Osteogenesis imperfecta - type I

Case contributed by Dr Matt Skalski


The clinical presenting symptoms for this study are unknown.

Patient Data

Age: 25 years
Gender: Female

The ribs are gracile (thin/slender), and there is severe osteopenia of all visualized skeletal structures. No fractures are identified.   


All visualized skeletal structures demonstrate gracile bones with severe osteopenia. A rush rod is in place in the left femur with no evidence of complication.

The mid diaphysis of the left femur is mildly deformed from an old, healed fracture. There are several transverse lucent lines extending through the posterior cortex of the mid diaphysis of the fibula with surrounding cortical thickening, indicating stress fractures at this site (looser's zones).

The pelvis is triradiate. 

There is a triradiate deformity of the pelvis, which is a combination of bilateral protrusio acetabuli and caudal migration of the sacrum secondary to softening of the pelvic bones. Again noted are bilateral Rush nails in the femurs, with no evidence of complication.  

As before, all visualized skeletal structures demonstrate gracile bones with severe osteopenia.

Case Discussion

The findings in this case are typical of mild osteogenesis imperfecta (type 1). 

The triradiate deformity of the pelvis (not to be confused with the triradiate cartilage in the pediatric pelvis) is a common finding in OI, but may also be see in other conditions such as Paget disase of bone, osteomalacia, rickets, inflammatory arthritidities (eg RA), or a number of other conditions that may have bilateral protrusio acetabuli

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Case information

rID: 29279
Published: 14th May 2014
Last edited: 2nd Jan 2019
Inclusion in quiz mode: Included

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