Osteogenesis Imperfecta

Osteogenesis imperfecta

• Inherited disorder of connective tissue - type 1 collagen

  • Collagen mutation results in fragile bones

• Aka brittle bone disease

• No cure

Pathophysiology of types I-IV

• Defect in collagen synthesis

• Collagen fibers fail to mature beyond the reticular fiber stage

• Osteoblasts have normal or increased activity, but fail to produce and organize the collagen

Pathophysiology of type V

• Lamellar organization in an irregular mesh-like pattern

Pathophysiology of types VI, VII, VIII

• Normally developed type I collagen fibers, but can’t be translated into bone

Sillence classification

• Uses a numeric system to delineate the different subtypes of OI

• 11 subtypes

Mild OI

Types I, IV

• Type I most common

Characteristics of mild OI

• Normal/near normal stature

• Bone fragility (fewer fractures over lifespan)

• Minimal to no bone deformity

• Blue or gray sclerae

• Normal life expectancy

• May have dentinogenesis imperfecta

• Hearing loss common in adulthood

Functional ability of mild OI

• Ambulates independently without assistive devices in most cases

• Temporary mobility aids after fractures

• Participates in age-appropriate activities with fracture precautions (no contact sports)

• Normal lifespan

PT focus for mild OI

• Safe mobility

• Fitness

• Posture

• Education on activity modification (post fx)

Moderate OI

Types V, VI, VII, XII

Characteristics of moderate OI

• Moderate bone fragility w/ recurrent fractures

• Variable short stature (often below average but not extreme)

• Bone deformity - typically bowing of long bones

• May have scoliosis, vertebral compression fractures

• Ligamentous laxity and muscle weakness

• Hearing loss in adolescence/adulthood

• Generally normal to slightly reduced lifespan

Functional ability in moderate OI

• Many ambulate - may require bracing (KAFOs, HKAFOs) or occasional assistive devices (walker, crutches, or wheelchair for distance)

• Frequent fractures = limit endurance and participation

• Stature usually shorter than peers

• Functional independence possible w/ adaptations

PT focus for moderate OI

• Strengthening

• Joint protection

• Adaptive equipment

• Endurance training

Severe OI

Types II, III, VIII, IX, X, XI

Characteristics of severe OI

• Severe bone fragility - multiple fractures at birth or infancy

• Very short stature

• Significant bone deformities (long bone bowing, scoliosis, chest wall deformity)

• Type II: perinatal lethal

• Type III: most severe survivable form, progressive deformities, wheelchair dependence

• Dentinogenesis imperfecta

• Respiratory complications often limit lifespan

Functional ability of severe OI

• Most require wheelchair for mobility

  • Some = limited household ambulation with orthotics and assistive devices

• Progressive deformities and recurrent fractures limit standing/walking ability

• Independence in self care achievable with adaptations & equipment

PT focus for severe OI

• Safe transfers (caregiver or patient training to decrease risk of fx)

• Respiratory care

• Supported mobility (wheelchair skills, standing programs)

• Maximizing participation

Signs/symptoms associated with OI

• Lax joints

• Weak muscles

• Osteoporosis

• Recurrent fractures

• Bowing of long bones

• Scoliosis

• Blue sclerae

• Dentinogenesis imperfecta (Graying of teeth w/ frequent cracking & decaying)

• Deafness

• Hernias

• Easy bruising

• Excessive sweating

Progression of OI

• Dependent upon type

• Dependent upon fracture management/healing

• Growth patterns play a role in subsequent impairments

• Many children use assistive devices for mobility to prevent further fx & remain functional

Medical management of OI

• Biophosphonates inhibit osteoclast activity, decreasing normal bone turnover

• Vitamin D assists w/ calcium absorption

• Bone marrow transplant may improve collagen and mineral content

• Surgery:

  • Intramedullary rods: telescoping rods can be adjusted with growth

    • Provides internal stability, deformity correction, and fx reduction & promotes proper alignment

  • Spinal fusion: seen w/ scoliosis especially to point where it is affecting pulmonary function

• Often casted following surgery: resume WB asap to promote bone growth

PT evaluation for OI

• History and fracture history

• Gross motor development/timing of milestones - standardized assessment

• ROM/strength

  • AROM safer than passive

  • Caution w/ MMT; may use observational assessment instead

• Posture

• Endurance

• Gait/mobility

• Coordination/balance

• Pain

• Assistive devices/bracing

Safe handling techniques DOs

• Handle gently at broad surface areas

  • Lift under buttocks and shoulders together to distribute support

• Support head, trunk, and extremities simultaneously

  • Use pillow under infant to lift

• Soft padding during positioning, transfers, or therapy

• Encourage independent mobility/movement

• Keep trunk and limbs in midline position

• Carry infants close to your body

Safe handling technique DONTs

• Lifting by underarms, limbs or rib cage

• Sudden, jerky movements

• PROM or manual assistance

• Twisting or segmental separation of trunk

• Grasping or lifting through fingertips (utilize whole hand)

PT goals for children w/ OI

• Family education

• Safe weight bearing

• Aerobic conditioning

• Strengthening in a safe environment (body-weight, open chain light resistance)

• Maximizing gait and functional independence

• Interdisciplinary approach

PT management for children w/ OI

• Education on fracture care and safe handling

• Age-appropriate developmental skills

• Weight bearing activities to improve bone density

• Positioning

  • Seating

  • Standing frames

• Good skeletal alignment

• Mobility

  • Alternative mobility early

• Strengthening

• Aerobic activity

• Maximize independent mobility and function

Whole body vibration for children w/ OI

• Good results

• Contraindicated in those with telescoping rods or joint subluxations

Aquatic therapy for children w/ OI

• Safe, gravity eliminated environment

Take home points for PTs working with children w/ OI

• Positioning

• Prevention of fractures

• Increase bone density

• Safe mobility

• Developmental and functional skills