summary Lateral Epicondylitis (also know as Tennis Elbow) is an overuse injury caused by eccentric overload at the origin of the common extensor tendon, leading to tendinosis and inflammation of the ECRB. Diagnosis is made clinically with tenderness over the lateral epicondyle made worse with resisted wrist extension. Treatment is primarily nonoperative with NSAIDs, activity modification and bracing. Rarely, operative management is indicated for patients with persistent symptoms who fail nonoperative management. Epidemiology Incidence most common cause for elbow symptoms in patients with elbow pain affects 1-3% of adults annually commonly in dominant arm Demographics up to 50% of all tennis players develop risk factors poor swing technique heavy racket incorrect grip size high string tension common in laborers who utilize heavy tools workers engaged in repetitive gripping or lifting tasks most common between ages of 35 and 50 years old men and women equally affected Etiology Pathophysiology mechanism tenodesis effect to optimize grip causes overuse of ECRB precipitated by repetitive wrist extension and forearm pronation common in tennis players (backhand implicated) pathoanatomy usually begins as a microtear of the origin of ECRB may also involve microtears of ECRL and ECU pathohistology microscopic evaluation of the tissue reveals angiofibroblastic hyperplasia disorganized collagen Associated conditions radial tunnel syndrome is present in 5% Anatomy Common extensor origin muscles that originate from lateral supracondylar ridge extensor carpi radialis longus muscles that originate on lateral epicondyle extensor carpi radialis brevis extensor carpi ulnaris extensor digitorum extensor digiti minimi anconeus shares same attachment site as ECRB Ligaments lateral ulnar collateral ligament Nerves posterior interosseus nerve (PIN) enters the supinator just distal to the radial head compression can lead to radial tunnel syndrome (may co-exist with lateral epicondylitis) Presentation Symptoms pain with resisted wrist extension pain with gripping activities decreased grip strength Physical exam palpation & inspection point tenderness at ECRB insertion into lateral epicondyle few mm distal to tip of lateral epicondyle neuromuscular may have decreased grip strength neurological exam helps to differentiate from entrapment syndromes provocative tests the following maneuvers exacerbate pain at lateral epicondyle resisted wrist extension with elbow fully extended resisted extension of the long fingers maximal flexion of the wrist passive wrist flexion in pronation causes pain at the elbow Imaging Radiographs recommended views AP/Lateral of elbow findings usually normal may reveal calcifications in the extensor muscle mass (up to 20% of patients) may reveal signs of previous surgery MRI not necessary for diagnosis increased signal intensity at ECRB tendon origin may be seen (up to 50% of cases) thickening edema tendon degeneration Ultrasonography requires experienced operator (variable sensitivity/specificity) most useful diagnostic tool in experienced operator hands ECRB tendon appears thickened and hypoechoic Studies Histology histopathological studies of the ECRB tendon tissue shows fibroblast hypertrophy disorganized collagen vascular hyperplasia Diagnosis diagnosis is primarily based on symptoms and physical exam Differential Posterolateral plica Posterolateral rotatory instability Radial tunnel syndrome palpation 3-4 cm distal and anterior to the lateral epicondyle pain with resisted third-finger extension pain with resisted forearm supination Occult fracture Cervical radiculopathy Capitellar osteochondritis dissecans Triceps tendinitis Radiocapitellar osteoarthritis Shingles Treatment Nonoperative activity modification, ice, NSAIDS, physical therapy, ultrasound indications first line of treatment techniques tennis modifications (slower playing surface, more flexible racquet, lower string tension, larger grip) counter-force brace (strap) steroid injections (up to three) physical therapy regimen acupuncture iontophoresis/phonophoresis extracoproeal shock wave therapy outcomes up to 95% success rate with nonoperative treatment, but patience is required Operative release and debridement of ECRB origin indications if prolonged nonoperative (6-12 months) fails clear diagnosis (isolated lateral epicondylitis) intra-articular pathology contraindications inadequate trial of nonsurgical treatment patient noncompliance with the recommended nonsurgical treatment Techniques Release and debridement of ECRB origin open incision is positioned over the common extensor origin lift ECRL off of ECRB (located deep and posterior to ECRL) excise degenerative tissue decorticate epicondyle repair capsule if breached side-to-side closure of tendon arthroscopic advantages include visualization and ability to address and intraarticular pathology resect lateral capsule anteriorly (do not pass midradial head to protect LUCL) release ECRB from origin (where muscle tissue begins) decorticate lateral epicondyle Complications Iatrogenic LUCL injury excessive resection of the LUCL should not extend beyond equator of radial head may lead to posterolateral rotatory instability (PLRI) Missed radial nerve entrapment syndrome common in up to 5% of patients with lateral epicondylitis Iatrogenic neurovascular injury radial nerve injury Heterotopic ossification decrease risk with thorough irrigation following decortication Infection Missed concomitant pathology (i.e. PLRI, radial tunnel) Prognosis Non-operative treatment effective in up to 95% of cases Factors associated with increased liklihood of requiring operative managment ipsilateral radial tunnel syndrome history of prior injection (any kind) workers' compensation