Osteogenesis imperfecta is a genetic disorder caused by mutations in COL1A1 and COL1A2 genes affecting type 1 collagen. It is characterized by fragile bones that fracture easily, skeletal deformities, blue sclera, and dentinogenesis imperfecta. There are several classifications of OI based on inheritance, clinical features, and severity. Management involves medications like pamidronate to increase bone density and reduce fractures, bracing and surgery to correct deformities, and physical therapy to aid mobility. Genetic testing can confirm the diagnosis.

1. OSTEOGENESIS
IMPERFECTA
BY-
Dr. Ummul Barka Safa
House Surgeon (2018)
Department of Orthopaedics
DCMS.

2. Osteogenesis Imperfecta is a genetic
disorder of the connective tissue
resulting from mutations in COL1A1
and COL1A2 genes that code for
type 1 collagen. All tissues containing
type 1 collagen are affected.
BONES & LIGAMENTS: Structurally
incompetent bones vulnerable to
fractures, skeletal deformities,
generalised osteoporosis, conductive
hearing loss. Kyphosis or scoliosis or
both.
SCLERA: Blue sclera
TEETH: Fragile opaque teeth
(Dentinogenesis Imperfecta)
U

3. TYPE INHERITANCE SCLERAE CLINICAL FEATURES
TYPE I
A- Normal teeth
B- Dentinogenesis
imperfecta
Autosomal dominant Blue
Mildest form. Presents
at preschool age.
Hearing deficit in 50%.
TYPE II Autosomal recessive Blue
Lethal in perinatal
period.
TYPE III Autosomal recessive Normal
Fractures at birth.
Progressively short
stature. More severe
survivable form.
TYPE IV
A- Normal teeth
B- Dentinogenesis
imperfecta
Autosomal dominant Normal
Moderately severe.
Bowing bones and
vertebral fractures
common. Hearing normal.
SILLENCE CLASSIFICATION OF OI (SIMPLIFIED)

4. TYPE V
Hypertrophic callus after fracture. Ossification
of IOM between radius & ulna and tibia & fibula.
TYPE VI Moderate severity. Similar to type IV.
TYPE VII Associated with rhizomelia and coxa vara.
The only two characteristics present in all patients of osteogenesis imperfecta are
Fractures &
Generalised osteoporosis
These 3 additional types do not have Type 1 collagen mutation but have
abnormal bone on microscopy and a similar phenotype.

5. Clinical manifestations:
Protean and determined by individual pattern of involvement.
In type II, multiple fractures occur from minimal trauma at the time of delivery, usually
fatal due to intra cranial haemorrhage or respiratory insufficiency due to incompetence
of the rib cage.
In non lethal types, bone fragility is the exceptional feature. Recurrent fractures at
multiple sites often with trivial trauma are a common finding.
Progressive long bone deformity due to fracture malunion or due to underlying
abnormalities of collagen.
Growth is arrested due to multiple micro fractures at the epiphyseal ends.
In later life, joint degeneration due to long standing malalignment is a common
consequence resulting in painful osteoarthritis requiring total joint replacement.

6. RADIOGRAPHIC FINDINGS:
Thin cortices of long bones due to
generalised osteopenia.
Fractures at multiple stages of
healing.
Proximal femoral shepherd’s crook
deformity.
Protrusio acetabuli.
Wormian bones in skull - non specific.
Popcorn calcification in bones.
Biconcave vertebrae.

7. Prenatal ultrasound:
Useful in type II and type III forms.
Detects Limb length abnormalities at 15-18 weeks
Bowing of long bones.
Shortened long bones especially femur.
Multiple rib fractures.
Super visualisation of intracranial contents due to
decreased calvarial ossification.
The skull may compress/deform with transducer
pressure.
LAB DIAGNOSIS:
Serum calcium, phosphorus may be
normal.
Confirmatory results can only be
obtained through genetic analysis of
disease causing genes
(COL1A1, COL1A2)

8. MANAGEMENT
MEDICAL MANAGEMENT:
PAMIDRONATE: Mainstay of OI treatment.
Increases cortical thickness by inhibiting
osteoclastic bone resorption. Cyclic IV
pamidronate therapy at the dose of 6-9
mg/kg body weight shows reduction in bone
pain and fracture rate. Increase in bone
density and vertebral height seen. ZEBRA
STRIPE SIGN seen on x ray.
GROWTH HORMONE: Stimulate osteoblast
functions.
BONE MARROW TRANSPLANT:
Introducing normal marrow stem cells that
could potentially differentiate into
osteoblasts. Limited use.
Physiotherapy, walking aids and
orthotics to maximise mobility.
Protective bracing to prevent fractures and
aid in ambulation.
Infants with birth fractures need only careful
supportive handling to prevent further injury.
External splinting may be used for a week
or two if the fracture is unstable.
Light weight plastic and metal HKAFO are
used to reduce incidence of lower extremity
fractures, to allow patients to stand or walk.
Use of motorised wheelchairs in non
ambulatory patients.

9. SURGICAL MANAGEMENT:
OBJECTIVES:
To correct deformities which inhibit function.
To prevent fractures and refractors.
To restore anatomical axes of long bones and
correct limb length discrepancy.
Intra medullary fixation is preferred.
Plates and screws are not used as they can
cause stress fractures at the end of these plates
or through screw holes.
Avoid excessive immobilization at any age as it
can aggravate osteopenia and further increases
risk of fractures.

10. SURGICAL MANAGEMENT:
Indicated if there are recurrent fractures
induced by a deformity
Sofield & Millar’s multiple osteotomies,
realignment of fragments and medullary
nail fixation for long bones.
Bailey & Duval’s elongating telescoping
medullary rods.
Fassier-Duval telescoping rods -
percutaneous placement using k-wire
guides.
SPINE:
If curvature >45°, anterior decompression
and posterior fusion is done.
Caption

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