Courtesy: Prof Hitesh Shah, Professor of Paediatric Orthopaedics, KMC Manipal, India

Coxa Vara in Children

Introduction

Coxa vara is a pediatric hip deformity characterized by a decreased femoral neck-shaft angle.

The condition alters:

Hip biomechanics
Abductor function
Limb alignment

If progressive, it can lead to gait abnormalities, limb shortening, and long-term hip dysfunction.

Normal Femoral Alignment

The femoral neck-shaft angle changes with age.

At Birth

Approximately 150°

At Skeletal Maturity

Approximately 125°

Because the angle changes during growth, assessment must always be:

Age-based

Definition

Coxa vara is defined as:

Femoral neck-shaft angle less than 2 standard deviations below the normal mean for age

Etiology

Congenital Causes

Important congenital causes include:

Proximal femoral focal deficiency (PFFD)

Developmental Coxa Vara

A common pediatric form characterized by:

Progressive deformity during growth

Acquired Causes

Other causes include:

Post-infective deformity
Post-traumatic deformity
Fibrous dysplasia
Metabolic bone disease
Osteogenesis Imperfecta
Legg-Calvé-Perthes disease
Slipped Capital Femoral Epiphysis

Pathophysiology

Varus deformity of the proximal femur leads to:

Increased shear forces across the femoral neck
Progressive deformity
Weakening of hip abductors
Limb shortening

This contributes to gait abnormalities and mechanical dysfunction.

Clinical Features

Common Symptoms

Patients may present with:

Limp
Hip pain
Fatigue during walking
Limb shortening

Gait Abnormalities

Typical gait findings include:

Trendelenburg gait
Abductor weakness

Important Clinical Sign

A classic examination finding is:

Adduction greater than abduction

This is an important diagnostic clue.

Radiographic Evaluation

Standard Imaging

Radiographic evaluation usually includes:

AP pelvis radiograph
Frog-leg lateral view
Long-leg alignment radiographs

Important Measurements

Neck-Shaft Angle

Determines severity of varus deformity.

Hilgenreiner Epiphyseal (HE) Angle

The HE angle is a key parameter used to guide management.

Interpretation

Less Than 25°

Usually considered normal

25–45°

Observation may be appropriate

Greater Than 60°

Surgical correction is generally recommended

Adduction Radiograph

An adduction view helps assess:

Potential correction
Femoral head coverage
Reducibility of deformity

This is useful for surgical planning.

Types of Coxa Vara

Major categories include:

Congenital coxa vara
Developmental coxa vara
Acquired coxa vara

Management depends on underlying cause and progression.

Management

Observation

Observation may be appropriate for:

Mild deformity
Non-progressive cases
Low HE angle

Regular follow-up is important.

Valgus Osteotomy

Main Surgical Treatment

Valgus-producing proximal femoral osteotomy is the primary surgical treatment.

Goals of Surgery

The procedure aims to:

Correct varus deformity
Reduce shear forces
Improve hip biomechanics
Restore abductor function

Growth Modulation

Growth-guiding procedures may be considered when:

Physeal abnormalities contribute to deformity

Trochanteric Epiphysiodesis

Indications

Performed in younger children, typically:

Before 8–9 years of age

Purpose

Helps prevent:

Greater trochanter overgrowth
Progressive abductor dysfunction

Trochanteric Transfer

May be required in selected patients to:

Improve abductor mechanics
Reduce impingement

Neck Lengthening Procedures

Neck lengthening may be:

Relative
Absolute

depending on deformity severity and anatomy.

Special Situations

Post-Traumatic Coxa Vara

Management focuses on:

Correction of deformity
Treatment of non-union if present

Osteopenic Bone

Patients with poor bone quality may require:

Intramedullary fixation
Specialized implants

for improved stability.

Complications

Potential complications include:

Recurrence of deformity
Growth arrest
Implant-related complications
Persistent limp
Residual limb length discrepancy

Long-term follow-up is essential.

Follow-Up

Patients should be monitored until:

Skeletal maturity

This helps identify:

Recurrence
Progressive deformity
Growth-related complications

Key Clinical Pearls

Coxa vara is defined using age-based neck-shaft angle values.
Developmental coxa vara is a common pediatric form.
Adduction greater than abduction is a classic clinical sign.
HE angle is critical for treatment planning.
Valgus osteotomy is the primary surgical treatment.
Trochanteric overgrowth can worsen abductor dysfunction.
Long-term follow-up until skeletal maturity is essential.

Final Take-Home Message

Coxa vara in children is a proximal femoral deformity characterized by decreased neck-shaft angle and altered hip mechanics.

The condition may be congenital, developmental, or acquired, and careful evaluation of the underlying cause is essential.

Management depends on:

Severity
Progression
HE angle
Functional impairment

Valgus osteotomy remains the cornerstone of treatment for progressive deformity, while long-term surveillance is necessary to monitor growth and prevent recurrence.

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