Causes / typical injury mechanism: Madelung deformity is a rare congenital malformation caused by disruption of the ulnar volar growth plate of the distal radius. When this malformation is not congenital, it is called a Madelung-like deformity.

Classic history and presentation: The typical patient is an adolescent female who presents with a prominent distal ulna in the affected wrist and may also complain of decreased grip strength or decreased range of motion. The affected hand will be volar displaced. This can be a congenital problem or caused by repetitive trauma (as seen in gymnasts).

Madelung deformity is also seen in patients with Leri-Weill dyschondrosteosis or Turner syndrome.

Prevalence:

• Age – usually seen in early adolescence (ages 8-14 years)
• Sex / gender – more commonly seen in females compared to males (4:1 ratio)

Risk factors:

• Autosomal dominant inheritance
• Genetic alteration of the short stature homeobox (SHOX) gene
• Leri-Weill dyschondrosteosis
• Turner syndrome
• Ollier disease
• Repetitive wrist trauma

Pathophysiology: The inciting factor is not clear when there is early closure of the distal radial physis at the volar ulnar aspect. One potential cause is Vicker's ligament (the ligament running from the distal radius to the lunate) restricting growth at that part of the radius. Improper growth of the radius leads to the ulna being forced out of its proper position.

Grade / classification system: Vender and Watson classification.

• Post-traumatic
• Dysplastic
• Genetic
• Idiopathic