CHAPTER 4

Elbow

EPIDEMIOLOGY OF ELBOW PAIN

ELBOW PAIN IN THE GENERAL POPULATION

Prevalence and common causes

•  7% in 40 to 50 years of age to 14% in people older than 50 years

•  Common underlying causes: overuse or trauma (strain, sprain, fracture, and dislocation)

Lateral elbow

•  Most common (MC) location for elbow pain

•  Prevalence: 1% to 3% in adults of working age (MC cause: epicondylitis)

ELBOW PAIN IN ATHLETES

Prevalence and common causes

•  25% of all injuries in sports occur in the elbow, forearm, and wrist

•  Single-stress injury usually caused by contact sports such as football and wrestling

•  Repetitive injury: common in tennis (epicondylitis is seen in up to 50% of players, but not necessarily from sports), bowling, cross-country skiing, rowing, and gymnastics

•  Highest rate of pediatric elbow injuries occurs in baseball, tennis, and gymnastics

Medial elbow: MC location of elbow pain in young athletes (especially throwing athletes)

ELBOW PAIN AT WORK (1)

Musculoskeletal (MSK) disorders of the elbow

•  Usually related to occupational ergonomic stressors

•  Ergonomic stressors: repetitive and stereotyped motions, forceful exertions, non-neutral postures, vibrations, or combinations of these exposures (2)

Epicondylitis

•  Higher in at-risk industry (up to 29%) than in general population (prevalence: 5%) (3)

•  Prevalence varies: 8.9% in meat cutters, ~15% in fish-processing-industry workers

•  Risk factors: repetitive movement of hands or wrists, handling loads >5 kg, activities demanding high hand grip forces and the use of vibrating tools

Ulnar neuropathy at elbow (cubital tunnel syndrome)

•  More commonly seen in workers who perform repetitive motions, commonly flexed at elbow and directly leaning on elbow (eg, driver)

•  Prevalence: 2.8% in workers with repetitive work to 6.8% in floor cleaners

DIFFERENTIAL DIAGNOSIS

MSK and neuropathic causes of elbow pain based on location are listed as follows (4) (Flowchart 4.1 and Figure 4.1):

FIGURE 4.1

Surface anatomy of the elbow (A) anterior and (B) posterior views of the elbow.

FLOWCHART 4.1

Differential diagnosis of elbow pain.

Fx, fracture; MSK, musculoskeletal; N, nerve; PIN, posterior interosseous nerve.

*Adapted from (5). Simons DG, Travell JG, Simons LS. Travell & Simons’ Myofascial Pain and Dysfunction: The Trigger Point Manual. 2nd ed. Baltimore, MD: Williams & Wilkins; 1999:1.

h/o, history of; M, muscle; MC, most common; med., medial; N, nerve; Syn., syndrome; Tx, treatment.

ELBOW INSTABILITY

Differential diagnosis based on the location

•  Lateral elbow instability (6): posterolateral rotatory instability common

      Lateral collateral ligament (LCL) disruption: more stable in pronation

      Dislocation with inadequate ligamentous healing (single trauma): MC

      Valgus instability (usually from chronic overuse), lateral epicondylitis, radial tunnel syndrome, and proximal radioulnar joint instability with radial head dislocation

      Iatrogenic causes: prior lateral epicondylitis release, multiple steroid injections, and radial head excision

      Tardy posterolateral instability: cubitus varus deformity from pediatric supracondylar humerus fracture

•  Medial elbow instability (7)

      Medial collateral ligament (MCL) injury/rupture: more stable in supination

      Common flexor-pronator muscle/tendon insufficiency or disruption

      Valgus extension overload in chronic medial insufficiency: posteromedial osteophytes and soft tissue/synovial hypertrophy

      Congenitally shallow ulnohumeral joint

SNAPPING ELBOW (8)

Differential diagnosis based on etiologies

STIFFNESS (10,11)

Differential diagnosis based on etiologies

•  Traumatic: fracture, dislocation, osteochondritis defect (loose body), crush injuries, and heterotopic ossification

•  Atraumatic: rheumatoid arthritis (RA), osteoarthritis (OA), post septic arthritis, hemophilia-associated hemarthrosis, congenital contracture (arthrogryposis), congenital radial dislocationstatus post elective elbow surgery, biceps repair, or elbow arthroscopy

Heterotopic ossification: can occur secondary to burns, head trauma (if combined with elbow trauma: very high), spinal cord injury, trauma, as well as certain surgeries (commonly seen in multiple surgeries 1–2 weeks after trauma)

ANATOMY

BONE AND JOINT

Bone (12) (Figure 4.2)

•  Distal humerus: medial condyle (more prominent, spool-like trochlear) and lateral condyle (spherical capitellum)

      Three fossa: coronoid (trochlear-ulnar side), radial (above capitellar-radial side), anterior, and olecranon (posterior)

•  Proximal radius: cylindrical radial head with a concave surface, radial neck angled 15° from shaft

•  Secondary ossification centers appear and fuse at predictable ages: need bilateral x-ray to properly evaluate for pathology in pediatric patients (13)

•  Tendon attachment site

      Coronoid process of ulnar: insertion of the brachialis tendon

  Attachment site for anterior bundle of ulnar collateral ligament (UCL): medial facet of the sublime tubercle (~1.8 cm distal to the coronoid tip)

      Tuberosity of the radius: insertion of the biceps tendon

Joints

•  Ulnohumeral (coronoid-trochlear) joint: a hinge (also called ginglymus)—allows flexion/extension and dictates carrying angle

•  Radiocapitellar and radioulnar joints (also called trochoid joints): allow for axial rotation (pronation/supination) or pivoting at the joint

FIGURE 4.2

Bony anatomy of the elbow. (A) Anterior aspect and (B) posterior aspect.

LCL, lateral collateral ligament; LUCL, lateral ulnar collateral ligament; UCL, ulnar collateral ligament.

•  Clinical implication

      Inherent stability at <20° and >120°

      Carrying angle is formed by the long axis of humerus and ulnar bone

  Freedom of movement in flexion/extension and pronation/supination

LIGAMENT (FIGURE 4.3)

Medial (ulnar) collateral ligament

•  Formed by three bundles—the anterior, posterior, and oblique bands

•  Prevents valgus instability, especially the anterior bundle

•  Anterior band is attached from the anteroinferior medial epicondyle to the body of the coronoid process

      Taut in valgus loading in 0° to 85°, during late cocking and early acceleration

      Common location of tear is midsubstance to proximal

•  Posterior band forms the floor of the cubital tunnel

      Contracture of this band would lead to a significant deficit of flexion

      Taut in valgus loading in 55° to 145°

      Experimental sectioning of the posterior band does not increase valgus instability

FIGURE 4.3

Lateral and medial elbow ligaments.

Source: Adapted from Ref. (14). Bryce CD, Armstrong AD. Anatomy and biomechanics of the elbow. Orthop Clin North Am. 2008;39(2):141–154, v.

Lateral collateral ligament (LCL)

•  Lateral UCL

      From the posteroinferior aspect of the lateral epicondyle, courses along the posterolateral margin of the radial head, and inserts on the supinator crest of the ulna (and partially to the annular ligament)

      Main function is to prevent posterolateral rotatory instability

      Common location of injury: avulsion at the humeral origin

•  Other LCLs: the annular ligament, radial collateral ligament, and accessory LCL

NERVE

Nerves in the elbow

•  The ulnar nerve is located at retrocondylar groove and the cubital tunnel between the two heads of flexor carpi ulnaris (FCU; posteromedial)

•  The radial nerve is located at the lateral aspect between the brachioradialis and brachialis

      Gives off the posterior interosseous nerve, which travels in the radial tunnel between the two heads of supinator to the posterior forearm

•  The median nerve lies medial to the biceps tendon and brachial artery

      Enters the forearm between the two heads of pronator teres (PT)

Joint innervation (15) (Figure 4.4)

•  Elbow joint is innervated by multiple nerves: musculocutaneous, median, radial, and ulnar nerve

      Musculocutaneous nerve/lateral antebrachial cutaneous (LABC) nerve: supplies the anterior radial and ulnar aspect of the joint

      Median nerve: supplies the ulnar (medial)-anterior aspect of the joint, distal 1/3 of the humerus, and the medial epicondyle

  Anterior interosseous nerve: supplies the proximal radio-ulnar joint

      Radial nerve: supplies the anterior-radial aspect and lateral epicondyle

      Ulnar nerve: supplies the posterior-medial elbow joint, 2 to 3 cm proximal to humeral condyle to the level of the ulnar head of FCU

      Other contributor is the medial antebrachial cutaneous (MABC) nerve: courses near the ulnar nerve

•  Overlapping of innervation

      Medial (ulnar)/posterior forearm: ulnar and MABC nerve

      Medial (ulnar)/anterior forearm: median and LABC nerve

      Radial-anterior forearm: radial and musculocutaneous nerve

•  Nerves connected with each other by articular branches plexus

Epicondyle

•  Lateral epicondyle: innervated predominantly by radial nerve branches

      Branches from a radial nerve include a collateral branch, branch to the anconeus branch to the supinator, and the posterior cutaneous nerve

      Resection of radial nerve branches is performed for recalcitrant lateral epicondylitis

•  Medial epicondyle: innervated by the articular branch of ulnar nerve at the ulnar groove

FIGURE 4.4

Nerve innervation of the elbow and site for nerve entrapment.

Source: Adapted from Ref. (16). De Kesel R, Van Glabbeek F, Mugenzi D, et al. Innervation of the elbow joint: is total denervation possible? A cadaveric anatomic study. Clin Anat. 2012;25(6):746–754.

MUSCLE

Flexor and pronator muscles

•  Origin at the medial elbow

•  Dynamic support to valgus stress across the medial elbow

•  FCU and flexor digitorum superficialis (FDS) over the anterior bundle of UCL: strengthening exercises implicated in medial elbow instability

•  The maximal valgus force (290 N) on the medial elbow in the late cocking and acceleration phase in pitching but UCL can hold up to 260 N

•  Secondary flexor muscles: PT, extensor carpi radialis longus (ECRL), and flexor carpi radialis (FCR)

Extensor and supinator muscles

•  Inserted to the lateral elbow

•  Supinator: biceps (major) and supinator. Finger and wrist extensors: weaker supinator

•  Secondary extensor muscles: extensor carpi ulnaris (ECU) and FCU

Correlation with ultrasound (US) and MRI (cross-­sectional images; Figure 4.5)

•  Posterior: triceps tendon; anconeus. Medial: accessory muscle in retro-condylar groove

•  Lateral: brachioradialis; ECRL; common extensor tendon; extensor digitorum; extensor carpi radialis brevis; ECU; supinator (superficial head; deep head)

•  Anterior: biceps tendon; brachialis; brachial artery and vein; PT (humeral head; ulnar head); common flexor tendon; flexor digitorum profundus; FCU (ulnar head; humeral head); flexor digitorum superficialis; palmaris longus; FCR

FIGURE 4.5

Cross-sectional image of the elbow showing the relationship of the major nerves around the elbow.

BIOMECHANICS

KINETIC AND KINEMATICS

Loads across the elbow (14,17)

•  Loading through radiocapitellar joint (57%) and the ulnohumeral joints (43%)

•  Force transmission at the radiocapitellar joint: greatest between flexion and pronation, more than supination

      As elbow flexes from full extension, the contact moves from medial part of trochlear notch to lateral trochlear notch (at 90° flexion) then to the radial head and capitulum (in full flexion)

•  Joint force

      Even with falling onto an outstretched hand only from 6-cm height, the axial joint compression is at 50% of body weight

      During a push up, the joint force is 45% of body weight across the elbow

•  Elbow in sports activity

      Transfer of energy between the shoulder and elbow during throwing (17)

  Baseball pitching (rapid extension ~2,400°/s and valgus torque; highest at ball release to prevent elbow distraction)

      Tennis: larger demand on the elbow during serving motion than ground strokes

Kinematics

•  Two-degree freedom: flexion/extension by hinge-like motion at ulnohumeral joint and rotational axis at the trochlea and capitellum

      Normal flexion–extension range of motion (ROM): 0° to 150°

      Supination–pronation: axis through distal ulna and the center of the radial head ROM: 75° pronation and 85° supination

•  ROM: crucial for activities of daily living (ADL)

ELBOW STABILITY

Stabilizer

•  Bony architecture (only at the extremes of flexion and extension) and the stabilizing ligaments/muscles

Bone

•  The elbow is a highly congruent, complex hinge joint (ulnohumeral joint)

•  Olecranon: 75% to 85% of valgus stress resisted by proximal half of olecranon

•  Coronoid (distal half of sigmoid notch): resists 60% to 67% of varus stress

Ligamentous and muscular stabilizer

•  The MCL (anterior band) is the main constraint to valgus instability

      Large valgus force is transmitted during throwing (late cocking and acceleration phase)

      MCL; stronger and less elastic than LCL

•  The lateral UCL is the main constraint to posterolateral rotational instability (18)

•  Posterolateral instability (19)

      MC type of symptomatic chronic instability of the elbow

      When the elbow is extended with the forearm in supination (with arm by the side), the forearm pivots around the medial soft tissue restraints, causing posterolateral subluxation of the radial head with respect to the capitellum

  The annular ligament remains intact so the radioulnar joint does not dislocate

•  Forearm flexor (FCU, lies over MCL): primary dynamic stabilizer against valgus stress

•  Posteromedial rotational instability: caused by varus, axial loading internal rotation and coronoid overloading or coronoid fracture and LCL disruption

Elbow stability with forearm rotation

•  Elbow: more stable in supination (especially in the setting of coronoid fracture)

•  Forearm pronation and supination with decreased valgus laxity compared to the neutral forearm

      Radius moves proximally with pronation of the forearm and distally with supination

      Passive tension in the flexor-pronator muscle with forearm supination

      With passive flexion, the MCL-deficient elbow is more stable in supination, whereas the LCL-deficient elbow is more stable in pronation

ELBOW FUNCTION IN ADL

•  Most ADL require 100° of forearm rotation (50° of pronation and supination [slightly more than pronation]) and ~110° (30°–145°) elbow flexion and extension (20)

•  Reach the head: 140° of flexion

Loss of forearm pronation: Can be compensated to a certain extent by shoulder abduction; however, there is no effective mechanism to replace supination

Elbow in Sports: Overhead Throwing

•  Common cause of overuse injuries in the elbow

Maximal valgus torque

•  Occurs during the cocking and acceleration phases of throwing, in which torque peaks immediately before ball release

•  Pitching: wind-up, stride, arm cocking, arm acceleration, arm deceleration, and follow-through

•  During acceleration the elbow extends from about 110° to 20° at a rate of up to 3,000°/s

•  Significant compressive force (500 N) at the radio-capitellar joint: need static stabilizer (ulnar collateral lig.) and dynamic stabilizer (flexor-pronator muscle)

Repetitive stress of valgus extension overload (21)

•  Medial tension: MCL sprain, tear, rupture, flexor/pronator tendonitis/rupture, and possible ulnar neuropathy

•  Posterior loading: posteromedial osteophyte and olecranon stress fracture

•  Lateral compression of radiocapitellar joint: arthrosis, fragmentation (osteochondritis dissecans) [OCD] and loose body

Fall on Outstretched Hand (22)

•  Varus extension injury without frank dislocation

Soft tissue injury pattern after a fall: circular from lateral to medial in three stages

•  Stage 1: disruption of the lateral ulnar collateral ligament (LUCL)

      Rotatory subluxation of the ulnohumeral joint due to an incompetent LUCL, resulting in posterolateral instability

•  Stage 2: disruption of the LCL complex and the anterior and posterior capsule

•  Stage 3: partial or complete disruption of the MCL (grossly unstable)

PHYSICAL EXAMINATION

INSPECTION (23)

Carrying angle

•  Normally ~5° in male, ~15° in female by long axis of humerus and ulnar

•  Cubitus varus (gunstock deformity): history of supracondylar fracture childhood)

•  Cubitus valgus in the lateral epicondylar fracture can cause tardy ulnar nerve palsy

Swelling

•  Joint effusion

      Flexed elbow on rest: accommodate more fluid with flexion (25–30 mL at 80° flexion) usually at ~ 45° flexion with limitation of extension

      Bulging of soft spot (triangle made up of radial head, lateral epicondyle, and olecranon)

  Normally subtle concave; compared with the other side

•  Bursal effusion: olecranon bursa (posterior and superficial; common) and bicipitoradial bursa (anterior and deep)

Ecchymosis

•  Anterior ecchymosis: rule out (R/O) distal biceps rupture (not always present because of lacertus fibrosis)

•  Medial ecchymosis: MCL rupture (blood vessels with posterior MCL)

PALPATION

•  Palpate for tenderness (systematic way): lateral, medial, posterior, and anterior

•  Lateral: epicondyle, radio-capitellar joint, radial head (rotation of the forearm helps to distinguish epicondyle (not rotating) and radial head (rotating)

•  Medial: epicondyle and MCL

      Tenderness on MCL: highly sensitive but low specificity for tear

       Retro-condylar groove for ulnar nerve palpation

  Tinel sign of ulnar nerve on the retro-condylar groove (compare with the other side)

      Snapping or subluxation/dislocation of ulnar nerve and/or medial head of triceps muscle (medially over the medial epicondyle) as elbow flexes gradually

•  Posterior

      Triangle of olecranon, medial, and lateral epicondyle on flexion. On extension, malalignment of triangle seen in dislocation (eg, supracondylar fracture)

      Olecranon fossa on flexion of the elbow (site for elbow joint injection)

      Focal swelling ± warmth and/or erythema seen in olecranon bursitis

•  Muscle/tendon palpation

      Hook test: distal biceps tendon rupture

  With the patient’s shoulder abducted and the elbow flexed at 90°, the examiner hooks a finger around the lateral side of the distal biceps tendon while the patient actively supinates the forearm. By having the patient supinate the forearm without actively flexing the elbow, an intact biceps tendon becomes more prominent, while the brachialis muscle remains relaxed and is less likely to be mistaken for the biceps tendon

      Lateral to medial at anterior elbow: PT, FCR, PL, and FCU (unable to distinguish by palpation)

      Triceps rupture can be easily overlooked because of continuity of the lateral fascia and anconeus muscle (elbow extensor): often minimal weakness compared to the normal side

•  Lymph node palpation: enlarged medial supracondylar lymph node (24)

      Differential diagnosis: skin infection, rarely lymphoma, and skin malignancies

RANGE OF MOTION

Normal and functional ROM

Stiffness frequently defined as loss of extension of >30° and flexion <120°

SPECIAL TESTS

MCL, medial collateral ligament.

DIAGNOSTIC STUDIES

FLOWCHART 4.2

Diagnostic workup and management of elbow pain.

CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; POC, point-of-care; ROM, range of motion; Tx, treatment; US, ultrasound.

PLAIN RADIOGRAPHS (29)

Indications

•  Persistent pain (despite initial conservative management) ± decreased ROM to evaluate inflammatory or degenerative joint disease

•  Early imaging indicated if trauma, decreased ROM of the joint, and systematic disease (inflammatory, such as RA etc.)

•  Useful (not necessarily sensitive) for detecting fractures, arthritis, calcified loose bodies, heterotopic ossification, and destructive processes, such as osteomyelitis and tumors

Limitations: low capability to assess soft tissues (except tendon calcification), articular cartilage, intra-articular lesion, or bursal effusion. Limited in evaluating complex fracture (CT with 3-D reconstruction)

Individual views

•  Routine: Anteroposterior (AP) and lateral view

      True lateral: elbow flexed at 90°

      Fat pad sign: lucency on the lateral view indicating effusion (especially posterior fat pad sign, anteriorly [sail sign]); indicating ≥5 to 10 mL fluid

      Anterior humeral line: line drawn along anterior surface of humerus; transects the middle 1/3 of the capitellum on true lateral view. Anteriorly displaced in supracondylar fracture

      Radiocapitellar line: line drawn along the radial neck; intersect the capitellum. If not, radial head dislocation or subluxation should be considered.

•  Oblique view

      Oblique view with internal rotation to evaluate humeroulnar joint (trochlear notch/coronoid process of ulna) and tip of olecranon process

      Oblique view with external rotation to evaluate radiocapitellar and proximal radioulnar joints

•  Valgus stress radiography

      Compare with the asymptomatic elbow

      May be useful in asymmetric medial joint space opening in patients with insufficiency of the MCL

•  Bilateral views in pediatric patients

      Ossification centers: “CRITOE” mnemonic for capitellum, radius, medial (internal) epicondyle, trochlear, olecranon, lateral (external) epicondyle, ossified at 1, 3, 5, 7, 9, and 11 years, respectively, although it can be highly variable

POINT-OF-CARE ULTRASONOGRAPHY (30)

Common indications and findings: soft tissue pain, effusion, and superficial joint structural pain (31)

•  Lateral/medial epicondylitis (common extensor/flexor tendinosis [insertional tendinosis]/tear)

•  Tendon: partial/full thickness tear of biceps and triceps

•  Ulnar and radial collateral ligament tears

•  Cubital, bicipitoradial, or olecranon bursitis (bursal effusion)

•  Ulnar entrapment neuropathy, posterior interosseous nerve entrapment (radial tunnel syndrome), median neuropathy (ligament of Struthers, PT)

•  Soft tissue mass evaluation; ganglion cyst, lipoma, and enlarged lymph node

•  Joint evaluation

      Joint effusion (able to detect 1–3 mL)

  US elbow flexed at 90°, palm facing the table, posteriorly on the olecranon fossa; more sensitive than x-ray finding of fat pad elevation

      Synovial hypertrophy and increased vascularity in synovitis

      Intra-articular loose body; often not sensitive

MRI/MRA (32)

Common indications

•  Evaluation of intra-articular or periarticular (eg, ligaments) structure

•  Recalcitrant pain (despite conservative treatment) and planning for surgery (providing clearer relationship between the structures) or further evaluation of mass lesion (33)

Evaluation of common abnormal findings

•  Muscle, tendon, and ligament pathologies

      Posterior: pathology for triceps and medial side, for example, accessory muscle in retro-condylar groove (posteromedial)

      Lateral: common extensor tendon, LCL, supinator (radial tunnel)

      Anterior: biceps/brachialis insertion, pronator (medially), brachioradialis (laterally), medial and radial nerve

  Tear/rupture of distal biceps attachment to radial tuberosity and brachialis attachment to coronoid process

      Medial: common flexor tendon, UCL

•  Location of common entrapment neuropathies

      The ulnar nerve at the retro-condylar groove and cubital tunnel (by the two heads of FCU)

      The posterior interosseous nerve at the radial tunnel (between the two heads of supinator)

      The median nerve between the two heads of PT, under lacertus fibrosus, and flexor digitorum superficialis

      Common abnormal findings: focal enlargement/signal change, increased T2 SI, nonuniform fascicles, subluxation/dislocation, abnormal muscle pathologies (increased T2 SI, atrophy, and fatty infiltration) and underlying structural pathology for entrapment syndrome (aberrant muscle, ganglion cyst, and osteophytes, etc)

•  Subtle bony lesion can be seen in Little Leaguer’s Elbow: fragmentation or distraction of the medial epicondyle or apophysis

MRA

•  OCD, loose body, and plica pain

•  UCL and LCL (axial and coronal images)

      Helpful in patients without joint effusion for subtle ligament tears

CT SCAN

•  Performed when evaluating bony structures, when MRI is contraindicated and quicker modality is preferred

      Osteoid osteoma or myositis ossificans, calcified loose bodies, and fragmented osteochondral lesions

•  3-D construction: for surgical planning, CT arthrogram when MRI is contraindicated

TREATMENT

NONOPERATIVE MANAGEMENT

Education

•  ROM/stretching at the end range a few times a day at least, if not contraindicated

      Prevent elbow flexion contracture (maintain elbow extension)

•  Avoid leaning on the elbow (in ulnar neuropathy at retrocondylar groove)

•  Gradual increase in resistive strengthening exercise

Physical or occupational therapy

•  A, AA ROM exercise ± dynamic splinting or static progressive splinting (less discomfort and better compliance)

•  Eccentric strengthening exercise of wrist extensor and flexor usually after stretching with full pain free ROM

•  Evaluate ergonomics and abnormal biomechanics (neighboring joint dysfunction, evaluation of sports or work equipment)

•  Taping: different methods available, parallel to the common extensor, diamond tape (center on the lateral epicondyle) for lateral epicondylitis or others (34)

•  Modality for temporary pain relief

Medication

•  Patch/gel (nonsteroidal antiinflammatory drug [NSAID]; diclofenac, lidocaine, capsaicin, and nitroglycerin), acetaminophen, or NSAIDs

Orthotics

•  Elbow strap (medial and lateral epicondylitis), elbow hinged orthosis (with/without dynamic control), or wrist splint (often useful for resting wrist flexor/extensor muscles in epicondylitis)

Common elbow orthoses

Injection

•  Landmark-based injection

      Elbow joint injection to the soft spot (by triangle of olecranon, lateral epicondyle, and radial head, see Figure 4.1)

      Olecranon bursal effusion (to bulging mass)

      Lateral and medial epicondylitis (needling to the bone)

•  US-guided injection

      Common indications: tenotomy (needling or Tenex^®, joint injections, small ganglion cyst removal, and injection around the nerve, or when using biologics)

SURGERY

Indications

•  Failed conservative treatment for disabling pain

•  Contracture: flexion >30° and extension <130°

•  Loose body, OCD with pain, and decreased range

•  Recalcitrant OA and RA

•  Recalcitrant lateral or medial epicondylitis

•  Repair of collateral ligament tear (in high-performing athletes or failed conservative management)

•  Severe ulnar neuropathy or symptomatic mass (ganglion or soft tissue mass)

Total elbow arthroplasty

•  Indications: >65 years old, severe pain throughout ROM/limited motion/functional deficits despite nonoperative interventions, or painful RA (MC)

•  Contraindications: aseptic loosening (~5%, clinically), infection, inadequate soft tissue envelope, instability, ulnar neuropathy, triceps insufficiency

•  Humeral and ulnar implant ± resection of the head of radius

•  Precaution after procedure: avoid lifting >10 lb, repetitive lifting >2 lb after the procedure

TENDON, LIGAMENT, AND BURSA PATHOLOGY

LATERAL EPICONDYLITIS

Introduction

•  Epidemiology: 1% to 3% of the population, peak between 35 to 50 years old and male = female

•  Pathology: angiofibroblastic tendinosis, degenerative rather than an inflammatory process

      MC involved tendon: extensor carpi radialis brevis (lateral epicondyle to third metacarpal)

      Two hypovascular zones: at the lateral epicondyle and 2 to 3 cm distal to the extensor insertion

•  Etiology and risk factors

      Direct trauma, overuse (backhand tennis stroke, more common in novice player), fluoroquinolone antibiotics, and anatomic predisposition

      Neighboring joint pathologies (rotator cuff pathology, de Quervain tenosynovitis, and carpal tunnel syndrome)

  Underrecognized shoulder pathology with decreased internal rotation of the shoulder

           –  Requires increased wrist flexion with increased eccentric contraction of the wrist extensor muscle (increased risk of lateral epicondylitis) (35)

      Others: oral steroid treatment, previous history of smoking, and so on (36)

History and physical examination

•  Pain and tenderness on lateral elbow (epicondyle) ± referred pain to the wrist

      Location of tenderness not changing with forearm rotation (supination/pronation) versus rotating tenderness in radial head/neck lesion (radial tunnel syndrome)

•  Neurologic test: usually normal

      Symptomatic posterior interosseous nerve irritation: ~ 5% of patients with lateral epicondylitis

•  Provocative test: Cozen’s test, Mill’s test, and Maudsley’s test

Diagnosis

•  Clinical diagnosis supported by imaging study

•  Imaging modality to rule out unusual pathologies in recalcitrant case or unresponsive to the typical treatment: do not order initially

      X-ray: cortical irregularity, spur, and calcification

      US

  Common findings: focal hypoechoic swelling with loss of fibrillar pattern in the common extensor tendon origin, calcification of the common extensor tendon, and complete or partial discrete cleavage tears

  Specific (67%–100%), but not as sensitive (64%–82%) as MRI (sensitivity: 90%–100% and specificity: 67%–100%) (37)

      MRI: to evaluate intra-articular pathology, radial collateral ligament, or extent of the tear

  Usually not necessary unless the presentation is atypical or unresponsive to the treatment

  Common findings: diffuse heterogeneity, increased T2 signal within the extensor tendon, tendon thickening in symptomatic elbows and edema of the common extensor origin (38)

  Abnormal finding common in asymptomatic population (up to 35%)

•  Differential diagnosis (39)

      Radial tunnel (supinator) syndrome (40)

  Rare (compared to lateral epicondylitis), radiating pain distally (more common than epicondylitis), tenderness 3 to 4 cm distal to the lateral epicondyle (near the radial neck)

      Radiocapitellar arthrosis and plica (often concurrent)

  A painful clicking at terminal extension and forearm supination as well as maximal tenderness over the posterior radiocapitellar joint

      Osteochondral defect of the capitellum

      Lateral UCL injury/posterolateral rotatory instability

      Partial tear of the distal biceps tendon

Treatment

•  Benign neglect: initial brief rest (with gradual increase of activity) and observation

•  Education on use of sports equipment: for proper tennis racket grip

      Nirschl technique: circumference of the racket handle should be equivalent to the distance between the proximal palm crease to the tip of the ring finger

•  Therapy

      Isometric and eccentric exercises are better than a contract relax stretching program

  Initially pain-free resistive strengthening (three sets of 15, bid of wrist curl, elbow flexion/extension, forearm pronation and supination), as well as scapular stabilization

      Eccentric strengthening exercises using device (Thera-Band FlexBar^® or rubber band) and grip strength (2–3 minutes, bid)

      Deep friction massage (2–3 minutes, bid), ice massage (5 minutes, bid), and stretching (quick varus force to the forearm that is supinated and extended, 30 for 5 reps, tid)

      Iontophoresis and phonophoresis

•  Medications: NSAIDs, diclofenac patch, or topical nitric oxide patch (1/4 of glyceryl trinitrate, 1.25 mg/d patch, cautious of headache or dizziness initially)

•  Orthotics: counterforce band and cock-up splint (no significant long-term benefit)

•  Injections

      Steroid injection: for short-term pain relief (not for the long term)

      Platelet-rich plasma (PRP) injection: for younger athletes and may have longer duration of effect (41)

      Tenotomy (needling, use large gauge needle) under US guidance

      Tenex^®; ultrasonic percutaneous tenotomy in recalcitrant lateral epicondylitis (42)

•  Extracorporeal shock wave

•  One year follow-up evaluation success rates for treatments: 69% for injection, 91% for physiotherapy, and 83% for observation (43)

LATERAL COLLATERAL LIGAMENT SPRAIN

Introduction (26)

•  Uncommon cause of pain in the lateral elbow ± posterolateral instability

      Underrecognized often coexisting with lateral epicondylitis

•  Anatomy and biomechanics (6)

      Lateral ulnar collateral ligament (most important lateral stabilizer), radial collateral ligament, and annular ligament work together to stabilize the ulnohumeral and radiocapitellar joints

      Dynamic posterolateral stabilizers: extensor muscles (ECU) and supinator

  Radial nerve injury (affecting dynamic stabilizers) can cause instability

•  Etiology

      Trauma (fall on outstretched hand with forearm supinated; MC), elbow dislocation, iatrogenic injury (lateral epicondyle injection and/or radial head fracture with cubitus varus)

      Delayed onset: cubitus varus (eg, history of pediatric supracondylar humerus fracture), crutch walking, or connective tissue disorder

History and physical examination

•  Pain on lateral elbow ± locking, clicking, and snapping

      Aggravated by activities resulting in supination, extension, and valgus forces, such as carrying a grocery bag with possible elbow giving out

•  Provocative test to assess for concomitant posterolateral instability

      The posterolateral rotatory instability test (pivot shift)

      Floor push-up test

      Chair apprehension signs: a sitting push-up

Diagnosis

•  Clinical suspicion confirmed by imaging study

•  X-ray (stress radiograph during pivot shifting test): slight malalignment of the ulnohumeral joint, overlap of the radial head and capitellum

•  US: calcification in LCL located deep to the common extensor tendon, often fibrocartilaginous meniscus homolog (which is attached to the LCL). Loss of continuity and fibrillar pattern, often challenging (44)

•  MRI and magnetic resonance arthrography (MRA)

      Coronal MR is best view for tear of the LCL on humeral attachment. Sagittal MR is best view to see posterolateral subluxation of the radial head with respect to the capitellum (45)

Treatment

•  Hinged elbow brace with forearm in full pronation for 4 to 6 weeks in acute sprain/injury

•  Strengthening dynamic stabilizers (extensor and supinator muscles) in patient with instability

•  Surgery referral if failure to respond to conservative treatment for chronic recurrent lateral instability with impaired ADLs/affecting profession (athletes)

MEDIAL EPICONDYLITIS

Introduction (46)

•  Epidemiology

      Prevalence: 0.3% to 0.6% in men and 0.3% to 1.1% in women, common in 40 to 60 years

  Twenty percent of all epicondylitis (or more), underrecognized

      Seventy-five percent in the dominant arms

      Ulnar nerve and UCL injury often coexist (upto 23%–50%) (47)

•  MC involved tendons: PT and FCR muscles

•  Etiology and risk factor

      Activities involving respective forearm pronation and wrist flexion

  Athletes: pitchers (valgus force at late cocking and acceleration) and also seen in golf (improper swing), tennis, bowling, racquetball, football, archery, weightlifting, and javelin throwing

  Occupations: carpentry, plumbing, and meat cutting

History and physical examination

•  Pain of insidious onset along the medial elbow, worsened by activities (forearm pronation and wrist flexion)

      ± Tingling, numbness in the medial hand/fingers (due to concomitant ulnar nerve injury)

•  Tenderness 5 to 10 mm distal and anterior to the midpoint of the medial epicondyle (overlapping with UCL)

•  Symptom reproduction by resisted wrist flexion and pronation

Diagnosis

•  Clinical diagnosis supplemented by imaging study

      X-ray: soft tissue calcification in proximity to the epicondyle (20%–30%) and cortical irregularity

      US to evaluate the UCL as well as ulnar nerve (focal swelling and subluxation) in addition to common flexor tendon (calcification and hypo/heterogenic echogenicity)

  Evaluate traumatic tears to the flexor/pronator origin at the epicondyle

      MRI: if unresponsive to initial management or to evaluate intra-articular/intracortical pathology

      Electrodiagnosis (EMG) for ulnar neuropathy at elbow if sensory or motor symptoms from ulnar neuropathy persists

•  Differential diagnosis

      UCL injury (often coexist)

      Ulnar neuropathy and irritation of medial antebrachial cutaneous nerve

      Medial elbow intra-articular pathology

      FCR/pronator avulsion: usually concomitant with UCL rupture

Treatment

•  Nonoperative management

      Temporary cessation of offending activities while maintaining flexibility and ADLs

      PT: initial flexibility (stretching) exercises and then gradually progress to eccentric strengthening exercises of wrist/finger flexor/forearm pronator strengthening

  Premature discontinuation (of home exercise program) is common reason for failure

      Counterforce bracing (rarely cause AIN/posterior interosseous nerve [PIN] irritation), night splinting, or ice massage

      NSAIDs and steroid injection to subaponeurotic recess deep to the flexor pronator mass (no clear benefit for 3 months and 1 year)

      Prolotherapy or PRP injection if unresponsive or high-performance athlete (with concomitant treatment of UCL lesion)

      Extracorporeal shock wave therapy

•  Surgery: after at least 3 to 6 months trial of nonoperative treatment or may be considered earlier in elite throwing athletes

      Excision, firm reattachment, and/or repair of the resultant defect

      Management of any concurrent ulnar nerve or UCL pathology

LITTLE LEAGUE ELBOW

Introduction (48)

•  A group of symptoms in the elbow caused by overuse stress injuries during childhood and adolescents

      Traction apophysitis, medial epicondyle avulsion fracture, OCD

•  Etiology and risk factors

      Repetitive valgus extension overload and compression of the lateral structure (radial head and capitellum)

      Pitching with fatigued arm, competitively pitching for >8 months/yr, and >80 pitches per appearance

History and physical examination

•  Pain ± popping, giving way when throwing

•  Point tenderness over the medial epicondyle and pain with resisted flexion and pronation

Diagnosis

•  Clinical diagnosis with imaging study for differential diagnosis

•  X-ray: normal, avulsion difficult to diagnose, compare with noninvolved side

Treatment

•  Complete rest from throwing for 4 to 6 weeks (minimum) ± posterior elbow splint followed by slow progressive throwing program over 6 to 8 weeks

      Average return to competitive pitching: 12 weeks

•  If OCD present, protect elbow for a few months and early ROM in 1 to 2 weeks

•  Ortho referral if apophysis is widely displaced. Early ROM exercise recommended

•  Prevention: limiting pitching to <105 pitches per game (recommendations based on age: 50 pitches in 8–10 years to 105 pitches in 17–18 years), breaking pitches (ie, curve balls and sliders) should not be thrown until skeletal maturity, no more than 9 months per year

ULNAR COLLATERAL LIGAMENT (UCL) INJURY

Introduction (7,22)

•  Most commonly injured ligament in the elbow (18)

      Common in overhead sports (baseball, tennis, volleyball, golf, javelin, and football)

•  MC location of injury: anterior bundle, at the humeral insertion with avulsion of the medial epicondyle

•  Etiology: chronic repetitive stress to the elbow

      Late cocking and acceleration phase in overhead throwing

•  Sequels of chronic medial instability from UCL injury (causing valgus extension overload)

      OCD of the capitellum, radiocapitellar chondromalacia/arthritis, posterolateral synovial plica thickening, posteromedial osteophyte/stress fracture of the olecranon, ulnar neuritis, flexor/pronator weakness

History and physical examination

•  Pain (may be minimal, medial elbow initially), impaired performance (loss of control), and instability ± ulnar nerve irritation (by hematoma in acute tear or valgus force)

•  Inspection for carrying angle/muscle mass, ROM (elbow flexion contracture common), and normal neurological examination (±Tinel sign for ulnar nerve at retro-condylar groove; not specific)

•  Provocation test

      Static valgus test at 70° to 90°, moving valgus stress test (more accurate), and milk test

Diagnosis

•  Clinical suspicion confirmed by imaging study

•  X-ray (AP and lateral): avulsion fragment in acute injury, ossification of the UCL, loose bodies, and radiocapitellar or ulnohumeral osteophytes in chronic cases

      Valgus stress view (negative in partial tears)

•  US: elbow slightly flexed (20°–30°) and forearm supinated Normally cord-like structure with broad attachment to the medial epicondyle

      Injured UCLs: hypoechoic, disrupted fibers (cautious of normal anisotropic artifact), calcification of the ligament, nonvisualization of the ligament

      Dynamic maneuver with valgus stress (with side to side difference of ulnohumeral joint gap and symptom reproduction)

•  MRA: most sensitive and specific.

      MRI/A: to evaluate differential diagnosis/concomitant pathologies: radiocapitellar impaction, lateral instability patterns, and nonosseous loose bodies

Treatment

•  Nonoperative management

      Temporary cessation of offending activities, NSAIDs, ice/modality, and elbow splint at 90° at night

      PT: strengthening exercise (pronator, flexor muscle) gradually then return to sports (in 2–3 months) once strength is normalized. General upper body strengthening is important as well

  Average return to play for thrower: 6 months after the diagnosis. Recommend use of elbow extension braces for throwing and lifting

      PRP injection to UCL (49)

•  Operative management: UCL reconstruction “Tommy John surgery” for high-performing throwing athletes (25% of major leaguers and 10% of minor leaguers have undergone the surgery) (29)

VALGUS EXTENSION OVERLOAD SYNDROME (POSTEROMEDIAL IMPINGEMENT)

Introduction (30)

•  Epidemiology: common in throwing athletes (>50% in professional baseball players), swimmers, volleyball players, gymnasts, racquet sports athletes, and golfers

•  Pathophysiology

      Chronic anterior MCL injury shear force at the posteromedial olecranon olecranon osteophytes/chondromalacia common flexor tendinosis and ulnar neuropathy

History and physical examination

•  Posterior (posteromedial) elbow pain near elbow terminal extension (pain at ball release in thrower)

•  Mild decrease in range (extension; common in dominant throwing arm) with pain otherwise normal

      Tenderness on posteromedial aspect of the olecranon

      Symptom reproduction with valgus stress on elbow in 20° to 30° of flexion while forcing the elbow into terminal extension (vs UCL stress test from valgus stress with 0°–20° flexion)

Diagnosis

•  Clinical diagnosis supplemented by imaging study

•  X-ray: AP, lateral, and axial (check contralateral elbow): posteromedial olecranon osteophytes or loose body

•  MRI: if diagnosis is in question or to evaluate concomitant injury (especially MCL injury suspected) or for differential diagnosis

      MCL attenuation, redundancy, osteophytes on the posteromedial olecranon, and intra-articular loose body

      Stress fracture of olecranon (pain during or after throwing)

•  Differential diagnosis

      Distal triceps tendonitis: posteromedial pain with resisted arm extension (not necessarily at end range)

Treatment

•  Nonoperative management

      Active rest: resting from throwing and other activities (no throwing for 10–14 days), rotator cuff strengthening, flexor pronator strengthening, and improvement in mechanics gradual interval throwing program with plyometric exercise

      Intra-articular steroid injection to control acute pain

•  Surgery: in failed conservative management

      Resection of osteophytes, removal of loose bodies, and debridement of chondromalacia

DISTAL BICEPS TENDINOPATHY/TEAR

Introduction (22)

•  Distal biceps tendon rupture: uncommon compared to the proximal rupture, 1.2/10⁵, ~3% of all biceps tendon injury

      Male > female, peak incidence in 40 to 60 years of age, from single trauma (a sudden eccentric contraction)

      Full rupture (more common than partial tear) with intact aponeurosis only mild proximal retraction of muscle (therefore underrecognized)

•  Etiologies and risk factors (31)

      MC activity: weight training (lifting ≥40 kg usually)

      Minor trauma (incomplete/partial tear) and overuse

      Systemic risk factors: tendon degeneration and rupture more commonly seen in ankylosing spondylitis (AS), rhematoid arthritis (RA), acute rheumatic fever, systemic lupus erythematosus (SLE), end-stage renal disease (ESRD), and hyperparathyroidism

      Local risk factors; hypovascularity and impingement

  Common location: 1 to 2 cm from the insertion (radial tuberosity): hypovascular zone

  Impingement between the radius and ulnar during pronation

           –  Distance between radius and ulna: decreased from 8 to 4 mm during pronation

  Impingement by osteophyte-enthesopathy at the radial tuberosity or by bicipitoradial and interosseous bursa

History and physical examination

•  Pain on the antecubital fossa (in acute trauma or a rupture) or poorly defined lateral elbow pain (tendinopathy or partial tear)

      In rupture: “pop,” mass in the arm, ecchymosis, and mild weakness with supination (eg, turning screwdriver)

•  Provocation tests

      Hook test, biceps squeeze test, and biceps crease interval test

Diagnosis (32)

•  Clinical diagnosis confirmed by imaging

•  Imaging study

      US: often difficult to scan in long axis; oblique sagittal (medial-proximal to lateral-distal), tilting down distally

  Dynamic images (supination and pronation) and compare with the contralateral side

      MRI: can evaluate neighboring structure (bony hypertrophy, bone marrow edema in high-grade tears)

•  Differential diagnosis: bicipitoradial bursitis (can be secondary finding), interosseous bursitis, and cubital bursitis

Treatment (33)

•  Activity modification, articulating elbow orthotic, and US-guided injection to bicipitoradial or interosseous bursa for pain control. Strengthening exercises of elbow flexor and supinator

•  Surgical indication: in acute rupture in high-performing athletes (even during the season as chronic repair/reconstruction not predictable) or in individuals with persistent pain despite conservative treatment, anatomic repair, and/or reconstruction

BICIPITORADIAL BURSITIS

Introduction (50)

•  Rare but underrecognized as well

•  Etiologies

      Overuse by repeated pronation/supination

  Bicipitoradial bursa decreases friction forces between the biceps tendon and the radial tuberosity during elbow movements

      RA, synovial chondromatosis, synovitis, synovial cyst, and infection

History and physical examination (51)

•  Anterior elbow (cubital fossa) pain or discomfort with elbow movements

•  Worsening/reproduction of pain with pronation (jamming between biceps tendon and radial tuberosity) ± signs of median nerve irritation

      Fullness in severe cases

Diagnosis

•  Clinical suspicion confirmed by imaging study

•  US (effusion surrounding biceps tendon) (52) or MRI to further evaluate neighboring structures (intra-articular and intracortical lesion)

•  Differential diagnosis: interosseous bursitis, lipoma, infection, tenosynovitis, ganglion cysts, pigmented villonodular synovitis, or malignant tumor

Treatment

•  Nonoperative management with NSAIDs, maintain flexibility, aspiration of the bursa, and steroid injection to the bursa under US

•  Surgery if nerve (median or AIN) compression, biceps tendon degeneration/tear, persistent or recurrent symptoms despite conservative management

TRICEPS TENDINOPATHY AND TEAR (22)

Introduction (53)

•  Epidemiology: rare

      Male with heavy manual labor jobs or sports activity: weight lifter (bench pressing), football player, javelin thrower, baseball player, and gymnast

      Triceps tendon rupture: very rare (<1% of all tendon injury)

  Partial tear more common than complete tear

•  Etiology and risk factors

      MC mechanism of tear/rupture: eccentric contraction of the elbow (fall on the outstretched hand or direct blow)

      Risk factors: anabolic steroid use, diabetes, ESRD, lupus, hyperparathyroidism, olecranon bursitis, or steroid injection

•  Triceps tendinopathy: often accompanied by posterior impingement, loose bodies, or tennis elbow

History and physical examination

•  Posterior elbow pain (especially on resisted extension), mild weakness (with pain), and tenderness

•  Snapping triceps syndrome: medial slip or muscle belly detached from the main tendon, snap over the medial epicondyle, may cause ulnar neuropathy (asymptomatic in most cases)

•  Rupture

      Ecchymosis (in acute), defect (later), inability to extend the elbow actively (in full rupture)

      Modified Thompson test (often difficult due to long lever arm, small cross-section size of triceps compared to gastrocsoleus muscle)

Diagnosis

•  Clinical diagnosis confirmed by imaging study

•  AP and lateral x-ray (may see flakes sign: flecks or avulsed fragment from olecranon [pathognomic])

      X-ray of the wrist for concomitant injury

•  US: fluid-filled defect within the distal triceps tendon, avulsion fracture, distinguish partial versus complete tear

      Partial tear: medial side of tendon insertion area is more commonly involved

      Complete tear: a large fluid-filled gap between the distal end of the triceps tendon and the olecranon process

•  MRI for further soft tissue evaluation and associated osseous injuries: radial head fracture, and distal radius fx (CT if MRI is contraindicated)

Treatment

•  Nonoperative: good result, splint immobilization for ~4 weeks at 30° flexion, then gradual stretching and strengthening

      Indications: partial (<50%) or complete within muscle belly, mild weakness, or fatigue

      Tendinopathy: usually resolve in 3 to 6 months of conservative management (54)

•  Surgical if acute complete tear at the tendinous insertion with significant loss of triceps strength or failed conservative treatment in highly active patients with partial tears

      Earlier (ideally within 2 weeks) intervention, the better outcome

OLECRANON BURSITIS

Introduction (55,56)

•  Epidemiology: incidence unknown, male > female, and common in 30- to 60-year age group

•  Anatomy

      Olecranon bursa: synovium-lined sac promoting gliding between the olecranon and the overlying skin

•  Etiology and risk factors

      Traumatic, inflammatory, and infectious (20%)

  Septic bursitis: Staphylococcus and other gram-positive organism: MC

  Trauma/sports: common in football

      Predisposing conditions: RA, gout, pseudogout, chondrocalcinosis, and pigmented villonodular synovitis

History and physical examination

•  Swelling over the proximal olecranon (usually unilateral) ± pain

•  Joint mobility: intact; may result in sympathetic effusion in the bursa and extension to the forearm

•  Usually not tender (tenderness in only up to 20%–45%), fever (up to 50% in infectious bursa), and erythema (more often in septic form)

•  Increased temperature (>2.2°C difference: 100% sensitivity and 94% specificity)

Diagnosis

•  Clinical diagnosis confirmed by imaging study

•  Imaging: x-ray R/O olecranon fracture, US to confirm and evaluate soft tissue lesion (triceps tendinopathy/tear or joint effusion), MRI in presence of abscess or to R/O osteomyelitis

•  Aspiration (18–20 G, usually from lateral approach) for fluid analysis

      Gram stain (positive in 50%–60%), culture, WBC count (<1,000/mm³: aseptic; >10,000/mm³: septic), and glucose level (<50% of serum level: septic)

Treatment

•  Ice, compressive dressing, and avoidance of aggravating activity (eg, leaning on elbow)

•  Aspiration to R/O infection; 90% resolves in 6 months

•  Intrabursal steroid injection: lack of clear benefit, related to the infection, skin atrophy, and chronic pain

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