Madelung Deformity

Madelung’s deformity is a congenital abnormality of the wrist caused by a growth disturbance that retards development of the ulnar and volar portions of the distal radial physis.

The eponym gives credit to Madelung, who described this entity. Carpus curvus, radius curvus, and progressive subluxation of the wrist, manus valgus, and manus furca are other terms used for this condition.

The primary deformity is bowing of the distal end of the radius, which in the most typical form curves in a volar diorection while the ulna continues to grow in a straight line. The distal ends of the radius and ulna are at different levels in the lateral plane. That of the ulna has maintained its original normal position, while that of the radius has curved down to a volar level.

It is the distal end of the radius that is displaced. Becaue of its curvature and growth disturbance, the radius has become short while the ulna has ocntineus to grow normally and has become relatively longer.

Etiology

There are four categories of Madelung deformity

• Posttraumatic:  Following trauma  that disrupts growth of the distal radial ulnar-volar physis
• Dysplastic: Associated with bone dysplasias like multiple hereditary osteochondromatosis, Ollier disease, achondroplasia, multiple epiphysial dysplasias, and the mucopolysaccharidoses . This type can also be seen secondary to sickle-cell disease, infection, tumor, and rickets.
  The most important dysplasia associated with MD, however, is Leri-Weill dyschondrosteosis.
• Chromosomal : As in Turner syndrome
• Idiopathic – Where no cause or association can be found

The exact nature of the pathologic process that causes the disturbance in the growth of the distal radial physis is unknown.

The asymmetrical growth disturbance is similar to that seen in Blount’s disease or tibia vara. Madelung’s deformity is a hereditary disorder, transmitted as an autosomal dominant trait with incomplete penetrance.

Sporadic forms do occur.

It is more common in the female; involvement is frequently bilateral.

Normally, the distal articular surface of the radius is tilted 5 degrees toward its volar surface and 25 degrees toward the ulna, with its dorsal surface and radial margin convex and its volar surface and ulnar border concave.

There are two types of Madelung’s deformity.

• Typical, or regular
• Atypical, or reverse.

In the typical form, the distal articular surface of the radius may tilt toward its palmar surface as much as 80 degrees and ulnarward as much as 90 degrees. In the normal wrist, the proximal row of the carpal bones is arranged in an arc, with its proximal surface forming a convex dome.

In Madelung’s deformity, this dome becomes peaked, its apex resting on the lunate bone. The radius and ulna are separated, with the peak of the carpal bones wedged into the interosseous space. The entire carpus is shifted toward the ulnar and volar side of the wrist. Coalition of carpal bones may be present.

In reverse, or atypical, Madelung’s deformity (which is rare), the distal end of the radius is tilted dorsally, reversing the plane of the distal end of the articular surface with a shift of the carpus toward the dorsal side. The distal end of the ulna then appears to be displaced volarly instead of dorsally.

Genetics

Primary chromosomal association with Madelung deformity has been observed in patients with Turner syndrome (Patients having only one X chromosome). Within families affected by a short stature dysplasia, a mutation has been found in  short stature homeobox-containing gene, SHOX, present on X chromosome.

But families with this mutation and individuals with Turner syndrome and families with a history of MD have been shown to exhibit a variable expression of MD and dyschondrosteosis. This raises a possibility of  a modifier gene on another area of the X chromosome or on an autosomal gene may be involved.

Clinical Features

Deformity of the wrist is the initial presenting complaint; it usually becomes obvious in late childhood or early adolescence, between the ages of 8 and 12 years.

In typical Madelung’s deformity the distal end of the ulna remains in its normal anatomic position and grows distally, causing a visible prominence on the dorsal and ulnar aspects of the wrist. Normally, the radial styloid process is long and is located 1 cm distal to the ulnar styloid. In Madelung’s deformity, the radius is shortened at the wrist; the radial styloid process may be on the same horizontal line as the ulnar styloid or may reach a point proximal to it.

The range of motion of the wrist is limited, especially in dorsal extension and ulnar deviation. Because of the diasthesis between the distal radius and ulna and the displacement of the carpus between the two separated bones of the forearm, pronation and supination of the forearm are also limited; as a rule, supination is definitely decreased, and pronation is impaired to a slight degree.

In reverse Madelung’s deformity palmar flexion of the wrist is decreased, while dorsiflexion is increased. Range of rotatio in of the forearm, especially pronation, is decreased. When it is minimal, madelung’s deformity may be asymptomatic. In moderate or severe deformity, however, pain develops insidiously at the wrist.

Initially it is minimal, disappearing on rest. With progression of the deformity and impingement of the displaced carpus on the distal ulna, the pain increases. Volar displacement of the carpus may cause discomfort in the region of the median nerve and flexor tendons. Weakness of the wrist may result from progressive instability of the joint.

Diagnosis

Characteristic radiographic findings include dorsal and radial curvature of the distal radius; exaggerated palmar and ulnar tilt of the distal articular surface of the radius; pyramiding of the carpal bones; greater length of the ulna as compared with the radius; wide interosseous space; and assumption of a relatively dorsal position by the ulnar head, which appears to be enlarged.

In the differential diagnosis, one should consider the possibility of trauma (dislocation of the distal radioulnar joint), rickets, inflammatory conditions of the wrist such as rheumatoid arthritis, and infection involving the ulnar half of the distal radial physis.

Treatment

Treatment is primarily directed toward the relief of pain and the restoration of function, with cosmetic improvement as a secondary consideration.

The majority of patients with Madelung’s deformity do not require surgical treatment.

Conservative measures consist of curtailing physical activities that may cause forced dorsiflexion of the wrist and wearing a plastic wrist splint to provide support and relieve symptoms.

Surgical treatment is directed toward shortening the ulna, correcting the bowing deformity of the distal radius by wedge osteotomy, stabilizing the carpus, and preventing recurrence of deformity by controlling the asymmetrical growth of the distal radius.

The ulna can be shortened by Milch’s cuff resection in children or Darrach’s resection.

Deformity correction is achieved by either a closing wedge or an opening wedge osteotomy of the distal radius at its metaphyseal-diaphyseal junction.

Fusion of the radial half of the distal radial physis will prevent recurrence of deformity.