Examination of lower limb in a child with cerebral palsy

• Cerebral palsy (CP) is a qualitative disorder of movement and posture due to nonprogressive damage to the brain before the completion of its growth and development.
• The main types of CP are spastic, dyskinetic, ataxic and athetoid.
• Spastic type accounts for 87% of CP.
• Spastic CP is due to corticospinal tract dysfunction resulting in impaired excitatory and inhibitory control of muscle function.
• Spastic CP results in motor weakness, impaired selective motor control, spasticity and shortened musculotendinous units which in turn may affect the growth and development of musculoskeletal system which may lead to progressive deformities.
• Even though the damage to the developing brain is nonprogressive, the resultant musculoskeletal abnormalities are usually progressive.
• Functional deficits in cerebral palsy may be due to the following.
  • Muscle weakness
  • Abnormal muscle tone
  • Poor selective muscle control
  • Joint deformities due to soft tissue contractures
  • Lever-arm dysfunctions
  • Torsional malalignment

Components of evaluation

When examining a patient with cerebral palsy the following components of examination are to be done.

1. History
2. Functional assessment
3. Gait analysis
4. Physical examination
5. Imaging
6. Assessment of goals of the patient and parents

1. History

• The following are the points to be elicited in the history.
• Birth history
  • Antenatal problems
  • Term of pregnancy at birth
  • Mode of delivery
  • When the patient cried after birth
  • Whether kept in neonatal ICU
• Developmental history
• Medical history
• Surgical history
• Current physiotherapy 
• Current medications
• Pain

2. Functional Assessment

The function is assessed in the following categories.

• Self-care
• Activities of daily living
• Ambulation – Walking, running, stair climbing, jumping
• Occupational disabilities 
• Sports
• Behavior abnormalities
• Learning difficulties

Functional assessment at current levels may be done by several tools such as the following. 

A. GMFCS – Gross motor function classification system (Palisano 1997)

Level I – Can walk indoors and outdoors and climb stairs without using hands or other forms of support. Can perform usual activities such as running and jumping with decreased speed, balance, and coordination.

Level II – Can climb stairs with the support of railing, but has difficulty with uneven surfaces, inclines, or in crowded places. Ability to run or jump limited.

Level III – Can walk on level grounds indoor and outdoor with the support of assistive devices. Can climb stairs using a railing. Can propel a manual wheelchair, but needs assistance for long distances or uneven surfaces.

Level IV – Walking ability severely limited even with assistive devices. Can propel powered wheelchair. Can do standing transfers, with or without assistance.

Level V – Severe restriction of voluntary control of movements. Poor head, neck, and trunk control. All areas of motor function impaired. Cannot sit or stand independently even with adaptive equipment.

B. FAQ- Functional assessment questionnaire

C. POSCI- POSNA outcomes data collection instruments

D. FMS- Functional mobility scale

3. Gait analysis

4. Physical Examination

The following are the major components of physical examination.

1. Strength and selective motor control of isolated muscle groups.
2. Degree and type of muscle tone.
3. Degree of static muscle and joint contracture.
4. Torsional and other bone deformities.
5. Fixed and mobile foot deformities.
6. Balance, equilibrium responses, and standing posture.
7. Gait by observation.

Drawbacks of physical examination

• Examination findings are based on static responses while function depends on dynamic responses.
• There is no correlation between crouch gait and the measured popliteal angle.
• Tone can change depending on time of day, cooperation of child and level of excitement.
• Functional deficit may be due to defective timing of muscle firing which cannot be addressed by surgery.

A. Muscle strength testing

Muscle power testing can be done by the following methods. 

• Manual muscle testing.
• Isometric testing with dynamometer.
• Isokinetic muscle testing.
• Muscle power testing is not reliable under 5 years of age.

B. Selective motor control of major muscles

• In spastic CP, corticospinal tract dysfunction impairs the ability to control the force, speed, and timing of muscle contractions resulting in disturbance in the pattern of voluntary movements.
  • When testing look for the following.
    • Ability to perform voluntary isolated movement.
    • Whether the timing of muscle contraction is appropriate.
    • Whether the movement occurs with or without overflow movement.
• Impaired selective motor control is defined as ‘impaired ability to isolate the activation of muscles in a selected pattern in response to demands of a voluntary posture or movement’.
• Impaired selective motor control leads to co-activation of flexor or extensor muscles resulting in simultaneous, obligatory flexor or extensor pattern at two or more joints called synergistic mass movement pattern.
• Selective Control Assessment of the Lower Extremity (SCALE) is an observation-based measure for children with spastic CP to quantify selective motor control impairment in the lower extremity. 

Selective Control Assessment of the Lower Extremity (SCALE)

Unable – Desired movement sequence not initiated or done using synergistic mass flexor or extensor pattern.

Impaired – Partially isolated movement observed. Movement occurs in one direction, observed movement is < 50% of the approximate available passive ROM found during the passive demonstration; movement occurs at a non-tested joint (including mirror movements); or the time for execution exceeds the approximate three-second verbal cadence.

Normal – Desired movement sequence completed is completed within the verbal count without movement of untested ipsilateral or contralateral lower extremity joints.

Selective motor control grading

2. Isolated muscle contraction without movement in other joints, opposite limb or trunk.

1. Muscle contraction with nonobligatory movement in other joints of the limb, opposite limb or trunk.

0. Muscle contraction with obligatory movement in other joints, opposite limb or trunk.

Selective motor control testing

Hip flexion – Patient seated supported or unsupported with hips at a 90⁰ angle, legs over the side of the table. Arms folded across chest or resting in lap (not on the able or hanging on to the edge). Ask the patient to flex the hip. Flexion without rotation, adduction or trunk extension is graded as 2, with nonobligatory rotation or adduction or trunk extension graded as 1 and 0 if obligatory.

Hip extension (Hamstrings plus gluteus maximus) – Patient lying prone, head resting on pillow (prone on elbows not allowed). Knees in maximum possible extension. Pelvis stabilized as necessary.

Hip extension (Gluteus maximus) – Patient lying prone, head resting on pillow (prone on elbows not allowed). Knees in 90⁰ flexion or more, hips in neutral extension, pelvis flat on table. Pelvis stabilized as necessary.

Hip abduction – Patient side-lying, the hip in neutral or slight hip extension, neutral medial or lateral rotation, knee in maximum possible extension. Pelvis stabilized as necessary. 

Hip adduction – Side-lying body in straight line with legs, the hip in neutral or slight hip extension, neutral medial or lateral rotation, knee in maximum possible extension, opposite limb supported in alight abduction. Pelvis stabilized as necessary.

Knee extension – Patient seated supported or unsupported with hips at a 90⁰, knees at 90⁰ resting over the side of the table. Thigh stabilized as necessary.

Knee flexion – Patient lying prone, head resting on pillow (prone on elbows not allowed). Knees in maximum possible extension. Pelvis and thigh stabilized as necessary.

Ankle dorsiflexion (Tibialis anterior) – Patient seated supported or unsupported with hips at a 90⁰ angle, knees in extension (flexion may be allowed to achieve a range of dorsiflexion). Lower leg supported. Thigh stabilized as necessary.

Ankle plantarflexion – Patient lying prone, head resting on pillow (prone on elbows not allowed). Knees in 90⁰ of flexion. Lower leg stabilized proximal to the ankle as necessary. Ankle in neutral plantarflexion/ dorsiflexion position.

Ankle dorsiflexion (gastrocnemius) – Patient lying prone, head resting on pillow (prone on elbows not allowed). Knees in maximum extension, foot projecting over the end of the table. Lower leg stabilized proximal to the ankle as necessary. Ankle in neutral plantarflexion/dorsiflexion position.

Ankle inversion – Patient seated supported or unsupported with hips at a 90⁰, thigh in lateral rotation, knees in flexion with lower leg stabilized proximal to the ankle. Ankle in neutral plantar/dorsiflexion.

Ankle eversion (Peroneus longus and brevis) – Patient seated supported or unsupported with hips at a 90⁰ angle, thigh in medial rotation, knees in flexion with lower leg stabilized proximal to the ankle. Ankle in neutral plantar/dorsiflexion.

Ankle eversion (Peroneus tertius) – Patient seated supported or unsupported with hips at a 90⁰ angle, knees in flexion with lower leg stabilized proximal to the ankle. Ankle in neutral plantar/dorsiflexion. Ask to evert the ankle with ankle dorsiflexion and dorsiflexion of 2nd to 5th toes.

Great toe dorsiflexion – Patient seated supported or unsupported with hips at a 90⁰ angle, knees in flexion with lower leg supported. Ankle in neutral plantar/dorsiflexion. Ask the patient to extend the first metatarsophalangeal joint.

Great toe plantarflexion – Patient seated supported or unsupported with hips at a 90⁰ angle, knees in maximum extension with lower leg supported. Ankle in neutral plantar/dorsiflexion. Ask the patient to plantarflex the first metatarsophalangeal joint. 

C. Assessment of tone

• Tone is defined as resistance to passive stretch in a relaxed state of muscle activity.
• Affected by cooperation, apprehension and excitement.
• Hypertonia – abnormally increased resistance to an externally imposed movement of a joint.
• Increased in spasticity, rigidity, dystonia or a combination.
• How to assess tone? (Sanger)
  • Talk to the patient for a while to relax the patient.
  • Palpate the muscle to identify spasm or contracture.
  • Slowly move the joint to assess the passive range of movement.
  • Move the joint at different speeds to detect a catch. If there is a catch, note its timing and the angle at which it appears.
  • Change the direction of motion and see how it differs.
  • Ask the patient to move the opposite joint and look at the response on the contralateral joint.
• Initial end points are more important than stretched end points for functional ability.
• Spasticity to test for spasticity
  • Hip flexors
  • Hip adductors
  • Hamstrings
  • Gastrosoleus
  • Tibialis posterior
  • Spasticity grading
  • Modified Ashworth scale

0 – No increase in muscle tone

1 – Slight increase in muscle tone, manifested by a catch and release or by minimal resistance at the end of the ROM

1+ – Slight increase in muscle tone, manifested by a catch, followed by minimal resistance throughout the remainder (less than half) of the ROM

2 – More marked increase in muscle tone through most of the ROM, but affected part(s) can be easily moved

3 – Considerable increase in muscle tone, passive movement difficult

4 – Affected part(s) are rigid in flexion or extension

Tardieu scale

Measures tone in slow and fast speeds.

V1 – Velocity of stretch as slow as possible

V2 – Velocity of stretch at the speed of limb segment falling under the influence of gravity

V3 – Velocity of stretch as fast as possible

R1- Angle that is short of full ROM when first catch is detected at V2 or V3 speed of stretch.

R2- Maximum ROM achieved at V1 speed of stretch.

Difference between R1 and R2 indicate the deformity produced due to dynamic component of muscle spasm.

Small R1-R2 difference indicate more of static contracture and large R1-R2 difference indicate that deformity is mainly due to dynamic component of spasticity.

Examination of joints

Examination of hip

Range of movement

Flexion assessed with the patient supine. Flex both hips and knees till the lumbar lordosis is obliterated and the anterior superior iliac spine and posterior superior iliac spines are at the same level. Now extend one hip and knee at a time while keeping the other hip and knee fully flexed. If a fixed flexion deformity is present, identify and measure. Flex the hip further to measure the range of flexion. (Modified Thomas test)

Extension assessed with knee in extension and in 90⁰ knee flexion. Patient is prone. Stabilise the pelvis with one hand. Support the thigh just above the knee with the other hand and extend the hip with knee in extension. Measure the degree of extension possible. Now, hold the leg just above the ankle and extend the hip with the knee flexed to 90 degree. Note the degree of extension possible. If there is a rectus femoris contracture, the hip will go into flexion when the knee is flexed. (Duncan Ely test)

Abduction in flexion and in extension – Patient supine. Flex the hip to 90 degrees and flex the knee as well. Keep the feet together and assess the abduction in hip flexion. To assess hip abduction in knee extension, patient is examined in supine position. Square the pelvis if the anterior superior iliac spines are not level. Stabilize the pelvis by keeping fingers of one hand over the anterior superior iliac spine in a small patient or by placing the forearm across the ASIS in a large patient. Assess the range of abduction and adduction.

Abduction with knee flexion and knee extension (Phelps test for gracilis contracture) – Done if there is an adduction deformity of hip or if the abduction is severely limited. Done either in the prone position or in the supine position by bringing the patient down to the end of the examination couch till the knee is at the end of the examination couch. Assess the range of hip abduction first with the knee extended and then with the knee in 90 degrees of flexion. If the range of abduction improves with knee flexion in comparison to knee extension, gracilis muscle spasticity is the cause of limitation of hip abduction or adduction deformity.

Adduction

Internal rotation

External rotation

Muscle testing of hip flexors, extensors, adductors and abductors

Thomas test

Ober test

Craig test for anteversion

Examination of knee

Range of movement

• Knee flexion deformity may be due to capsular contracture, hamstring contracture or hamstring spasm.
• Knee flexion deformity with the hip in extension and ankle in plantar flexion is due to capsular contracture.
• Hamstring contracture is present if there is a FFD with the hip flexed to 90 degrees. (Popliteal angle)
• Popliteal angle measured as the degrees lacking from full extension of knee with hip in 90 degree flexion.
• Normal popliteal angle is 0-49 degrees in the 5-18 age group. 
• Bilateral popliteal angle measured with the contralateral hip flexed till the ASIS and PSIS are in the same line.
• Hamstring shift – Significantly smaller popliteal angle when the pelvic tilt is corrected by flexing the contralateral hip. It is due to proximal migration of hamstring origin due to anterior tilting of pelvis produced by FFD of hip of opposite hip.
• Hamstring shift of more than 20 degrees indicate excessive lumbar lordosis due to hip FFD, weak anterior abdominal muscles or weak hip extensors.
• With every 10 FFD of hip there is 20 increase in knee flexion.
• Hamstring lengthening weakens hip extension.
• Clinical assessment of hamstring contracture should be confirmed by gait analysis befor doing hamstring lengthening.
• Extension in prone and in supine position
  • Muscle testing of quadriceps and hamstrings
    • Selectivity of motor control 
    • Spasticity of hamstrings
  • Duncan Ely’s test
  • Popliteal angle
    • Unilateral
    • Bilateral
    • Hamstring shift
  • Extensor lag
    • Patient supine. Knee flexed at the end of the table. Ask the patient to actively extend the knee.
  • Patella alta
    • Patient supine with knee extended. Compare the level of proximal pole of patella and the adductor tubercle. Normally the superior pole of patella is one finger breadth above the adductor tubercle.
  • Tibiofemoral angle
  • • Range of movement
      • Plantarflexion
      • Dorsiflexion with knee in extension and in 90 degree flexion
    • Muscle testing of Tendoachilles, tibialis anterior, tibialis posterior, EHL, EDL, FHL, FDL, Peroneus longus, Peroneus brevis
      • Selectivity of motor control 
      • Spasticity
    • Silfverskiold test
      • Supine
      • Knee flexed to 90 degrees.
      • Dorsiflex and invert the ankle. Note the degree of dorsiflexion.
      • Extend the knee. If ankle goes into plantarflexion, there is contracture of gastrocnemius.
    • Confusion test
  • • Pronation and supination are pure rotational motion that occur through an oblique axis which produce movement in all three planes.
    • Foot must function as a mobile adaptor and as a rigid lever during different phases of gait.
    • In CP, patient may have structural abnormalities or nonstructural compensations for deformities in proximal or distal joints.
    • The structural abnormalities and resultant compensations are identified by first identifying the subtalar joint neutral position (STJN) and the range of supination and pronation from this position. 
    • Compensations are nonstructural changes in alignment to compensate for structural abnormalities.
    • Subtalar joint neutral position (STJN) identified by palpating the talonavicular joint to identify the position of symmetrical reduction of talonavicular joint.
    • Keep the foot in the STJN position and assess the relationship between hindfoot and the distal third of the leg to identify the hindfoot deformity
      • If the bisectors of lower leg and hindfoot are linear the hind foot is in neutral position in relation to the lower leg. Hindfoot varus and valgus in relation to hindfoot can be seen. 
    • Keep the foot in the STJN position and assess the relationship between forefoot and the hindfoot to identify the forefoot deformity.
      • Frontal plane – Relationship between level of metatarsal heads and the plane of the calcaneum to identify forefoot-hindfoot varus or valgus.
        • Two types of forefoot-hindfoot valgus deformity – With valgus of 1st metatarsal alone or valgus of all metatarsals- total forefoot valgus.
      • Sagittal plane- Relationship between plantar surface of the metatarsals and the plantar surface of calcaneus to look for forefoot equinus(cavus)/planus.
      • Transverse plane – Relationship between midline and the axis of hindfoot to look for forefoot adduction/abduction
    • Structural forefoot varus is compensated by hyperpronation of hindfoot. Hyperpronation leads to eversion of calcaneus, forefoot abduction and lowering of first ray. This will be compensated by internal rotation of the whole limb. If hindfoot deformity is flexible, then placing a block underneath the medial forefoot will correct the hindfoot compensation.
    • Structural forefoot varus is compensated by hypersupination of hindfoot. Hypersupination leads to inversion of calcaneus, forefoot adduction and increased height of medial longitudinal arch. This will be compensated by external rotation of the whole limb. If hindfoot deformity is flexible, then placing a block of 0.5cm to 2.5 cm underneath the lateral forefoot will correct the hindfoot compensation (Coleman block test). If hindfoot corrects, only the forefoot deformity needs to be addressed, if not, the forefoot and hindfoot needs to be addressed.
    • Forefoot equinus is compensated by ankle dorsiflexion. If ankle dorsiflexion is reduced, then compensation occurs through the midfoot.
    • Foot in weight bearing
      • Hindfoot position
      • Arch
      • Forefoot position 1
      • Forefoot position 2
    • Foot in non-weight bearing
      • Subtalar neutral
      • Hindfoot position
      • Hindfoot inversion and eversion
      • Arch
      • Midfoot motion
      • Forefoot position 1
      • Forefoot position 2
      • Bunion deformity
      • First MTPJ dorsiflexion
  • • Femoral anteversion
      • Craig’s test
        • Patient prone. Knee flexed to 90 degrees. Rotate the hip internally and externally till the greater trochanter is maximally prominent. The angle between tibia and the vertical gives the femoral anteversion.
        • Normal anteversion is 45 degrees at birth, remodels between 1year to 4 years and reach adult value at 8 years.
        • Normal anteversion is 10 degrees in males and 155 degree in females.
    • Tibial torsion
      • Thigh foot angle
        • Patient prone. Knee flexed to 90 degrees. Hindfoot vertical in the subtalar neutral position. Dorsiflex the ankle to neutral position. Place the goniometer arms in the axis of the thigh and along the heel bisector to a point between the 2nd and 3rd metatarsal heads to measure the thigh foot angle.
      • Bimalleolar axis
        • Patient supine. Knee extended. Rotate the limb till the medial and lateral femoral condyles are horizontal. Mark the tip of lateral and medial malleolus. Measure the angle between the bimalleolar axis and condylar axis.
      • 2nd toe test
        • Patient prone. Knee extended. Rotate the limb till the second toe is vertical to the ground. Hold the limb in this degree of rotation and flex the knee to 90 degrees. Measure the angle between tibia and the vertical.
    • Heel bisector angle
  • • Winter’s classification of gait in hemiplegic cerebral palsy

Type 1 hemiplegia gait – Drop foot type

Type 2 hemiplegia gait – True equinus with or without recurvatum knee

Type 3 hemiplegia gait – Stiff knee gait

Type 4 hemiplegia gait – Ankle in equinus, knee in flexion, hip in flexion adduction and internal rotation and the pelvis in anterior tilt.

• Rodda classification of gait in spastic diplegia

Type 1 – True equinus

Type 2 – Jump gait

Type 3 – Apparent equinus

Type 4 – Crouch gait

• Look for contracture of biarticular muscles under anesthesia also.
  • Differentiation between contracture and spasticity can be done under anesthesia.
  • Thomas test can be done with flatten-the-lordosis method or by making ASIS and PSIS at the same level.
  • 2-joint muscle contracture
    • • Supine
      • Knee flexed to 90 degrees.
      • Dorsiflex and invert the ankle. Note the degree of dorsiflexion.
      • Extend the knee. If ankle goes into plantarflexion, there is contracture of gastrocnemius.

knee flexed, indicates that  contracture of the gracilis is the cause.

• Duncan Ely test
  • Assessment of hypertonia
    • • Involuntary movement or posture with tactile stimulation of distant body part, on purposeful movement of distant body part, or increased tone with movement of distant body part suggest dystonia.
      • Spastic catch and velocity dependent resistance to passive movement indicate spasticity.
      • Equal resistance to passive stretch during bi-directional movement and maintenance of limb position after passive movement indicate rigidity.

References

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