Workers’ Comp Insights: Dr. Enoki on TFCC, Carpal Tunnel & More

The triangular fibrocartilage complex (TFCC) is a structure that stabilizes and supports the distal ends of the radius and the ulna at the distal radioulnar joint (DRUJ). The TFCC is composed of the dorsal radioulnar ligament, the volar radioulnar ligament, and cartilage that spans between them.

The TFCC can be injured acutely, for example, after a fall onto an outstretched hand, or there can be a chronic degenerative etiology, for example, with arthritis, or with mechanical injury when the distal ulna is slightly longer than the radius (ulnar positive variance). The underlying cause of the TFCC tear, and the severity of the tear, can impact recovery time.

Question:

What is the difference between carpal tunnel and cubital tunnel? What is the etiology of these injuries and do these injuries have similar recovery timeframes?

Answer:

Carpal tunnel
The carpal tunnel is an anatomic space at the palmar aspect of the wrist. The median nerve passes through this space at the palmar wrist, along with the finger and thumb flexor tendons.

Cubital tunnel
The cubital tunnel is an anatomic pathway at the medial aspect of the elbow, beginning at the far distal end of the triceps muscles above the elbow, extending behind the medial epicondyle of the distal humerus and then to the upper portion of the forearm flexor muscles. The ulnar nerve passes through the cubital tunnel as it traverses from the arm to the wrist.

Carpal tunnel syndrome and cubital tunnel syndrome occur when compression, or stretch on the nerve, exceeds what the nerve can tolerate, resulting in symptoms of numbness, tingling, pain, and other symptoms. Recovery time for carpal tunnel syndrome and cubital tunnel syndrome varies depending upon the severity of the nerve injury.

Question:

What are the most common reasons that cause the de Quervain's tenosynovitis condition?

Answer:

De Quervain's tenosynovitis is a painful inflammation of the tendons that are located at the thumb side of the wrist and hand, and is the result of overuse. The most common cause of de Quervain's tenosynovitis is repetitive movement of the wrist during lifting activities. Clinically it must be distinguished from other possible causes of pain at this location to include arthritis, and nerve-related pain.

Dr. Nathan Enoki is an orthopedic hand surgeon in Portland, OR and has been in practice for more than 20 years. He received his medical degree from the University of Hawaii at Manoa John A. Burns School of Medicine and is board-certified in hand surgery. 

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A Previous "Ask the Doctor" Response
In our previous "Ask the Doctor" blog, Dr. Berg unravels the complexities of foot pain, from plantar fasciitis to the etiology of stress fractures.