Review Question - QID 211864

This patient has an ulnar nerve injury based on the clinical image and has lost the function of his intrinsics in his hand. To properly determine tendon transfer location one must perform the Bouvier test, which is correctly described by blocking full MCP extension and PIP joint extension does not occur.

Intrinsic minus hand or ulnar claw hand is a result of ulnar nerve injury. In this particular scenario, this patient has lost intrinsic hand function. A physical examination test to guide tendon transfer procedure is the Bouvier test. The Bouvier test is performed by holding the wrist in neutral and blocking full MCP joint extension and seeing if the patient can extend the PIP joints. If the patient is able to extend the PIP joints, then it is considered positive. A positive test indicates simple claw hand and an intact central slip. Tendon transfer procedures are then aimed at re-creating MCP flexion. To correct this, the tendons are either attached to the A1 pulley, A2 pulley or proximal phalanx. However, if the patient is unable to extend the PIP joints, then the test is considered negative. A negative test indicates complex claw hand and tendon transfers must correct both MCP flexion and PIP joint extension via insertion into the lateral bands.

Sammer and Chung discuss the pertinent anatomy and function of the median and ulnar nerves in the forearm and hand. They discuss the different clinical deficits associated with median and ulnar nerve injuries based on their location. They describe various treatments including their risks, benefits, indications and post-operative care.

Burkhalter and Strait in 1973 described a metacarpophalangeal flexor replacement for loss of instrinsic hand function. They found that it increased grip strength, reduced clawing and improved flexion pattern. They concluded that the procedure was biomechanically sound and can be done in the early course of ulnar nerve injury.

Muzykewicz et al. compared the Zancolli-lasso and the House procedure in 12 cadaver hands. They found that the Zancolli-lasso procedure resulted in finger IP joint flexion then MCP joint flexion and the House procedure resulted in MCP joint flexion then IP joint flexion. They concluded that both procedures improved hand grasp and fingertip-to-palm distance, but the House procedure restored function similarly to an intrinsic-activated hand. Subsequently, the House procedure was more recommended for restoring intrinsic function in tetraplegic patients.

Figure A is a clinical photograph depicting an intrinsic minus or ulnar claw hand.

Illustration A is a clinical photograph depicting the Bouvier Test. The wrist is placed in neutral and full MCP joint extension is blocked. If the patient can extend the PIP joint (positive test) then the central slip is intact and indicates simple claw hand. The inability to extend the PIP joints (negative test) indicates complex claw hand.

Incorrect Answers:
Answer 1: This describes the Elson test, which is used to diagnose central slip injuries.
Answer 2: This describes Extrinsic Tightness.
Answer 3: This is describing the tenodesis effect, which can be used to identify flexor or extensor tendon injuries. In this example, there is likely a flexor digitorum profundus injury.
Answer 5: This describes Froment’s sign, which is important to identify ulnar nerve pathology, but does not guide tendon transfer location for claw fingers.