Ulnar Clubhand (Ulnar Deficiency of Forearm) 

Updated: Nov 24, 2021
Author: Minoo Patel, MBBS, PhD, MS, FRACS; Chief Editor: Harris Gellman, MD 


Practice Essentials

Ulnar clubhand is much less common than radial clubhand and is more appropriately referred to as ulnar deficiencies of the forearm.[1] Most cases are sporadic in occurrence, though genetic syndromes are associated with ulnar dysplasia.[2, 3]

Close to 70% of cases of ulnar clubhand are unilateral. A partial rather than complete absence of the ulna is common. Ulnar shortening with radial bowing and abnormal digits is the classic presentation of this condition, and digital anomalies can be found in close to 90% of cases with postaxial absence of ulnar rays.[4]  The fourth and fifth metacarpals, as well as the capitate, lunate, triquetrum, hamate, and pisiform, are absent or deformed.

Synostosis with the humerus is possible when the ulna is present; radiohumeral synostosis can also be present. The radial head is dislocated in close to 50% of cases.

Radial bowing is produced by the tethering effect of the fibrocartilaginous ulnar anlage, which can also tether the carpus, producing limitation of wrist movement. The radiocarpal joint has a fixed ulnar deviation in these cases. In most cases, however, function is very good, and the carpus can be actively centralized. The presence of a thumb makes for a functional hand, unlike the case for radial clubhands.

In patients with ulnar clubhand, surgery is indicated for the following (see Treatment):

  • Ulnar deviation
  • Anlage
  • Bowing of radius
  • Forearm in less than useful rotation
  • Radial head dislocation
  • Unstable elbow
  • Radiohumeral synostosis

Nonspecific contraindications for ulnar clubhand surgery are as follows:

  • Presence of no or minimal functional deficit 
  • Any surgical risk factor due to associated syndromes
  • Severely affected limb and poor neurologic function


Elliott et al studied 28 patients with posterior congenital dislocation of the radial head and proximal radioulnar fusion to help determine whether they are different clinical manifestations of the same primary developmental abnormality.[5] Of 28 patients studied, 16 had bilateral involvement (eight with posterior dislocation of the radial head only, five with posterior radial head dislocation with radioulnar fusion, and two with radioulnar fusion without dislocation). Nine patients had only left-side involvement, and three had only right-side involvement.

According to Elliott et al, the suggestion of a developmental relation between posterior dislocation of the radial head and proximal radioulnar fusion is supported by the fact that the two anomalies can occur in the same patient.[5] In addition, they noted that both anomalies can be seen in different patients with the same genetic diagnosis, a finding that further supports the notion that these defects are developmentally related.

Oberg et al described the rare combination of right radial and left ulnar deficiencies in two cases.[6]  In one case, there was a history of two separate, distinct episodes of bleeding during early gestation. In the other , there was associated hematoma formation early in development. According to the authors, variation in longitudinal deficiencies is likely related to the timing and duration of an insult during early limb development, and in experimental models, teratogenic insults have been shown to induce ulnar deficiencies earlier in gestation than radial deficiencies.

Nygaard et al evaluated the pressure distribution in the wrist joints with ulnar shortening and lengthening and made the following findings[7] :

  • Compressive forces in loaded wrists were distributed with 67% across the radiocarpal joint and 33% across the ulnocarpal joint
  • Shortening the ulna by 3 mm increased load in the radius to 80%
  • Lengthening the ulna by 1 mm increased its load to 55%

In addition, they noted that load share of the distal radioulnar joint was constant even when the ulna was shortened 3-4 mm.[7] They therefore suggested shortening the ulna by 3 mm, since the increased load in the related joints are constant within a range of –2 to –4 mm.


Most cases of ulnar deficiency of the forearm are sporadic in occurrence, though genetic syndromes are associated with ulnar dysplasia.

Focal dermal hyperplasia, or Goltz syndrome (also known as Goltz-Gorlin syndrome), is an X-linked dominant condition that consists of ulnar dysplasia, long-bone defects, and split-hand or split-foot, with skin atrophy; anal, vulval, or lip papillomata; microphthalmia; iris coloboma; and mental retardation.[8, 9, 10, 11, 12] Split-hand and split-foot with ulnar dysplasia have an autosomal dominant inheritance.[13] An ulnar defect with mammary gland aplasia syndrome is associated with polydactyly or camptodactyly.[14]



History and Physical Examination

The patient's affected upper limb is examined in supination, pronation, extension, and flexion. Clinical considerations of this condition include the following:

  • Ulnar deviation of the hand
  • Absent ulnar digits [15]
  • Syndactyly
  • Elbow stability
  • Elbow stiffness
  • Limited pronation, supination, or both
  • Radial head subluxation or dislocation
  • Deficient carpal bones
  • Stable wrist
  • Upper limb-length discrepancy


According to the traditional classification, there are four types of ulnar deficiencies of the forearm, which can have varying degrees of radial bow, with or without radial head dislocation.

In this classification, type 1 is defined as ulnar shortening (distally), with minor radial bow, and includes the following:

  • Hypoplasia of the ulna
  • Proximal and distal epiphyses present
  • Hypoplastic or absent ulnar digits
  • Minimal radial bowing

Type 2 is defined as significant ulnar shortening, with a fibrocartilaginous anlage attached to the ulnar carpus, with significant radial bowing, and includes the following:

  • Partial aplasia of the ulna, distal third
  • Distal ulnar anlage
  • Bowed radius with anlage acting as a tether
  • Presence/absence of progressive radial head dislocation

Type 3 is defined as complete absence of the ulna and includes the following:

  • Unstable elbow
  • Straight radius

Type 4 is defined as complete absence of the ulna, with a fibrocartilaginous anlage attached to the ulnar carpus, and includes the following:

  • Radiohumeral synostosis at the elbow
  • Bowed radius

Paley and Herzenberg combined the classifications of Kummel, Ogden, Swanson, and Johnson and Omer to create a classification that related directly to the treatment strategies of ulnar deficiencies of the forearm, as follows[16] :

  • Type 1 – Hypoplastic ulna with the distal epiphysis intact - This type is the most common with congenital dislocation of the radial head
  • Type 2 – Absence of the distal third of the ulna
  • Type 3 – Absence of the distal two thirds of the ulna
  • Type 4 – Complete absence of the ulna
  • Type 5 – Radiohumeral synostosis


Imaging Studies

Serial radiographic evaluation of the elbow, forearm, wrist, and hand can be useful in assessing the degree and course of the aplasia.[17]

Magnetic resonance imaging (MRI) can be used to delineate noncalcified tissues such as the fibrocartilaginous anlage. This modality is also useful for studying the joint surfaces in the largely unossified cartilaginous articulations.

Other Tests

All affected patients should undergo a detailed evaluation by a hand and upper limb therapist to assess hand function. Ongoing evaluation during treatment is important to avoid restriction of hand and elbow function. In addition, appropriate genetic evaluation and counseling for individuals with syndromic ulnar aplasia are important in certain instances.



Approach Considerations


In patients with ulnar clubhand, surgery is indicated for the following.

Ulnar deviation

Treatment involves casting from birth, long arm casting, and gradual stretching of the tight ulnar structures. Mild cases will correct by age 6 months.


With an early presentation, the anlage should be excised before the occurrence of radial bowing or radial head dislocation, around age 6 months. The procedure is performed through an ulnar incision along the wrist. Care is taken to protect the ulnar artery and nerve. Excision of the entire anlage is not necessary; however, at least 50% should be excised. The wrist is placed in maximal radial deviation in a long arm cast for a month. Night splints are worn for up to 6 months to maintain the correction.

With a late presentation, the entire anlage should be excised. Z-plasty of the skin and selective tenotomies may be necessary.

In the case of radiohumeral synostosis, the anlage should be excised, in that the anlage tether can cause progressive bowing.

Bowing of radius

Treatment consists of radial corrective osteotomy.

Forearm in less than useful rotation

Treatment consists of radial corrective osteotomy. It is better to wait until the child is mature enough to make a decision about the appropriate position.

Radial head dislocation

Treatment involves observation, resection only, or resection with the creation of a single-bone forearm. Ulnar osteotomy has been performed with or without shortening,[18] with open reduction and stabilization of the radial head and plus/minus early radial head prosthetic replacement.[19, 20]  A single-bone forearm is created through a posterior approach, with the posterior interosseous nerve protected. A sufficient amount of proximal radius is excised to achieve proper approximation and alignment with the ulna. An intramedullary nail or a plate is used for stabilizing the fusion.

Unstable elbow

Treatment consists of ulnohumeral or radiohumeral arthrodesis or elbow ligamentous reconstruction.

Radiohumeral synostosis

In young children, the ulnar anlage should be excised. In older children, a distal humeral osteotomy should be performed to improve forearm alignment.


Nonspecific contraindications for ulnar clubhand surgery are as follows:

  • Minimal or no functional deficit - In such cases, the surgeon should be wary of making the condition functionally worse; in most cases, the hand is reasonably functional, and correction of the forearm deformity is required to position the hand in a more favorable position in space
  • Any surgical risk factor due to associated syndromes
  • Severely affected limb and poor neurologic function

Type-Specific Surgical Therapy

Type 1 without radial head dislocation

This type is treated with ulnar lengthening, radius shortening, or both. Large amounts of radial shortening can result in radial head instability and dislocation. The radial bow is also corrected through the distraction osteotomy.[16] The treatment is repeated throughout childhood as the limb grows and as the discrepancy increases.

Type 1 with radial head dislocation

The radial head dislocation probably represents a relatively longer radius in the presence of a short ulna. The radial head can be left in its dislocated position if the forearm rotation is well maintained along with elbow stability and mobility, and the radial head is not tender. Radial head reduction requires one of the following:

  • Ulnar corrective osteotomy and radial shortening (similar to an untreated Monteggia fracture-dislocation)
  • Ulnar corrective osteotomy and lengthening – The distal radioulnar relationship is preserved with a wire that transfixes the two bones; as the ulna lengthens, the radius is pulled distally, reducing the radial head; following reduction, additional proximal radioulnar joint reconstruction may be needed; it may also be necessary to extend the external fixation to the humerus via a hinged elbow

Types 2 and 3 with radial head dislocation

The ulnar clubhand appearance is pronounced with these two types. The primary goal of treatment is to correct the alignment of the hand and forearm. If only the distal third of the ulna is absent, the ulna can be transported distally to support the carpus. If the distal two thirds of the ulna is absent, creation of a single-bone forearm[21] is a better alternative. If forearm rotation is good, all attempts should be made to transport the ulna distally.

The radius is osteotomized at one or two places, and the alignment is corrected. The ulna is osteotomized and distracted independently or with the radius.

Type 4

The ulnar clubhand deformity and elbow stability are the main issues to consider. Both can be improved with a corrective osteotomy to realign the hand and forearm. Lengthening requires extension of the external fixation to the humerus via a hinged elbow external fixator.

Type 5

An elbow-level osteotomy is performed to correct the elbow position. A radial osteotomy, an ulnar osteotomy, or both can be used to realign forearm rotation and lengthen the forearm.


Most children learn to cope functionally with their condition.[22]

One of the common complications that is seen in the lengthening reconstruction treatment of ulnar deficiencies of the forearm is the tightening of the flexor tendons to the digits, which restricts hand function.

Dislocation of an unstable elbow is also a potential complication. This can be avoided by protecting the elbow with a hinged fixator.