Courtesy: Dr Ashok Shyam, Dr. Shital Parikh, Ortho TV

Physeal Bar (Growth Arrest)

Introduction

A physeal bar, also known as growth arrest, occurs when a bony bridge forms across the growth plate (physis), leading to partial or complete cessation of growth.

Because longitudinal bone growth occurs through the physis, damage to this structure can result in:

Angular deformity
Limb length discrepancy
Joint distortion

Early recognition and treatment are critical to minimizing long-term deformity.

Historical Background

The physiology of the growth plate was first described by:

John Hunter

who recognized that:

Bone growth occurs at the physis

This concept remains fundamental to pediatric orthopedics.

Consequences of Physeal Disturbance

Damage to the growth plate may lead to:

Premature physeal closure
Growth restriction
Progressive deformity

The severity depends on:

Size of the physeal injury
Remaining growth potential
Location of the affected physis

Factors Affecting Outcome

Several factors influence prognosis and deformity progression.

Location of the Physis

Certain physes contribute significantly to limb growth and are therefore high risk.

Important high-risk physes include:

Around the knee
Distal ulna

Type of Injury

The severity and pattern of physeal damage strongly affect outcome.

Higher-grade injuries are more likely to produce:

Bone bridge formation
Growth arrest

Skeletal Maturity

Younger children with substantial growth remaining are at greater risk for:

Progressive deformity
Limb length discrepancy

Etiology

Common causes of physeal bar formation include:

Trauma
Infection
Vascular insult
Tumors

Trauma is the most common cause.

Types of Physeal Problems

Loss of Physis

In some cases, the physis may initially appear normal but later undergo:

Premature closure

This can be difficult to identify early.

Physeal Arrest

A physeal arrest occurs when:

Bone bridge formation develops across the growth plate

This restricts growth and may produce deformity.

Park-Harris Growth Lines

Park-Harris lines are useful indicators of growth behavior.

Parallel Lines

Parallel growth arrest lines suggest:

Symmetrical and normal growth recovery

Converging Lines

Converging lines indicate:

Physeal tethering
Location of a physeal bar

These findings help localize growth arrest.

Imaging Evaluation

Plain Radiographs

X-rays are the initial imaging modality and help evaluate:

Angular deformity
Limb alignment
Growth disturbance

CT Scan

CT is particularly useful for:

Identifying bony bridges
Defining the size and shape of the physeal bar

It provides excellent osseous detail.

MRI

MRI is especially valuable because it evaluates:

Cartilage
Remaining physis
Soft tissue anatomy

MRI is considered the best modality for:

Physeal bar mapping

MRI Mapping

MRI mapping helps determine:

Exact location of the bar
Percentage of physeal involvement

This information is essential for surgical planning.

Clinical Assessment

Comprehensive evaluation should include:

Full-length standing radiographs
Limb alignment assessment
Scanogram for limb length discrepancy
Skeletal age estimation

Careful follow-up is important.

Types of Physeal Bars

Central Bar

A central physeal bar commonly causes:

Limb shortening

with relatively less angular deformity.

Peripheral Bar

Peripheral bars usually produce:

Angular deformity

because one side of the physis continues growing.

Linear Bar

Linear bars are commonly associated with:

Traumatic injuries

and may produce combined shortening and angulation.

Management Principles

Treatment depends primarily on:

Remaining growth
Size of the bar
Severity of deformity

Management Algorithm

More Than 2 Years of Growth Remaining

Bar Involving Less Than 30% of the Physis

Physeal bar resection is generally recommended

Bar Involving More Than 30% of the Physis

Epiphysiodesis may be preferred

because successful resection becomes less likely.

Angular Deformity Management

Deformity Greater Than 20°

Management often requires:

Osteotomy
Combined with bar resection

Deformity Less Than 20°

Less severe deformity may be treated with:

Guided growth techniques

Less Than 2 Years of Growth Remaining

Observation may be appropriate because:

Limited growth remains
Progression risk is lower

Physeal Bar Resection Technique

Surgical Technique

Typical steps include:

Guide pin placement
Reaming of the bar
Removal of the bone bridge

Arthroscopic visualization may improve accuracy.

Interposition Materials

After resection, interposition material is commonly inserted to prevent recurrence.

Common options include:

Fat graft
Bone cement

Special Consideration: Distal Radius

The distal radius has relatively limited remaining growth potential.

Untreated arrest may result in:

Relative ulnar overgrowth
Ulnar impingement

Careful monitoring is essential.

Osteotomy

Corrective osteotomy may be required for:

Established angular deformity
Joint malalignment

The procedure aims to restore:

Mechanical alignment
Joint orientation

Prevention of Physeal Bars

Preventive strategies are extremely important.

Key Preventive Measures

Important principles include:

Avoid repeated manipulations
Achieve anatomical reduction in Salter-Harris III and IV injuries
Remove interposed periosteum
Protect the physis during surgery

Early appropriate management reduces the risk of growth arrest.

Complications

Potential complications include:

Recurrent bar formation
Persistent deformity
Limb length discrepancy
Joint incongruity
Secondary osteoarthritis

Long-term follow-up is necessary until skeletal maturity.

Key Clinical Pearls

Growth arrest may lead to shortening, angulation, or joint deformity.
Trauma is the most common cause of physeal bars.
Parallel Park-Harris lines indicate normal growth.
Converging lines suggest physeal tethering.
MRI is best for physeal bar mapping.
Bars involving less than 30% of the physis are better candidates for resection.
Peripheral bars typically cause angular deformity.
Prevention through careful fracture management is critical.

Final Take-Home Message

Physeal bars are important causes of growth disturbance in children and adolescents.

Successful management depends on:

Early diagnosis
Accurate imaging assessment
Understanding remaining growth potential

MRI mapping plays a major role in surgical planning, while prevention through meticulous treatment of physeal injuries remains the most effective strategy.

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