Elbow Pain

Robert N. Hotchkiss

The articular anatomy of the elbow is unique because it contains two independent axes of motion in the same synovial pouch. The ulnohumeral joint determines flexion and extension, and the radiocapitellar joint determines pronation and supination of the forearm. The axis of rotation moves very little throughout flexion and extension, making a nearly perfect hinge that is highly constrained. The normal range of motion is 0 to 140 degrees of flexion and extension, 80 degrees of pronation, and 90 degrees of supination.

The elbow naturally deviates away from the body (the “carrying angle”), the extent of the deviation varying from person to person.

The hemicircumferential articulation of the humerus and ulna combined with tension in the biceps–brachialis and triceps makes the elbow extremely stable. The radial head also contributes to stability by providing a wider base of support.

I. LIGAMENTS

Because of the natural valgus (away from the body) angulation at the elbow, valgus stress develops when a load is thrown or borne. The medial collateral ligament, specifically the anterior portion, is the most important stabilizer.
On the lateral side, the radial collateral ligament helps stabilize the ulna and humerus. The annular ligament wraps around the radial head, securing the proximal radius to the proximal ulna while allowing rotation of the radius.

II. MUSCLES

Flexors. The biceps and brachialis combine to function as the most powerful muscles in the upper extremity. Because of the location of the long head of the biceps, proximal ruptures can occur. The distal biceps tendon can also rupture. Depending
on the patient’s needs of function and mobility, some of the ruptures should be surgically repaired.
Extensors. The triceps is less powerful than the combined flexors. Active extension is needed for throwing and is especially important for patients who use their arms while transferring from bed to wheelchair or while using crutches. The triceps is much less prone to injury or rupture than the biceps.

III. NERVES

The medial, ulnar, and radial nerves cross the elbow. The ulnar nerve is subcutaneous along the medial side and is palpable posterior to the medial epicondyle in the cubital tunnel. The radial nerve courses along the lateral side and is not palpable. The median nerve lies next to the brachial artery in the cubital fossa.

CLINICAL MANIFESTATIONS AND PHYSICAL EXAMINATION

I. ETIOLOGY

In the examination of a painful elbow, it is helpful to categorize patients according to the suspected etiology.

Acute pain after trauma is most likely to be associated with fracture or dislocation. Muscle tears of the biceps can also occur in middle-aged men. Acute pain on the medial or lateral sides of the elbow may be associated with sports such as golf or tennis because of an acute muscle tear. In the absence of a history of trauma, inflammation from gout, infection, rheumatoid arthritis (RA), or other rheumatic conditions should be investigated.
Chronic pain that develops slowly may be related to repetitive use; it is sometimes seen in assembly line workers and in golf or tennis players. RA can present as recurrent, warm effusions in the elbow or progressive, indolent loss of motion.
Episodic pain, characterized by sudden twinges and locking of the elbow, may be caused by loose cartilaginous fragments, commonly referred to as loose bodies.

II. Localization of pain

by the patient is the single most important part of the examination. If the patient can specifically identify a reproducible location for the pain, the chances of diagnosis are greatly enhanced. Once the pain has been localized, or at least regionalized, the most common causes of pain in the given region can be investigated.

III. PALPATION

Point of maximal tenderness. Once the pain is localized by the patient, he/she should be examined for tenderness at that same location. It should be checked whether the application of direct pressure (gently applied) reproduces the discomfort. If pressure causes pain, local inflammation, from any of the sources listed in the subsequent text, should be suspected.
Synovitis and effusions. Proliferative synovium is usually associated with RA. Unlike effusions in the knee, effusions in the elbow are often difficult to notice. Effusions can sometimes be palpated just anterior or posterior to the radial head, where arthrocentesis is performed.
Crepitus. Grinding and popping in a joint as it moves through a range of motion can often indicate severe erosions of articular cartilage. Both flexion–extension and pronation–supination should be checked. The status of the radial head can be assessed by placing a thumb over the radiocapitellar joint during passive forearm rotation.

IV. RANGE OF MOTION

Flexion–extension. Flexion and extension should be recorded both actively and passively. With mild inflammation or minor trauma, loss of the range of extension is the first to be noted. It is helpful to compare active and passive extension in the affected joint against the range of motion on the other side.
Pronation–supination. Forearm rotation should also be measured and compared with that on the other side.

IMAGING AND OTHER DIAGNOSTIC TECHNIQUES

I. PLAIN RADIOGRAPHS

Plain radiographs of the elbow should include a true lateral and an anteroposterior film. The lateral film is the most difficult to obtain. If a flexion contracture exists, an anteroposterior film of the distal humerus and of the proximal
forearm can be of help. A radiocapitellar view can sometimes be helpful in assessing the radiocapitellar joint. In the normal elbow, the head of the radius always points toward the capitellum in all views. If an effusion is present, the lateral view may demonstrate displacement of the anterior or posterior fat pad.

II. Bone scans

can be useful in an attempt to localize or diagnose pain of unknown origin. A single-phase, “bone static” image may show uptake in a particular region and may lead to closer scrutiny.

III. Computed tomography (CT)

scan of the elbow can be useful in fracture and reconstructive problems. It is important to review the clinical history with the radiologist and to describe the area of interest. The slice thickness for proper detail is usually 0.8 to 1 mm.

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