Arthroscopy for the Thrower’s Elbow

Michael J. O’Brien and Felix H. Savoie, III

• Valgus extension overload can cause posteromedial pain in the thrower’s elbow as osteophytes form on the posteromedial aspect of the olecranon and impinge on the olecranon fossa. Repetitive microtrauma produces attenuation and instability of the medial ulnar collateral ligament (MUCL), as well as increased forces on the radiocapitellar joint causing chondromalacia and possible osteochondritis dissecans (OCD). Arthroscopic spur resection and removal of loose bodies can relieve pitchers’ pain and return them to their preinjury level of throwing.

Important Points

• Indicated for throwers with posteromedial elbow pain in the acceleration and follow-through phases of the throwing cycle, arthroscopic resection limited to only the spur can be performed safely, and rehabilitation can be progressed rapidly.

• Contraindicated as an isolated procedure for pitchers with tears of the MUCL.

Clinical and Surgical Pearls

• Arthroscopic spur resection is performed with a posterolateral viewing portal and a direct posterior working portal.

• Valgus instability should be assessed arthroscopically before and after spur resection.

Clinical and Surgical Pitfalls

• Resection of only the spur should be performed, leaving the normal native olecranon intact.

• Do not resect more than 3 mm of the native olecranon, as this can place added stress on the MUCL.

• Avoid iatrogenic injury to the ulnar nerve.

The throwing motion in overhead athletes, particularly pitchers, places a tremendous amount of force across the medial ulnar collateral ligament (MUCL) on the medial side of the elbow. The anterior band of the MUCL is the primary restraint to valgus stress, especially at 20 to 120 degrees of flexion, where most athletic activity occurs (Fig. 41-1). The stress of the throwing motion can lead to developmental anatomic changes in the young thrower and places the overhead athlete at risk for specific injury patterns. Continued insult can lead to significant ligament and tendon injuries in the experienced athlete, valgus instability and attenuation of the MUCL, and posterior osteophyte formation.

Figure 41-1 The medial ulnar collateral ligament is composed of the anterior band, posterior band, and transverse band.

During the pitching cycle the valgus stress applied to the extending elbow causes a wedging effect of the medial olecranon into the olecranon fossa (Fig. 41-2). The valgus stress on the elbow joint created by the humeral torque generated during pitching causes near-failure tensile stresses on the anterior band of the MUCL during the early acceleration phase of the throwing cycle. This repetitive microtrauma can lead to progressive valgus instability, with attenuation of the MUCL and subsequent posteromedial impingement of the elbow joint, and increased compressive forces across the radiocapitellar joint. This results in reactive osteophyte production on the posteromedial aspect of the olecranon (Fig. 41-3). The posteromedial osteophyte abuts the medial aspect of the olecranon fossa, causing pain, loose bodies, and a painful area of chondromalacia. Compressive and rotatory forces are increased across the radiocapitellar articulation, leading to the development of synovitis and osteochondral lesions (osteochondritis dissecans and osteochondral fractures) that can fragment and become loose bodies. This continuum of instability and impingement has been referred to as valgus extension overload (VEO).^1,2 It is associated with medial compartment distraction, lateral compartment compression, and posterior compartment impingement.

Figure 41-2 The valgus stress produced during the throwing motion produces medial compartment distraction, lateral compartment compression, and posterior compartment impingement. Arrows indicate areas of impingement.

Figure 41-3 Valgus extension overload osteophyte formation on the posteromedial olecranon, and medial instability with insufficiency of the medial ulnar collateral ligament. Arrows show direction of force in valgus extension overload.

Arthroscopic resection of the posteromedial osteophyte complex and removal of loose bodies can alleviate these painful symptoms experienced by overhead athletes. Kamineni and colleagues ³ found that the function of the anterior band of the MUCL is compromised by resection of the posteromedial olecranon of more than 3 mm. This must be taken into consideration before performance of debridement procedures for posteromedial impingement because excessive resection of bone may further destabilize the elbow and expose a compromised MUCL to further stress and failure.⁴

Identifying and preventing overuse injuries is the key, especially in the young pitcher. Joint injuries in the shoulder and elbow occur when motion segments of the kinetic chain are not properly coordinated during the throwing cycle. This can lead to poor pitching mechanics, overuse injuries, and structural damage. Injury prevention and rehabilitation should center on proper pitching mechanics, core and hip abductor strengthening, scapular control, internal rotation stretching, and joint range of motion.

Preoperative Considerations

History

When obtaining the history from the athlete, it is always important to elucidate the timing of the injury, chronicity of symptoms, and any previous injuries to the elbow, shoulder, or trunk. For the overhead athlete, it is imperative to also discuss features that relate to training and performance. The treating physician should inquire about any changes in training regimens, pitch counts, and types of pitches thrown; about any recent changes in performance such as changes in throwing velocity, loss of control, or loss of stamina; and whether the pain consistently occurs at a specific phase of the throwing cycle.

Athletes will have a chief complaint of posterior or posteromedial elbow pain in the dominant throwing arm. A loss of full extension may also be reported. Baseball players are by far the most commonly affected; the athlete will most often be a pitcher, although infielders and outfielders can also sustain these injuries. Athletes describe pain between the acceleration phase and the follow-through phase of the pitching motion ² (Fig. 41-4). Whereas tears to the ulnar collateral ligament (UCL) usually occur suddenly, with a memorable “pop” and immediate searing pain felt during a single pitch, VEO more commonly develops slowly over time. Pitchers gradually become ineffective and may be able to pitch for two or three innings, followed by a gradual loss of control that becomes evident. An early release because of posteromedial elbow pain will cause the ball to sail high. Chronic impingement and VEO can cause ulnar nerve irritation, loss of elbow extension, and posterior compartment arthritis. Athletes may report symptoms of catching or locking when loose bodies develop.

Figure 41-4 Pain associated with valgus extension overload occurs in the acceleration and follow-through phases of the pitching cycle.

Physical Examination

A throwing athlete’s arm undergoes bony as well as muscular hypertrophy.⁵ One area of bony hypertrophy includes the medial aspect of the olecranon. The patient may experience tenderness over the tip of the olecranon or the medial aspect of the olecranon. A flexion contracture may be present. King and colleagues⁶ reported that 50% of all pitchers have flexion contractures, and about 30% of these pitchers have cubitus valgus deformities.

Range of motion of the elbow should be tested and compared with the contralateral extremity. Flexion contracture may result from posterior osteophyte impingement or anterior capsular contracture, and crepitus may be associated with loose bodies. The ulnar nerve must be evaluated for anterior subluxation out of the groove.

• Tenderness at the posteromedial tip of the olecranon is pathognomonic.

• VEO test: extending the elbow while applying a valgus stress reproduces the pain.

• Posterior olecranon impingement or extension impingement test: pain elicited with forced terminal extension.

• Valgus stress test: increased medial joint space opening, loss of end point, or pain elicited is significant for UCL insufficiency.

• Milking maneuver and gliding valgus stress test: maneuver eliciting pain, instability, or apprehension signifies insufficiency of UCL.

• Examination of the elbow should also evaluate for other causes of medial-sided elbow pain, such as isolated UCL insufficiency, ulnar neuropathy, medial epicondylitis, and flexor-pronator rupture.

Imaging

Routine radiographs should be obtained, including AP, lateral, and oblique images. A posterior osteophyte on the tip of the olecranon can usually be visualized on the lateral radiograph and on the anteroposterior view. Wilson and colleagues ² described two oblique olecranon axial radiographs with the upper arm flat on the cassette and the elbow flexed 110 degrees. This visualizes the posteromedial aspect of the olecranon on profile, demonstrating posteromedial olecranon osteophytes and traction injuries to the medial epicondyle. Magnetic resonance imaging (MRI) and computed tomography (CT) can be helpful to further define the osteophytosis. MRI can also identify chondral lesions, loose bodies, and injury to the UCL.