Musculoskeletal Disorders and Conditions in Children Frank Caruso PA-C, MPS, EMT-P Skin Bones, Hearts & Private Parts 2019 Musculoskeletal Alterations • Overview: – Congenital • Clubfoot – Hereditary • Muscular dystrophy – Acquired • Legg-Calvé-Perthes – May be acute, chronic, or terminal – Common pediatric fractures Embryonic Development of Bone • Ossification is the term for the formation of bone • There are two ways that bone can ossify during embryonic development: – Intramembranous ossification – Endochondral ossification Bone Formation • Intramembranous formation: – On or within the mesenchyme (stem cells) – Cranium, facial bones, clavicles and parts of the jaw bone (flatbones) arise from this fetal membrane called a mesenchyme • These bones grow by a process of intramembranous formation of bone (from skeletal tissue) • Endochondral formation: – Cartilage embryonic cells (anlage): Defines the shape of the bone , usually found by 6 weeks gestation – Perichondrium: Contains cells that develop into osteoblasts – Periosteal collar: Osteoblasts that form a collar of bone, around a cartilage model – Secondary centers of ossification: result of the periosteal collar thickening and becoming wider toward the bone ends of the cartilage model. Intramembranous and Endochondral Bone formation • Intramembranous bones are always the flat bones • Endochondral bones include the long, short, and irregular bones • Most bones start off as cartilage and is later replaced by bone – endochondral ossification Intramembranous Ossification • Connective tissue forms in sheets at sites where flat bones will eventually be, highly invested with blood vessels which also contain osteoblasts • Osteoblasts begin laying down the bone, extracellular matrix, forming spongy bone • The osteoblasts get trapped within the hard matrix and then are called osteocytes – this creates a sandwich where the connective tissue sheets are the “bread” and the spongy bone is the “meat” • This then forms the basis which the bone will finish developing. Endochondral Ossification • Bone forms by replacing hyaline cartilage (the embryonic skeleton, early on is mainly made up of hyaline cartilage) • The cartilage is considered to simply be a “model” for the shape the bone should take on, and so it is often referred to as a “cartilaginous model” • This model is for most long, short and irregular bones Bone Growth • Until adult stature achieved, bone growth occurs at the epiphyseal plate through endochondral ossification: – Cartilage cells at the epiphyseal side of the physeal plate multiply and enlarge – As rapidly new cartilage cells form, cartilage cells at the metaphyseal side of the plate are destroyed and replaced by bone • Distal physis in the femur contributes 80% of the overall growth in length in contrast to the proximal physis at the hip contributing only 20% of long bone growth. • Epiphyseal closure: – Unites the metaphysis and the epiphysis – Occurs earlier in females than males because of earlier puberty in females Growth in Diameter of Bone • Occurs by deposition of new bone on an existing bone surface • Bone matrix is laid down by osteoblasts on the periosteal surface – at the same time bone resorption occurs on the endosteal surface – this allows for an increase in the diameter of the medullary cavity which contains marrow and spongy bone Cartilage : Ends of Long Bones • Two regions of growing cartilage can be found at the end of long bones: – Articular cartilage over the free ends of bone – Physeal plate: layer of cartilage between the metaphyhsis and epiphysis: • Retains the ability to form and calcify new cartilage and deposit bone until the skeleton matures roughly one year after sexual maturity (11-15 females, 15-18 males) Bone Formation Bone Growth • Factors affecting bone growth – Growth hormone (secreted by pituitary) – Nutrition – General health – Many growth factors and regulators (fibroblast growth factor) Skeletal Development • 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 Skeletal Development • Genu varum (peaks by 2½ years) – Occurs in all newborns due to intrauterine stress – Bowleg • Genu valgum (peaks by 5-6 years) – Knock-knees • Persistence past peak times is pathologic 5 Adult 2 yrs like yrs Muscle Development • 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 Congenital Defects • Syndactyly: most common congenital defect of the upper extremity: – Webbing of the fingers – Fusion of the soft tissues of the fingers – True syndactyly also includes fusion of the bones and nails • Vestigial tabs: – Extra digits Congenital Defects • 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 Congenital Defects • Developmental dysplasia of the hip (Congenital dislocation of the hip): – 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 Congenital Defects • Developmental dysplasia of the hip – Manifestations: • Asymmetry of gluteal or thigh folds • Limb length discrepancy • Limitation of hip abduction • Positive Ortolani sign • Positive Barlow test • Positive Trendelenburg gait • Pain Developmental Dysplasia of the Hip Congenital Defects • Deformities of the foot: – Metatarsus adductus (forefoot adduction) • Mild, moderate, or severe (degree of deformity and flexibility) – Equinovarus deformity (clubfoot): • Positional equinovarus (in utero positioning) • Idiopathic congenital equinovarus Congenital Defects • Treatment – Braces – Sequential casts – Surgery Osteogenesis Imperfecta • “Brittle bone disease” • Genetic defect in collagen production: – Bone and vessel collagen • Results in: – Osteoporosis – Bowed and deformed limbs – Short stature – Spine curvature – Bluish sclera • Can be evident before birth (in utero fractures) Osteogenesis Imperfecta • Severe – 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 Osteogenesis Imperfecta Rickets • Disorder causing mineralization failure, “soft” bones, and skeletal deformity • Causes: – Insufficient vitamin D – Insensitivity to vitamin D – Renal wasting of vitamin D – Inability to absorb calcium or vitamin D in the gut Rickets Scoliosis • Rotational curvature of the spine: – 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 Scoliosis Evaluation • Is there a curve? • Is it structural? • Is it idiopathic? • How large is the curve? • How mature is the patient? Scoliosis Scoliosis • Lateral curvature of the spine of > 10°: – Small curves are not scoliosis • Thoracic or lumbar spine (occasionally both): – Associated vertebral rotation with kyphosis or lordosis • May be congenital: – Vertebral anomalies • Commonly idiopathic • May be secondary to other disorder: • Cerebral palsy • Muscular dystrophy • Myelomeningocele Idiopathic Scoliosis • Develops in early adolescence: – Male = female in curves < 10° – Female 7X more likely to have significant, progressive curve requiring treatment. – Progression typically girls at age 10-16 years – Not associated with pain • Pain suggests primary condition and requires further evaluation Curve size Girls:Boys 6-10° 1:1 11-20° 1.4:1 >21° 5.4:1 *JBJS 60A:173,1978 Scoliosis • Physical exam: – Forward bending test: • Observe from behind • Elevation of rib cage, scapula or paravertebral muscle mass positive finding – Also assess: • Skin • Leg length • Feet alignment • Neuromuscular status – Beware! • Left side thoracic curves have high incidence of spinal cord abnormalities Scoliosis Is There A Curve? Is There A Curve? Is The Curve Structural? Is The Curve Structural? • Postural curves – Pain – Leg length inequality – Behavioral Is The Curve Structural? • Congenital: – Vertebral anomalies • Neuromuscular: – Cerebral Palsy – Myelomeningocele – Muscular dystrophy – Polio • Miscellaneous: – Post surgical – Marfan syndrome – Trauma Congenital Scoliosis Beware! • Unusual curves: – Left thoracic curves • Unusual symptoms: – Significant pain – Radiculopathy • Unusual findings: – Neurologic deficit – Skin changes – Hair patches (bottom of spine) – Asymmetry of lower extremities How Large is The Curve? How Large is The Curve? • Diagnostic tests: – PA and lateral full- length radiographs with patient standing and knees straight – Measure Cobb angle: • Describe as if patient is being examined from behind Scoliosis Treatment • If angle < 50° at skeletal maturity: – Progression usually ceases • If angle > 60° at skeletal maturity: – Progression into adulthood common and may compromise respiratory function: • Unusual if angle less than 90° and healthy • Back pain may occur in adulthood: – Not usually a major disability Scoliosis