High Yield Overview
GENU VALGUM AND GENU VARUM
Angular Knee Deformities | Physiological vs Pathological | Blount Disease | Guided Growth
0-2 yrsPhysiological varus normal
3-4 yrsMaximum physiological valgus
7 yrsAchieve adult alignment
15-20°Varus red flag in young child
DEFORMITY TYPES
Physiological
PatternAge-appropriate development
TreatmentObservation, reassurance
Pathological
PatternDisease-related deformity
TreatmentAddress cause, guided growth
Blount Disease
PatternTibia vara, medial proximal tibial physis
TreatmentBracing (infantile), surgery
Critical Must-Knows
- Physiological evolution: Birth varus (10-15°) → neutral (18-24mo) → peak valgus (3-4yrs, 10-15°) → adult alignment (7yrs, 5-7° valgus)
- Red flags for pathology: Asymmetry, rapid progression, extreme angle, short stature, onset after walking established
- Blount disease: Tibia vara from disrupted medial proximal tibial physis. Infantile (1-3yrs) vs adolescent types
- Rickets: Systemic cause of angular deformity - nutritional or renal. Bilateral, symmetric, physeal widening
- Guided growth: Hemiepiphysiodesis with 8-plates to correct angular deformity in skeletally immature patients
Examiner's Pearls
- "Measure intercondylar distance (varus) or intermalleolar distance (valgus) clinically
- "Mechanical axis deviation on standing long leg X-ray is the gold standard
- "Drennan metaphyseal-diaphyseal angle greater than 16° suggests Blount disease
- "Always check calcium, phosphate, vitamin D, ALP in bilateral deformity
Clinical Imaging
Imaging Gallery
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Critical Angular Deformity Exam Points
Physiological Pattern
Normal evolution: Babies born with 10-15° varus (bowlegs). Straightens by 18-24 months. Peaks at valgus 10-15° (knock-knees) by age 3-4. Gradually corrects to adult alignment (5-7° valgus) by age 7. Symmetric, follows expected pattern.
Pathological Red Flags
Suspect pathology if: Asymmetric deformity, rapid progression beyond expected pattern, extreme angles (varus greater than 15° after age 2, valgus greater than 15° after age 5), short stature, lateral thrust in gait, persisting/worsening after expected correction age.
Blount Disease
Tibia vara from medial proximal tibial physis disorder. Infantile (1-3yrs, often bilateral) vs Adolescent (greater than 10yrs, unilateral, obese). Drennan MDA greater than 16° diagnostic. Infantile may respond to bracing; adolescent requires surgery.
Guided Growth
Hemiepiphysiodesis with tension-band plating (8-plate). Applied to convex side of physis to retard growth and allow correction. Requires at least 2 years growth remaining. Correct approximately 1°/month. Remove hardware after correction achieved.
Quick Decision Guide - Genu Varum
| Feature | Physiological Varus | Blount Disease | Rickets |
|---|---|---|---|
| Age pattern | Less than 2 yrs, resolving | Infantile: 1-3yrs, progressive | Any age, often bilateral |
| Symmetry | Symmetric | Often bilateral but may be asymmetric | Symmetric |
| X-ray findings | Normal physes | Medial tibial beaking, MDA greater than 16° | Physeal widening, cupping, fraying |
| Other features | None | Lateral thrust, internal tibial torsion | Short stature, rachitic rosary, bowing |
| Treatment | Observation | Brace (early) or surgery | Vitamin D/phosphate, guided growth |
Mnemonic
ALIGNALIGN - Approach to Angular Deformity
A
Age at presentation
Matches expected physiological pattern?
L
Lateral thrust in gait?
Suggests pathological varus
I
Investigate if red flags
X-ray, bloods if bilateral
G
Growth remaining?
Key for treatment planning
N
Natural history
Physiological corrects, pathological persists
Memory Hook:ALIGN the approach - check age, look for thrust, investigate appropriately, and consider growth.
Mnemonic
BLOUNTBLOUNT - Blount Disease Features
B
Beaking of medial tibia
Characteristic X-ray finding
L
Lateral thrust gait
Clinical sign of instability
O
Obesity (especially adolescent)
Major risk factor
U
Unilateral or bilateral
Infantile often bilateral, adolescent often unilateral
N
No systemic features
Unlike rickets, isolated to knee
T
Tibia vara from physis
Medial proximal tibial physis affected
Memory Hook:BLOUNT affects the proximal tibia physis, causing Beaking on X-ray and Lateral thrust.
Mnemonic
RICKETSRICKETS - Features of Rickets
R
Rachitic rosary
Costochondral junction swelling
I
Impaired mineralization
Low calcium/phosphate
C
Cupping and fraying of physes
X-ray hallmark
K
Knock-knees or bowlegs
Both patterns seen
E
Epiphyseal widening
Wide growth plates
T
Treat the cause
Vitamin D, phosphate replacement
S
Short stature
Generalized growth impairment
Memory Hook:RICKETS is systemic - look for rosary, cupping, short stature, and treat the metabolic cause.
Overview and Epidemiology
Angular knee deformities are common presenting concerns in pediatric orthopaedics. Understanding the normal physiological development is essential to differentiate benign patterns from pathological conditions requiring intervention.
Definitions:
- Genu varum: "Bowlegs" - tibiofemoral angle in varus, knees apart when ankles together
- Genu valgum: "Knock-knees" - tibiofemoral angle in valgus, ankles apart when knees together
Physiological Evolution
Birth to adult pattern: Newborns have 10-15° varus (intrauterine positioning). This straightens by 18-24 months to neutral. Maximum valgus (10-15°) occurs at age 3-4 years. Gradual correction to adult alignment (5-7° valgus) by age 6-7 years.
Epidemiology:
- Physiological angular deformity is extremely common and usually normal
- Infantile Blount disease: more common in African descent, early walkers, obese
- Rickets: nutritional form rare in developed countries; renal osteodystrophy in chronic kidney disease
Pathophysiology and Mechanisms
Lower Limb Mechanical Axis
Limb Alignment Parameters
| Parameter | Definition | Normal Value |
|---|---|---|
| Mechanical axis | Center of femoral head to center of ankle | Passes through or just medial to knee center |
| Anatomical axis | Femoral and tibial diaphyseal axes | 5-7° valgus tibiofemoral angle |
| MPTA | Medial proximal tibial angle | 85-90° |
| LDFA | Lateral distal femoral angle | 85-90° |
Physeal Growth and Correction
Growth Plate Principles
- Proximal tibia: 55% of tibial growth
- Distal femur: 70% of femoral growth, 37% of leg length
- Asymmetric loading affects physeal growth
- Hueter-Volkmann law: compression retards, tension stimulates growth
Guided Growth Mechanics
- Hemiepiphysiodesis: Retard growth on one side
- 8-plate creates tension band effect
- Screw/staple methods also used
- Correct approximately 1°/month at distal femur
- Need at least 2 years growth remaining
Contribution of Each Physis
Distal femur contributes more to angular correction than proximal tibia due to faster growth rate. Consider site of maximum deformity (CORA - center of rotation of angulation) when planning surgery. Overcorrection is a risk if hardware not removed promptly.
Classification Systems
Etiology-Based Classification
| Category | Examples | Management Approach |
|---|---|---|
| Physiological | Normal developmental pattern | Observation, reassurance |
| Developmental (Blount) | Infantile tibia vara, adolescent tibia vara | Bracing (infantile), surgery |
| Metabolic | Rickets (nutritional, X-linked hypophosphatemic, renal) | Treat metabolic cause, then guided growth |
| Skeletal dysplasia | Achondroplasia, multiple epiphyseal dysplasia | Manage deformity, often complex |
| Post-traumatic | Physeal injury, malunion | Depends on growth remaining |
| Infection | Post-septic physeal damage | May need surgical correction |
Identifying the cause is essential for appropriate management.
Clinical Assessment
Systematic Examination
Step 1History
- Age of onset: When parents first noticed deformity
- Progression: Improving, stable, worsening
- Walking age: Early walkers at risk for Blount
- Family history: Skeletal dysplasia, rickets
- Diet/sun exposure: Vitamin D intake, risk for nutritional rickets
- Medical history: Renal disease, GI malabsorption
Step 2Gait Assessment
- Lateral thrust: Knee appears to "pop out" laterally in stance
- This is pathological and suggests significant varus
- In-toeing or out-toeing: May coexist with angular deformity
- Assess overall gait pattern and foot progression angle
Step 3Standing Examination
- Intercondylar distance (ICD): Measure with ankles together (varus)
- Intermalleolar distance (IMD): Measure with knees together (valgus)
- Symmetry: Compare both sides
- Rotational profile: May coexist tibial internal torsion
Step 4Systemic Examination
- Height: Short stature suggests skeletal dysplasia or rickets
- Wrist exam: Physeal widening in rickets
- Rachitic rosary: Costochondral swelling
- Dysmorphic features: Skeletal dysplasia
Lateral Thrust = Pathological
A lateral thrust during gait is NEVER physiological. It indicates significant varus with medial collateral laxity or tibial vara. This finding warrants investigation and likely treatment.
Investigations
When to Image
X-ray if: Asymmetric deformity, extreme angles, not following physiological pattern, lateral thrust, short stature, or clinical concern. Request standing AP long leg X-ray for accurate mechanical axis assessment.
Investigation Modalities
| Investigation | When Used | What to Look For |
|---|---|---|
| Standing long leg X-ray | Angular deformity requiring assessment | Mechanical axis deviation, site of deformity |
| AP/Lateral knee X-rays | Initial assessment, Blount diagnosis | Physeal changes, metaphyseal beaking, MDA |
| Wrist X-ray | Suspected rickets | Physeal widening, cupping, fraying |
| Bloods: Ca, PO4, Vit D, ALP | Bilateral deformity, suspected metabolic cause | Low Ca/PO4/Vit D, high ALP in rickets |
| MRI | Physeal bar suspected, Blount assessment | Physeal status, bar extent |
Key Radiographic Measurements:
- Mechanical axis deviation (MAD): Distance from mechanical axis to knee center
- Metaphyseal-diaphyseal angle (MDA/Drennan): Greater than 16° suggests Blount disease
- Tibial metaphyseal angle: Assesses tibia vara severity
Management Algorithm
Conservative Management
Physiological Deformity:
- Most common presentation
- Follows expected pattern for age
- No lateral thrust, symmetric
Management:
- Reassurance and education
- Clinical follow-up every 6-12 months
- Serial clinical photos to document
- X-rays rarely needed if following typical pattern
- Expect correction by age 6-7 for valgus, earlier for varus
No bracing or orthotics required for true physiological deformity. They do not hasten correction.
Surgical Technique
Tension-Band Plating (8-Plate)
Standard guided growth technique for angular deformity.
Surgical Steps
Step 1Planning
- Standing long leg X-ray to assess mechanical axis
- Identify site(s) of deformity (CORA)
- Decide distal femur vs proximal tibia vs both
Step 2Positioning
- Supine on radiolucent table
- Affected side accessible
- Image intensifier available
Step 3Incision
- Small (2-3cm) incision over physis
- On convex side of deformity
- For valgus: lateral distal femur
- For varus: medial proximal tibia
Step 4Plate Placement
- Identify physis with fluoroscopy
- Extraperiosteal placement of 8-plate
- One screw in epiphysis, one in metaphysis
- Screws parallel, with plate on tension side
Step 5Closure
- Confirm position with imaging
- Close in layers
- No immobilization required
Technical Points:
- Screws must be parallel for tension-band effect
- Plate should sit flush on bone
- Do not violate physis with plate, only screws cross it
Post-operative: Weight-bear as tolerated; follow-up X-rays every 3 months.
Complications
Complications of Treatment
| Complication | Incidence | Prevention/Management |
|---|---|---|
| Overcorrection | Common if hardware not removed | Regular monitoring, prompt removal |
| Undercorrection | Variable | Ensure adequate growth remaining |
| Recurrence | Blount: significant if growth remaining | Address physeal bar, consider osteotomy |
| Hardware prominence/irritation | Common (8-plate) | May need removal after correction |
| Physeal arrest (iatrogenic) | Rare with 8-plate | Proper technique, avoid physeal damage |
| Compartment syndrome (osteotomy) | Rare but serious | Prophylactic fasciotomy for large corrections |
Overcorrection Risk
Overcorrection is common if 8-plates are not removed promptly. Follow patients closely (every 3 months) and remove hardware as soon as correction is achieved. Correcting past neutral is easy but creates opposite deformity.
Postoperative Care and Rehabilitation
Post-Guided Growth Protocol
ImmediateDay 0-7
- Wound care
- Weight-bearing as tolerated immediately
- No immobilization needed
- Discharge day 0-1
EarlyMonths 0-3
- Normal activities resume quickly
- First follow-up X-ray at 6-8 weeks
- Assess early correction
MonitoringEvery 3 months
- Clinical and radiographic assessment
- Measure mechanical axis on long leg films
- Continue until correction achieved
Hardware RemovalAt Correction
- Once alignment normalized or slightly overcorrected
- Remove 8-plate as day surgery
- May rebound slightly after removal
- Post-removal X-ray at 3-6 months
Post-Osteotomy Rehabilitation:
- Protected weight-bearing for 6-8 weeks
- Knee ROM exercises
- Progress to full weight-bearing and activity
Outcomes
Physiological Deformity:
- Nearly 100% spontaneous resolution
- No intervention needed in vast majority
Guided Growth:
- High success rate for appropriate candidates
- Predictable correction if adequate growth remaining
- Low morbidity, reversible if overcorrects
Blount Disease:
- Infantile: better prognosis if treated early
- Adolescent: higher recurrence, often needs osteotomy
- Long-term: risk of OA if residual malalignment
Evidence Base
8-Plate Guided Growth
Stevens PM • J Pediatr Orthop (2007)
Key Findings:
- Tension-band plating effective for angular deformity
- Predictable correction rate approximately 1° per month
- Low complication rate
- Requires adequate growth remaining
Clinical Implication: 8-plate guided growth is the standard technique for correcting angular deformities in the growing child.
Limitation: Retrospective series, selection bias.
Bracing for Infantile Blount Disease
Raney EM et al • J Pediatr Orthop (1998)
Key Findings:
- Bracing effective in Langenskiöld I-II stages
- Higher success in children less than 3 years
- Full-time wear required
- Later stages usually require surgery
Clinical Implication: Early bracing in infantile Blount can prevent need for surgery in selected cases.
Limitation: Historical series, variable compliance measurement.
Adolescent Blount Disease Outcomes
Sabharwal S et al • J Bone Joint Surg Am (2007)
Key Findings:
- Adolescent Blount has higher recurrence than infantile
- Often requires osteotomy rather than guided growth
- Obesity is major risk factor
- Long-term risk of osteoarthritis
Clinical Implication: Adolescent Blount disease is more challenging. Weight management and careful surgical planning are important.
Limitation: Retrospective review, variable follow-up.
Physiological Genu Valgum Natural History
Salenius P et al • J Bone Joint Surg Am (1975)
Key Findings:
- Documented physiological evolution of tibiofemoral angle
- Peak valgus at 3-4 years (10-15°)
- Adult alignment by age 7
- Basis for current understanding of normal development
Clinical Implication: Understanding normal evolution is essential to avoid unnecessary treatment of physiological deformity.
Limitation: Historical study, measurement techniques differ from modern.
Rickets-Related Deformity
Pettifor JM • Bone (2014)
Key Findings:
- Rickets causes angular deformity through physeal widening
- Both varus and valgus patterns can occur
- Treat metabolic cause first
- Guided growth after metabolic control achieved
Clinical Implication: In rickets, metabolic stabilization is the priority. Surgical correction follows once disease is controlled.
Limitation: Review article.
Exam Viva Scenarios
Practice these scenarios to excel in your viva examination
VIVA SCENARIOStandard
EXAMINER
"A mother brings her 18-month-old child concerned about 'bowlegs'. The child started walking at 11 months and the mother feels the legs are bowed."
VIVA Q&A
Q1:How would you approach this clinically?
I would take a history focusing on age of onset, progression, walking age, family history of short stature or skeletal conditions, and dietary history (vitamin D). On examination, I would assess the child standing - measure the intercondylar distance with ankles together, check for symmetry, and observe the gait for any lateral thrust. At 18 months, 10-15° varus is physiologically normal. I would expect the legs to appear bowed but with no lateral thrust, symmetric, and the child should be at the appropriate height for age. If this pattern fits, it is physiological genu varum.
Q2:What would concern you for pathological cause?
Red flags for pathological genu varum include: (1) Asymmetry between the two legs. (2) Lateral thrust during gait - the knee appears to pop outward in stance phase. (3) Extreme angle - greater than 15-20° especially if persisting after age 2. (4) Not following expected pattern - worsening instead of improving after 18-24 months. (5) Short stature or other systemic features suggesting rickets or skeletal dysplasia. (6) Very early walking (less than 10 months) which is a risk factor for Blount disease. If any of these are present, I would investigate with standing AP X-rays of the lower limbs.
Q3:The legs appear mildly bowed, symmetric, no thrust, good height. What is your management?
This is consistent with physiological genu varum, which is normal at 18 months. My management would be: (1) Reassurance and education - explain the normal evolution of leg alignment to the parents. Varus is expected at this age and should correct to neutral by 2 years and then go into mild valgus. (2) No intervention required - specifically, no bracing or orthotics as they do not accelerate correction of physiological deformity. (3) Clinical follow-up - I would review in 6-12 months to confirm the expected pattern of correction. No X-rays are needed unless the pattern deviates from expected.
KEY POINTS TO SCORE
18 months with varus is typically physiological
Lateral thrust is a key pathological sign
Physiological: symmetric, no thrust, appropriate height
Observation and reassurance, no bracing needed
COMMON TRAPS
✗Over-investigating physiological deformity
✗Prescribing orthotics for physiological varus
✗Missing lateral thrust on gait examination
LIKELY FOLLOW-UPS
"When would you X-ray?"
"What is the expected alignment at age 4?"
VIVA SCENARIOChallenging
EXAMINER
"A 2.5-year-old child presents with progressive bowlegs. They have been walking since 10 months. On examination, there is a noticeable lateral thrust during gait, and the varus appears worse on the right side."
VIVA Q&A
Q1:What is your differential diagnosis and what investigations would you order?
Given the progressive nature, lateral thrust, asymmetry, and early walking, my main concern is Blount disease (infantile tibia vara). Differential includes: pathological genu varum, rickets, or skeletal dysplasia. I would order: (1) Standing AP X-ray of both lower limbs (long leg film) to assess mechanical axis and identify site of deformity. (2) AP and lateral X-rays of the knees to look for proximal tibial changes - medial metaphyseal beaking, physeal irregularity. (3) I would calculate the Drennan metaphyseal-diaphyseal angle - greater than 16° is suggestive of Blount disease. (4) If bilateral or systemic features, bloods for calcium, phosphate, alkaline phosphatase, and vitamin D to exclude rickets.
Q2:X-ray shows right MDA of 20° with medial tibial beaking, Langenskiöld stage II. What is your management?
This confirms right infantile Blount disease, Langenskiöld stage II. At 2.5 years with stage II, there is still potential for bracing success. My management: (1) KAFO brace with valgus strap for the right side, to be worn full-time (22-23 hours/day). (2) I would also closely follow the left side which may develop. (3) Follow-up every 3-4 months with clinical and radiographic assessment to monitor response. (4) If no improvement at 6-9 months of bracing, or progression to higher Langenskiöld stage, I would proceed to surgical intervention. The family needs to understand the importance of compliance and that surgery may still be needed.
Q3:Despite compliant bracing for 9 months, the deformity has progressed. What is your next step?
Given bracing failure with progression, I would proceed to surgical correction. Options at this age include: (1) Guided growth with 8-plate hemiepiphysiodesis - place on the lateral proximal tibia to retard lateral growth and allow varus correction. This requires at least 2 years of growth remaining, which this child has. (2) However, for significant Blount disease that has failed bracing, some surgeons prefer proximal tibial valgus osteotomy for more immediate correction, with plating or external fixation. Given the young age and growth remaining, I would likely try guided growth first, with the understanding that recurrence is possible and osteotomy may eventually be needed. Post-operatively, close monitoring with X-rays every 3 months.
KEY POINTS TO SCORE
Lateral thrust + asymmetry = suspect Blount disease
MDA greater than 16° diagnostic for Blount
Bracing for infantile Blount Stage I-II
Guided growth or osteotomy if bracing fails
COMMON TRAPS
✗Delaying investigation in presence of lateral thrust
✗Not emphasizing brace compliance
✗Missing contralateral involvement
LIKELY FOLLOW-UPS
"What is the risk of recurrence after osteotomy?"
"How does adolescent Blount differ?"
VIVA SCENARIOCritical
EXAMINER
"A 9-year-old child presents with bilateral knock-knees that have been present for several years. The parents are concerned it is getting worse. The child is otherwise well and of normal height."
VIVA Q&A
Q1:Is this presentation concerning?
Yes, this is concerning. By age 7, the child should have achieved adult alignment of approximately 5-7° valgus. If knock-knees are severe enough to cause parental concern at age 9, this suggests persisting pathological genu valgum. At this age, physiological valgus should have resolved. I need to determine if this is: (1) Idiopathic pathological valgus - simply persisting beyond expected. (2) Related to underlying cause - though the normal height makes skeletal dysplasia and rickets less likely. (3) Contributing to functional problems - pain, instability, difficulty with activities. I would examine for the intermalleolar distance, gait pattern, and any features of underlying conditions.
Q2:IMD is 12cm, symmetrical. Standing long leg X-ray shows mechanical axis passing 3cm lateral to knee center bilaterally. How would you manage this?
This is significant bilateral genu valgum with mechanical axis deviation of 3cm lateral to the knee center. At age 9, this child likely has 3-4 years of growth remaining. My management: (1) Guided growth with 8-plate hemiepiphysiodesis at the medial distal femur bilaterally. This will retard medial growth and allow valgus to correct. (2) Distal femur is preferred as it has the highest growth rate and is where most valgus typically originates. (3) Expected correction of approximately 1° per month means with 3cm MAD (approximately 8-10° mechanical valgus), correction could take 8-10 months. (4) Close follow-up every 3 months with standing X-rays. (5) Remove 8-plates promptly once alignment is neutral to slightly over-corrected, to prevent varus overcorrection.
Q3:What if this child was 14 years old with closed physes?
If the child is skeletally mature with closed physes, guided growth is not an option. I would manage with corrective osteotomy: (1) Standing long leg films to confirm mechanical axis deviation and identify level of maximum deformity (CORA). (2) If deformity is primarily at distal femur: medial closing wedge or lateral opening wedge femoral osteotomy to correct alignment. (3) If tibial contribution: may need tibial osteotomy as well. (4) Fixation with plate or external fixator depending on extent of correction. (5) The goal is to restore mechanical axis to pass through the knee center. This is a more significant procedure than guided growth, with longer recovery, but is effective for mature patients.
KEY POINTS TO SCORE
Genu valgum persisting at age 9 is pathological
Guided growth with 8-plate on medial distal femur for valgus
Correct approximately 1° per month, remove plates promptly
Osteotomy if skeletally mature
COMMON TRAPS
✗Observing pathological valgus too long
✗Leaving 8-plates in and overcorrecting
✗Not obtaining standing long leg films
LIKELY FOLLOW-UPS
"What if only 1 year of growth remaining?"
"How would you manage asymmetric valgum?"
MCQ Practice Points
Physiological Evolution
Q: At what age is peak physiological genu valgum expected? A: Age 3-4 years, with approximately 10-15° valgus. This corrects to adult alignment (5-7° valgus) by age 7.
Blount Diagnosis
Q: What Drennan metaphyseal-diaphyseal angle suggests Blount disease? A: Greater than 16°. This measurement helps distinguish Blount disease (tibia vara) from physiological varus.
Guided Growth
Q: Where is an 8-plate placed to correct genu valgum? A: On the medial side of the distal femur (convex side). This retards medial growth and allows valgus to correct.
Correction Rate
Q: What is the expected correction rate with 8-plate at the distal femur? A: Approximately 1° per month. Correction at the proximal tibia is slightly slower.
Medicolegal Considerations
Documentation Points:
- Age, height, and clinical measurements (ICD/IMD)
- Gait assessment including lateral thrust
- Family history and dietary assessment
- Radiographic findings and measurements
Consent for Surgery:
- Need for hardware removal after correction
- Risk of overcorrection or undercorrection
- May need additional surgery (recurrence, other side)
- Osteotomy risks: compartment syndrome, nerve injury
Follow-up Compliance
Missing follow-up after 8-plate insertion can lead to overcorrection. Emphasize the importance of regular monitoring and document the follow-up plan clearly.
Australian Context
Epidemiology:
- Physiological deformity common presenting concern
- Blount disease less common than in some other populations
- Rickets rare but seen in high-risk groups (covered skin, dark complexion, low sun exposure)
Access to Care:
- Pediatric orthopaedic surgery at tertiary children's hospitals
- Long leg X-ray facilities in major centers
- Guided growth well-established technique
Cultural Considerations:
- Parental concern may be driven by cultural norms about leg shape
- Important to reassure about physiological patterns
- Vitamin D supplementation recommendations for at-risk groups
High-Yield Exam Summary
Physiological Pattern
- •Birth: 10-15° varus (bowlegs)
- •18-24 months: Neutral
- •3-4 years: Peak valgus (10-15°)
- •7 years: Adult alignment (5-7° valgus)
Red Flags for Pathology
- •Lateral thrust during gait
- •Asymmetry between sides
- •Extreme angle beyond expected
- •Short stature or systemic features
Blount Disease
- •Tibia vara from medial proximal tibial physis
- •Infantile (1-3yrs) vs Adolescent (greater than 10yrs)
- •MDA greater than 16° diagnostic
- •Langenskiöld staging determines treatment
Guided Growth (8-Plate)
- •On convex side of deformity
- •Valgus: medial distal femur
- •Varus: lateral proximal tibia
- •Correct approximately 1°/month
- •Remove promptly after correction
Key Numbers
- •MDA greater than 16° = Blount disease
- •5-7° = Normal adult tibiofemoral angle
- •1°/month = 8-plate correction rate
- •At least 2 years growth needed for guided growth