Cerebral Palsy - Gait Disorders - Pediatrics

summary
- Gait Disorders in Cerebral Palsy are commonly caused by lower limb spasticity and are the primary reason for orthopaedic consultations in CP patients.
- Diagnosis is made with quantitative evaluation using kinematic, kinetic and EMG analysis.
- Treatment is usually physical therapy, orthotics and bracing in patients with mild gait disorders. Single-event, multi-level surgery (SEMLS) has become the gold standard surgical intervention for patients with continued difficulty with gait.

Epidemiology
- Incidence
  - gait disorder is the primary reason for orthopaedic consultations in CP patients
    
    independent gait expected between 12 to 18 months old in non-CP children

Etiology
- Cerebral Palsy General
- Pathophysiology
  - Divided into:
    
    primary deviations
    
    those caused by the primary CNS insult including
    
    spasticity
    
    weakness
    
    compromised proprioceptive pathways
    
    secondary deviations
    
    growth-related deviations that arise due to abnormal loading in the setting of primary gait deviations, including:
    
    anatomic shortening of muscle-tendon units (e.g., myotatic contractures)
    
    persistent bony deformities (e.g., femoral anteversion)
    
    joint subluxations/dislocations (e.g., hip subluxation or equinoplanovalgus feet)
    
    tertiary deviations
    
    compensations related to secondary gait deviations
- Etiology
  - both qualitative and quantitative analysis has been used to describe gait
  - quantitative evaluation (kinematic/kinetic/EMG analysis) have changed how we understand, classify, and treat this condition
    
    new treatment strategies focus on understanding the
    
    underlying pathophysiology (deviations)
    
    planes of deformity (sagittal, coronal, transverse)
    
    anatomic level (hip, knee, ankle)

                        Classification
                    
                        Descriptive  (Qualitative) classification
                    
                        useful for simplification, though high variability of segmental deviations in each pattern
                    
                        descriptive classifications have been unsuccessful at classifying up to 40% of CP gait patterns.
                    
                        common descriptive classifications are shown in table below.
                    
                        Descriptive Classification
                    
                        Equinus Gait
                    
                        Term "equinus" used to refer to the isoloated abnormality in foot position relative to the tibia, i.e. a one-level deviation (e.g. no knee/hip involvement)
                    
                        characterized by absence of heal strike during gait
                    
                        isolated equinus gait is common in hemiplegics
                    
                        Equinus is either:
                    
                         true equinus: defined by the foot position in relationship to the tibia being less than plantigrade
                    
                         apparent equinus: defined by a foot position that is normal in relationship to the tibia, however heel strike does not occur due to more proximal deviations (flexion of the knee most common)
                    
                        Jump Gait
                    
                        Deformity includes hip flexion, knee flexion, and equinus ankle deformity ( could result in apparent ankle equinus)
                    
                         Multi-level gait deviations where treatment of underlying spasticity should be considered
                    
                        Crouch Gait
                    
                        A combination of hip flexion, knee flexion, and excessive ankle dorsiflexion (the latter may be represented by flatfoot or calcaneus)
                    
                        Common in diplegic CP
                    
                        Pathophysiology: often an iatrogenic consequence of isolated lengthening the achilles in a jump gait pattern if the other levels of gait deviations are not addressed properly
                    
                        Levels of deviation
                    
                        Calcaneal contact pattern throughout stance phase
                    
                        Increased knee flexion throughout stance phase due to disruption of the ankle plantar flexion-knee extension couple
                    
                        Compensated crouch gait
                    
                         refers to tertiary deviations that allow the knee extensor mechanism to be off-loaded during stance phase (e.g. pelvic or truncal forward tilt) - this may be well-tolerated by younger children with CP and low body mass
                    
                        Uncompensated crouch gait
                    
                         occurs secondary to persistent overloading of the extensor mechanism. This occurs in all crouch eventually, if untreated
                    
                        Stiff Knee Gait 
                    
                        Common in spastic diplegic CP
                    
                        Characterized by limited knee flexion in swing phase due to rectus femoris firing out of phase (seen on EMG)
                    
                         note the above gait decriptions are stance phase deviations
                    
                        Evaluation
                    
                        gait analysis reveals quadriceps activity from terminal stance throughout swing phase
                    
                        Complications
                    
                        Stiff knee gait can be a compensation due to deviations at the hip; surgical management will not help this subset of stiff-knee gait
                    
                        Term "equinus" used to refer to the isoloated abnormality in foot position relative to the tibia, i.e. a one-level deviation (e.g. no knee/hip involvement)
                    
                        characterized by absence of heal strike during gait
                    
                        isolated equinus gait is common in hemiplegics
                    
                        Equinus is either:
                    
                        true equinus
                    
                        defined by the foot position in relationship to the tibia being less than plantigrade
                    
                        apparent equinus
                    
                        defined by a foot position that is normal in relationship to the tibia, however heel strike does not occur due to more proximal deviations (flexion of the knee most common)
                    
                        Quantitative classification 
                    
                        uses technology to better characterize the pathoanatomy of abnormal gait, particularly when multiple planes and segments of deformity exist
                    
                        characterizes gait into 3 planes of deformity
                    
                        sagittal plane
                    
                        includes:
                    
                        anterior or posterior pelvic tilt
                    
                        hip flexion/extension
                    
                        knee flexion/extension
                    
                        ankle dorsiflexion/plantarflexion
                    
                        coronal plane
                    
                        includes:
                    
                        pelvic elevation/depression
                    
                        hip abduction/adduction
                    
                        transverse plane
                    
                        transverse plane is least reliable plane described in instrumented gait analysis
                    
                        includes:
                    
                        pelvic and hip internal and external rotation deformities, foot progression angle

Comprehensive Gait Analysis
- Gait analysis
  - has helped identify distinct problems and guide orthopaedic treatment
    
    quantitative gait analysis is more accurate at detecting gait abnormalities than is qualitative assessment alone
  - comprehensive gait analysis may include the following components:
    
    physical exam findings
    
    spasticity assessment, contractures and torsional abnormalities
    
    kinetic analysis
    
    forces (procuce linear accelerations) and moments (produce rotational accelerations) acting on and within the body
    
    kinematic analysis
    
    description of movement, typically described in segments and joints in 3 planes sagittal/coronal/transverse
    
    pedobarography
    
    special force plate that shows contact pressures through the stance phase
    
    dynamic electromyography
    
    muscle activation detected at different (normal or abnormal) start points in gait
    
    video

Treatment
- Nonoperative
  - physical therapy
    
    indications
    
    plays an important role in both operative an nonoperatively treated patients
  - chemodenervation (botulinum neurotoxin A)
    
    may be used to temporize certain muscle groups in order to delay surgical management or as a primary treatment modality
    
    indications
    
    hamstring spasticity without fixed deformity in ambulatory patient
  - orthoses
    
    solid ankle foot orthosis (AFO)
    
    indications
    
    flexible equinus deformities
    
    ankle is passively correctable to neutral while maintaining a subtalar neutral position
    
    posterior leaf-spring (or hinged) orthoses
    
    indications
    
    used in presence of excessive ankle plantar flexion in the swing phase
- Operative
  - single-event, multi-level surgery (SEMLS)
    
    overview
    
    SEMLS approach has become the gold-standard of CP gait surgery
    
    goal is to address all primary (spasticity) and secondary (i.e. contractures) deviations at multiple levels during a single surgery
    
    addressing multiple deviations at once is essential to avoiding iatrogenic worsening of gait
    
    procedures used during a SEMLS
    
    lever arm dysfunction due to increased femoral anteversion: external rotation proximal femur osteotomy
    
    hip flexion contracture: intramuscular psoas lengthening
    
    knee contractures
    
    medial hamstring lengthening(lateral may result in excessive weakness) if minimal fixed contracture
    
    guided growth
    
    distal femur extension osteotomy
    
    rectus transfer for stiff knee gait
    
    equinus: tendo-achilles lengthening or gastrocnemius recession
    
    flatfoot reconstruction
    
    rehabilitation
    
    AFOs and aggressive physical therapy for re-training and strengthening following releases is an essential component of SEMLS intervention
    
    expect one year for recovery

Techniques
- External rotation proximal femur osteotomy
  - indications
    
    femoral anteversion / hip internal rotation deviation
- Rectus Transfer
  - indications
    
    stiff knee gait
  - technique
    
    create knee flexion vector with rectus activation by transferring it posterior to the center of rotation of the knee
- Medial hamstring lengthening
  - indications
    
    for mild knee dysfunction, usually younger patients with less than 5 degrees knee flexion deformity
  - technique
    
    fractional lengthening at the myotendinous junction is ideal
  - complications
    
    hamstring contractures often recur, especially in jump gait
- Guided growth surgery
  - indications
    
    knee flexion deformities of 10-25 degrees in the patients with at least two years of growth remaining
- Supracondylar femur extension osteotomy +/- patellar tendon advancement or shortening
  - indications
    
    for knee flexion deformities of 10-30 degrees, with severe quadriceps lag close to or already at skeletal maturity
- Gastrocnemius recession
  - indications
    
    Silfverskiöld test positive
  - technique
    
    horizontal or vertical incision at the level of the myotendinous junction of the gastroc
    
    identify and protect the sural nerve (superficial to fascia)
    
    sharply divide the tendon only, preserving the muscle fibers not yet joined to the tendon
    
    incise all deeper bands that prevent release of contracture (small raphes may be present in the tendon
    
    manipulate the ankle
    
    goal of treatment is 10 degrees of dorsiflexion
- Tendo-achilles lengthening
  - indications
    
    rigid deformities - ankle is not passively correctable to neutral
    
    true equinus
    
    Silfverskiöld negative
  - techniques
    
    multiple hemi-lengthenings or a Z-lengthening can be performed
    
    avoid overlengthning

Complications
- Recurrent hamstring contracture
- Worsening crouch gait secondary to isolated and overlengthening of achilles
- Patella alta
  - elongated patellar tendon (patellar alta) is another complication of this condition that is difficult to treat
  - Multiple simultaneous soft tissue releases without careful gait analysis
- Knee pain
  - tendo-achilles lengthening may worsen knee pathology if careful gait analysis isn't performed

Action	Numeric Key	Letter Key	Function Key
Show Bullets		S	Enter (frontside only)
20%	1	N
40%	2	H
60%	3	F	Enter (backside only)
80%	4	E
100%	5	M
Toss	0	T

Descriptive Classification
Equinus Gait	Term "equinus" used to refer to the isoloated abnormality in foot position relative to the tibia, i.e. a one-level deviation (e.g. no knee/hip involvement) characterized by absence of heal strike during gait isolated equinus gait is common in hemiplegics Equinus is either: true equinus: defined by the foot position in relationship to the tibia being less than plantigrade apparent equinus: defined by a foot position that is normal in relationship to the tibia, however heel strike does not occur due to more proximal deviations (flexion of the knee most common)
Jump Gait	Deformity includes hip flexion, knee flexion, and equinus ankle deformity ( could result in apparent ankle equinus) Multi-level gait deviations where treatment of underlying spasticity should be considered
Crouch Gait	A combination of hip flexion, knee flexion, and excessive ankle dorsiflexion (the latter may be represented by flatfoot or calcaneus) Common in diplegic CP Pathophysiology: often an iatrogenic consequence of isolated lengthening the achilles in a jump gait pattern if the other levels of gait deviations are not addressed properly Levels of deviation Calcaneal contact pattern throughout stance phase Increased knee flexion throughout stance phase due to disruption of the ankle plantar flexion-knee extension couple Compensated crouch gait refers to tertiary deviations that allow the knee extensor mechanism to be off-loaded during stance phase (e.g. pelvic or truncal forward tilt) - this may be well-tolerated by younger children with CP and low body mass Uncompensated crouch gait occurs secondary to persistent overloading of the extensor mechanism. This occurs in all crouch eventually, if untreated
Stiff Knee Gait	Common in spastic diplegic CP Characterized by limited knee flexion in swing phase due to rectus femoris firing out of phase (seen on EMG) note the above gait decriptions are stance phase deviations Evaluation gait analysis reveals quadriceps activity from terminal stance throughout swing phase Complications Stiff knee gait can be a compensation due to deviations at the hip; surgical management will not help this subset of stiff-knee gait