TIS
Chapter 11
The Elbow and Forearm


Overview of the Elbow:

The elbow contains three articulations within a single joint capsule: the ulno-humeral and radio-humeral joints and the proximal radio-ulnar joint. The forearm and elbow motions respectively serve to rotate the forearm to allow for maneuvering of the hand, and to lengthen and/or shorten the distance of the hand to the upper body allowing for such functions as grooming, eating, dressing, etc. (Lehmkuhl & Smith, 1983).

Functional Anatomy and Brief Biomechanical Considerations:

Elbow stability: The elbow is a relatively stable joint with two degrees of freedom: flexion-extension at the ulno-humeral joint, and pronation-supination at the proximal radio-ulnar articulation of the forearm. The elbow is not prone to instability, however, it is less stable with valgus stresses than to varus stresses.

The ulno-humeral joint: The trochlea of the humerus articulates with the trochlear notch of the ulna. The strong structural stability of this joint is derived from both its bony configuration and its collateral ligaments (Lehmkuhl & Smith, 1983). The trochlea extends more distally than the capitulum, therefore when the elbow is extended and the forearm supinated, the forearm deviates laterally in relation to the humerus. This angulation is called the carrying angle or cubital angle of the elbow. This angle is usually between 10 and 25 degrees of valgus (Stralka & Brasel, 1994).

The radioulnar articulation: The proximal and distal articulations between the radius and the ulna allow the radius to rotate in relation to the ulna. The proximal radioulnar joint lies within the capsule of the elbow, with the medial aspect of the head of the radius articulating with the radial notch of the ulna.

The cubital fossa: the triangular space located at the anterior aspect of the elbow. This area contains the biceps tendon, the brachial artery and its terminal branches, and parts of the median and radial nerves (Moore, 1980).

The Joint Capsule of the Elbow:

The capsule of the elbow completely surrounds the humero-radial/ulnar and the radio-ulnar joints. Its anterior and posterior parts are thin and weak, but its sides are strengthened by the collateral ligaments. The capsular pattern of the elbow is flexion, then extension with more limitations of flexion than extension.

Ligaments of the Elbow:

Instability of the elbow is not common, however, when it is present, it occurs primarily with the valgus stress. Nature has compensated for this to a certain extent, in that the medial collateral ligaments of the elbow are stronger than the lateral collateral ligaments (Hammer, 1991).

Medial or ulnar collateral ligaments: Consist of anterior oblique and posterior oblique bundles and a transverse ligament.

Lateral or radial collateral ligament: Originates from the lateral condyle and inserts on the annular ligament of the radius. According to Hammer, the elbow does not have a functional lateral collateral ligament (Hammer, 1991).

Annular ligament: Forms a ring around the head of the radius and has firm fibrous connections with the ulna and is anchored to the neck of the radius. The head of the radius rotates this ring, which permits rotation but prevents movement in other directions.

Muscles:

Muscles acting at the elbow and forearm have attachments all along the upper extremity. Applying resistance while using midpositional muscle positions will assist the therapist in isolating pathologies in specific muscles.

Soft Tissue Disorders of the Elbow

Dislocations, Subluxations, and Sprains: again, elbow instability due to dislocation, subluxation, or sprain, is not a common problem.

Dislocations: when dislocations do occur, they are almost always posterior and may be due to direct trauma, such as a fall on the outstretched arm, or due to "structural fatigue" of the ligaments due to overuse (Hammer, 1991). Dislocations are classified as posterior, anterior, recurrent, and divergent (Stralka & Brasel, 1994). Posterior dislocations of the ulna on the humerus are by far the most common. Anterior dislocations are almost always associated with fractures of the olecranon. Recurrent dislocations account for only 1 to 2% of elbow dislocations and result from insufficient healing of the capsular and ligamentous restraints, which allows dislocation with forces much less than those responsible for the initial injury. In divergent dislocations, the radius becomes displaced from the ulna. This type of dislocation is associated with severe trauma and is a rare injury. With dislocations, fractures are of concern, as are injuries to nerves, arteries, muscles, and ligaments.

Dislocation/subluxation of the radial head: Radial head dislocation/subluxation is commonly known as "nursemaid’s elbow", and is seen in children. This condition is the result of a sudden pull or jerk on the child’s arm, resulting in dislocation or subluxation of the radial head from the annular ligament (Salter, 1983). This pathology can be confirmed via the radial apprehension test.

Sprains: The elbow is more prone to instability with valgus forces, and activities such as repetitive throwing or hammering can cause chronic valgus insufficiency/sprain of the medial collaterals. Repetitive valgus stress creates microtears in the ligament(s), which can lead to the formation of scar tissue, bone spurs, etc., which can ultimately result in rupture of the ligament. Check for primary ligamentous instability: stress the ligament in 20-30 degrees of flexion. Surgery for medial collateral ligament is usually performed if the person’s livelihood is affected by the sprain. If medial collateral ligament is of secondary importance, many times the physician will not surgically intervene, and will simply allow scar formation to augment stability.

Tendinitis and Muscle Strains:

Grade III strain of the triceps tendon: varying methods of reattachment. The person may be immobilized at 30 degrees flexion for 3-4 weeks, then dynamic splinting performed, with movements greater than 100 degrees of flexion prohibited for approximately 6 weeks, then progressive ROM can be initiated.

Distal biceps tendinitis: irritation due to lifting, repetitive hyperextension of the elbow with pronation, or repetitive pronation-supination movements. The most involved site is the distal belly and musculotendinous regions.

Grade III biceps strain: requires surgical connection, which is dependent of the location of the rupture. Avulsion fractures are easiest, tears occurring in the belly are more difficult. The elbow is immobilized at 45 to 90 degrees for 3-4 weeks, then gentle active motion is performed. At 8 weeks - 2 months, begin progressive stretching and strengthening. Full extension is difficult to reacquire; dynamic splinting may be very effective.

Brachialis strains: because the brachialis crosses the elbow as muscle, not as tendinous tissue, it is prone to hemorrhage when injured and has a high potential for significant scar formation. An occasional complication of brachialis strains is myositis ossificans. The brachialis is frequently prone to contractures post-injury.

Epicondylitis:

Lateral epicondylitis/tennis elbow: irritation of the common origin of the wrist extensors, primarily the extensor carpi radialis brevis, due usually to actions that are stressful to wrist extension and repetitive in nature. This pathology is confirmed by Cozen’s test/ test for lateral epicondylitis: resisted wrist extension while palpating the lateral epicondyle. A positive sign is indicated by pain in the area of the lateral epicondyle of the humerus.

Medial epicondylitis/golfer’s elbow: less common than lateral epicondylitis involving irritation of the medial epicondyle, and associated with activities that stress wrist flexion and active pronation, such as baseball pitching, golf swings, or the pull through phase of swimming strokes (Stralka & Brasel, 1994). The flexor carpi radialis and pronator teres are commonly involved, with this condition occurring most often in middle-aged patients involved in baseball, golf, or swimming, or in occupations that require a strong hand grip and an adduction movement of the elbow.

Bursitis: of the various bursae of the elbow, the two olecranon bursae (the subcutaneous olecranon and the subtendinous olecranon bursa) are the only bursae of clinical significance (Moore, 1980).

Subcutaneous olecranon bursitis is the most common bursitis at the elbow, and is usually due to repeated excessive friction on a hard surface. It presents as a edematous area at the elbow.

Subtendinous olecranon bursitis is much less common, but may result from excessive friction between the triceps tendon and the olecranon.

Entrapment Syndromes: often the clinical findings of entrapment are similar to those of the epicondylitis lesions (Hammer, 1991). The specific etiology of the entrapment may be due to a crush injury, repetitive motion resulting in chronic irritation from muscular hypertrophy, fascial thickenings, bony or vascular anomalies, or hypermobile nerves. Therapists must recognize that entrapment/compression can occur at a number of sites for a number of nerves. Entrapment symptoms depend on the type of nerve affected and the amount of compression.

Ulnar nerve entrapment: in the elbow region, the most common site of entrapment is at the cubital tunnel. Signs and symptoms include paresthesia of the 4th and 5th digits, weak/clumsy interossei muscles, positive Tinel sign, and positive elbow flexion test. Surgery may be performed to transpose/redirect the nerve. Usually the elbow is splinted at 30 degrees for a week before surgery to "calm down" the nerve. Transposition/redirection often involves an epicondylectomy with re-routing of the nerve under the flexor-pronator muscles. The elbow is usually immobilized for 3 weeks, then gentle AROM initiated at 3 weeks. At 6 to 8 weeks, the patient is returned to light-to-moderate activity.

Radial nerve entrapment/posterior interosseous syndrome: The most frequent site of compression is at the arcade of Frohse, the arch formed by the proximal edge of the supinator. Symptoms include weakness of the extensors of the forearm and functional wrist drop, so the patient has difficulty or is unable to stabilize the wrist for proper hand function. Irritation of the radial nerve or the posterior interosseous nerve may mimic lateral epicondylitis (Hammer, 1991).

Median nerve entrapment: there are two types of median nerve entrapment:

Fractures of the Elbow and Forearm: can be quite complicated, with factors such as difficulties of diagnosis of the fracture and maintenance of reduction, neurovascular complications, malunion, and post-injury stiffness.

Humerus: Intercondylar and condylar fractures of the humerus offer a poor prognosis for restoration of full elbow range of motion due to difficulty maintaining good reduction of the fragments, and due to post-traumatic arthritis when articulating surfaces are involved. Medial and lateral epicondylar fractures are usually the result of avulsion fractures of the respective ligaments.

Ulna: Radius: Post-traumatic Stiffness:

Injury to the elbow and forearm can often lead to post-injury stiffness. The structures that may become stiff vary, but almost always stiffness is associated with immobilization and/or guarding of the injured arm near the trunk. The history is important to determine a time frame of events that indicates the date of injury, subsequent surgeries (if any), duration of mobilization, and date of removal of supports or splints. Also want to determine whether there have been previous attempts at remobilization, and to identify the factors that may contribute to stiffness. Factors contributing to stiffness may be extrinsic, intrinsic, a combination of extrinsic and intrinsic, or acquired.

Extrinsic stiffness: involves extra-articular structures, which include: periarticular muscle contractures, shortening of the collateral ligaments due to fibrosis, and stiffening of the joint capsule.

Intrinsic stiffness: caused by intra-articular structures, such as loose bodies or articular incongruities that interfere with mechanical motion.

"Acquired" stiffness: as a result of arthritis, burns, paralysis, sepsis.

Evaluation of the Elbow and Forearm:

The evaluation should be reflective of the general orthopedic evaluation, including a thorough chart review, pertinent history, and physical examination, proceeding from a general approach to a specific approach. Although a person’s diagnosis may be specific to the elbow, it is important that the therapist not be so focused on the elbow joint that other areas of involvement may be missed. It is extremely important for the occupational or physical therapist to assess the impact that the elbow pathology has had on the person’s life roles. Once the general evaluation has been performed, then tests specific to the elbow can be administered.

Differential Tests of the Elbow include:


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