Madelung deformity is a growth disorder of the forearm that results in a malpositioned arm and an abnormally long ulna. The patient’s bone formation is disturbed, causing dysostosis, which usually becomes noticeable in adolescence as a result of weight-bearing. The deformity can be corrected surgically.
What is a Madelung deformity?
Madelung deformity belongs to the group of congenital deformities. The clinical picture is characterized by a growth disorder of the forearm, which typically leads to a significant deformity of the arm. The surgeon Otto Wilhelm Madelung first described the deformity in the 19th century. The surgeon is also the namesake of Madelung’s hand deformity, which is clearly distinguishable from Madelung’s deformity. Before Madelung described the growth disorder with resulting malposition of the forearm, six other physicians had already attempted to describe it, for example Dupuytren. The deformity occurs in the context of various symptom complexes and clinical pictures. The ideopathic form of Madelung deformity is extremely rare. In addition to enchondromatoses, syndromes such as Ullrich-Turner syndrome and Léri Weill dyschondrosteosis frequently accompany the deformity.
Causes
Madelung deformity does not appear to occur sporadically but is apparently subject to familial clustering. An autosomal dominant mode of inheritance has been observed several times. The deformity results from a dysostosis caused by impaired enchondral bone formation. During growth, the distal radius metaphysis is left behind on the ulnar and dorsal sides, thus causing the radius to bend and grow shorter than the ulna. In idiopathic Madelung deformity, the ligamentous structure is additionally abnormal due to a Vickers ligament between the proximal carpus and the distal end of the radius, causing subluxation of the carpal row. The abnormal Vickers ligament consists of fibrotic and fibrocartilaginous structures. Patients with dyschondrosteosis Léri Weill therefore regularly suffer from Madelung deformity because they are affected by a deficit of SHOX proteins.
Symptoms, complaints, and signs
The ulna of patients with Madelung deformity protrudes widely dorsally at the wrist. Their radius bends widely ulnar and volar, causing the so-called bayonet deformity with subluxation at the carpus. The mobility of the wrist is limited with a volar or radially tilted joint position. The same is true for forearm rotation, which limits patients primarily in supination and pronation. Dorsal extension and abduction in the ulnar direction are also impeded, so mainly due to bony inhibition. Although the Madelung deformity is one of the congenital deformities, it does not become apparent until adolescence and is apparently absent in childhood. Patients’ first complaints are of the prominent ulna. Most affected individuals initially complain of strain-related difficulties. The Madelung deformity does not always cause symptoms. Some patients even remain asymptomatic throughout their lives. In the long term, however, the Madelung deformity can promote secondary diseases. The most common secondary disease is osteoarthritis, which is promoted by the deformity and the associated incorrect loading of the joints.
Causes
Madelung deformity is usually diagnosed by imaging. The first suspicion of the deformity usually comes to the physician during history taking, after which x-rays are usually ordered. For example, radiographs of the wrist show a severe deformity on the distal surface of the radius joint. The joint appears tilted in the ulnar and volar directions. Imaging also provides evidence of the affected person’s ulna being overlong. In most cases, the x-ray also shows a greatly enlarged gap between the radius and ulna, which often appears wedge-shaped. Sometimes the lunate bone slips into the gap and deforms in a similar wedge-shaped fashion. All other carpal bones are subluxated. The prognosis for patients with Madelung deformity is relatively favorable.
Therapy and treatment
When treating a Madelung deformity, improving joint mobility is the most important goal. In most cases, growth must first be completed before therapy.If the bones stop growing, surgical intervention can take place. Surgical treatment is indicated only if the patient perceives the limitation of movement as an impairment or experiences pain during movement. Surgical intervention used to be shortening of the ulna or Suave-Kapangi-Lowenstein surgery. However, modern medicine applies corrective osteotomies to the distal radius, as this area of the radius is the causative deformity. The Vickers ligament is cut during surgery as a standard procedure to allow the patient to move the wrist without pain in the future. A metaphyseal arcuate corrective osteotomy is performed via an anterior approach during surgery, allowing three-dimensional correction by tilting at the distal radius fragment. Radially inserted Steinmann pins hold the correction in place. After surgery, the affected arm is immobilized by a humeral cast for approximately two months. Surgical correction of the deformity is performed in pediatric hand surgery specialty centers. If the correction takes place before the completion of the growth phase, recurrences usually occur in the course of further growth. Thus, the younger the patient, the more likely a recurrence of symptoms. Because of the risk of osteoarthritis, correction of the deformity may also be appropriate in previously asymptomatic patients.
Prevention
Madelung deformity cannot be prevented because in most cases it is an autosomal dominant inherited deformity. Consequential diseases such as osteoarthritis can be prevented by timely correction.
