Anteroposterior x-ray of an 8-year-old girl with left ankle pain
Lateral x-ray of the patient
An 8-year-old girl presents with left ankle pain after “stepping wrong” 2 days previously. She has not been able to put full weight on the ankle since the event. The patient appears very small for her age and has a dysmorphic face but is of normal intelligence for her age. Her mother states that her daughter has had more than 30 fractures and several operations before this recent injury. X-rays of the tibia and fibula show a nondisplaced fracture of the fibula. A bowed tibia is also seen on lateral x-ray.
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The physical examination and medical history findings are typical of classic type III osteogenesis imperfecta (OI). Findings of OI include extremely fragile bones and a history of multiple fractures, short stature, bowing of long bones, blue sclera, abnormal skull shape and tooth formation, and hearing loss beginning in the second decade of life. OI is a heritable disorder caused by a decrease in type 1 collagen, which provides tensile strength to bones, skin, tendons, dentin, and sclera.1
The Sillence classification system describes 7 types of OI based on genetic and clinical criteria. Type I (mild) is autosomal dominant with clinical features of blue sclera, mild bone fragility and joint laxity, and a higher incidence of hearing loss. Type I accounts for 50% of all OI. Type II is the most severe form of OI, with fractures occurring at birth, and babies often die in the perinatal period. Those with type I and II OI have very dark blue or gray sclera. Type III is the most severe form of OI in those who survive the neonatal period. Patients may have fractures at birth, frequent fractures throughout childhood, short stature, and a triangular face shape. Those with type IV OI are moderately affected, with fewer fractures and less growth retardation than in type III. Types I and IV are autosomal dominant and types II and III are autosomal recessive. Type V, VI, and VII OI are similar to type IV except for a few characteristic findings. Type V is associated with large hypertrophic callus formation following fracture. Type VI is rare and can be differentiated from type IV by characteristic mineralization on bone biopsy. Type VII is associated with infantile white sclera and coxa vara.1,2
OI is a diagnosis based on genetics, presence of fractures, and other clinical features. Bisphosphonates are commonly used in treatment to help increase bone density, decrease fractures, and improve quality of life in those with OI. Surgical fixation with telescoping rods and realignment osteotomy procedures are used for fracture fixation and deformity correction. Fractures will become less frequent when skeletal growth slows and often cease after puberty. However, most of those with OI will have osteoporosis in adulthood and require treatment to improve bone density.1
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor-in-chief of the Journal of Orthopedics for Physician Assistants (JOPA).
- Osteogenesis Imperfecta Foundation website. www.oif.org. Accessed April 11, 2016.
- Burnei G, Vlad C, Georgescu I, Gavriliu TS, Dan D. Osteogenesis imperfecta: diagnosis and treatment. J Am Acad Orthop Surg. 2008;16(6):356-366.