dimensional gait analysis (3DGA) to clarify the gait adaptation needed to compensate for it. 3DGA was performed in 8 WS children with impaired visuospatial recognition (mean age, 11.8 years) and 9 age-, sex-, height-, and weight-matched controls. Clinical data, fundamental motor tests, and gait variables while walking on a flat surface and walking up a mat were compared between the two groups, and the correlations between variables were analyzed in the WS children. WS children showed impairment of balance function without muscle weakness. In walking on a flat surface, the WS group showed reduced walking speed, short step length, increased variability of step length, increased knee flexion throughout the stance phase, increased horizontal pelvic range of motion (ROM), and a low Gait Deviation Index and a high Gait Profile Score, which are indices of gait quality. In walking up a mat, the WS group showed further reduced walking speed and decreased sagittal hip flexion and ankle dorsiflexion ROM in the swing phase. Impaired balance function was significantly correlated with increased variability of step length and decreased sagittal ankle dorsiflexion ROM in the swing phase. The detailed gait pattern of WS children with impaired visuospatial recognition was presented. These findings show that impaired visuospatial recognition and balance function contribute to gait adaptation.

Crouch gait or flexed-knee gait in cerebral palsy: Is there a difference? A systematic review

BACKGROUND

Crouch or flexed-knee gait is one of the most common pathological gait patterns in cerebral palsy (CP). Differences exist in definitions used; the degree of knee flexion, inclusion of hip or ankle position, and timing in the gait cycle. This ambiguity may be responsible for variations in prevalence rates and difficulty comparing data across studies.

RESEARCH QUESTION

What are the kinematic parameters used to define crouch or flexed-knee gait in CP gait? A secondary aim was to examine the quality of data reporting, focusing on the sample characteristics, inclusion/exclusion criteria and the choice of limb included for analysis.

METHODS

Articles included in this review reported on a specified cohort of adults or children with crouch or flexed-knee gait assessed with 3-dimensional gait analysis. A customised data extraction and quality assessment table was designed specific to the research question.

RESULTS

The majority (75 %) of included studies used the term crouch gait. Where the pattern was defined, 80 % of crouch papers and 94 % of flexed-knee gait papers based this solely on knee position. Kinematic parameters were clearly defined when they provided objective values of knee flexion, supported this with rationale and provided a reference point in the gait cycle. Only 22 % of crouch papers and 19 % of flexed-knee gait papers provided this information. The majority of studies (67 % crouch; 90 % flexed-knee) specified which limb(s) were included for analysis with the majority including both limbs. Objective values of knee flexion ranged from 8 o to 30 o.

SIGNIFICANCE

This review highlights that crouch and flexed knee are synonymous and ambiguity exists in the kinematic definition making it difficult to make compare data amongst study cohorts. Future research should provide detailed definitions including the threshold value of knee flexion, how it was derived, the timing in the gait cycle and the limb(s) included in analysis.

Toward a hybrid exoskeleton for crouch gait in children with cerebral palsy: neuromuscular electrical stimulation for improved knee extension

BACKGROUND

Neuromuscular Electrical Stimulation (NMES) has been utilized for many years in cerebral palsy (CP) with limited success despite its inherent potential for improving muscle size and/or strength, inhibiting or reducing spasticity, and enhancing motor performance during functional activities such as gait. While surface NMES has been shown to successfully improve foot drop in CP and stroke, correction of more complex gait abnormalities in CP such as flexed knee (crouch) gait remains challenging due to the level of stimulation needed for the quadriceps muscles that must be balanced with patient tolerability and the ability to deliver NMES assistance at precise times within a gait cycle.

METHODS

This paper outlines the design and evaluation of a custom, noninvasive NMES system that can trigger and adjust electrical stimulation in real-time. Further, this study demonstrates feasibility of one possible application for this digitally-controlled NMES system as a component of a pediatric robotic exoskeleton to provide on-demand stimulation to leg muscles within specific phases of the gait cycle for those with CP and other neurological disorders who still have lower limb sensation and volitional control. A graphical user interface was developed to digitally set stimulation parameters (amplitude, pulse width, and frequency), timing, and intensity during walking. Benchtop testing characterized system delay and power output. System performance was investigated during a single session that consisted of four overground walking conditions in a 15-year-old male with bilateral spastic CP, GMFCS Level III: (1) his current Ankle-Foot Orthosis (AFO); (2) unassisted Exoskeleton; (3) NMES of the vastus lateralis; and (4) NMES of the vastus lateralis and rectus femoris. We hypothesized in this participant with crouch gait that NMES triggered with low latency to knee extensor muscles during stance would have a modest but positive effect on knee extension during stance.

RESULTS

The system delivers four channels of NMES with average delays of 16.5 ± 13.5 ms. Walking results show NMES to the vastus lateralis and rectus femoris during stance immediately improved mean peak knee extension during mid-stance (p = 0.003*) and total knee excursion (p = 0.009*) in the more affected leg. The electrical design, microcontroller software and graphical user interface developed here are included as open source material to facilitate additional research into digitally-controlled surface stimulation ( github.com/NIHFAB/NMES ).

CONCLUSIONS

The custom, digitally-controlled NMES system can reliably trigger electrical stimulation with low latency. Precisely timed delivery of electrical stimulation to the quadriceps is a promising treatment for crouch. Our ultimate goal is to synchronize NMES with robotic knee extension assistance to create a hybrid NMES-exoskeleton device for gait rehabilitation in children with flexed knee gait from CP as well as from other pediatric disorders.

TRIAL REGISTRATION

clinicaltrials.gov, ID: NCT01961557 . Registered 11 October 2013; Last Updated 27 January 2020.

Tibial rotation outcomes following hamstring lengthening as part of single event multilevel surgery in children with cerebral palsy

BACKGROUND

Hamstring lengthening remains the most common surgical procedure in the treatment of crouch gait for children with cerebral palsy (CP). While sagittal plane knee kinematics have been shown to improve post-surgery, the effects on transverse plane kinematics have not been reported. Given the differing actions of the medial and lateral hamstring muscles there is potential for change in tibial rotation post hamstring lengthening.

RESEARCH QUESTION

What is the effect of medial only versus combined medial and lateral hamstring lengthening on tibial rotation during gait in children with CP?

METHODS

A retrospective analysis of children with a diagnosis of CP who underwent a hamstring lengthening procedure. These children were divided into 2 groups: G1 (n = 18) had isolated medial hamstring lengthening while G2 (n = 30) had combined medial and lateral hamstring lengthening. A matched non-surgical control group (n = 15) was also included. Kinematic data were analysed pre and post-operatively. Pre-operative to post-operative outcomes for G1 and G2, a comparison at baseline for both groups and the difference in outcomes between the groups were analysed. Baseline to follow-up outcomes for the control group were also analysed.

RESULTS

External tibial rotation increased significantly within groups (G1: -10°, p < 0.01; G2: -11°, p < 0.001, control: -7.7, p < 0.01), with no significant difference in the change between the intervention groups. Foot progression angles became more external in both intervention groups (G1: -15°, p < 0.001; G2: -15°, p < 0.0001) and did not change in the control group.

SIGNIFICANCE

Results demonstrated similar increases in external tibial rotation, regardless of whether an isolated medial or combined medial and lateral surgery was performed. The control group demonstrated a similar change in external tibial rotation suggesting that hamstring lengthening surgery does not contribute to increased external tibial rotation in children with CP compared to what would be expected due to natural progression.

Knee pain and crouch gait in individuals with cerebral palsy: what impact does crouch-related surgery have?

AIM

To investigate the effect of crouch-related surgery on knee pain in individuals with cerebral palsy.

METHOD

We retrospectively identified individuals with two three-dimensional gait analyses at baseline and follow-up visits. All individuals walked in crouch gait at baseline. Visits were 9 months to 42 months apart. Baseline knee pain, age, crouch-related surgery (yes/no), and minimum knee flexion at follow-up were entered into a logistic regression to predict follow-up knee pain.

RESULTS

Thirty-two individuals (21 males, 11 females; mean [SD] age 12y 10mo [2y 5mo]; 8y 1mo-18y 7mo) received crouch-related surgery, while 19 were managed non-surgically. At baseline, knee pain prevalence was 38% in the surgical group and 21% in the non-surgical group. At follow-up, 34% of the surgical group and 16% of the non-surgical group had knee pain (odds ratio: 2.809, p=0.285).

INTERPRETATION

Crouch-related surgery does not appear to decrease knee pain prevalence compared to a comparison group, based on this preliminary study. Further investigation of the roles of these procedures is indicated with regards to this patient-reported outcome. What this paper adds Approximately 38% of individuals undergoing crouch-related surgery had knee pain. Approximately 42% of individuals with baseline knee pain who had surgery still had knee pain 1 year postoperatively. Approximately 50% of those with baseline knee pain managed non-surgically still had knee pain 1 year later. Crouch-related surgery tended not to decrease knee pain prevalence 1 year postoperatively.

A prospective assessment of the progression of flexed-knee gait over repeated gait analyses in the absence of surgical intervention in bilateral cerebral palsy

BACKGROUND

Flexed-knee gait is a common pattern associated with cerebral palsy (CP). It leads to excessive forces on the knee and is thought to contribute to pain and deformity. While studies have shown improvements in mid-stance knee flexion following surgery there remains a lack of prospective data on the progression of flexed-knee gait in the absence of surgery.

RESEARCH QUESTION

Does knee flexion progress over repeated assessments in the absence of surgery in a prospectively assessed cohort with CP?

METHODS

Inclusion criteria were a diagnosis of bilateral CP, knee flexion at mid-stance >19° and no surgery within one year of the first gait analysis. Gait analysis was carried out at six-month intervals (minimum of three and maximum of six assessments). The progression of knee flexion over repeated analyses was assessed. The association between changes in knee flexion between assessments and gender, age, GMFCS level, change in ankle dorsiflexion, change in height and change in weight was examined.

RESULTS

Forty-eight participants met the initial inclusion criteria and 32 (GMFCS I = 11, II = 17, III = 4) completed the minimum three assessments. Of the 32 included participants, 21 participants (66%) demonstrated decreased knee flexion at mid-stance (mean decrease 6.6° ± 3.4°; range 2.0°-13.0°) and 11 participants (34%) demonstrated increased knee flexion at mid-stance (mean increase 10.4° ± 7.1°; range 2.0°-20.0°) at one-year follow-up. Eighteen (56%) then demonstrated an overall decrease (mean 7.4° ± 5.1°) in knee flexion between the first and last assessment with last follow-up at 1-2 years (n = 3), 2-3 years (n = 3) and 3-4 years (n = 12). The majority of participants (78%) demonstrated episodes of both increasing and decreasing Knee flexion between individual assessments and further analysis found that age was associated with this inter-assessment variability in knee flexion.

SIGNIFICANCE

Flexed-knee gait is not always progressive in bilateral CP and demonstrated variability associated with age.

Single-event multilevel surgery, but not botulinum toxin injections normalize joint loading in cerebral palsy patients

BACKGROUND

Many patients with cerebral palsy present a pathologic gait pattern, which presumably induces aberrant musculoskeletal loading that interferes with natural bone growth, causing bone deformations on the long term. Botulinum toxin interventions and single-event multilevel surgeries are used to restore the gait pattern, assuming that a normal gait pattern restores musculoskeletal loading and thus prevents further bone deformation. However, it is unknown if these interventions are able to restore musculoskeletal loading. Hence, we investigated the impact of botulinum toxin injections and single-event multilevel surgery on musculoskeletal loading.

METHODS

Gait data collected in 93 children with bilateral cerebral palsy, which included pre- and post multi-level botulinum toxin (49 children) and single-event multilevel surgery (44 children) assessments, and 15 typically developing children were retrospectively processed using a musculoskeletal modelling workflow to calculate joint angles, moments, muscle and joint contact force magnitudes and orientations. Differences from the typically developing waveform were expressed by a root-mean square difference were compared using paired t-tests for each intervention separately (alpha <0.05).

FINDINGS

Botulinum toxin induced significant changes in the joint angles, but did not improve the muscle and joint contact forces. Single-event multilevel surgery induced significant kinematic and kinetic changes, which were associated with improved muscle and joint contact forces.

INTERPRETATION

The present results indicate that botulinum toxin injections were not able to restore normal gait kinematics nor musculoskeletal loading, whereas single-event multilevel surgery did successfully restore both. Therefore, single-event multilevel surgery might be protective against the re-occurrence of bone deformation on the longer term.

State of the Evidence Traffic Lights 2019: Systematic Review of Interventions for Preventing and Treating Children with Cerebral Palsy

PURPOSE OF REVIEW

Cerebral palsy is the most common physical disability of childhood, but the rate is falling, and severity is lessening. We conducted a systematic overview of best available evidence (2012-2019), appraising evidence using GRADE and the Evidence Alert Traffic Light System and then aggregated the new findings with our previous 2013 findings. This article summarizes the best available evidence interventions for preventing and managing cerebral palsy in 2019.

RECENT FINDINGS

Effective prevention strategies include antenatal corticosteroids, magnesium sulfate, caffeine, and neonatal hypothermia. Effective allied health interventions include acceptance and commitment therapy, action observations, bimanual training, casting, constraint-induced movement therapy, environmental enrichment, fitness training, goal-directed training, hippotherapy, home programs, literacy interventions, mobility training, oral sensorimotor, oral sensorimotor plus electrical stimulation, pressure care, stepping stones triple P, strength training, task-specific training, treadmill training, partial body weight support treadmill training, and weight-bearing. Effective medical and surgical interventions include anti-convulsants, bisphosphonates, botulinum toxin, botulinum toxin plus occupational therapy, botulinum toxin plus casting, diazepam, dentistry, hip surveillance, intrathecal baclofen, scoliosis correction, selective dorsal rhizotomy, and umbilical cord blood cell therapy. We have provided guidance about what works and what does not to inform decision-making, and highlighted areas for more research.

Maturation of feedforward toe walking motor program is impaired in children with cerebral palsy

Voluntary toe walking in adults is characterized by feedforward control of ankle muscles in order to ensure optimal stability of the ankle joint at ground impact. Toe walking is frequently observed in children with cerebral palsy, but the mechanisms involved have not been clarified. Here, we investigated maturation of voluntary toe walking in typically-developing children and typically-developed adults and compared it to involuntary toe walking in children with cerebral palsy. Twenty-eight children with cerebral palsy (age 3-14 years), 24 typically-developing children (age 2-14 years) and 15 adults (mean age 30.7 years) participated in the study. EMG activity was measured from the tibialis anterior and soleus muscles together with knee and ankle joint position during treadmill walking. In typically-developed adults, low step-to-step variability of the drop of the heel after ground impact was correlated with low tibialis anterior and high soleus EMG with no significant coupling between the antagonist muscle EMGs. Typically-developing children showed a significant age-related decline in EMG amplitude reaching an adult level at 10-12 years of age. The youngest typically-developing children showed a broad peak EMG-EMG synchronization (>100 ms) associated with large 5-15 Hz coherence between antagonist muscle activities. EMG coherence declined with age and at the age of 10-12 years no correlation was observed similar to adults. This reduction in coherence was closely related to improved step-to-step stability of the ankle joint position. Children with cerebral palsy generally showed lower EMG levels than typically-developing children and larger step-to-step variability in ankle joint position. In contrast to typically-developing children, children with cerebral palsy showed no age-related decline in tibialis anterior EMG amplitude. Motor unit synchronization and 5-15 Hz coherence between antagonist EMGs was observed more frequently in children with cerebral palsy when compared to typically-developing children and in contrast to typically-developing participants there was no age-related decline. We conclude that typically-developing children develop mature feedforward control of ankle muscle activity as they age, such that at age 10-12 years there is little agonist-antagonist muscle co-contraction around the time of foot-ground contact during toe walking. Children with cerebral palsy, in contrast, continue to co-contract agonist and antagonist ankle muscles when toe walking. We speculate that children with cerebral palsy maintain a co-contraction activation pattern when toe walking due to weak muscles and insufficient motor and sensory signalling necessary for optimization of feedforward motor programs. These findings are important for understanding of the pathophysiology and treatment of toe walking.

Gait abnormalities in people with Dravet syndrome: A cross-sectional multi-center study

OBJECTIVE

To quantify gait abnormalities in people with Dravet syndrome (DS).

METHODS

Individuals with a confirmed diagnosis of DS were enrolled, and stratified according to knee flexion at initial contact (IC) and range of motion (ROM) during stance (atypical crouch: knee flexion >20° at IC and knee ROM >15° during stance; straight: knee flexion <20° at IC). A 1D ANOVA (α = 0.05) was used to test statistical differences among the joint kinematics and spatio-temporal parameters of the cohort and an age-matched control group. Clinical (neurological and orthopaedic evaluation) and anamnestic data (seizure type, drugs, genetic mutation) were collected; distribution between the two gait phenotypes was assessed with the Fisher exact test and, for mutation, with the chi-squared test (p < 0.05). Linear regression between maximum knee flexion and normalised walking speed was calculated.

RESULTS

Seventy-one subjects were enrolled and evaluated with instrumented gait analysis. Fifty-two were included in final analysis (mean age 13.8 ± 7.3; M 26). Two gait patterns were detected: an atypical crouch gait (34.6%) with increased ankle, knee and hip flexion during stance, and reduced walking speed and stride length not associated with muscle-tendon retractions; and a pattern resembling those of healthy age-matched controls, but still showing reduced walking speed and stride length. No differences in clinical or anamnestic data emerged between the two groups.

SIGNIFICANCE

Objectively quantified gait in DS shows two gait patterns with no clear-cut relation to clinical data. Kinematics abnormalities may be related to stabilization issues. These findings may guide rehabilitative and preventive measures.

The short-term effects of selective dorsal rhizotomy on gait compared to matched cerebral palsy control groups

Objectives

To examine the short-term effects of selective dorsal rhizotomy (SDR) ± soft-tissue surgery on gait in cerebral palsy (CP) compared to matched controls with no surgical intervention.

Methods

Participants had gait analysis before and one year after SDR. Non SDR participants were retrospectively matched for age and all significant gait parameters. The SDR group was further subdivided into those who had concomitant orthopaedic surgery and those who had SDR only.

Results

The SDR group consisted of 29 participants (mean age 5.8 years at baseline, 7.7 years at follow-up). Of these, 13 had concomitant orthopaedic surgery. The non SDR group consisted of 18 participants (mean age at baseline 6.1 years, 8.1 years at follow-up). SDR ± soft-tissue surgery significantly improved step-lengths, knee flexion at initial contact and mid-stance, ankle dorsiflexion, foot progression and timing of peak knee flexion. None of these improvements in gait were seen without surgical intervention. While more improvements were seen in those who had SDR and orthopaedic surgery, SDR only resulted in improved step-lengths, knee extension, foot progression and timing of peak knee flexion.

Conclusions

SDR ± soft-tissue surgery results in short-term improvements in gait which are not seen without surgical intervention. While those who had SDR and soft-tissue surgery demonstrated more changes in gait, many improvements were attributable to SDR only.

Effect of a Combined Stretching and Strength Training Program on Gait Function in Children with Cerebral Palsy, GMFCS Level I & II: A Randomized Controlled Trial

Background and objectives: Ambulant children with cerebral palsy (CP) often develop impaired gait, and reduced active knee extension is often a part of the problem. This study aimed to evaluate the effect of a combined intervention program including stretching and progressive resistance exercise (PRE) targeting active knee extension on gait function, in children with spastic CP. Materials and methods: Thirty-seven children (21 boys, 16 girls, mean age 10.2 (±2.3) years), classified by Gross Motor Function Classification System I-III, were randomized to an intervention (n = 17) and a comparison group (n = 20). The intervention group received a 16-week combined exercise program (3 sessions per week) including stretching of hamstrings and PRE targeting the lower extremities, followed by a 16-week maintenance program (1 session per week). The comparison group received care as usual. Gait function was evaluated by three-dimensional gait analysis (3DGA); knee, hip and pelvic kinematics in the sagittal plane, step length and speed, Gait Deviation Index (GDI), and Six-Minute Walk test (6MWT) at 0, 16, and 32 weeks. Results: There were no statistically significant differences between the intervention group and the comparison group for any of the gait parameters measured at 16 and 32 weeks. There was a significant increase in gait distance measured by 6MWT within both groups; however, no differences between the groups were found. Conclusion: A 16-week combined stretching and PRE program followed by a 16-week maintenance program did not improve gait function in ambulant children with CP.

Computational modeling of neuromuscular response to swing-phase robotic knee extension assistance in cerebral palsy

Predicting subject-specific responses to exoskeleton assistance may aid in maximizing functional gait outcomes, such as achieving full knee-extension at foot contact in individuals with crouch gait from cerebral palsy (CP). The purpose of this study was to investigate the role of volitional and non-volitional muscle activity in subject-specific responses to knee extension assistance during walking with an exoskeleton. We developed a simulation framework to predict responses to exoskeleton torque by applying a stretch-reflex spasticity model with muscle excitations computed during unassisted walking. The framework was validated with data collected from six individuals with CP. Framework-predicted knee angle at terminal swing was within 4 ± 4° (mean ± sd) of the knee angle measured experimentally without the addition of spasticity. Kinematic responses in two-thirds of the participants could be accurately modeled using only underlying muscle activity and the applied exoskeleton torque; incorporating hamstring spasticity was necessary to recreate the measured kinematics to within 1 ± 1° in the remaining participants. We observed strong positive linear relationships between knee extension and exoskeleton assistance, and strong negative quadratic relationships between knee extension and spasticity. We utilized our framework to identify optimal torque profiles necessary to achieve full knee-extension at foot contact. An angular impulse of 0.061 ± 0.025 Nm·s·kg^-1·deg^-1 with 0.013 ± 0.002 Nm·kg^-1·deg^-1 of peak torque and 4.1 ± 1.9 W·kg^-1·deg^-1 peak mechanical power was required to achieve full knee extension (values normalized by knee excursion). This framework may aid the prescription of exoskeleton control strategies in pathologies with muscle spasticity. https://simtk.org/projects/knee-exo-pred/.

Current practice and preferences to management of equinus in children with ambulatory cerebral palsy: A survey of orthopedic surgeons

Introduction: The consensus among orthopedic surgeons on the management of equinus deformity in cerebral palsy (CP) children has not been reported previously despite being a prevalent deformity. The goals of this study were to examine the orthopedic surgeons’ current practice regarding the management of equinus deformity in children with ambulatory CP, and analyze variations in current practice between general orthopedic and pediatric orthopedic surgeons.

Methods: We implemented a brief cross-sectional self-reported questionnaire that addressed the areas of clinical examination and decision-making skills of management of equinus deformity in CP children. We targeted a convenience sample of 400 participants. Surgeons that provided complete responses to the questionnaire were 223 with a response rate of 56%, of which 123 (55%) were general orthopedic surgeons, whereas 100 (45%) were pediatric orthopedic surgeons. The target population consisted of orthopedic surgeons who were further sub-classified in accordance with practice age, general versus pediatric, and exposure to children’s orthopedics during the last three years of their practice. For analytical statistics, the Chi-Square test and Fisher’s exact test were used to examine the relationship between two qualitative variables.

Results: The overall clinical practice preferences of all survey participants were unimpressive with discordant survey responses. Pediatric orthopedic surgeons generally demonstrated a statistically significant difference regarding clinical assessment skill items of the survey, in contrast to general orthopedic surgeons. However, we found no differences between pediatric orthopedic and general orthopedic surgeons regarding most of the decision-making/knowledge items.

Discussion: Generally, there are insufficient clinical practice trends of both general and pediatric orthopedic surgeons regarding equinus treatment in CP children. This may indicate a knowledge–practice gap with potential risks to CP children undergoing surgery for equinus. There is a need for a more competent exposure to CP in orthopedic surgeons’ educational curricula and an updated health referral system.

Skeletal Muscle Adaptations and Passive Muscle Stiffness in Cerebral Palsy: A Literature Review and Conceptual Model

This literature review focuses on the primary morphological and structural characteristics, and mechanical properties identified in muscles affected by spastic cerebral palsy (CP). CP is a non-progressive neurological disorder caused by brain damage and is commonly diagnosed at birth. Although the brain damage is not progressive, subsequent neuro-physiological developmental adaptations may initiate changes in muscle structure, function, and composition, causing abnormal muscle activity and coordination. The symptoms of CP vary among patients. However, muscle spasticity is commonly present and is one of the most debilitating effects of CP. Here, we present the current knowledge regarding the mechanical properties of skeletal tissue affected by spastic CP. An increase in sarcomere length, collagen content, and fascicle diameter, and a reduction in the number of satellite cells within spastic CP muscle were consistent findings in the literature. Studies differed, however, in changes in fascicle lengths and fiber diameters. We also present a conceptual mechanical model of fascicle force transmission that incorporates mechanisms that impact both serial and lateral force production, highlighting the connections between the macro and micro structures of muscle to assist in deducing specific mechanisms for property changes and reduced force production.

The natural history of crouch gait in bilateral cerebral palsy: A systematic review

AIM

To systematically review the natural history of crouch gait in bilateral cerebral palsy (CP) in the absence of surgical intervention and to review any relationship between clinical variables and progression of knee crouch.

METHODS

Relevant literature was identified by searching article databases (PubMed, CINAHL, EMBASE, and Web of Science). Included studies reported on participants with bilateral CP who had 3-dimensional gait analysis on at least two occasions with no surgical interventions between analyses.

RESULTS

Five papers (4 retrospective cohort studies; 1 case report) comprised the final selection. Studies varied in follow-up times and participant numbers. Increased knee flexion over time was reported in the four retrospective studies with two distinct patterns of increasing knee flexion evident. Only the case-study reported improved knee extension between assessments. Four studies demonstrated increased hamstring tightness over time with the biggest increases related to longer follow-up time rather than increase in crouch.

CONCLUSION AND IMPLICATIONS

The existing literature suggests that the natural history of crouch gait is towards increasing knee flexion over time. Future prospective studies of bigger groups are needed to examine the relationship between increasing crouch and clinical variables.

A lower-extremity exoskeleton improves knee extension in children with crouch gait from cerebral palsy

The ability to walk contributes considerably to physical health and overall well-being, particularly in children with motor disability, and is therefore prioritized as a rehabilitation goal. However, half of ambulatory children with cerebral palsy (CP), the most prevalent childhood movement disorder, cease to walk in adulthood. Robotic gait trainers have shown positive outcomes in initial studies, but these clinic-based systems are limited to short-term programs of insufficient length to maintain improved function in a lifelong disability such as CP. Sophisticated wearable exoskeletons are now available, but their utility in treating childhood movement disorders remains unknown. We evaluated an exoskeleton for the treatment of crouch (or flexed-knee) gait, one of the most debilitating pathologies in CP. We show that the exoskeleton reduced crouch in a cohort of ambulatory children with CP during overground walking. The exoskeleton was safe and well tolerated, and all children were able to walk independently with the device. Rather than guiding the lower limbs, the exoskeleton dynamically changed the posture by introducing bursts of knee extension assistance during discrete portions of the walking cycle, a perturbation that resulted in maintained or increased knee extensor muscle activity during exoskeleton use. Six of seven participants exhibited postural improvements equivalent to outcomes reported from invasive orthopedic surgery. We also demonstrate that improvements in crouch increased over the course of our multiweek exploratory trial. Together, these results provide evidence supporting the use of wearable exoskeletons as a treatment strategy to improve walking in children with CP.