Chapter 43
Alterations of Musculoskeletal
Function in Children
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Musculoskeletal Alterations
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Overview
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Congenital
• Clubfoot
Hereditary
• Muscular dystrophy
Acquired
• Legg-Calvé-Perthes
May be acute, chronic, or terminal
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Bone Formation
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Bone formation begins in two phases at about
the eighth week of gestation
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Delivery of bone cell precursors to sites of bone
formation
Aggregation of the bone cell precursors at primary
centers of ossification
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Bone Formation
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Intramembranous formation
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On or within the mesenchyme
Endochondral formation
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Cartilage anlage
Perichondrium
Periosteal collar
Secondary centers of ossification
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Bone Formation
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Bone Growth
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Until adult stature achieved, bone growth
occurs at the epiphyseal plate through
endochondral ossification
Epiphyseal closure
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Unites the metaphysis and the epiphysis
Occurs earlier in females than males because of
earlier puberty in females
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Bone Growth
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Factors affecting bone growth
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Growth hormone (secreted by pituitary)
Nutrition
General health
Many growth factors and regulators (fibroblast
growth factor)
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Skeletal Development
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In the newborn, the entire spine is concave
anteriorly (kyphosed)
In the first 3 months of life, the cervical spine
begins to arch (lordotic)
Curve of lumbar spine develops with sitting
Compared to adult, a newborn has a large head,
long spine, and short extremities
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Skeletal Development
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Genu varum (peaks by 2½ years)
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Genu valgum (peaks by 5-6 years)
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Occurs in all newborns due to intrauterine stress
Bowleg
Knock-knees
Persistence past peak times is pathologic
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Muscle Development
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
Between birth and maturity, muscle nuclei in
the body increase 14 times in boys and 10
times in girls
The composition and size of muscles vary
with age
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Congenital Defects
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Syndactyly
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Webbing of the fingers
Fusion of the soft tissues of the fingers
True syndactyly also includes fusion of the bones and
nails
Vestigial tabs
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Extra digit
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Congenital Defects
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
Anomalies on the medial or radial aspect of
the arm often associated with abnormalities
of blood, heart, or kidneys.
Lateral or ulnar-sided defects are less often
associated with systemic anomalies and are
far more rare
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Syndactyly
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Congenital Defects
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Developmental dysplasia of the hip
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Formerly: congenital dislocation of the hip
Abnormality of the proximal femur, acetabulum, or
both
Risk factors
• Female, metatarsus adductus, torticollis,
oligohydramnios, first pregnancy, and breech
presentation

The hip can present as subluxated, dislocatable,
or dislocated
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Congenital Defects
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Developmental dysplasia of the hip
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Manifestations
• Asymmetry of gluteal or thigh folds
• Limb length discrepancy
• Limitation of hip abduction
• Positive Ortolani sign
• Positive Barlow test
• Positive Trendelenburg gait
• Pain
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Developmental Dysplasia of the Hip
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Congenital Defects
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Deformities of the foot
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Metatarsus adductus (forefoot adduction)
• Mild, moderate, or severe (degree of deformity and
flexibility)
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Equinovarus deformity (clubfoot)
• Positional equinovarus
• Idiopathic congenital equinovarus
• Tetratologic equinovarus
• Pes planus (flat foot)
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Congenital Defects
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Treatment
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Braces
Sequential casts
Surgery
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Osteogenesis Imperfecta
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“Brittle bone disease”
Defect in collagen production
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Bone and vessel collagen
Sillence classification
Results in osteoporosis, bowed and deformed
limbs, short stature, spine curvature, and bluish
sclera
Can be evident before birth (in utero fractures)
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Osteogenesis Imperfecta
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Severe
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
Child may be stillborn or die soon after birth;
intrauterine fractures
Mild


May not be diagnosed until child begins to walk
May be mistaken for child abuse
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Osteogenesis Imperfecta
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Rickets
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
Disorder causing mineralization failure, “soft”
bones, and skeletal deformity
Causes
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Insufficient vitamin D
 Insensitivity to vitamin D
 Renal wasting of vitamin D
 Inability to absorb calcium or vitamin D in the gut
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Rickets
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Scoliosis
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Rotational curvature of the spine
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Nonstructural
• Curvature is from a cause other than the spine
Structural
• Curvature associated with vertebral rotation
• Skeletal abnormalities, neuromuscular disease, trauma,
extraspinal contractures, bone infections of the
vertebrae, metabolic bone disorders, joint disease, and
tumors
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Scoliosis
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Osteomyelitis
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Often associated with septic arthritis because
infant’s bone has blood vessels that perforate
the growth plate
In children frequently begins as a blood abscess
in the metaphysis of the bone
In adolescents and adults may involve the
vertebrae
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
Back pain for several weeks may be only complaint
This age group is less often affected than younger
populations
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Osteomyelitis
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Much less common after the epiphyseal
plates are closed, except in the vertebral
body
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
Infection may develop in any part of a bone, and
abscesses spread slowly
Destruction of the cortex in a localized area may
result in a pathologic fracture
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Osteomyelitis
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Infection spreads under the periosteum and
along the bone shaft or into the bone marrow
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Sequestra
• Sections of dead bone from periosteal separation
 Involucrum
• Periosteal new bone
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Osteomyelitis
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Juvenile Rheumatoid Arthritis
(JRA)
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Childhood form of rheumatoid arthritis
The basic pathophysiology of JRA is the
same as the adult form
One difference is the mode of onset
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Arthritis in fewer than five joints
Arthritis in more than five joints
Systemic disease
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Juvenile Rheumatoid Arthritis
(JRA)
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Differences in JRA and adult RA
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Large joints are affected
Subluxation, ankylosis of the cervical spine
Joint pain is not as severe
Positive antinuclear antibody test
Chronic uveitis
Low detection of rheumatoid factor
Limited subcutaneous rheumatoid nodules
• Common in heart, lungs, eyes, and other organs
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Osteochondrosis
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Avascular diseases of the bone
Legg-Calvé-Perthes disease
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Interrupted blood supply to the femoral head
Self-limiting disease
Deformation due to ischemia is permanent
Osgood-Schlatter disease
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Tendinitis of the anterior patellar tendon and
osteochondrosis of the tubercle of the tibia
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Legg-Calvé-Perthes Disease
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Cerebral Palsy
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

A static disorder of muscle tone and balance
caused by an ischemic insult to the brain
Perinatal disorder
Disease patterns
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Hemiplegia, diplegia, quadriplegia
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Muscular Dystrophies
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
Group of disorders that cause degeneration
of skeletal muscle fibers
The muscular dystrophies cause progressive,
symmetric weakness, and wasting of skeletal
muscle groups
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Duchenne Muscular Dystrophy
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Most common muscular dystrophy
X-linked recessive inheritance
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Deletion of segment of DNA or single gene defect
on short arm of the X chromosome
Duchenne muscular dystrophy gene
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
Encodes for the dystrophin protein
Dystrophin mediates the anchorage of the actin
cytoskeleton of the skeletal muscle fiber to the
basement membrane
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Duchenne Muscular Dystrophy
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Manifestations appear by 3 years of age
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Slow motor development
Progressive weakness
Muscle wasting
Sitting and standing are delayed
The child is clumsy, falls frequently, and has
difficulty climbing stairs
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Muscular Dystrophy
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Muscular Dystrophies
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Becker muscular dystrophy
Fascioscapulohumeral muscular dystrophy
Scapuloperoneal muscular dystrophy
Limb girdle muscular dystrophy
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Bone and Muscle Tumors
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Nonossifying fibroma
Simple bone cysts
Aneurysmal bone cysts
Osteoid osteoma
Fibrous dysplasia
Osteosarcoma
Ewing sarcoma
Rhabdomyosarcoma
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Nonaccidental Trauma
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“Corner” metaphyseal fractures
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Long bone fractures caused by a twisting force
Transverse tibial fractures are the most common
Associated with child abuse, but osteogenesis
imperfecta must be ruled out
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Nonaccidental Trauma
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