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

Case report: Intensive rehabilitation program delivered before and after single-event multilevel surgery in a girl with diplegic cerebral palsy

Introduction

Diplegic cerebral palsy (CP) is often associated with musculoskeletal disorders that contribute to worsen walking function. The standard care in these cases is single-event multilevel surgery (SEMLS) followed by rehabilitation. Our aim was to investigate whether a rehabilitation program starting even before SEML could add a benefit with respect to standard postoperative programs considered by previous research.

Methods

From 2 months before to 13 months after SEMLS (except for the first month after surgery), the participant underwent a motor training focused on ROM exercises with tactile and kinaesthetic feedback. Walking performance, walking capacity, and quality-of-life were assessed before and after SEMLS at different follow-up times.

Results

Walking capacity improved 3 months after SEMLS (i.e., earlier than in current literature) and walking performance improved 12 months after SEMLS (instead of simply returning to baseline as previously reported), with a positive impact on quality-of-life.

Conclusions

This case suggests that a rehabilitation program starting even before SEMLS could add benefits over walking function and quality-of-life of children with diplegic CP compared to postoperative programs only.

Crouch Gait in Cerebral Palsy: Current Concepts Review

Background and Objective

Crouch gait is the most common pathological gait pattern in cerebral palsy and is commonly seen in patients with spastic diplegia. It is characterized by excessive knee flexion throughout the stance phase of gait cycle. The aim of this review is to discuss the current literature about CG for a more comprehensive understanding.

Methods

A literature review about various aspects of crouch gait in cerebral palsy was undertaken. This included its etiology and pathophysiology, biomechanics in crouch gait, natural history of untreated crouch gait, clinical and radiological evaluation and different modalities of available treatment.

Results

The etiology is multifactorial and the pathophysiology is poorly understood. This makes its management challenging, thereby leading to a variety of available treatment modalities. Inadvertent lengthening of muscle-tendon units is an important cause and can be avoided. A meticulous clinical and radiological evaluation of patients, supplemented by observational and instrumented gait analysis is mandatory in choosing correct treatment modality and improving the treatment outcome. Younger children can be managed satisfactorily by various non-operative methods and spasticity reduction measures. However, crouch gait in cerebral palsy has a progressive natural history and surgical interventions are needed frequently. The current literature supports combination of various soft tissue and bony procedures as a part of single event multilevel surgery. Growth modulation in the form of anterior distal femur hemiepiphysiodesis for correction of fixed flexion deformity of knee has shown encouraging results and can be an alternative in younger children with sufficient growth remaining.

Conclusions

In spite of extensive research in this field, the current understanding about crouch gait has many knowledge gaps. Further studies about the etiopathogenesis and biomechanics of crouch using instrumented gait analysis are suggested. Similarly, future research should focus on the long term outcomes of different treatment modalities through comparative trials.

Functional popliteal angle tests improve identification of short hamstring muscle-tendon length in patients with a central neurological lesion

This study introduces a functional exercise protocol to improve the identification for short hamstring muscle-tendon length (HMTL), a common contributor to crouch gait in patients with central neurological lesions (CNL). The functional exercise protocol incorporates a knee extension movement with hip in a flexed position, while standing on one leg (functional popliteal angle test) and walking with large steps to the current standard protocol (walking at comfortable speed and as fast as possible). The main aim was to establish whether the new protocol allows better determination of maximum HMTLs and diagnostics of short HMTL in patients with a CNL. Lower limb 3D marker position data from 39 patient limbs and 10 healthy limbs performing the exercises were processed in OpenSim to extract HMTLs. The new protocol provoked significantly larger HMTLs compared to the current standard protocol. The total number of limbs classified as having too short HMTLs reduced from 16 to 4 out of a total of 30 limbs walking in crouch. The new protocol improves determination of maximum HMTL, thereby improving short HMTL diagnostics and identification of patients in need of lengthening treatment. Inter-individual variability observed among patients, indicating the need to include all exercises for comprehensive diagnosis.

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.

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.

Distal femoral extension osteotomy and patellar tendon advancement or shortening in ambulatory children with cerebral palsy: A modified Delphi consensus study and literature review

PURPOSE

In children with cerebral palsy, flexion deformities of the knee can be treated with a distal femoral extension osteotomy combined with either patellar tendon advancement or patellar tendon shortening. The purpose of this study was to establish a consensus through expert orthopedic opinion, using a modified Delphi process to describe the surgical indications for distal femoral extension osteotomy and patellar tendon advancement/patellar tendon shortening. A literature review was also conducted to summarize the recent literature on distal femoral extension osteotomy and patellar tendon shortening/patellar tendon advancement.

METHOD

A group of 16 pediatric orthopedic surgeons, with more than 10 years of experience in the surgical management of children with cerebral palsy, was established. The group used a 5-level Likert-type scale to record agreement or disagreement with statements regarding distal femoral extension osteotomy and patellar tendon advancement/patellar tendon shortening. Consensus for the surgical indications for distal femoral extension osteotomy and patellar tendon advancement/patellar tendon shortening was achieved through a modified Delphi process. The literature review, summarized studies of clinical outcomes of distal femoral extension osteotomy/patellar tendon shortening/patellar tendon advancement, published between 2008 and 2022.

RESULTS

There was a high level of agreement with consensus for 31 out of 44 (70%) statements on distal femoral extension osteotomy. Agreement was lower for patellar tendon advancement/patellar tendon shortening with consensus reached for 8 of 21 (38%) of statements. The literature review included 25 studies which revealed variation in operative technique for distal femoral extension osteotomy, patellar tendon advancement, and patellar tendon shortening. Distal femoral extension osteotomy and patellar tendon advancement/patellar tendon shortening were generally effective in correcting knee flexion deformities and extensor lag, but there was marked variation in outcomes and complication rates.

CONCLUSION

The results from this study will provide guidelines for surgeons who care for children with cerebral palsy and point to unresolved questions for further research.

LEVEL OF EVIDENCE

level V.

Age related progression of clinical measures and gait in ambulant children and youth with bilateral cerebral palsy without a history of surgical intervention

BACKGROUND

Age related progression needs to be considered when assessing current status and treatment outcomes in cerebral palsy (CP).

RESEARCH QUESTION

What is the association between age, gait kinematics and clinical measures in children with bilateral CP?

METHOD

A retrospective database review was conducted. Subjects with bilateral CP with baseline and follow-up 3D gait analyses, but no history of intervening surgery were identified. Clinical and summary kinematic measures were examined for age related change using repeat measures correlation. Interactions with GMFCS classification and whether surgery was recommended were examined using robust linear regression. Timeseries kinematic data for baseline and most recent follow-up analyses were analysed using statistical parametric mapping.

RESULTS

180 subjects were included. 75% of participants were classified as GMFCS I or II at baseline. Mean time to follow-up was 4.89 (2.8) years (range 1-15.9 years) with a mean age of 6.4 (2.4) at baseline and 11.3 (3.4) at final follow-up. 15.5% of subjects demonstrated an improvement in GMFCS classification while GDI remained stable. Age related progression was noted across many clinical measures with moderate correlations (r ≥ 0.5) noted for reduced popliteal angle, long lever hip abduction and internal hip rotation range. In gait, there was reduced hip extension in late stance (p < 0.001), increased knee flexion in mid-stance (p < 0.001), reduced peak knee flexion in swing (p < 0.001) and increased ankle dorsiflexion in stance (p < 0.001). In the coronal plane, there was reduced hip abduction in swing (p < 0.001). In the transverse plane, increased external rotation of the knee (p < 0.001) and reduced external ankle rotation were noted in early stance and through swing (p < 0.001). There were no changes in foot progression or hip rotation.

SIGNIFICANCE

Individuals with CP show age related progression of clinical and kinematic variables. Treatment can only be deemed successful if outcomes exceed or match these age-related changes.

Comparison of Surgical Outcomes for Distal Rectus Femoris Transfer and Resection Surgeries in Children With Cerebral Palsy With Stiff Knee Gait

BACKGROUND

Children with cerebral palsy (CP) often present with a stiff knee gait pattern because of rectus femoris (RF) spasticity and/or contracture. Rectus femoris transfers (RFTs) and resections are surgical procedures aimed at reducing muscle stiffness, thereby improving knee flexion during the swing phase of gait. Previous research has consistently demonstrated objective benefits of rectus transfer using instrumented gait analysis (IGA). Rectus femoris resection (RFR), a relatively simpler procedure, shows similar improvement in knee range of motion during gait. The objective of this study was to compare surgical outcomes between rectus transfers and resections using 3-dimensional IGA.

METHODS

Children with spastic CP who had RFTs or resections were retrospectively matched by walking speed and preoperative knee kinematics from 3-dimensional IGA (peak and timing of peak knee flexion in swing). Secondary outcomes included knee range of motion and maximum knee extension during gait.

RESULTS

Twenty-eight children were included in both the transfer group [age 9.4±2 y; Gross Motor Function Classification System (GMFCS) I (3 children), II (15 children), III (8 children), and IV (2 children)] and the resection group [age 10.6±2.5 y; GMFCS I (1 child), II (14 children), and III (13 children)]. Both surgical groups showed statistically significant short-term postsurgical improvements in peak knee flexion during swing (P<0.001 for the transfer group and P=0.003 for the resection group) and Duncan-Ely test (P=0.004 for the transfer group and P<0.001 for the resection group). Further analysis by GMFCS level showed children at GMFCS levels III/IV had a greater tendency to crouch after RFT when compared with children at GMFCS levels I/II. This tendency was not observed in the RFR group.

CONCLUSIONS

Both transfer and resection surgeries significantly improved gait kinematics short-term outcomes in children with spastic CP who present with stiff knee gait pattern. Further studies are required to compare long-term outcomes of both surgeries.

LEVEL OF EVIDENCE

Level III-retrospective matched-cohort study.

The importance of a consistent workflow to estimate muscle-tendon lengths based on joint angles from the conventional gait model

BACKGROUND

Musculoskeletal models enable us to estimate muscle-tendon length, which has been shown to improve clinical decision-making and outcomes in children with cerebral palsy. Most clinical gait analysis services, however, do not include muscle-tendon length estimation in their clinical routine. This is due, in part, to a lack of knowledge and trust in the musculoskeletal models, and to the complexity involved in the workflow to obtain the muscle-tendon length.

RESEARCH QUESTION

Can the joint angles obtained with the conventional gait model (CGM) be used to generate accurate muscle-tendon length estimates?

METHODS

Three-dimensional motion capture data of 15 children with cerebral palsy and 15 typically developing children were retrospectively analyzed and used to estimate muscle-tendon length with the following four modelling frameworks: (1) 2392-OSM-IK-angles: standard OpenSim workflow including scaling, inverse kinematics and muscle analysis; (2) 2392-OSM-CGM-angle: generic 2392-OpenSim model driven with joint angles from the CGM; (3) modif-OSM-IK-angles: standard OpenSim workflow including inverse kinematics and a modified model with segment coordinate systems and joint degrees-of-freedom similar to the CGM; (4) modif-OSM-CGM-angles: modified model driven with joint angles from the CGM. Joint kinematics and muscle-tendon length were compared between the different modelling frameworks.

RESULTS

Large differences in hip joint kinematics were observed between the CGM and the 2392-OpenSim model. The modif-OSM showed similar kinematics as the CGM. Muscle-tendon length obtained with modif-OSM-IK-angles and modif-OSM-CGM-angles were similar, whereas large differences in some muscle-tendon length were observed between 2392-OSM-IK-angles and 2392-OSM-CGM-angles.

SIGNIFICANCE

The modif-OSM-CGM-angles framework enabled us to estimate muscle-tendon lengths without the need for scaling a musculoskeletal model and running inverse kinematics. Hence, muscle-tendon length estimates can be obtained simply, without the need for the complexity, knowledge and time required for musculoskeletal modeling and associated software. An instruction showing how the framework can be used in a clinical setting is provided on https://github.com/HansUniVie/MuscleLength.

[Correction of complex defomities around the Knee Joint]

Complex deformities around the knee joint are usually severe and have several aetiologies. They can be present in one or more planes, with variations in severity between planes. The occurrence and progression of the deformity can be influenced by local and systemic factors. Several types of osteotomies and fixation methods are available to correct these complex deformities. The selection of the osteotomy used to correct a deformity depends on the type of deformity, its severity and its aetiology. Therefore, precise planning taking into consideration the above factors is necessary to achieve the goal.

Interrater reliability for unilateral and bilateral tests to measure the popliteal angle in children and youth with cerebral palsy

Background

Short hamstring muscles can cause several problems for children with cerebral palsy. The results of the clinical measurement of hamstring length are often used in decision-making about treatment of children with cerebral palsy. There are different ways of performing this measurement. The aim of this study was to evaluate the interrater reliability of the unilateral and bilateral measurement of the popliteal angle in children and youth with cerebral palsy.

Methods

Two methods for estimating hamstring length using unilateral and bilateral measurements of the popliteal angle were applied in children with cerebral palsy. Both tests were applied bilaterally by two independent examiners on the same day for each child. The intraclass correlation coefficient (ICC) was calculated to evaluate the interrater reliability of both measurements. Seventy young people with cerebral palsy (32 females, 38 males, mean age 10 years 8 months, range 5–22 years) at Gross Motor Function Classification System levels I (n = 17), II (n = 31), III (n = 12) and IV (n = 10) were included.

Results

The interrater reliability was good for both measurements. The ICC values were 0.80 on the right and 0.86 on the left for the unilateral popliteal angle, and 0.82 on the right and 0.83 on the left for the bilateral popliteal angle.

Conclusions

Both unilateral and bilateral measurement of the popliteal angle is a reliable method for estimating hamstring length in children and youth with cerebral palsy.

The mechanics behind gait problems in patients with Dravet Syndrome

BACKGROUND

Dravet Syndrome (DS) is a developmental and epileptic encephalopathy starting in infancy and characterised by treatment resistant epilepsy with cognitive impairment and progressive motor dysfunction. Walking becomes markedly impaired with age, but the mechanical nature of gait problems remains unclear.

RESEARCH QUESTION

What are the kinetic strategies characterised in gait of patients with DS?

METHODS

This case-control study compared 41 patients with DS aged 5.2-26.1 years (19 female, 22 male) to 41 typically developing (TD) peers. Three dimensional gait analysis (VICON) was performed to obtain spatiotemporal parameters, kinematics and kinetics during barefoot, level walking at self-selected walking velocity. The sagittal plane support moment was analysed using Statistical Parametric Mapping (SPM). Three DS subgroups were identified based on differences in kinetic strategies characterised by the net internal knee joint moments and trunk lean. Kinematic and kinetic time profiles of the subgroups were compared to the TD group (SPM t-test). Clinical characteristics from physical examination and parental anamnesis were compared between DS (sub)groups using non-parametric tests (Kruskal-Wallis, Wilcoxon rank-sum, Fisher's exact).

RESULTS

Support moments in stance were significantly increased in the DS group compared to TD and strongly related to minimum knee flexion in midstance. Persistent internal knee extension moments during stance were detected in a subgroup of 27 % of the patients. A second subgroup of 34 % showed forward trunk lean and attained internal knee flexion moments. The remaining 39 % had neutral or backward trunk lean with internal knee flexion moments. Subgroups differed significantly in age and functional mobility.

SIGNIFICANCE

Inefficient kinetic patterns suggested that increased muscle effort was needed to control lower limb stability. Three distinct kinetic strategies that underly kinematic deviations were identified. Clinical evaluation of gait should pay attention to knee angles, trunk lean and support moments.

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.

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.