Madelung Deformity

Madelung deformity is a developmental abnormality of the wrist in which the distal radius grows in the wrong shape because part of its growth plate stops working. It is named after Otto Madelung, who described it in the 19th century. The typical patient is an adolescent girl who develops a bent-looking wrist with a prominent bump on the little-finger side (the ulnar head), often in both wrists, with pain and reduced movement.

The simplest way to understand it is to think of the distal radius growth plate as having a corner that fails. The volar (palmar) and ulnar corner of the physis stops growing, while the rest of the radius carries on. The result is a joint surface that tilts towards the ulna and towards the palm, a carpus that slides into the gap that forms, and an ulna that ends up looking too long because the radius has shortened on that side. Running across the front of the failing physis is an abnormal thick band, the Vickers ligament, which tethers the lunate to the volar radius and is central to both the pathology and the surgery.

For the exam, Madelung deformity is a favourite because it links genetics (the SHOX gene and Leri-Weill dyschondrosteosis), growth-plate biology, three-dimensional deformity, and a maturity-dependent treatment decision. Get the classic picture, the Vickers ligament, and the growing-versus-mature treatment split, and you have answered most of what an examiner will ask.

The distal radius normally grows from a physis (growth plate) that contributes most of the length of the radius. In Madelung deformity, the volar-ulnar part of this physis is abnormal and arrests early, while the dorsal-radial part keeps growing. This asymmetric growth twists the distal radius:

• In the coronal plane, the joint surface tilts so its ulnar side is lower - this is increased radial inclination, and it points the carpus towards the ulna.
• In the sagittal plane, the joint surface tilts towards the palm - increased volar (palmar) tilt - so the carpus and lunate are carried forwards (palmar carpal displacement).
• Because the radius shortens on the affected side while the ulna grows normally, the ulna becomes relatively long and its head sits prominent and often dorsal at the wrist.

The carpus adapts to this distorted radius. The lunate sinks into the notch that forms between the tilted radius and the ulna (lunate subsidence), and the proximal carpal row takes on a wedge or pyramid/triangle shape pointing proximally - a classic descriptive sign on the X-ray.

The Vickers ligament is the abnormal structure at the centre of it all. According to PubMed, histopathological study of patients with Leri-Weill dyschondrosteosis and a confirmed SHOX abnormality showed widespread disorganisation of the radial growth plate - the normally neat parallel columns of cartilage cells are disrupted - and confirmed that the Vickers ligament blends with the triangular fibrocartilage complex (TFCC) (Munns et al., Hand Surg 2001, DOI). This abnormal volar tether is thought to bowstring across the volar physis, both reflecting and reinforcing the local growth disturbance.

Not all Madelung deformity has the same cause. It is useful to split it into a genetic/dysplastic group, where the physis is intrinsically abnormal, and an acquired group, where something damages a previously normal physis.

The SHOX gene (short-stature homeobox gene) sits in the pseudoautosomal region at the tip of the X and Y chromosomes. Losing one working copy (haploinsufficiency) causes Leri-Weill dyschondrosteosis, a mesomelic (middle-segment) short-stature dwarfism in which Madelung deformity is the most characteristic limb feature. According to PubMed, SHOX haploinsufficiency accounts for around 80% of genetic causes of Leri-Weill dyschondrosteosis, and SHOX-deficient bone shows a disrupted columnar growth plate with an expanded hypertrophic layer and altered programmed cell death of the cartilage cells - the cellular basis of the deformity (Seki et al., Clin Pediatr Endocrinol 2014, DOI).

There is no single universally used classification, but examiners expect you to be able to categorise by cause and to describe the deformity in a structured way. A practical scheme groups Madelung deformity by aetiology, direction, severity, and radiographic measurement:

The classic story is an adolescent girl (commonly early teens) who notices that her wrists look bent and that there is a bump on the ulnar side (the prominent ulnar head). It is frequently bilateral, and there may be a family history and short stature if there is underlying Leri-Weill dyschondrosteosis.

Symptoms:

• Deformity and cosmetic concern - often the main reason for presenting, especially the prominent dorsal ulnar head.
• Pain - typically ulnar-sided wrist pain, worse with loading and activity, often emerging in adolescence as the deformity matures.
• Stiffness - loss of wrist extension and especially loss of forearm rotation (supination), and loss of radial deviation.
• Weakness of grip in symptomatic wrists.

Examination findings:

• A characteristic wrist contour with the hand looking displaced towards the palm and the ulnar head prominent dorsally (the "bayonet" or step look).
• Reduced range of movement, particularly forearm rotation and wrist extension.
• The forearm may look mesomelically short (shortened middle segment) if there is dyschondrosteosis; check the other wrist and the patient's height.

The single most important decision is skeletal maturity: a growing physis can be modulated, whereas an established deformity in a mature wrist can only be corrected by cutting and realigning bone. Severity and symptoms then refine the plan.

Madelung deformity sits at the crossroads of paediatric hand surgery, genetics, and growth-plate biology, which is exactly why it is a recurring exam topic. It teaches the principle that a physeal growth disturbance produces a predictable three-dimensional bony deformity, and that timing surgery to skeletal maturity changes the whole strategy - growth modulation while the physis is open, correction once it is closed. It also rewards the candidate who looks beyond the wrist: recognising the link with SHOX and Leri-Weill dyschondrosteosis turns an isolated wrist problem into a diagnosis that may need genetic and endocrine input. In practice, the everyday skills it tests - reading the deformity on plain films, deciding who needs surgery, and choosing between ligament release, physiolysis, osteotomy, and salvage - are the same judgements that come up across deformity correction in the upper limb.

According to PubMed, the following studies support the modern, maturity-dependent approach to Madelung deformity.

• No high-level guideline or registry governs Madelung deformity - it is rare, so the evidence base is case series (level IV) and a systematic review of them, and practice is guided by paediatric hand surgery experience rather than randomised trials.
• Consistent global principle: treat symptoms and progression, not the X-ray alone. Mild, painless deformity is observed with serial radiographs everywhere; surgery is reserved for pain, functional loss, or progressive deformity.
• Maturity-based strategy is universal: growth modulation (Vickers ligament release with radial physiolysis, sometimes ulnar epiphysiodesis) in the skeletally immature wrist, and corrective osteotomy (commonly a distal radial dome osteotomy, with ulnar-sided procedures as needed) once mature. Salvage arthrodesis is reserved for severely damaged joints.
• Multidisciplinary input: because of the strong link with SHOX-related Leri-Weill dyschondrosteosis, bilateral disease in a short child prompts genetic and endocrine assessment in addition to orthopaedic care - a point valued internationally.