A 9-year-old boy who sustained a supracondylar fracture of the humerus two years ago, treated elsewhere in a cast, now presents with his forearm deviated medially and limited elbow function. His carrying angle measures 20 degrees of varus. The most likely diagnosis is:

• A Cubitus valgus from growth arrest of the lateral condyle
• B Cubitus varus (gunstock deformity) from malunion of the supracondylar fracture ✓
• C Congenital radial head dislocation
• D Physeal bar formation of the medial condyle with overgrowth

Explanation

Malunion of a paediatric supracondylar fracture, typically with medial tilt and rotation of the distal fragment, produces cubitus varus, the gunstock deformity, which is the commonest late deformity of this injury. Cubitus valgus instead follows malunion or nonunion of a lateral condyle fracture and carries the risk of tardy ulnar nerve palsy. Corrective osteotomy of the distal humerus is the standard treatment once the deformity is established, usually undertaken near skeletal maturity.

Reference: Apley and Solomon's System of Orthopaedics and Trauma, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.