High Yield Overview
Cerebral Palsy
Non-Progressive UMN Lesion | GMFCS and Hip Surveillance
2 per 1000Incidence
GMFCSClassification Key
HipSurveillance Mandatory
SEMLSGold Standard Surgery
GMFCS Levels (Simplifed)
Level I
PatternWalks without limitations.
TreatmentObservation / Minor Soft Tissue
Level II
PatternWalks with limitations (uneven ground).
TreatmentOrthotics / Soft Tissue
Level III
PatternWalks with handheld mobility device.
TreatmentSEMLS / Bony Surgery
Level IV
PatternSelf-mobility with limitations (Powered).
TreatmentPalliative / Hip Salvage
Level V
PatternTransported in manual wheelchair.
TreatmentSpasticity Management / Comfort
Critical Must-Knows
- Definition: A group of permanent disorders of the development of movement and posture, causing activity limitation, that are attributed to non-progressive disturbances that occurred in the developing fetal or infant brain.
- Hip Surveillance: ALL children with CP need hip surveillance. The frequency is determined by GMFCS level (Level V = Every 6 months).
- GMFCS: The most robust predictor of motor development and hip displacement risk.
- Spasticity vs Contracture: Spasticity is velocity-dependent tone (dynamic). Contracture is fixed shortening (static). Differentiate them using examination (R1/R2) or EUA.
- Lever Arm Dysfunction: Torsional deformities (femoral anteversion, tibial torsion) degrade the power generation of muscles. Must be corrected in SEMLS.
Examiner's Pearls
- "GMFCS Level is the single most important prognostic factor.
- "Hip dislocation is silent in CP! Hence surveillance.
- "Never lengthen the Achilles in a crouch gait (makes it worse).
- "Hemiplegic kids nearly always walk (Level I/II).
The Hip Trap
Silent Dislocation
Pain free? hips can dislocate without pain initially. By the time they hurt, the head is destroyed. Screening is mandatory.
Spasticity vs Dyskinesia
Surgery Risk. Dyskinesia (Dystonia/Chorea) responds POORLY to orthopaedic surgery. Rule out dystonia before cutting tendon/bone.
The Birthday Syndrome
Single Event. Avoid "Birthday Syndrome" (surgery every year). Aim for Single Event Multi-Level Surgery (SEMLS) at age 8-10.
Crouch Gait
Do NOT lengthen T-Achilles. In crouch gait, the T-Achilles is often already long (over-lengthened). Lengthening it further causes calcaneal gait (disaster).
At a Glance: Spasticity vs Dystonia
| Feature | Spasticity | Dystonia |
|---|---|---|
| Definition | Velocity-dependent resistance | Involuntary muscle contractions/postures |
| Feel | Clasp-knife | Lead-pipe / Fluctuating |
| Sleep | Persists (reduced) | Disappears |
| Surgery | Responds well | Contraindicated / Unpredictable |
Mnemonic
Climb, Cane, Crutch, Car, CartGMFCS Levels
I
Climb
Walks without limitation (Climbs stairs without rail)
II
Cane
Walks with limitation (Stairs with rail, uneven ground)
III
Crutch
Walks with handheld mobility device (Walker/Crutches)
IV
Car
Self-mobility with limitations (Powered mobility / Car)
V
Cart
Transported in manual wheelchair (Pushed)
Memory Hook:The 5 C's of GMFCS (Simplified).
Mnemonic
1234Hemiplegia Patterns (Winters)
1
Drop Foot
Weak Tib Ant
2
Equinus
Tight Gastroc (Most common)
3
False Crouch
Equinus + Knee Hyper-extension / Stiff Knee
4
Hip
Equinus + Knee/Hip Flexion/Adduction
Memory Hook:Winters Classification for Hemiplegia.
Mnemonic
POSTERRisk Factors
P
Prematurity
Major risk (PVL)
O
Obstetric
Complications (rarely purely asphyxia)
S
Sepsis
Meningitis, TORCH
T
Twin
Multiple pregnancy
E
Encephalopathy
HIE
R
Rhesus
Kernicterus (rare now)
Memory Hook:POSTER child for CP.
Overview and Epidemiology
Definition: Cerebral Palsy (CP) is defined by the Rosenbaum (2005) consensus: "A group of permanent disorders of the development of movement and posture, causing activity limitation, that are attributed to non-progressive disturbances that occurred in the developing fetal or infant brain. The motor disorders are often accompanied by disturbances of sensation, perception, cognition, communication, and behavior, by epilepsy, and by secondary musculoskeletal problems."
Epidemiology:
- Incidence: 2-2.5 per 1000 live births (Stable despite obstetric advances, due to survival of extreme preterms).
- Risk Factors: Prematurity (strongest), Low Birth Weight, Multiple gestation, Infection (Chorioamnionitis).
- Asphyxia: Intrapartum asphyxia accounts for only 10% of cases.
Primary Prevention:
- Magnesium Sulfate: Given to mothers in preterm labor (neuroprotection). Reduces risk of CP by 30%.
- Cooling (Therapeutic Hypothermia): Standard of care for term infants with HIE. Reduces mortality and severe disability.
- Corticosteroids: Antenatal steroids for lung maturity also reduce IVH risk.
Pathophysiology and Mechanisms
Brain Lesions:
- Periventricular Leukomalacia (PVL): Necrosis of white matter near lateral ventricles. Affects Medial fibers of Corticospinal tract (Legs > Arms). Classic cause of Spastic Diplegia in Premature infants.
- Intraventricular Hemorrhage (IVH): Common in preterms.
- HIE (Hypoxic Ischemic Encephalopathy): Global injury. Often leads to Quadriplegia or Dyskinetic CP.
- Stroke (MCA Infarct): Cause of Hemiplegia.
Musculoskeletal Pathology: The brain lesion is static, but the MSK issues are progressive.
- Primary: Loss of selective motor control, spasticity, balance loss.
- Secondary: Muscle contracture (myostatic contracture), lever arm dysfunction (torsion).
- Tertiary: Bony deformity (hip dislocation, scoliosis), joint degeneration.
Lever Arm Dysfunction: Skeletal deformities reduce the efficiency of muscles.
- Femoral Anteversion: Intoeing. Glutes lose abduction power.
- Tibial Torsion: External. Foot pressure axis lateral.
- Pes Valgus: Midfoot break. Gastroc power lost (lever arm shortens).
Classification
Gross Motor Function Classification System (GMFCS)
The gold standard for prognosis and communication. Based on self-initiated movement sitting/walking.
- Level I: Walks without limitations. Runs/Jumps.
- Level II: Walks with limitations (railings, uneven ground). No running.
- Level III: Walks with handheld mobility device (Walker/Crutches). Wheelchair for long distance.
- Level IV: Self-mobility with limitations (Powered chair). Can stand for transfers.
- Level V: Transported in manual wheelchair. Head control issues.
GMFCS is stable over time.
Clinical Assessment
History:
- Birth history (Gestation, ICU stay).
- Milestones (Sit by 2? Walk by ?).
- Communication/Feeding status.
Physical Examination:
- Tone: Modified Ashworth Scale (0-4). Tardieu Scale (R1/R2).
- R1: Angle of first catch (velocity dependent).
- R2: Angle of Max passive range (static length).
- R2-R1: Dynamic component (Spasticity).
- Selective Motor Control (SMC): Ability to isolate joint movement.
- Rotational Profile: Anteversion, Tibial Torsion.
- Spine: Scoliosis check.
- Hips: Abduction range (Risk of dislocation if less than 45).
- Spine: Scoliosis check. Sitting balance. Pelvic obliquity.
Selective Motor Control (SMC): This is the ability to isolate joint movement.
- Test: Ask patient to dorsiflex ankle without flexing hip/knee.
- Significance: Poor SMC predicts poor outcome from tendon transfers. If SMC is absent, transfer will not work "in phase" (but may act as a tenodesis).
Gait Analysis (Observational):
- Sagittal Plane: Look for the "Gait Deviations".
- True Equinus: Hips extended, Knee extended, Ankle plantarflexed.
- Jump Gait: Hip flexed, Knee flexed, Ankle plantarflexed.
- Apparent Equinus: Hip flexed, Knee flexed, Ankle neutral (but looks equinus due to knee flexion).
- Crouch Gait: Hip flexed, Knee flexed (greater than 30 deg), Ankle dorsiflexed (Calcaneus).
- Coronal Plane:
- Scissoring: Adductor spasticity.
- Trendelenburg: Abductor weakness.
- Transverse Plane:
- Intoeing: Femoral anteversion vs Internal Tibial Torsion.
- Outtoeing: External Tibial Torsion (often iatrogenic or compensatory).
Anesthetic Considerations:
- Respiratory: High risk of aspiration (swallow dysfunction) and post-op pneumonia.
- Seizures: Ensure anticonvulsants are continued.
- Latex Allergy: Higher prevalence in CP/Spina Bifida.
- Positioning: Contractures make positioning on the table difficult. Pad purely bony prominences.
- Pain Assessment: FLACC scale for non-verbal children. High risk of under-treatment.
Differential Diagnosis: CP vs HSP
| Feature | Cerebral Palsy | Hereditary Spastic Paraparesis |
|---|---|---|
| Onset | Birth / Infancy (Static) | Childhood / Adult (Progressive) |
| Family History | Rare | Common (Autosomal Dominant) |
| MRI Brain | Abnormal (PVL/IVH) | Normal |
| Progression | Non-progressive (MSK worsens) | Neurology worsens |
Investigations
1. Hip Surveillance (X-rays):
- Why?: To prevent dislocation. Dislocation leads to pain, scoliosis, and hygiene issues in GMFCS V.
- Metric: Reimer's Migration Percentage (MP).
- Calculation: Percentage of the femoral head lateral to Perkins' line (Lateral edge of acetabulum).
- Normal: Less than 10% in normal children. Less than 30% acceptable in CP.
- Risk: Greater than 30% ("Hip at Risk"). Often "Silent" (Pain free).
- Dislocated: Greater than 100%. The head is completely lateral to the acetabulum.
2. Gait Analysis (3D Motion Lab):
- Gold Standard for surgical planning in walkers (GMFCS I-III).
- Kinematics: Joint angles.
- Kinetics: Forces/Moments (Joint powers).
- EMG: Muscle firing timing (rectus spasticity in swing?).
- Pedobarography: Foot pressure. 3. Gait Velocity and Oxygen Cost:
- Children with CP use 3-5x more energy to walk than peers.
- Oxygen Cost: measured in mL/kg/m.
- Goal of Surgery: Improve efficiency (Lower Oxygen cost).
4. GDI (Gait Deviation Index):
- A single number representing gait pathology.
- 100: Normal.
- Every 10 points below 100: One standard deviation from normal.
- Typical CP: GDI 60-70.
- Post-SEMLS: Expect increase of 5-10 points (Clinically significant).
5. Functional Assessment Tools:
- GMFM (Gross Motor Function Measure): Even more detailed than GMFCS. Used to track change over time (e.g. pre/post SDR).
- GMFM-88: Validated for CP and Down Syndrome. Includes lying/rolling.
- GMFM-66: Rasch-scaled version. Only for CP.
- FMS (Functional Mobility Scale): Rates mobility at 3 distances (Home, School, Community).
- 5 meters: Home.
- 50 meters: School.
- 500 meters: Community.
- Rating: 1 (Crawler) to 6 (Independent on all surfaces).
- CP-CHILD: Caregiver-reported Quality of Life measure (Comfort, Positioning).
Management Algorithm
📊 Management Algorithm
Click to expand
Multidisciplinary Management
- Physiotherapy: Stretch, Strengthen, Functional training.
- Orthotics:
- AFO (Ankle Foot Orthosis): Solid (for crouch/equinus) or Hinged (for simple drop foot).
- GRAFO: Ground Reaction AFO (Pre-tibial shell) for CROUCH gait (prevents tibial advancement).
- Tone Management:
- Oral: Baclofen, Diazepam (global effect).
- Botox: Focal spasticity. Good for young kids (dynamic phase). Target: Gastroc, Hamstrings, Adductors.
- Intrathecal Baclofen (ITB): For severe severe quadriplegia (GMFCS IV/V) with dystonia.
Botox is most effective in the "Dynamic Phase" (Age 2-6).
Surgical Technique
Hip Reconstruction
Hip Surveillance Surgery
For Migration greater than 30-40% or progressive subluxation.
- Soft Tissue (Preventive): Adductor/Psoas Release.
- Indication: MP greater than 30% in young child (less than 4) with abduction less than 30 deg.
- Bony Reconstruction: VDRO + Acetabuloplasty (Dega/San Diego).
- Indication: MP greater than 40-50% in older child (greater than 4).
- VDRO: Shorten (release tension), Varus (better cover), Derotate (fix anteversion).
- Pelvis: Hinge osteotomy to cover anterior/lateral head.
- Dega Technique: Curvilinear cut above acetabulum (leaving posterior cortex intact). Lever down the roof. Bone graft wedge. Ideal for deficient anterior/lateral coverage.
- San Diego: Similar to Dega but extends to sciatic notch (more coverage).
- Salter: Less common in CP (re-directs whole acetabulum, but creates retroversion which is bad in CP).
- Salvage: Castle Procedure (Resection Interposition) or Proximal Femoral Replacement.
- Indication: Painful GMFCS V dislocated hip with destroyed head.
Total Hip Arthroplasty is generally contraindicated in GMFCS V due to high dislocation risk.
Complications
Surgical Complications
| Complication | Risk Factor | Management |
|---|---|---|
| Over-lengthening | TAL (Tendo-Achilles) | Calcaneal gait (Crouch). Hard to fix. |
| Recurrence | Young age (less than 6) at time of surgery | Repeat surgery |
| Hip Re-dislocation | GMFCS V / Scoliosis | Salvage surgery |
| Pathologic Fracture | Osteopenia / Cast immobilization | Gentle handling / Bisphosphonates |
| Baclofen Pump Risk | Catheter kink / Infection / Overdose | Emergency pump interrogation |
Baclofen Pump Failure:
- Overdose: Coma, Respiratory depression, Hypotension. Support airway. Physostigmine (controversial).
- Withdrawal: Itchy, Agitated, Rigid, Seizures, Hyperthermia. Life threatening. Restore Baclofen (oral/intrathecal) immediately.
Postoperative Care
Pain management is critical, especially in Spastic CP where pain triggers spasm, which triggers more pain.
- Spasm Protocols: Benzodiazepines (Diazepam) + Gabapentin.
- Immobilization: Petrie Casts (Broomstick) or Spica for hips.
- Rehab: Intensive inpatient rehab for 6-12 weeks post-SEMLS.
Outcomes
- Walking: GMFCS I/II walk well. III walk with aids. IV/V do not walk.
- Employment: Competitive employment rates are low (GMFCS dependent).
- Pain: Over 50% of adults with CP report chronic musculoskeletal pain.
- Life Expectancy: Reduced in GMFCS V (respiratory issues). Near normal in I-III.
Hamstring Surgery Outcomes
Click to expand
Click to expand
Evidence Base
Hip Surveillance
Key Findings:
- Consensus guidelines for hip surveillance.
- Level I: X-ray at 12-24 months.
- Level V: X-ray every 6 months until maturity.
- Level I: Discharge if normal at 5 years.
Clinical Implication: Standard of care worldwide.
Limitation: Guideline
GMFCS Stability
Key Findings:
- Developed the GMFCS.
- Showed it is stable over time (children rarely jump levels).
- Predicts hip displacement risk.
Clinical Implication: Use GMFCS for prognosis, not just description.
Limitation: Observational
SEMLS Efficacy
Key Findings:
- Systematic review of SEMLS.
- Found sustained improvement in GDI (Gait Deviation Index) at 5 years.
- Outcome better than single-level surgery.
Clinical Implication: SEMLS is the gold standard for gait correction.
Limitation: Heterogeneous studies
Botox vs Placebo
Key Findings:
- RCT showing Botox reduces spasticity and improves gait in dynamic equinus.
- Effect lasts 3-4 months.
Clinical Implication: Useful bridge to surgery or ensuring brace tolerance.
Limitation: Temporary effect
SDR Outcomes
Key Findings:
- Long term follow up of SDR.
- Muscle tone reduction persisted.
- But functional gains (walking) were modest compared to physio alone.
- Risk of spinal deformity (spondylolisthesis).
Clinical Implication: Strict selection criteria required.
Limitation: Retrospective
Viva Scenarios
Exam Viva Scenarios
Practice these scenarios to excel in your viva examination
VIVA SCENARIOStandard
The Intoeing Child
EXAMINER
"Discuss your management approach."
EXCEPTIONAL ANSWER
**Avoid Surgery for now.**
1. **Assessment**: Confirm GMFCS I. Check rotational profile.
2. **Natural History**: Anteversion improves up to age 10. Kids compensate well.
3. **Surgery Indications**:
- Functional tripping (severe).
- Lever arm dysfunction affecting power.
- Age greater than 8-10.
4. **Procedure**: Derotation Osteotomy (Femoral).
**Reasoning**: Operating too early risks recurrence. Operating for cosmesis in CP is controversial.
KEY POINTS TO SCORE
Wait until greater than 8 years
Function > Cosmesis
Rule out hip dysplasia
COMMON TRAPS
✗Derotating a GMFCS III/IV child (They need intoeing for stability!)
✗Using orthotics for rotation (Doesn't work)
LIKELY FOLLOW-UPS
"How do you fix anteversion?"
"What if they also have tibial torsion?"
VIVA SCENARIOStandard
The Hip at Risk
EXAMINER
"What is your plan?"
EXCEPTIONAL ANSWER
**Surgery is indicated.**
1. **Diagnosis**: 'Hip at Risk' / Subluxing hip. MP greater than 40%.
2. **Natural History**: Will progress to dislocation without intervention. GMFCS IV is high risk.
3. **Plan**:
- **Soft Tissue Release** alone? Failure rate high when MP greater than 40%.
- **Reconstructive Surgery**: VDRO + Pelvic Osteotomy (Dega).
4. **Goal**: Prevent dislocation, pain, and hygiene issues.
**Note**: Pain free status is irrelevant. We operate to prevent future pain.
KEY POINTS TO SCORE
MP greater than 40% = Surgery
Soft tissue release insufficient
Combined procedure needed
COMMON TRAPS
✗Waiting for pain
✗Trying bracing (swaddling makes it worse)
LIKELY FOLLOW-UPS
"What type of pelvic osteotomy?"
"Why VDRO?"
VIVA SCENARIOStandard
Crouch Gait Disaster
EXAMINER
"Explain the pathology and management."
EXCEPTIONAL ANSWER
**Iatrogenic Calcaneal Gait.**
1. **Pathology**: Original surgery (TAL) overlengthened the Gastroc-Soleus.
2. **Biomechanics**: The 'Plantarflexion-Knee Extension Couple' is lost. The tibia collapses forward (drop off) leads to Knee flexion which leads to Hip flexion.
3. **Result**: Severe energy inefficiency, patellar/anterior knee pain.
4. **Management**:
- **Difficult**.
- Address contractures (Hamstrings, Psoas).
- DFEO (Distal Femoral Extension Osteotomy) to straighten knee.
- Patellar tendon advancement.
- Ground Reaction AFOs.
KEY POINTS TO SCORE
Never lengthen Achilles in Crouch
PF-KE Couple loss
DFEO is the workhorse for correction
COMMON TRAPS
✗Lengthening hamstrings only (won't fix the lever arm)
✗Ignoring the foot
LIKELY FOLLOW-UPS
"What is the PF-KE couple?"
"How do you assess hamstring tightness?"
MCQ Practice Points
Most Common CP Type
Q: What is the most common physiologic type of CP? A: Spastic (Pyramidal) - approx 80%. Dyskinetic is 10-15%. Ataxic less than 5%.
Hip Surveillance GMFCS V
Q: How often should a GMFCS Level V child have a hip X-ray? A: Every 6 months. (High risk of rapid displacement). Level I usually discharged at 5 years.
GMFCS Level Determination
Q: What determines the difference between GMFCS II and III? A: Handheld Mobility Device. Level II walks without aids (may use rail). Level III needs crutches/walker.
GMFCS Level Determination IV vs V
Q: What determines the difference between GMFCS IV and V? A: Self-Mobility. Level IV can drive a powered chair or mobilize short distances. Level V has no means of independent mobility (must be pushed).
Hemiplegia Prognosis
Q: What is the likelihood of a child with Hemiplegic CP walking? A: Nearly 100% (Usually GMFCS I or II). If a hemiplegic child is not walking, reconsider diagnosis.
PVL Association
Q: Periventricular Leukomalacia (PVL) is most strongly associated with which CP pattern? A: Spastic Diplegia. The medial fibers (legs) of the corticospinal tract are affected.
Australian Context
- AusACPDM: Australasian Academy of CP and Developmental Medicine. Sets guidelines.
- Hip Surveillance: Established national guidelines.
- NDIS: National Disability Insurance Scheme funds equipment/therapy.
- CP Check-Up: Specialist multidisciplinary clinics in major children's hospitals.
High-Yield Exam Summary
GMFCS Levels
- •I: Walks / Runs
- •II: Walks / Railing / Uneven issues
- •III: Handheld Device (Walker)
- •IV: Powered Mobility
- •V: Pushed (Head control issues)
Hip Surveillance
- •Gold Standard: Reimer's MP
- •Normal: less than 10%
- •Risk: greater than 30%
- •Freq: GMFCS V = 6 monthly
Management
- •Botox: Focal Dynamic Spasticity
- •Baclofen: Global Spasticity
- •SEMLS: Age 8-10, Bony + Soft Tissue
- •SDR: Pure Spasticity, GMFCS II/III
Key Concepts
- •Non-progressive brain lesion
- •Progressive MSK deformity
- •Lever Arm Dysfunction
- •Avoid Birthday Syndrome