Cubitus varus

Cubitus varus (Opposite: Cubitus valgus) is a common deformity resulting from a Supracondylar fracture of the lower humerus. It can be corrected via a corrective osteotomy of the humerus and either internal or external fixation of the bone until union.

Cubitus varus is not able to be diagnosed until after healing of the prior fracture, as the arm must be in full extension, not flexion, for the deformity to be noticed.

A cubitus varus deformity is more cosmetic than limiting of any function, however internal rotation of the radius over the ulna may be limited due to the overgrowth of the humerus. This may be noticeable during an activity such as using a computer mouse.

Instances in which the medial epicondyle of the distal humerus is malformed due to the inital fracture at the humeral endplate may result in subluxation (snapping) of the ulnar nerve over the medial epicondyle with active flexion and extension of the elbow. In such instances,conductance of the ulnar nerve may be compromised due to chronic irritation, potentially resulting in irreversible ulnar neuropathy.

Cubitus varus is often referred to as 'Gunstock deformity', due to the crooked nature of the healing.