The Problem

Overhead throwing athletes place extraordinary demands on their elbow to generate and withstand substantial forces on a repetitive basis. Although the ‘throwing athlete’ encompasses many sports, it has been best studied in baseball pitchers. Professional pitchers place enormous valgus force across their elbow, generating torques as high as 64 N/m and angular velocities upwards of 3000 degrees per second. This produces large medial tensile forces, and lateral/posterior compressive forces that must be tolerated by muscular, ligamentous and osseous structures. The ulnar collateral ligament (UCL) is the most important static stabilizer of the throwing elbow. The UCL has three components: anterior, posterior, and oblique or transverse bundles. The anterior bundle extends from the medial epicondyle to a ridge just distal to the sublime tubercle, and resists valgus forces through the range of elbow flexion and extension. The flexor-pronator musculature conveys additional active stabilization against valgus force. Awareness of the negative consequences of overuse has prompted regulations on the number of pitches a young athlete can throw in the United States.

In contrast to other chapters, this resource will only detail the clinical approach and differential diagnosis of medial, lateral and posterior elbow pain in this unique population. Once a diagnosis is established, the clinician should refer to pertinent chapters for a more complete discussion of the available surgical and non-surgical treatment options.

Clinical Presentation

The throwing athlete will often seek assessment for elbow pain associated with impaired pitching performance (e.g., decreased pitch velocity or reduced accuracy). The initial assessment should begin with a detailed history. Age, handedness, sport, level of current competition and career aspirations help establish patient expectations and functional requirements. As with the assessment of all elbow pathology, the duration, location and intensity of the pain should be established in addition to provoking and relieving factors. A history of mechanical or neurological symptoms should be sought. The patient should be questioned about neck, shoulder and wrist pain.

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The presence of elbow symptoms should be understood in the context of training/competition (e.g., during warm-up, practice or competition), effort (e.g., with light versus maximal effort), and the general phases of throwing (windup, early cocking, late cocking, acceleration, deceleration, or follow through). The number of throws per week in both training and competition should be ascertained, as should any recent increase in frequency or intensity of pitches. Additional questions are sport specific, such as the type of throwing activity that is most bothersome (i.e., curveball versus fast-ball). Depending on circumstance, a discussion with the athlete’s trainer or coach may be appropriate to understand training schedule or concerns with pitching technique.

The history should be sufficient to identify the elbow pathology as medial, lateral and/or posterior to be further substantiated on clinical exam and imaging or other diagnostic tests.

Medial Elbow Pain

a. Ulnar Collateral Ligament Injury

  • i. While UCL injury is most often associated with pitching, it is much less prevalent than other overuse conditions that affect the elbow.

  • ii. History: Athletes report medial sided pain during late cocking or early acceleration and an inability to achieve prior maximal pitching velocity. A history of the elbow giving way during exertion raises the concern of an acute ligamentous rupture. Associated symptoms are common and may be due to concomitant ulnar neuropathy, posterior-medial overload syndrome, osteochondritis dissecans (OCD) of the capitellum, loose bodies or tendinopathies.

  • iii. Physical Exam: ligamentous stability is assessed through a variety of valgus-producing special tests. The valgus stress test involves application of a valgus force to a supinated elbow at 30 degrees of flexion; pain at the level of the medial joint line or medial joint widening raise the suspicion for a deficiency in the anterior band of the anterior bundle of the UCL. A similar test at 120 degrees of flexion is thought to isolate the posterior band of the anterior bundle. The milking maneuver also attempts to elicit medial pain in anterior bundle injuries; in this test, the examiner pulls on the thumb of a supinated forearm at 90 degrees of elbow flexion. Similarly, the moving valgus stress test ranges the elbow while the examiner pulls the thumb until maximal supination is achieved; most commonly pain is reproduced between 70 and 120 degrees of elbow flexion.

  • iv. Imaging: Static and stress radiographs can be useful to identify signs of osteoarthritis, loose bodies, OCD lesions or joint line opening. Opening of more than 3mm on a stress view is considered significant for a UCL injury. Ultrasound evaluation of the UCL complex has been described, but is operator dependent. MRI remains the best imaging modality to assess for UCL injuries, and MR arthrography may increase sensitivity for the detection of ligamentous pathology.

  • v. Treatment: Initial treatment is non-operative for nearly all athletes, including a period of rest from sport until asymptomatic followed by physical therapy to strengthen the flexor-pronator mass. A graduated return to pitching may then occur, with ~50% of athletes with these injuries able to return to the same level of sport. Surgical treatment is offered to those who fail non-operative treatment, those with acute complete tears, or those with significant elbow instability. While suture repair may be possible in avulsion injuries, ligament reconstruction remains the standard of care and is thought to offer the best chance for return to sport in the majority of athletes (~80%). Numerous reconstruction techniques have been described, with roughly equivalent clinical outcomes.

b. Ulnar Neuritis

  • i. During the overhead throwing motion the ulnar nerve moves through 1.2cm of excursion, withstands strains of 13% and pressure increases of 6 times its resting value.

  • ii. History: Athletes present with medial elbow pain, paresthesias in the ulnar distribution, hand clumsiness or heaviness, numbness during sleep and impaired throwing.

  • iii. Physical Exam: Percussion of the ulnar nerve at the elbow (Tinel’s sign) or a positive elbow flexion test in which elbow flexion and wrist extension for one minute reproduce the patient’s symptoms. The distribution of numbness and weakness to ulnar-innervated muscles should be documented. Subluxation of the ulnar nerve with elbow flexion should also be identified and recorded.

  • iv. Imaging: Standard radiographs of the elbow may identify osteophytes that might cause ulnar nerve irritation. An MRI is not routinely needed to confirm a diagnosis of ulnar neuropathy, unless a space occupying lesion or other elbow pathology is suspected. An ultrasound can document suspected ulnar nerve instability. Electrodiagnostic studies (EMG/NCV) are useful but can be normal early in the disease process.

  • v. Treatment: The initial focus of treatment is pain control, night splinting to limit elbow flexion, and a physical therapy program to maintain motion, improve strength around the elbow and focus on light sport-specific exercises. Competition or high-intensity practice should be limited until the patient is asymptomatic. Ulnar nerve decompression can be entertained in those failing conservative treatment. While subcutaneous or submuscular ulnar nerve transposition is an option, we reserve this procedure for those failing initial operative decompression or in those also requiring a UCL reconstruction. Return to play after isolated ulnar nerve decompression/transposition is typically 12 weeks.

c. Medial Epicondylitis

  • i. Less common in athletes than lateral epicondylitis.

  • ii. Etiology: Repetitive wrist flexion/forearm pronation and the stabilizing effect of the flexor/pronator mass during valgus loads are thought to predispose an athlete to this injury.

  • iii. History: Athletes report medial elbow pain exacerbated by activity but relieved by rest. Additional complaints corresponding to UCL injury or ulnar neuritis are common.

  • iv. Physical Exam: The most common physical finding is pain to palpation just distal to the medial epicondyle near the insertion of the flexor pronator mass. This discomfort is worsened with resisted wrist flexion and forearm pronation.

  • v. Imaging: Routine elbow radiographs should be obtained to rule out other pathology but are commonly negative. An MRI or ultrasound can be used to confirm the clinical diagnosis by looking for signs of inflammation within the flexor pronator mass, but commonly are not required for diagnosis.

  • vi. Treatment: Most patients can be successfully treated non-surgically with rest, activity modification, local modalities, NSAIDs and physical therapy with a focus on maintaining elbow motion and gradually strengthening the flexor pronator mass. Steroid injections can be considered in refractory cases, although concerns over iatrogenic injury should limit this treatment in the athletic population. Operative debridement and reattachment of the flexor pronator mass can be considered in those who fail non-operative treatment. While the goal of this operation is pain relief, some strength deficit may remain, and post-operative elbow contractures are also possible.

Lateral Elbow Pain

a. Osteochondritis Dissecans (OCD) of the Capitellum

  • Capitellar OCD lesions most commonly occur in adolescent throwing athletes or gymnasts. Valgus stresses from throwing create shear forces across the capitellum, which can damage cartilage and subchondral bone.

  • History: Patients most commonly complain of progressively increasing pain and stiffness that is aggravated by activity and relieved with rest. The pain can be vague and difficult to localize. A history of overuse or increase in activity is common. Mechanical symptoms (i.e. catching or locking) of the elbow are common and can help differentiate OCD of the capitellum from Panner’s Disease (osteochondrosis of the capitellum), which typically occurs in patients younger than 12 years of age.

  • Physical Exam: Pain to palpation over the radiocapitellar joint remains the simplest and most reliable clinical test. Crepitus can commonly be palpated with passive forearm rotation. A loss of 15-20 degrees of elbow motion compared to the contralateral side is frequently identified. The active radiocapitellar compression test reproduces symptoms by fully extending the elbow, and having the patient actively pronate and supinate, thereby compressing the radiocapitellar joint.

  • Imaging: Routine AP, lateral and oblique views of the elbow commonly show flattening of the anterolateral aspect of the capitellum. Loose bodies may be identified. MRI is capable of identifying changes not found on X-rays, and is considered the diagnostic modality of choice. Lesion size, presence of subchondral collapse, and fragment instability (gauged by fluid tracking around the lesion) can all be noted on MRI, and may be enhanced with intravenous or intra-articular gadolinium.

  • Non-operative Treatment: Remains the mainstay of therapy, and requires at least 6 months of rest from pitching to decrease forces across the joint and allow for healing. Physical therapy for motion and strengthening should progress based on patient symptoms. Frequent clinical follow-up with radiographs should be performed to identify healing or progression of the disease process. Once the lesion has healed, the patient may begin graduated return to sport, including an interval throwing program. Throw counts should be monitored and should be limited to avoid re-injury in the young athlete. With this treatment, healing rates are estimated to be approximately 90%, with higher rates of healing noted in those with open physes.

  • Operative Treatment: Surgery is recommended for unstable, symptomatic lesions and/or mechanical symptoms. The surgical management depends on lesion size, stability and the age of the patient. Chondroplasty, microfracture, fragment fixation or cartilage regeneration techniques are all options, but a detailed discussion of the indications of each are beyond the scope of this chapter. Increasing size of the lesion, articular fragmentation, osteoarthritic changes and skeletal maturity are all considered factors that may negatively influence outcomes.

b. Lateral Epicondylitis

  • Caused by repetitive wrist extension or supination/pronation activities, lateral epicondylitis is less common in throwing athletes than other types of overuse syndromes. The extensor carpi radialis brevis (ECRB) is the most common site of pathology.

  • History: Lateral elbow pain aggravated by activity and relieved by rest or NSAIDs.

  • Physical Exam: Pain to palpation just distal to the lateral epicondyle (i.e., the common extensor origin) or pain with resisted wrist extension and supination are characteristic of lateral epicondylitis. The exam should then focus on ruling out other pathologic entities that may affect the elbow.

  • Imaging: Routine elbow radiographs should be obtained to rule out other pathology but are commonly negative. Soft tissue calcification adjacent to the lateral epicondyle may be present. An MRI or ultrasound may demonstrate signs of inflammation within the common extensor origin, but commonly are not required.

  • Treatment: RICE, NSAIDs, physiotherapy for ROM and wrist extensor strengthening, and a graduated throwing program with a focus on proper mechanics remains the mainstay of treatment. In the general population, 80% of individuals will improve at 1 year with nonoperative treatment alone, although upwards of 40% will still have some discomfort with intense activities. Arthroscopic or open ECRB debridement +/- reattachment of the common flexor origin becomes a treatment option if non-operative treatment fails to relieve symptoms. Return to play is typically delayed for 3-6 months following surgery. It is estimated that only 5% of those with lateral epicondylitis require surgery, 95% have good-excellent pain relief post-operatively, and 85% are able to return to prior activities.

c. Radiocapitellar Plica

  • A recently described clinical entity where overuse results in synovial hypertrophy, producing a lateral snapping sensation as the elbow moves from flexion to extension. Often this is a diagnosis of exclusion.

  • History: athletes describe a vague sensation in their lateral elbow. Symptoms may appear similar to those associated with loose bodies, although the elbow rarely locks.

  • Physical Exam: occasionally a snapping or crepitus like sensation can be appreciated over the lateral elbow. Pain may be localized posterior to the lateral epicondyle along the lateral joint line. Beyond that the exam is frequently benign with no restrictions to range of motion or strength.

  • Imaging: X-rays should be obtained but are typically normal in this condition. MRI can be useful to rule out loose bodies or chondral injuries, but frequently do not show the plica.

  • Treatment: Patients may be treated empirically with RICE, NSAIDs and physiotherapy initially, as the diagnosis of synovial plica is challenging and often one of exclusion. Intra-articular steroid injections have been described, but are typically avoided in young, throwing athletes. Arthroscopic resection of the snapping plica can be considered for symptoms recalcitrant to non-operative treatment. Dynamic arthroscopic evaluation typically identifies the plica snapping over the radial head. Careful resection of the synovium and repeat arthroscopic assessment confirms an adequate resection. Post-operatively, patients are allowed progressive ROM and strengthening exercises, with an interval throwing program typically started at 8 weeks.

Posterior Elbow Pain

a. Valgus Extension Overload

  • Forceful, repetitive overhead throwing with resultant contact of the posteromedial olecranon during terminal elbow extension will overtime, produce posteromedial osteophytes that can impinge and cause pain.

  • History: Athletes commonly report posterior and/or medial elbow pain during ball release. As this condition often is associated with other pathology, such as UCL deficiency, symptoms may overlap.

  • Physical Exam: Pain on palpation of the olecranon posteriorly and/or medially is typical. A flexion contracture with loss of terminal extension is common. Special testing involves reproducing symptoms by applying a valgus force to an elbow flexed to 20-30 degrees, then quickly moving the elbow into full extension. Clinical examination should also test for UCL deficiency.

  • Imaging: Plain radiographs alone are typically sufficient to identify the posterior/medial osteophytes. CT scans can be utilized to further characterize these lesions with regards to size, geometry and location. MRI should be obtained if additional soft-tissue pathology is suspected.

  • Treatment: Initial treatment includes rest and a 2-3 week period of throwing restrictions followed by an interval throwing program. Improper pitching mechanics should be addressed during the sport-specific rehabilitation program. Failure to achieve pain-free pitching should prompt additional rest and a more gradual rehabilitation regimen. Intra-articular corticosteroids may provide short-term pain relief but will not address the underlying pathology. For patients requiring surgery, arthroscopic or open resection of the olecranon osteophyte/s can alleviate symptoms. Excessive bone resection can exacerbate pre-existing UCL deficiency, and thus should be avoided.

b. Olecranon Stress Fracture

  • Mechanism of this injury is thought to be similar to valgus extension overload, in which excessive forces are transmitted to the olecranon on a repetitive basis.

  • History: Posterior elbow pain with activity, an achy sensation at rest, posterior elbow swelling and tenderness over the olecranon are characteristic symptoms.

  • Physical Exam: similar to other fractures, posterior elbow swelling with tenderness over the olecranon is common. Often, the athlete lacks terminal extension.

  • Imaging: Bilateral elbow x-rays, including oblique views, can be helpful to detect subtle cortical fractures or physeal widening. If the diagnosis is suspected but not confirmed on x-rays, an MRI will identify intraosseous edema and fracture lines and has the added benefit of identifying other suspected pathology. While bone scans may be used, the widespread availability of MRI has largely removed nuclear scans from our investigation algorithm.

  • Treatment: Olecranon stress fractures should be treated like other fractures – rest, temporary splinting and serial clinical examinations/radiographs to assess healing. We avoid resumption of throwing until clinical and radiographic healing is achieved, which can take between 3-6 months in some patients. Internal fixation utilizing a large compression screw has been found to be a successful form of treatment in those patients who fail to respond to non-operative treatment.

  • Persistent Olecranon Physis: A variant of an olecranon stress fracture occurs in skeletally immature players. Tensile stress from throwing prevents the closure of the olecranon physis, resulting in posterior elbow pain. The presentation and work-up is identical to olecranon stress fractures. These patients are typically treated successfully with a period of prolonged rest from throwing.

Outcomes/Evidence in the Literature

Fleisig, G.S.. “Kinetic comparison among the fastball, curveball, change-up, and slider in collegiate baseball pitchers”. Am J Sports Med. vol. 34. 2006. pp. 423-30. (An analysis of the torques and forces generated at both the shoulder and elbow in collegiate baseball pitchers. The study found fastball and curveballs placed similar forces across these joints, while the change-up may be the safest pitch due to lowest kinetics. The implications of this study to athletes are unclear.)

Farrow, L.D.. “Quantitative analysis of the medial ulnar collateral ligament ulnar footprint and its relationship to the ulnar sublime tubercle”. Am J Sports Med. vol. 39. 2011. pp. 1936-41. (The anatomic study that established the footprint of the medial ulnar collateral ligament on the ulna, including a previously undefined osseous ridge just distal to the sublime tubercle. Mean length of the medial UCL was 53.9mm, and mean length of the footprint was 29.2mm.)

Duggan, J.P.. “The impact of ulnar collateral ligament tear and reconstruction on contact pressures in the lateral compartment of the elbow”. J Shoulder Elbow Surg. vol. 20. 2011. pp. 226-33. (A cadaveric study that quantified the detrimental impact of UCL transection on joint contact pressures and valgus laxity in a simulated throwing elbow. UCL reconstruction was demonstrated to restore native joint mechanics.)

Kim, N.R.. “MR imaging of ulnar collateral ligament injury in baseball players: value for predicting rehabilitation outcome”. Eur J Radiol. vol. 80. 2011. pp. e422-6. (A description of MRI findings in 39 baseball players with a clinically deficient UCL. Return to play with conservative treatment alone was only 31%, with higher-grade injuries on MRI predicting need for surgery.)

Cain, E.L.. “Outcome of ulnar collateral ligament reconstruction of the elbow in 1281 athletes: Results in 743 athletes with minimum 2-year follow-up”. Am J Sports Med. vol. 38. 2010. pp. 2426-34. (The largest series reporting on UCL reconstruction, following 942 patients for at least 2 years. The study found, in experienced hands, UCL reconstruction allowed return to previous level of function in 83% of athletes, with an average of 4.4 months required to return to throwing and 11.6 months to return to competition post-operatively.)

Matsuura, T.. “Conservative treatment for osteochondrosis of the humeral capitellum”. Am J Sports Med. vol. 36. 2008. pp. 868-72. (A retrospective review of 176 juvenile patients with OCD lesions of the capitellum where conservative treatment was attempted. Authors noted that lesion stage was related to radiographic healing and return to sport. Conservative treatment required almost 15 months of rest in stage 1 lesions, with nearly 80% of athletes returning to competitive level baseball. Patients that did not follow the authors protocol and resumed throwing prematurely had substantially lower healing rates.)

Levin, J.S.. “Posterior olecranon resection and ulnar collateral ligament strain”. J Shoulder Elbow Surg. vol. 13. 2004. pp. 66-71. (A cadaveric study testing the importance of posterior olecranon resection on resulting ulnar collateral stress during loads at different degrees of flexion. The study suggested that at low, mostly static, valgus loads the UCL is not affected by upwards of 12mm of posterior olecranon resection. Although 8mm and 12mm cuts placed increasing strain on the UCL, this did not reach statistical significance. The clinical importance of this in professional athletes, who place significant demands on their elbow, is unclear.)

Matsuura, T.. “The value of using radiographic criteria for the treatment of persistent symptomatic olecranon physis in adolescent throwing athletes”. Am J Sports Med. vol. 38. 2010. pp. 141-5. (The authors retrospectively reviewed 16 male baseball players with persistent olecranon physis. They subclassified patients into two groups – one with physeal widening (stage 1) and the other with sclerotic changes (stage 2). They noted that 92% of patients with stage 1 healing resolved with conservative treatments alone, while a small group of stage 2 lesions (4 patients) did not. The authors concluded sclerosis is a predictor of failure of conservative treatment.)


Extreme valgus forces, and the medial tension and lateral/posterior compression it produces, are key to understanding elbow pathology in throwers. While ulnar collateral ligament injury is most synonymous with the throwing elbow, many other diagnoses are possible and can occur at the same time. We describe a framework for the evaluation of the throwing elbow, isolating pain to the medial, lateral and posterior aspect of the elbow. While basic treatment algorithms are described here, we recommend a review of the specific chapters within this resource once a diagnosis has been made.