Elbow, Wrist and Forearm Injury Basics for the Physician Assistant Exam
For the Physician Assistant Exam (PANCE), it’s important to remember the names and components of specific injuries and orthopedic conditions related to the elbow, forearm, and wrist. This is especially true of fractures.
Epicondylar is a fancy way of saying, let’s look at the elbow for a second. The epicondyles are two bony areas found at the distal humerus; they are the medial epicondyle and the lateral epicondyle. Both can be inflamed, usually secondary to repetition or overuse. Here are some types of epicondylar injury:
Lateral epicondylitis (tennis elbow): Lateral epicondylitis is an inflammation of the tendons at the lateral epicondyle. Specifically, it’s an inflammation of the extensor carpi radialis brevis.
Medial epicondylitis (golfer’s elbow): Medial epicondylitis (ME) is an inflammation of the tendons that attach to the medial epicondyle. Golfer’s elbow can also involve the ulnar nerve and lead to complaints of neuropathy affecting the middle and last two digits.
Medial epicondylar apophysitis (Little League elbow): If children throw overhand, they can experience a valgus stress on the elbow joint. The repetitive motion can damage the structures of the elbow, resulting in an avulsion of the medial epicondylar apophysis (growth plate).
Presenting complaints for epicondylar injury can include pain over the affected area. Wrist extension can make the pain with lateral epicondylitis worse, and wrist flexion can make the pain with medial epicondylitis worse.
The treatments for both lateral and medial epicondylitis include stopping the underlying activity, a brief trial of nonsteroidals, alternating heat/ice treatments, and physical therapy. If someone fails to get better with conservative measures, surgery is an option, but it’s rarely needed.
Nursemaids elbow: A lift by the wrist
In children, a common elbow problem that you may be tested on is nursemaid’s elbow, sometimes called babysitter’s elbow. It occurs in the child, not the nursemaid. It can happen when someone grabs or pulls up the child by his or her wrist, causing slippage of the annular ligament.
On exam, the distal radius can be tender, and rotating the forearm can be difficult. The treatment is a closed reduction. In order to reduce the joint, the elbow has to be extended in combination with a pronated forearm.
Recall that a bursa is a pocket filled with synovial fluid. Its job is to act as a kind of padding around the joints. In the elbow, the olecranon bursa can get inflamed, leading to olecranon bursitis (student’s elbow or baker’s elbow).
Normally, you shouldn’t be able to feel a bursa. But when a bursa is inflamed, it’s enlarged and erythematous. Most of the time, the treatment for bursitis is conservative, including anti-inflammatory medication and rest. The fluid doesn’t need to be drained unless you suspect that an infection is present.
Nerves of the forearm
Neuropathy is a problem that affects many people. The most common cause is diabetes — you may recall that diabetic neuropathy has a stocking-glove distribution.
Recall that the ulnar nerve, which is the largest unprotected nerve in the human body, travels down the forearm to the medial aspect of the hand. The most common cause of ulnar neuropathy is nerve entrapment, such as from injury to the medial epicondyle. Other causes include connective tissue disease, diabetes, trauma, and tobacco use.
The most common presenting symptom of ulnar neuropathy is paresthesias involving the fourth and fifth digits. The person may also complain of elbow pain or a weak grip. Treatment can be nonsurgical or surgical. Indications for surgery include worsening weakness and muscle atrophy. Physical and occupational therapy, as well as conservative treatment, is recommended.
Carpal tunnel syndrome
Carpal tunnel syndrome (CTS) is an inflammation of the median nerve. Common presenting symptoms include paresthesias — weakness involving the thumb, first digit, and half of the second digit. Common causes of carpel tunnel syndrome include overuse and repetitive motion (such as typing at a keyboard incessantly, as Rich and Barry are doing), pregnancy, hypothyroidism, diabetes mellitis, sarcoidosis, and other connective tissue diseases.
Be aware of two physical exam signs concerning the diagnosis of carpal tunnel syndrome:
Phalen’s sign: Phalen’s sign refers to holding the dorsal aspect of both hands together in flexion for 1 minute. If the person experiences pain or paresthesias with this maneuver, carpal tunnel syndrome may be present.
Tinel’s sign: Tinel’s sign is tapping the wrist over the medial nerve, which you can do with a reflex hammer. Resulting pain and paresthesias suggest carpal tunnel syndrome.
The treatment of carpal tunnel syndrome can be conservative. It includes rest, anti-inflammatories, the use of wrist splints, and/or steroid injections. If these measures fail, consider surgery.
In any type of neuropathy, look for atrophy of the muscles innervated by that particular nerve. With regard to carpal tunnel syndrome, look for atrophy of the thenar eminence — that can be an indication for surgery.
Which of the following is associated with the development of carpal tunnel syndrome?
(B) Rheumatoid arthritis
(D) Diabetes insipidus
The answer is Choice (B), rheumatoid arthritis. Golfing, Choice (A), is associated with the development of medial epicondylitis. Hypertension, Choice (C), isn’t associated with carpal tunnel syndrome. Diabetes mellitus and hypothyroidism are associated with the development of carpel tunnel syndrome, but diabetes insipidus and hyperthyroidism, Choices (D) and (E), are not.
Colles’ fracture is a fracture of the distal radius, usually due to falling on an outstretched hand. Risk factors include underlying bone disease, including osteoporosis and renal osteodystrophy. (The kidney can be blamed for practically anything!)
Colles’ fracture is diagnosed by a radiograph. The radius is shortened and angulated dorsally. The treatment depends on the degree of displacement. Options for mild displacement include casting and closed reduction. For more serious angulation and displacement, open reduction internal fixation (ORIF) may be necessary.