Ulnar claw hand is term referred to condition of the hand that results due to ulnar nerve palsy. Ulnar nerve is responsible for supplying the lumbricals which are responsible for extension of interphalangeal joints and flexion of metacarpophalngeal joints.

The ulnar nerve palsy therefore would result in hyperextension of metacarpo-phalangeal joint and flexion at the interphalangeal joints of 4th and 5th digit.

A hand in ulnar claw position will have the 4th and 5th fingers drawn towards the back of the hand at the first knuckle and curled towards the palm at the second and third knuckles.

Following two photographs are of  a man with ulnar nerve palsy of right hand.

The deformity is more pronounced in the little finger as you can see.

Following photograph was taken for comparison. [Sorry for the background. OPD was heavy]

It is the extension of the MCP joints coupled with the slight flexion of the IP joints that gives the hand the claw-like appearance.

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Both closed and open fractures can be associated with neurovascular injuries.  Nature of injury to these structures is more serious in case of open fractures. Generally speaking, nerve injuries are more common than vascular injuries. 

Nerve Injury

Open fractures

In case of open fractures with nerve injury, a complete assessment of the injury must be made. Most of the open fractures are treated by debridement and external fixation. The nerve should be explored at the time of debridement to determine whether it is intact or divided. If it is divided, the ends should be tagged together with sutures to prevent retraction and facilitate later repair.

If the wound is clean, the nerve cleanly transected, and the soft tissue bed adequate, primary nerve repair at the time of wound closure is probably the appropriate treatment.

Closed fractures

If the nerve is injured along with fracture and If the fracture is being treated with closed reduction and plaster cast then nothing more needs to be done. Most of the closed fractures with nerve injury have a grade I nerve injury or neuropraxia. This kind of injury generally recovers on its own.

However, if there is an injury while reduction or manipulation, exploration is indicated.

If the treatment of the fracture is surgery, it is always prudent to explore the nerve as well if it is in vicinity of exposure. Otherwise, wait and watch protocol may be followed with re-exploration at a later date.

If the nerve is injured during operative procedure, it would be found only in postoperative period when the deficit becomes evident.

In such cases, incomplete nerve injuries can be observed for several weeks or months to determine if recovery will occur. If there is no evidence of recovery by 3 months, exploration should be done. Complete iatrogenic nerve injuries should be explored within a few days  if the  function does not show a progressive recovery. If there is an offending structure or hardware, it should be removed.

Note: In some rare cases, peroperative iatrogenic nerve injury becomes evident at the time of surgery. It should be repaired immediately.

Another factor that can cause nerve injury in areas of nerves which are superficial are plaster constriction or tight bandages. Most commonly the injury is neuropraxia and removal of offending tightness is all that desired and the nerve would recover.

If it does within reasonable period of time, the nerve conduction studies should be done to confirm the severity of lesion and plan for treatment.

Related posts:

1. Complications of Fracture – Vascular Injury
2. List of Complications Of A Fracture
3. Complications of Fracture – Non Union