Srinath Kamineni
Clinical History
A careful history is of the utmost importance since it can lead to the diagnosis in most cases. Before focusing on the main complaint, it is important to determine some basic information about your patient. With each piece of information obtained, the investigator should always continually be triaging some differential diagnoses. The patient's age allows an early distinction between possible congenital or developmental conditions when young, e.g., congenitally dislocated radial head presenting in a child unable to fully supinate the forearm in extension as compared with a greater tendency for degenerative pathologies in the elderly. Some pathologies (e.g., lateral epicondylitis) occur in the middle of an average life span, between 20 and 60 years, but not at the extremes beyond this range. The occupation may point toward some obvious diagnoses—e.g., the baseball pitcher is more prone to medial collateral ligament injury and valgus extension overload syndrome, whereas a manual laborer may present with primary degenerative arthrosis. Those in occupations involving a lot of weight bearing on the elbows—e.g., plumbers, carpenters, and gardeners—may show a tendency for olecranon bursitis. Which is the dominant arm(right, left, or ambidextrous), and is it the arm presenting with the current problem?
Primary Presenting Complaint
The most common primary symptom, the presenting complaint, is pain. Also note any secondary complaints, which may or may not be directly linked with the primary complaint; elbow pain with numbness of the hand as occurs in median nerve entrapment at the elbow is an example of linked symptoms. Which of the symptoms is most troublesome to the patient, with respect to being most disabling to his or her function? Ask for a subjective prioritization.
The following characteristics of pain are important to investigate:
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but with analgesics and anti-inflammatory medications, and an acute traumatic soft tissue injury (ligament sprain) is helped by cooling with an ice bag.
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TABLE 47-1 Location of Pain in Relation to Common Differential Diagnoses |
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Mechanism of Injury/Pathology
The mechanism of injury/pathology should also be sought from the patient. This is often the most fruitful part of the history taking. If there was a specific injury to account for the current complaint, the direction, magnitude, and timing of the forces involved should be examined. Distinguish between a single event (e.g., an eccentric single contraction of the biceps during a football tackle leading to an acute distal biceps rupture) or multiple events (e.g., multiple painful episodes during biceps curls while weight lifting, leading to a partial biceps rupture). Some pathologies arise as a result of overuse, which may seem unimportant to the patient—e.g., a prolonged period of gardening or sports followed by tennis elbow after 2 days. During the time of injury or unusual event(s), did the patient observe any noises or other symptoms—a pop suggestive of a ligament sprain or rupture, a click as in an elbow instability, locking of the joint owing to a trapped loose body or instability, immediate swelling of a hematoma, or a delayed swelling of a traumatic or inflammatory effusion?
Litigation
Is there any intention of or pending legal action concerning the complaint being presented? Although not all-inclusive, pending litigation may adversely affect the patient's perception of the problem with an alteration of the portrayal of the clinical symptoms and signs.
Patient's Perception
What does the patient understand of the presenting problem, what advice has been given previously, and what is the patient's perception of the final outcome? Understanding the patient's perception at the time of presentation gives valuable insight into the potential for a good outcome.
Physical Examination
A standard method of examination proceeds along a standard algorithm: inspection, active motion, passive motion, and relevant imaging. During the physical examination, the affected side should be compared with the contralateral (normal) side.
Inspection
The carrying angle is the angle of the forearm relative to the arm when the upper limb is in a neutral position next to the body (fully extended and supinated). Age, sex, and racial variations should be considered; normal is 5 to 10 degrees in males; 10 to 15 degrees in females.1 If the carrying angle is outside the normal range, the observable deformity (posttraumatic or growth disturbance—cubitus varus or gun stock deformity of <5 to 10 degrees [Fig. 47-1] or cubitus valgus >15 degrees), bearing in mind that all “deformity”
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may not be pathologic (normal racial or sexual variation). The skin color can be instructive in some conditions and should be compared with the contralateral nonpathologic limb; for example, an anterior ecchymosis as a result of a biceps rupture will be unilateral, and skin changes as a result of chronic psoriasis can be bilateral. Some skin changes can be nonpathologic but should be noted, e.g., port-wine stains, strawberry nevi, grey slate marks, and so on. Following trauma or some surgeries reflex sympathetic dystrophy can often lead to reddened skin that is shiny and painful.
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Figure 47-1 An 18-year-old man with a 20-degree cubitus varus deformity following a childhood malunited supracondylar distal humeral fracture. |
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TABLE 47-2 Location of Swelling in Relation To Common Differential Diagnoses |
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Swellings can occur in any part of the elbow, and their fundamental characteristics help to diagnose the underlying pathology. Basic characteristics to define are the exact location and size. Other characteristics require palpation and are outlined below. Scars can be either traumatic or iatrogenic/surgical. The size and shape of the scar is noteworthy and can be helpful for planning future surgeries. Also note the quality of the scar, which can indicate the patient's healing response; for example, a keloid scar may indicate a vigorous scar response and the potential for elbow capsular contracture, whereas a paper-thin scar may indicate a poor healing response, of relevance to ligamentous ruptures requiring repair. Finally note any muscle wasting. In the forearm that has undergone a Volkman ischemic contracture, owing to compartment syndrome, the forearm musculature can be markedly wasted (Fig. 47-6). In the hand, the wasting of interosseous muscles/hypothenar eminence may be indicative of ulnar nerve compression in the cubital or Guyon tunnel; and wasting of the thenar eminence may indicate median nerve entrapment between the two heads of pronator teres (pronator syndrome) or may indicate nerve compression in the carpal tunnel (carpal tunnel syndrome) (Table 47-2).
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Figure 47-2 Distal biceps tendon rupture with proximal migration of the muscle belly (Popeye sign). |
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Figure 47-3 Proximal biceps tendon rupture with distal migration of the muscle belly with associated bruising (Popeye sign). |
Motion
Active Range of Motion
Normal elbow motion is an arc of motion from 0 degrees (full extension) to 145 degrees (full flexion). Loss of extension can be a sensitive indicator of intra-articular pathology and can signal an acute event (e.g., intra-articular effusion [synovial or hematoma] or a chronic event (e.g., degenerative arthrosis with anterior capsular contracture). Loss of flexion can be a consequence of posterior capsular contracture.
The normal forearm axial rotational arc of motion is 70 to 90 degrees (pronation, palm down), 80 to 90 degrees (supination, palm up). When assessing forearm rotation, the examiner should ensure that the patient's elbow is flexed to 90 degrees and positioned next to the trunk, thereby avoiding shoulder abduction or adduction. These latter motions can falsely alter forearm motion, with shoulder abduction compensating for a restriction in pronation and shoulder abduction compensating for supination restriction. Thumb and hand motion relative to the distal radioulnar joint can also lead to a false sense of motion of the forearm axis.
Passive Range of Motion
If the active range of motion is incomplete, passive range of motion testing will highlight a difference since pain often inhibits the active range. If active and passive ranges are
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complete, the latter can be used to gain information about both the midarc and end-arc of the motion. The primary information that is sought regarding the mid-arc of motion is whether or not there is crepitus, which is suggestive of chondral degenerative pathology. This assessment can be enhanced by asking the patient to actively resist the passive motion, thereby increasing the joint reactive forces and accentuating signs originating from the bearing surfaces.
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Figure 47-4 Developmental dislocation of the radial head, producing a lateral swelling and restriction of prosupination. |
Gently pressuring the joint beyond the normal arc will provide information about the restraint to greater motion, but this test can be painful if done with excess zeal. During this assessment, one should continually consider whether the end point to the passive motion is rigid as in bony contact, or less rigid or soft implying a soft tissue cause of the end point (Table 47-3). With forced end-arc flexion, approximation of the forearm to arm musculature prevents greater flexion, whereas in thin patients the coronoid process may abut the coronoid fossa. In end-arc extension, there is the bony abutment between the olecranon process and its reciprocal fossa. In a normal joint such forced end-arc testing
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is not painful, but pain may be encountered with pathologic changes in osteophytosis and loose bodies.
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Figure 47-5 Typical position for rheumatoid nodules on the subcutaneous borders of the forearms (illustration), with a backgroundphotograph of severe rheumatoid swellings. |
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Figure 47-6 Volkman ischemic contracture of left forearm after an elbow fracture dislocation, treated in plaster cast. Forearm muscles have necrosed, and fibrotic scar tissue remains. |
For forearm rotation testing, the distal humerus should be immobilized and motion should be achieved by rotation of the forearm at the distal radioulnar joint. A common mistake is to hold the patient's hand to test for forearm rotation, which serves to build in an error to the rotation values so gained, since wrist joint laxity can be ≤15 degrees and more in patients with rheumatoid arthritis. Forced end-arc pronation and supination are normally resisted by forearm muscular stretching, although in thin subjects bony abutment can occur between the radius and ulna.
Isometric Strength Testing
For muscle strength testing, the elbow should be supported in 80 to 110 degrees of flexion with the forearm in neutral rotation. If tested either in greater extension or greater flexion, the maximum strength decreases to 75%.3 The examiner should support the flexed elbow in the cupped palm of one hand with the other hand holding the distal forearm to produce resistance to motion. When attempting to grade the power of muscles or to longitudinally track changes in their strength, a grading system is useful, notably the MRC muscle strength grading system (Table 47-4). This method of testing is for isometric strength, but the clinical history should guide the examiner to also test for eccentric and concentric contractions where appropriate, first without resistance then with resistance. The specific movements to be tested are elbow flexion and extension, forearm pronation and supination, and wrist flexion and extension. The latter two movements are relevant to the examination of the elbow since most of the muscles driving these actions cross the elbow joint and can be symptomatic at the elbow.
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TABLE 47-3 Differential Diagnoses Associated with Passive Motion |
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TABLE 47-4 MRC Grading of Muscle Strength |
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Figure 47-7 Medial supracondylar process and ligament of Struthers, sources of median nerve compression. |
Functional Evaluation
The elbow, in combination with the shoulder, functions to place the hand where needed to manipulate the environment. Whereas the shoulder motion defines a sphere centered on the glenohumeral joint, the elbow allows the hand to move in and out to the extremity of the sphere, along the radii of the sphere.4 To perform most activities of daily living, a full range of elbow motion is not necessary, and this is possible with a sagittal flexion arc from 30 to 130 degrees and forearm rotational arc of 50 degrees pronation and 50 degrees supination. A comprehensive assessment should include 15 activities of daily living that primarily test the flexion arc and 15 activities that test the forearm rotational arc of motion (Fig. 47-11). However, assessing the elbow function can be adequately and consistently performed using an overall evaluation scoring system, the Mayo Elbow Performance Score,4 in which five activities of daily living are addressed (Table 47-5).
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Figure 47-8 Cadaveric dissection demonstrating the origin of the anterior medial collateral ligament (AMCL) at the anteroinferior aspect of medial epicondyle and the insertion at the sublime tubercle of the proximal ulna. |
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Figure 47-9 Triceps rupture with a consequent inability to extend the elbow against gravity. |
Special Elbow Tests
The clinical history and the generic tests detailed above will enable the examiner to decide whether specific pathology related tests are required for further clarity of the presenting complaint. The tests outlined below in this section are not mandatory for all patients, but only for those about whom the examiner has a level of suspicion regarding the diagnosis. These special and specific tests fall broadly into three categories: (i) ligamentous instability tests, (ii) inflammation tests, and (iii) neurology-based tests.
Ligamentous Instability Tests
The arm is maintained in full extension with one hand supporting the elbow and the other producing a valgus or varus
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torque on the distal radioulnar joint. In this position the olecranon process is closed packed in the reciprocal fossa and may conceal less severe ligamentous injuries.
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Figure 47-10 Normal posterior alignment is present when the olecranon forms a straight line with the two epicondyles with the elbow extended. An equilateral triangle is formed when the elbow is flexed to 90 degrees. Inset photograph demonstrates malalignment of these bony points owing to a malunited supracondylar humeral fracture. ARM, LE, lateral epicondyle; ME, medial epicondyle; UN, ulnar nerve. |
To reduce the effect of bony restraint to valgus or varus deformation, the elbow is flexed to 20 to 30 degrees, which allows less severe ligamentous injuries to be uncovered. The difficulty with testing valgus/varus stability in this position is that the humerus rotates outside the examiner's control, thereby introducing an error to the extent of any instability detected. Hence when testing in slight elbow flexion, the
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effect of the shoulder is minimized by placing it in either full external rotation for valgus stress testing or full internal rotation for varus stress testing5 (Fig. 47-12). When considering what constitutes a positive test result, either increases in laxity compared with the normal contralateral limb or an increase in pain is a relevant finding. However, be wary of the contralaterally lax “normal” elbow when comparing with the known pathologic side.
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Figure 47-11 Fifteen activities of daily living. Those that can be achieved within a 100-degree arc of flexion (30 degrees–130 degrees) are in the central grey area. |
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Figure 47-12 Valgus stability testing in a fully extended elbow. The arm is stabilized, and the forearm is moved in the plane of testing. |
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TABLE 47-5 The Mayo Elbow Performance Score |
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TABLE 47-6 Differential Diagnoses for Nerve Dysfunction about the Elbow |
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In the moving valgus stress test, the examiner places, and maintains thoughout the test, a constant valgus torque on a fully flexed elbow, which is then rapidly fully extended (Fig. 47-13). This is essentially a motion version of the common
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milking test. A positive finding consists of medial elbow pain predominant in the flexion arc shear zone of between 120 and 70 degrees.6
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Figure 47-13 The moving valgus stress test for identifying medial collateral ligament (MCL) injuries. |
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Figure 47-14 The milking test for identifying anterior medial collateral ligament (AMCL) injuries in continuity. |
In the milking test, the examiner or the patient pulls the thumb of the pathologic limb with a valgus torque, with the elbow flexed between full 130 and 70 degrees7,8 (Fig. 47-14). Pain is produced at the site of the medial collateral ligament, anterior band. This test is especially sensitive when there is a medial collateral ligament injury.
The posterolateral rotatory instability test, also referred to as the pivot shift maneuver, tests for insufficiency of the lateral collateral ligament complex.9 The patient is positioned supine on a couch (Fig. 47-15). The radial head is seen to sublux/dislocate when the supinated forearm is axially compressed and stressed with a valgus torque and passively fully extended from 30-degree flexion. The radial head relocates with a clunk with flexion from full extension to 30-degree flexion (Fig. 47-15). This test is rarely positive in the awake patient but is quite helpful to perform while the patient is under anesthesia. In the awake patient, the push-up test may prove more patient friendly, with the patient requested to push up from a seated position, with the hands firmly pushing on the chair arms. The patient's hands should be in full supination. The patient will report pain or will not use the affected side to push up from the chair.
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Figure 47-15 Posterolateral instability test-degree starting flexed position. The posterior subluxed radial head will reduce with a clunk. |
Inflammatory Tests
In resisted wrist extension (lateral epicondylitis), the examiner resists the patient's effort to extend a flexed wrist while maintaining an extended elbow, pronated forearm, and radially deviated wrist. Pain originating from the lateral epicondyle constitutes a positive test.
In passive wrist flexion (lateral epicondylitis), the examiner fully flexes the patient's wrist, with a pronated forearm, and extends the elbow from a flexed starting position.
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A painful response can also emanate from radial nerve compression, requiring electrodiagnosis.
In resisted middle finger extension (lateral epicondylitis), resistance to the patient's attempt to maintain extension of the middle finger proximal interphalangeal joint causes pain at the lateral epicondyle. This tests the involvement of the extensor digitorum communis in the lateral epicondylar symptoms.
In resisted wrist flexion (medial epicondylitis), the examiner resists the patient's attempt to flex a fully extended wrist, with a supinated forearm and extended elbow. A positive result constitutes pain at the medial epicondyle.
In passive wrist extension (medial epicondylitis), with the patient's wrist flexed, the forearm fully pronated, and the elbow flexed to 15 degrees, the examiner performs wrist extension, forearm supination, and elbow extension simultaneously. Pain emanating from the medial epicondyle constitutes a positive result.
Neurology-Based Tests
Three major mixed nerves and cutaneous nerves need formal assessment, along with the dermatomal sensory distributions and motor end organs. The sensation of these dermatomes and cutaneous nerves should be performed as a matter of routine. The major mixed nerves acting on the elbow are the ulnar, radial, and median nerves.
The ulnar nerve can be palpated behind the medial epicondyle, and any irritability should be noted. A small percentage of normal subjects demonstrate subluxing ulnar nerves, which can be felt to sublux over the medial epicondyle during flexion and relocate during extension. In some, this finding is associated with irritability and some degree of ulnar nerve dysfunction. Sensation is tested with light touch and pin-prick testing of the little finger and ulnar half of the ring finger. Motor function is tested by the examiner, resisting the patient's attempt to spread apart the patient's fully extended fingers, a function of the ulnar nerve innervated interosseous muscles of the hand. However,Martin-Gruber anastomosis may produce normal interosseous muscle function in the presence of an ulnar nerve lesion at the elbow and should be borne in mind. This anatomic anomaly provides motor fibers for interosseous muscle innervation from the median nerve; these fibers enter the ulnar nerve in the forearm, distal to the cubital tunnel. Normally the innervation is entirely from the ulnar nerve, without interruption from the C8 and T1 spinal origin.
In the Tinel test (cubital tunnel syndrome), gentle tapping of the ulnar nerve, as it lies on the posterior aspect of the medial epicondyle, should not cause a tingling sensation in the forearm's ulnar nerve innervated territory and the little finger and ulnar half of the ring finger in the normal subject. When this test is positive, the indication is that there is nerve regenerative activity occurring at the test site, and hence, this is a useful test for tracking the progress of a recovering nerve. Care should be taken not to percuss the nerve too vigorously, since the Tinel sign will be positive even in normal subjects, leading to misdiagnosis. Another source of testing error can be a Guyon tunnel compression of the ulnar nerve at the wrist, which should be sought separately.
The elbow hyperflexion test (cubital tunnel syndrome) consists of maintaining full elbow flexion with wrist extension for 3 minutes.10 A positive finding constitutes pain, numbness, and ulnar nerve distribution tingling owing to this positionally induced nerve ischemia in the cubital tunnel.
The Froment test is a test of ulnar nerve motor dysfunction. The examiner pulls strongly on a sheet of paper that the patient is asked to hold firmly between the thumb and index finger. A positive test consists of the paper being withdrawn by the examiner, since the ulnar nerve innervated adductor pollicis and flexor pollicis brevis deep head are unable to maintain good pinch strength with thumb metacarpophalangeal joint (MCPJ) flexion and interphalangeal joint (IPJ) extension. With ulnar nerve (UN) dysfunction, the thumb MCPJ becomes hyperextended and the IPJ flexes in an attempt to maintain the pinch grip.
The radial nerve is not an easily palpable nerve, but can be palpated 1 to 2 cm distal to the anterior radiocapitellar joint while pronating and supinating the forearm. This motion allows the nerve to pass under the examiner's digit and causes symptoms of pain when the nerve is pathologically compressed. Sensory dysfunction of the main radial nerve trunk (proximal to the elbow) or the superficial radial nerve (distal to the elbow after bifurcation of the main nerve) leads to tingling or paresthesia of the first dorsal web space. Motor dysfunction at the elbow leads to a wrist drop owing to loss of innervation of the wrist extensors in the forearm.
In the resisted forearm supination test (radial tunnel syndrome), pain is reproduced when the examiner resists the patient's attempt at supinating the forearm. This is an important test to carry out when one of the differential diagnoses is tennis elbow because of the infrequent but recognized possibility that the two pathologies coexist.
The median nerve supplies the cutaneous innervation to the radial three and a half digits, along with the ulnar half of the volar forearm. It can be compressed by anomalous anatomy, notably the ligament of Struthers, a ligament that passes from the humeral shaft to the medial epicondyle in 1% of the population.11 Since the brachial artery accompanies the nerve on occasion, there may be concurrent symptoms of vascular compromise. The lacertus fibrosus can also be a source for median nerve compression, and resisted supination from a starting position of supination can cause pain in the median nerve distribution. The other common site for median nerve compression is the carpal tunnel of the wrist, but this latter does not cause any paresthesia of the forearm, as is the case with more proximal compressions. Motor signs of median nerve compression include weakness of forearm pronation (pronator teres), wrist flexion and abduction (flexor carpi radialis), and flexion of the thumb IPJ (flexor pollicis longus). Thenar eminence wasting may also be observed in long-standing cases.
For the resisted forearm pronation test (pronator teres syndrome), the examiner resists the patient's attempt to pronate the forearm with a flexed and extended elbow. The reproduction of tingling and paresthesia in the median nerve distribution in the forearm and hand constitutes a positive result.
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In the resisted middle finger flexion test (FDS compression of Median nerve), when the examiner resists the patient's attempt to flex the middle finger from a starting position of extension, a pathologic flexor digitorum superficialis fibrous arc can cause compression and distal signs as above.
With the Kiloh-Nevin sign (anterior interosseous nerve syndrome), when the patient is asked to form a tip-to-tip pinch with the thumb and index finger, making an O sign, the patient can form only a pulp-to-pulp pinch, reminiscent of a raindrop. The median nerve/anterior interosseous nerve, when compressed between the two heads of pronator teres, interrupts the motor innervation to the flexor pollicis longus and the radial half of the flexor digitorum profundus, with the subsequent inability to flex the terminal joints of the thumb and index finger.12
The lateral antebrachial cutaneous nerve (LACN) is the sensory terminus of the musculocutaneous nerve. Its sensory distribution is the radial half of the forearm between the elbow and wrist. When pathologic, a Tinel sign can be elicited with percussion of the nerve immediately lateral to the biceps tendon in the elbow flexion crease.
Abbreviations
References