Orthopaedic Surgery - Short Stature

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Basics

Short stature is generally defined as:

Height below the 3rd percentile for age and sex

relative to the general population.

There are many potential causes of short stature. From an orthopaedic perspective, the most important group is:

Skeletal dysplasia.

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Most Common Overall Cause

The most common causes of short stature overall are:

Familial short stature

and

Constitutional growth delay.

These typically produce proportionate short stature without a primary abnormality of:

Bone or cartilage development.

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Skeletal Dysplasia

Skeletal dysplasias are a diverse group of disorders characterized by intrinsic abnormalities of:

Cartilage formation

Bone growth

and

Skeletal remodeling.

Many become apparent at:

Birth

or during:

Early childhood.

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Synonym

The historical term:

Dwarfism

has been used to describe disproportionate short stature, although specific diagnostic terminology is preferred whenever possible.

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Classification

The most widely accepted classification system is the:

International Classification of Skeletal Dysplasias / Osteochondrodysplasias.

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Classification by Body Proportion

Skeletal dysplasias may be broadly grouped according to whether shortening predominantly involves the:

Limbs

or

Trunk.

Thus, patients may demonstrate:

Short-limb disproportion

or

Short-trunk disproportion.

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Classification by Bone Region

Disorders can also be classified according to the part of the long bone most severely affected:

Epiphyseal

Metaphyseal

or

Diaphyseal.

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Epiphyseal Disease

Patients with major epiphyseal involvement are particularly prone to:

Joint contractures

Early degenerative arthritis

and

Reduced range of motion

because the:

Articular surfaces

are directly affected.

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Rhizomelic Shortening

The term:

Rhizomelic

refers to disproportionate shortening that is greatest in the:

Proximal limb segments

such as the:

Humerus

and

Femur.

A classic example is:

Achondroplasia.

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Epidemiology

Skeletal dysplasias collectively are uncommon.

Historical estimates suggest an incidence of approximately:

1 in 3,000 to 1 in 5,000 live births.

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Risk Factors

Potential risk factors include:

Positive family history

Consanguinity

and membership in populations with a relatively high frequency of particular:

Inherited skeletal dysplasias.

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Geographic Clustering

Certain disorders occur more commonly in specific populations because of:

Founder effects.

Examples historically include:

Diastrophic dysplasia in Finland

and selected metaphyseal dysplasias in:

Amish communities.

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Genetics

Many skeletal dysplasias are inherited in:

Autosomal-dominant

or

Autosomal-recessive patterns.

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New Mutations

A substantial number of affected children have:

De novo mutations

despite no family history.

These individuals may subsequently transmit the disorder to their:

Children

depending on the mode of inheritance.

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Genetic Testing

Molecular testing is available for many skeletal dysplasias.

It may help with:

Diagnostic confirmation

Prognostic counseling

and

Family planning.

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Etiology

The molecular cause varies according to the specific disorder.

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Achondroplasia

Achondroplasia results from a pathogenic variant affecting:

FGFR3 – fibroblast growth factor receptor 3.

This produces abnormal regulation of:

Endochondral bone growth.

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Diastrophic Dysplasia

Diastrophic dysplasia is caused by abnormalities involving a cellular:

Sulfate transporter

which affects normal cartilage and skeletal development.

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Mucopolysaccharidoses

Mucopolysaccharidoses result from inherited deficiencies of enzymes involved in:

Glycosaminoglycan metabolism.

Accumulation of undegraded material affects:

Bone

Joints

and multiple organ systems.

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Other Disorders

Many additional skeletal dysplasias have now been linked to specific abnormalities of:

Receptors

Structural proteins

Enzymes

or

Extracellular matrix pathways.

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Associated Conditions

Depending on the diagnosis, skeletal dysplasias may be associated with:

Neurologic compromise

Respiratory problems

Spinal deformity

Hip dysplasia

Foot deformities

Joint contractures

Early arthritis

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Neurologic and Respiratory Problems

Spinal deformity or narrowing may cause:

Cord compression

Nerve-root compression

Spinal stenosis

or restrictive:

Pulmonary dysfunction.

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Developmental Delay

Some metabolic storage disorders, such as:

Hurler syndrome

may be associated with:

Neurodevelopmental impairment.

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Hip Abnormalities

Hip dysplasia and abnormal proximal femoral development may occur in several skeletal dysplasias and can lead to:

Pain

Instability

and

Early osteoarthritis.

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Clubfoot

Foot deformities, including:

Clubfoot

may occur in disorders such as:

Diastrophic dysplasia

and some forms of:

Spondyloepiphyseal dysplasia.

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Scoliosis

Scoliosis and kyphosis are common complications across many:

Skeletal dysplasias.

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Diagnosis

Diagnosis is based on:

Growth pattern

Body proportions

Physical examination

Radiographic features

and, increasingly,

Genetic testing.

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Achondroplasia

Achondroplasia is the:

Most common skeletal dysplasia.

Typical features include:

Rhizomelic limb shortening

Frontal bossing

Midface hypoplasia

Delayed motor milestones

Thoracolumbar kyphosis

Lumbar spinal stenosis

and

Foramen magnum narrowing.

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Adult Height in Achondroplasia

Adult height is typically markedly reduced and historically has often been:

Below approximately 50 inches

although individual height varies.

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Neurologic Concerns in Achondroplasia

Important neurologic issues include:

Foramen magnum stenosis

in infancy and childhood

and

Lumbar spinal stenosis

later in life.

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Multiple Epiphyseal Dysplasia

Multiple epiphyseal dysplasia is one of the more common skeletal dysplasias.

It is often inherited as:

Autosomal dominant.

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Multiple Epiphyseal Dysplasia Features

Characteristic findings include:

Abnormal ossification of multiple epiphyses

Mild short stature

Short limbs

Prominent joints

Joint pain

Reduced range of motion

and

Angular limb deformity.

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Joints Commonly Involved

The:

Hips

Knees

and

Ankles

are commonly affected.

Because short stature may be relatively mild, diagnosis may not occur until:

Later childhood.

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Adult Height in Multiple Epiphyseal Dysplasia

Historical adult heights have ranged approximately from:

57 to 67 inches.

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Hypochondroplasia

Hypochondroplasia is usually an:

Autosomal-dominant

mild short-limb skeletal dysplasia.

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Hypochondroplasia Features

Possible findings include:

Symmetric limb shortening

Mild frontal bossing

Lumbar lordosis

Mild kyphosis

and features that may overlap with:

Achondroplasia.

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Facial Features

Unlike classic achondroplasia, patients often have little or no:

Midface hypoplasia.

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Diastrophic Dysplasia

Diastrophic dysplasia is an:

Autosomal-recessive

skeletal dysplasia with prominent abnormalities of:

Cartilage

Joints

and

Extremities.

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Diastrophic Dysplasia Features

Typical findings include:

Rhizomelic shortening

Cauliflower ear

Major joint contractures

Hitchhiker thumb

Foot deformity

Scoliosis

and sometimes:

Cervical spinal abnormalities.

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Hitchhiker Thumb

The characteristic:

Hitchhiker thumb

refers to an abducted or unusually positioned thumb associated with:

Diastrophic dysplasia.

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Mucopolysaccharidoses

Common musculoskeletal and systemic features include:

Joint contractures

Organomegaly

Skeletal deformity

and, in some forms,

Cataracts

or

Developmental delay.

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Multiple Osteochondromas

Hereditary multiple osteochondromas is typically:

Autosomal dominant.

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Clinical Features

Patients may have:

Mild short stature

Multiple osteochondromas

Angular limb deformity

Leg-length discrepancy

and mechanical impingement involving:

Tendons

Nerves

or, rarely,

The spinal canal.

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Malignant Transformation

A small percentage of patients develop malignant transformation, most often to:

Secondary chondrosarcoma.

Historical estimates are around:

1%

although reported risk varies.

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Spondyloepiphyseal Dysplasia

Spondyloepiphyseal dysplasia may produce:

Short-trunk disproportion

Cervical instability

Scoliosis

Joint contractures

and

Hip and knee stiffness.

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Cervical Spine Risk

Cervical instability is particularly important because of the potential for:

Spinal cord injury.

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Down Syndrome

Musculoskeletal features may include:

Pes planus

Ligamentous laxity

and characteristic hand and facial findings.

Patients may also demonstrate:

Developmental delay.

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Turner Syndrome

Turner syndrome occurs in:

Females

with complete or partial loss of one:

X chromosome.

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Turner Syndrome Features

Typical findings include:

Short stature

Cubitus valgus

Webbed neck

and

Delayed or abnormal sexual development.

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Osteogenesis Imperfecta

Osteogenesis imperfecta may be associated with:

Broad cranial shape

Shortened and deformed long bones

Frequent fractures

Scoliosis

Kyphosis

and

Basilar invagination.

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X-Linked Hypophosphatemia

X-linked hypophosphatemia results from pathogenic variants involving:

PHEX.

Musculoskeletal findings may include:

Short stature

Lower-extremity deformity

and particularly:

Genu varum or genu valgum, depending on the individual.

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Physical Examination

Evaluation should determine whether short stature is:

Proportionate

or

Disproportionate.

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Birth Length

Document:

Length at birth

because congenital skeletal dysplasias often show disproportion from:

Early infancy.

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Current Growth

Record:

Current height

Growth percentile

and serial:

Growth velocity.

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Body Proportion

Compare:

Trunk length

with

Limb length.

Other useful measurements may include:

Sitting height

Arm span

and

Upper-to-lower segment ratio.

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Dysmorphic Features

Examine for characteristic:

Craniofacial

Hand

Foot

and

Soft-tissue abnormalities

that may suggest a specific diagnosis.

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Neurologic Examination

A complete neurologic assessment is important to identify complications of:

Spinal stenosis

Foramen magnum narrowing

or

Cervical instability.

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Joint Examination

Document:

Range of motion

Contractures

and

Joint stiffness.

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Limb Alignment

Assess for:

Varus

Valgus

Rotational deformity

and

Leg-length discrepancy.

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Spine Examination

Evaluate for:

Scoliosis

Kyphosis

Lordosis

and possible signs of:

Spinal instability.

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Laboratory Tests

Routine laboratory studies are often:

Not diagnostic

for skeletal dysplasia.

Testing should be directed by the suspected alternative or specific disorder.

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Chemistry

A chemistry panel may be useful when there is concern for:

Metabolic bone disease

or other systemic illness.

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Endocrine Evaluation

Endocrine studies may be appropriate when considering:

Growth hormone deficiency

Thyroid disease

or other hormonal causes of proportionate:

Short stature.

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Urinary Testing

Urine testing may help identify selected:

Storage disorders

or metabolic diseases.

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Specialized Testing

More specialized biochemical and genetic testing is often coordinated by a:

Medical geneticist

or

Endocrinologist.

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Imaging

A skeletal survey or targeted radiographic evaluation may help establish the pattern of:

Bone and cartilage abnormality.

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Suggested Radiographs

Common studies include:

Lateral skull

Cervical spine

Lateral thoracolumbar spine

AP pelvis

AP hand and wrist.

Additional imaging depends on:

Clinical findings

and the suspected diagnosis.

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Skull and Cervical Spine

These images may identify:

Foramen magnum narrowing

Cervical instability

Basilar invagination

or abnormal:

Vertebral development.

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Thoracolumbar Spine

Spinal imaging may identify:

Kyphosis

Scoliosis

Vertebral dysplasia

or

Spinal stenosis.

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Pelvis

Pelvic radiographs help evaluate:

Acetabular development

Proximal femoral morphology

and

Hip dysplasia.

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Hand and Wrist

Hand and wrist radiographs may demonstrate:

Epiphyseal abnormalities

Metaphyseal changes

and provide information regarding:

Skeletal maturity.

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Pathological Findings

Histologic abnormalities vary according to the specific disorder.

Many skeletal dysplasias involve altered development of:

Cartilage

Bone

Ligament

and

Tendon.

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Differential Diagnosis

Short stature should not automatically be attributed to:

Skeletal dysplasia.

Evaluation may require consultation with:

Genetics

and

Endocrinology.

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Important Alternatives

Differential diagnoses include:

Familial short stature

Constitutional growth delay

Malnutrition

Endocrine disease

Chronic systemic illness

Long-term corticosteroid use

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Constitutional Short Stature

Children with constitutional growth delay are often:

Proportionately short

and may have delayed:

Bone age

and

Pubertal development.

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Malnutrition

Insufficient caloric or nutrient intake may impair:

Linear growth

and should be considered when body weight is also:

Low.

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Hormonal Disorders

Possible causes include:

Growth hormone deficiency

Hypothyroidism

and other endocrine abnormalities.

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Chronic Disease

Long-standing conditions affecting the:

Heart

Lungs

Kidneys

Gastrointestinal tract

or other systems can impair normal:

Growth.

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Treatment

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General Principles

Orthopaedic management of skeletal dysplasia is primarily directed toward:

Function

Alignment

Stability

and prevention or treatment of:

Neurologic complications.

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Cervical Spine Instability

Cervical instability should be identified and monitored carefully.

Treatment may include:

Bracing

or

Surgical fusion

when instability threatens:

Neurologic function.

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Spinal Stenosis

Patients with symptomatic stenosis and:

Neurogenic claudication

or neurologic deficit may require:

Surgical decompression.

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Scoliosis and Kyphosis

Spinal deformities should be:

Documented

and followed over time.

Progressive deformity may require:

Bracing

or

Surgical correction.

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Genetic Counseling

Accurate:

Genetic counseling

is important for affected individuals and their families.

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Multidisciplinary Care

Management may require coordination among:

Orthopaedics

Medical genetics

Endocrinology

Neurology

Pulmonology

and other specialists depending on the diagnosis.

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Mobility

With increasing age, some patients develop:

Severe arthritis

or

Spinal disease

that reduces mobility.

Powered mobility devices may become useful for maintaining:

Independence

and reducing excessive energy expenditure.

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Growth Hormone

Growth hormone is generally not an effective treatment for increasing height in many forms of:

Disproportionate skeletal dysplasia.

It may, however, have a role in specific conditions such as:

Growth hormone deficiency

or selected syndromic causes of short stature under endocrine supervision.

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Limb Lengthening

Selected patients with:

Achondroplasia

or other short-limb dysplasias with relatively preserved joint and muscle function may consider:

Limb-lengthening procedures.

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Magnitude of Lengthening

Extensive staged lengthening may increase final height by as much as approximately:

One foot

in highly selected patients.

This involves substantial treatment burden and risk.

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Physical Therapy

Physical therapy cannot correct the underlying:

Skeletal dysplasia

or fixed bony deformity.

However, it may improve:

Strength

Mobility

Endurance

Joint function

and overall:

Independence.

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Medication

No single medication treats all forms of:

Skeletal dysplasia.

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Disorder-Specific Therapy

Some specific disorders now have:

Targeted medical therapies

or metabolic treatments.

Management should be tailored to the:

Underlying diagnosis.

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Surgery

Surgery is performed for:

Spinal instability

Neurologic compression

Progressive deformity

Severe limb malalignment

or

Advanced joint degeneration.

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Spinal Fusion

Fusion with instrumentation may be required for:

Progressive scoliosis

Kyphosis

or

Instability.

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Spinal Decompression

Decompression may be required for:

Lumbar stenosis

Cervical stenosis

or other neurologic compression.

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Osteotomy

Corrective osteotomy may be used for significant:

Varus

Valgus

or other angular deformities of the extremities.

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Joint Replacement

Patients with severe early osteoarthritis due to epiphyseal dysplasia may eventually require:

Total joint arthroplasty.

The:

Hips

and

Knees

are commonly affected.

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Follow-Up

Patients require long-term surveillance because many complications evolve during:

Growth

or later:

Adulthood.

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Monitoring Interval

Children may be reviewed approximately every:

6 months

depending on the specific disorder and clinical severity.

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Developmental Monitoring

Follow:

Motor milestones

Growth

Neurologic function

and

Skeletal deformity.

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Prognosis

The prognosis varies widely according to:

Specific diagnosis

Severity

and associated:

Neurologic

Respiratory

or

Systemic abnormalities.

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Spinal Complications

Many skeletal dysplasias are associated with:

Spinal stenosis

Cervical instability

and

Progressive deformity.

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Arthritis

Early degenerative disease of the:

Hips

and

Knees

is common in several epiphyseal dysplasias.

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Cervical Instability

Cervical instability is particularly associated with:

Spondyloepiphyseal dysplasia

and some:

Mucopolysaccharidoses.

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Basilar Invagination

Basilar invagination may occur in disorders such as:

Osteogenesis imperfecta.

This can result in compression of:

Brainstem

or

Upper cervical neural structures.

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Complications

Complications vary widely but may include:

Degenerative arthritis

Joint contractures

Spinal stenosis

Cervical instability

Scoliosis

Kyphosis

Neurologic compromise

Respiratory restriction

Limb deformity

Leg-length discrepancy

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Patient Monitoring

Follow-up should assess:

Growth

Developmental milestones

Body proportions

Neurologic status

Spinal alignment

Joint range of motion

Contractures

and

Limb deformity.

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Key Principle

Short stature is defined as height below approximately the 3rd percentile for age, but the cause may range from normal familial or constitutional variation to significant skeletal disease.

The most important orthopaedic causes are:

Skeletal dysplasias, which produce intrinsic abnormalities of cartilage and bone growth and often cause disproportionate short stature.

Evaluation should determine:

Body proportions, growth pattern, neurologic status, spinal deformity, joint contractures, and limb alignment, supported by targeted radiographs and genetic evaluation.

Orthopaedic treatment is directed primarily toward:

Maintaining function, correcting deformity, treating spinal instability or stenosis, and managing early joint degeneration, rather than simply increasing height.