Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

Featured on Channel NewsAsia

Short Stature

Basics
Description
  • Short stature is defined as height under the 3rd percentile for age of the general population.
  • Many causes for short stature exist; orthopaedic causes are addressed here.
    • Most common cause overall is familial or constitutional short stature
    • The most common orthopaedic cause is osteochondrodysplasia, a group of skeletal disorders (>600 types) characterized by an intrinsic abnormality in the growth and remodeling of cartilage and bone
  • Diagnosis usually is apparent from birth or early childhood.
  • Classification:
    • International Classification of Osteochondrodysplasia most widely accepted
    • According to body segment most severely affected: Short limb, short trunk
    • According to area of extremity involved: Epiphyseal, metaphyseal, diaphyseal
      • Patients with epiphyseal involvement are most likely to have contractures and arthritis because of involved joint surfaces.
      • The term rhizomelic often is used when extremity shortening is greatest in proximal segments, as in achondroplasia.
  • Synonym: Dwarfism, defined as disproportionate short stature
Epidemiology
Incidence
~1 per 3,000-1 per 5,000 live births.
Risk Factors
  • Family history
  • Consanguinity
  • Regionally concentrated dysplasias (e.g., diastrophic dysplasia in Finland, metaphyseal dysplasia in Amish communities)
Genetics
  • Most dysplasias are transmitted autosomally as dominant or recessive traits.
  • However, many affected persons acquire the disorder as a new mutation and may pass it on to their children.
  • Genetic testing is becoming available for many disorders and may be useful in family planning when the history is positive.
Etiology
  • A defect in the locus for the fibroblast growth factor receptor accounts for achondroplasia.
  • The gene for the cellular sulfate transporter accounts for diastrophic dysplasia.
  • Mucopolysaccharidoses are the result of enzyme deficiencies in the pathway of mucopolysaccharide metabolism.
  • Not all causes are identified.
Associated Conditions
  • Neurologic and respiratory symptoms, owing to spinal deformity
  • Mental retardation in Hurler syndrome
  • Hip dysplasia
  • Clubfeet in diastrophic dysplasia and spondyloepiphyseal dysplasia
  • Scoliosis
Diagnosis
Signs and Symptoms
  • Achondroplasia:
    • Most common skeletal dysplasia
    • Midface hypoplasia
    • Rhizomelic dwarfism
    • Frontal bossing
    • Delay in motor milestones
    • Thoracolumbar kyphosis
    • Spinal stenosis (mostly lumbar)
    • Overweight
    • Narrowed foramen magnum
    • Height usually <50 inches
  • Multiple epiphyseal dysplasia is 1 of the most common dysplasias.
    • Autosomal dominant with disturbed ossification in many epiphyses
    • Mild short stature, so may not present until later in childhood
    • Short limbs
    • Irregular epiphyseal ossification with deformity
    • Hips, knees, and ankles most severely involved
    • Joint pain
    • Decreased ROM
    • Prominent joints
    • Extremity angular deformities
    • Final height: 57-67 inches
  • Hypochondroplasia is an autosomal-dominant, mild, short-limb dwarfism.
    • Severe cases share many features with achondroplasia.
    • Mild frontal bossing
    • No midface hypoplasia
    • Symmetric shortening of extremities
    • Mild kyphosis and lordosis
  • Diastrophic dysplasia is a rhizomelic dwarfism.
    • Autosomal recessive transmission
    • Cauliflower ear
    • Major joint contracture
    • Hitchhiker (abducted) thumb
    • Foot deformity
    • Scoliosis
    • Cervical spina bifida with kyphosis
  • Mucopolysaccharidoses:
    • Joint contractures
    • Organomegaly
    • Often cataracts
    • Sometimes developmental delay
  • Multiple osteocartilaginous exostoses:
    • Autosomal dominant
    • Mild short stature
    • Local impingement on tendons, nerves, spinal canal
    • Deformity of extremities
    • Leg-length discrepancy
    • Risk of malignant degeneration in 1%
  • Spondyloepiphyseal dysplasia:
    • Cervical spine instability
    • Scoliosis
    • Joint contractures
    • Stiffness at hip and knee
  • Down syndrome:
    • Simian crease
    • Pes planus
    • Typical facies
    • Developmental delay
    • Ligamentous laxity
  • Turner syndrome:
    • Single X-chromosome
    • Females only
    • Cubitus valgus
    • Webbed neck
    • Delayed sexual development
Physical Exam
  • The patient should be examined for proportionality and physical maturity.
  • To make the diagnosis of skeletal dysplasia, it is important to know the following patient information:
    • Length at birth
    • Current height and percentile
    • Body proportion by comparing limb and trunk length ratio
    • Dysmorphism (morphologic variations of bone and soft tissue that may characterize disorder)
    • Complete neurologic examination to rule out stenosis or instability
    • Quantitated ROM and contractures
    • Examination for angular disturbances of the limbs and for scoliosis and kyphosis of the spine
Tests
Lab
  • The following tests usually are not indicated, but they can be useful to rule out other conditions if suspected:
    • Chemistry profile
    • Endocrine evaluation
    • Urine workup for storage disorder
Imaging
  • Radiographic evaluation should include:
    • Lateral skull and cervical spine
    • Lateral lumbar spine
    • AP film of the pelvis
    • AP film of the hand and wrist
Pathological Findings
  • Vary with the different types of disorder.
  • Most dysplasias show alterations in cartilage, ligament, and tendon.
Differential Diagnosis
  • Consult with a geneticist or endocrinologist.
  • Consider other alternatives:
    • Constitutional short stature
    • Malnutrition
    • Hormonal disorder
    • Chronic illness
    • Chronic steroid use
Treatment
General Measures
  • Orthopaedic management of patients with osteochondrodysplasia is mainly symptomatic, correcting and achieving alignment and stability.
    • Evaluate and treat cervical spine instability with collar or fusion, if indicated.
    • Decompress neurologic claudication from spinal stenosis, if indicated.
    • Document and follow scoliosis and kyphosis.
    • Accurate genetic counseling is indicated.
    • Recognition and treatment of musculoskeletal abnormalities and intrinsic medical problems are needed.
    • With age, many patients need powered devices for transport because arthritis or spinal disorder decreases mobility.
    • Growth hormone is not useful for increasing stature.
    • Limb lengthening may gain up to 1 additional foot of height in those with achondroplasia.
Special Therapy
Physical Therapy
Physical therapy will not correct skeletal deformity, but it may improve the patient’s function.
Medication
First Line
No medications are available for skeletal dysplasia at this time.
Surgery
  • Spinal fusion, decompression, and instrumentation are used to correct spinal disorders.
  • Osteotomy is used to correct extremity deformities.
  • Patients with early osteoarthritis from epiphyseal deformity may benefit from joint replacement.
Follow-up
Prognosis
Spinal instability, stenosis, and arthritis frequently are associated with many of the dysplasias.
Complications
  • Degenerative disease of the hips and knees is common.
  • Cervical instability is seen in spondyloepiphyseal dysplasia and mucopolysaccharidoses.
  • Complications vary with the different types of disorder.
Patient Monitoring
Patients should be followed approximately every 6 months to monitor developmental milestones and skeletal deformities.
Miscellaneous
Codes
ICD9-CM
  • 259.4 Dwarfism, nonspecific
  • 756.4 Achondroplasia
  • 756.56 Multiple epiphyseal dysplasia
  • 756.59 Other (Spondyloepiphyseal dysplasia)
Patient Teaching
  • Genetic counseling is indicated.
  • Refer families when a positive history becomes known.
FAQ
Q: How do I make the diagnosis of short stature?
A: It is a statistical definition: Height below 2 standard deviations from the mean for the age. The cause may be determined by physical examination, skeletal survey, and consultation by a geneticist or endocrinologist.
Q: What is the role of growth hormone in short stature?
A: The role varies with the cause. For all skeletal dysplasias, little gain in height occurs. For constitutional short stature, more benefit may accrue. An endocrinologist is best qualified to make recommendations.

Comments are closed.