Osteogenesis Imperfecta

Dr Osama Farouk Abdulaziz

M.B.B.Ch ,MSc, EBOT

Osteogenesis Imperfacta

Hereditary condition resulting from a decrease in the amount of normal Type I collagen

Type I collagen ( important for )BoneLigamentsTeethWhite ScleraSkin

Type I collagen deficiency can result from  decreased collagen secretion production of abnormal collagen 

Manifest by increase bone fragility low bone mass ( Osteopenia )

Both Autosomal dominant and Autosomal recessive forms

Can be severe or mild (Tarda )

Osteogenesis Imperfecta

Orthopaedic manifestations  Bone fragility and fractures

fractures heal in normal fashion initially but the bone is does not remodelcan lead to progressive bowing

ligamentous laxityShort statureScoliosisCodfish vertebrae (compression fx)

Basilar invagination  Olecranon apophyseal avulsion fx

Non-Orthopaedic manifestations

Blue sclera

Hearing loss less frequent than generally suspected

Dentinogenesis imperfecta brownish opalescent teeth

Wormian skull bones (puzzle piece intrasutural skull bones) 

Symptoms

Mild casesmultiple fractures during childhood 

Severe cases present with fractures at birth and can be fatal

Number of fractures typically decreases as patient ages and usually stops after puberty But deformity persist.

Basilar invagination  Brain Stem dysfunction apnea, altered consciousness, ataxia, or myelopathyusually in third or fourth decade of life, but can be as early as teenage years

Physical exam

Multiple fractures leads to

Saber shin appearance of tibia 

Bowing of long bones 

Scoliosis

Sillence Classification of Osteogenes Imperfecta (simplified)

Type IMildest form.  Presents at preschool age (Tarda).

Autosomal dominant

blue scleraHearing deficit in 50%.

Divided into type A and B based on tooth involvement

Type IIAutosomal recessiveBlue scleraLethal in perinatal period

Type IIIAutosomal recessive Normal sclereaFractures at birth. Progressively short stature. Most severe survivable form

Type IVAutosomal dominant normal Moderate severity. Bowing bones and vertebral fractures are common.Hearing normal. Divided into type A and B based on tooth involvement

Type V   Hypertrophic callus after fracture. Ossification of IOM ( radius/ulna and tibia/fibula )

Type VI   Moderate severity. Similar to type IV

Type VII Associated with rhizomelia and coxa vara

Type V, VI, VII Added to the original classification system .No Type I collagen mutation But have abnormal bone on microscopy and a similar phenotype

Radiographs

Thin cortices

Generalized osteopenia

Long bone thin and bowed

Pelvis may show acetabular protrusion

Fractures that are at different stages of healing

The vertebra maybe biconcave.

Diagnosis Diagnosis is based on family history associated

with typical radiographic and clinical features No commercially available diagnostic test( variety of genetic

mutations )

laboratory values are typically within normal range

Possible methods include Fibroblast culturing to analyze type I collagen (positive in 80%

of type IV) can be used for confirmation of diagnosis in equivocal cases

Collagen analysis of a punch biopsyIliac crest biopsy which shows a decrease in cortical widths

and cancellous bone volume, with increased bone remodeling.

Treatment

Fracture

Bone Deformity

Scoliosis

Prevention

Teratment

Treatment of Fractures

Fracture prevention

Early bracing Decrease deformity.Stabilize lax joints.Decrease fractures incidence.

Bisphosphonates  

Growth hormone Clinical studies showed no increase in bone mass

Bone marrow transplantation 

BisphosphonatesPrevent bone mass loss and decrease bone resorption by suppressing the

activity of osteoclasts. Indications

OsteoporosisMetastatic bone diseaseMultiple myelomaPaget's diseasePolyostotic fibrous dysplasiaTotal joint arthroplasty to prevent osteolysis Early stage avascular necrosis Osteogenesis imperfecta

ContraindicationsSevere renal diseaseLumbar fusion decreased spinal fusion rates Hypersensitivity.Pregnancy.

Side Effects & ComplicationsJaw osteonecrosis Atypical subtrochanteric and femoral stress fractures    Radiographic changes consistent with osteopetrosis

Bisphosphonates in O I

Indicated in most cases of OI to reduces fracture rate and pain

Combined with calcium and vitamin D

Increase cortical thickness by inhibiting osteoclasts

Does not affect development of scoliosis

Treatment is less effective after completion of growth.

Pamidronate Injectable bisphosphonate (Cyclic Intravenous )

Increases cortical bone thickness Increase bone mass and density. Decreases the incidence of fractures. Relieves chronic bone pain. Increases activity levels. Decreases the reliance on mobility

aids. Increases the height of the collapsed vertebral bodies.

BUT

Not decrease the incidence of scoliosis. Zebra lines

Radiographically Pamidronate therapy creates growth lines in the bone

Bone marrow transplantation Used with some success Introduces normal marrow stem cells that

could potentially differentiate into normal

osteoblasts, Problems of graft rejection and graft versus

host reactions limit this approach.

Fracture treatment Nonoperative child is less than 2 years

treat as child without OI

OperativeFixation with Telescoping rodes patients > 2 years

allow continued growth

Treatment of Long Bone Deformities

Realignment Osteotomy with rod fixation (Sofield-Miller procedure) 

Indicated in severe deformity to Correct the deformityReduce fracture rates

Techniques include Nontelescopic devicesTelescopic devices

Treatment of Scoliosis

Observation  Curve less than 45 ° Bracing is ineffective

Operativeposterior spinal fusion  

Indications for curves > 45 ° in mild forms and > 35 ° in severe forms

TechniqueChallenging due to fragility of bonesUse allograft instead of iliac crest autograftLarge blood loss

Thank You