Cubitus varus
Cubitus varus (gunstock deformity) is a malalignment of the distal humerus that results in a change of carrying angle from the physiologic valgus alignment (5-15 degrees) of the arm and forearm to varus malalignment. Historically, it is a complication of supracondylar fractures with a frequency as high as 30%. Its appearance is the major concern, as it causes little functional impairment
Pathology
This deformity results due to malalignment of a supracondylar fracture. Varus alignment can result from collapse of the medial column from comminution. It can also result from an extension and internal rotation of the distal fractured fragment. This deformity is usually static and does not remodel over time.
Complications
An ulnar nerve palsy may sometimes occur from compression of chronic malposition of the triceps.
Radiographic features
Plain radiographs
Plain AP and lateral x-rays of the affected and unaffected elbow should be obtained for comparison and operative planning if surgical correction is desired.
MRI
MRI scans of the elbow may be of value if growth disturbances of the distal humerus are suspected.
Differential diagnosis
Growth disturbances of the distal humerus medial condyle or trochlea.
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