The three most common baseball injuries are rotator cuff tears, ulnar collateral ligament sprains, and medial epicondyle injuries including thrower’s elbow and little league elbow.

Rotator Cuff Tears

Rotator cuff tears can occur from repetitive overhead throwing where the tendons become compressed as they pass through the shoulder joint. Of the five phases that make up the baseball pitching or throwing motion, the late cocking and follow-through phases place the greatest load of force on the shoulder. In order to generate maximum pitch or throwing speed, the thrower must bring the arm and hand up and behind the body which defines the late cocking phase. This arm position of extreme external rotation helps the thrower put speed on the ball. However, it also forces the head of the humerus to move forward, which places significant stress on the ligaments in the front of the shoulder and the dynamic rotator cuff tendons. During acceleration, the arm rapidly rotates internally with the follow-through phase. Once the ball is released, the follow-through begins and the ligaments and rotator cuff tendons at the back of the shoulder must handle significant stresses to decelerate the arm and control the humeral head. The forces on the shoulder while throwing many repetitions can lead to injury. Over time, the ligaments loosen, resulting in greater external rotation and greater pitching speed, but less shoulder stability. The four rotator cuff muscles including the supraspinatus, subscapularis, infraspinatus, and teres minor control shoulder stability and are very important in keeping the head of the humerus aligned in the joint. Rotator cuff tears can occur when the stresses of the shoulder joint supersede the strength of the tendons. Rotator cuff tears can be avoided via good throwing mechanics, a strong strengthening and stretching program focusing on postural alignment; shoulder mobility; and shoulder girdle, rotator cuff, core and hip exercises.

Ulnar Collateral Ligament Injuries

The UCL of the elbow is situated on the inside of the joint and helps to provide stability for the throwing arm. With excessive throwing, the UCL can be sprained or torn due to the impact the elbow joint has with the throwing mechanics. Signs that the UCL has been injured include loss of pitch control, pain in the inner elbow, and overall joint instability. If the ligament has been torn, surgery is usually required. However, preventing injury to the UCL should be the focus by having good shoulder range of motion, excellent upper extremity and core strength, and proper throwing mechanics.

Medial Epicondylitis

Thrower’s Elbow

Medial epicondylitis usually presents as pain on the inside the elbow (on the medial epicondyle), and sometimes pain on the inside of the wrist. This pain is caused by damage to the tendons that flex the wrist and palm towards the forearm. Symptoms commonly associated with this condition include pain and tenderness on the inside of the elbow, stiffness in the elbow, and possible weakness in the wrist or hand.

Little League Elbow

Little league elbow is an injury to the medial growth plate called the medial epicondyle in a young child. The repetitive stress of throwing causes injury to the growth plate cartilage and can cause inflammation of this tissue as well as alterations in the growth pattern of this growth center. Little League elbow will cause pain on the inner aspect of the elbow when throwing. The athlete may also develop some swelling and localized tenderness. Typically, the pain is of gradual onset, but occasionally can occur fairly quickly. Little league elbow is commonly associated with decreased velocity and/or accuracy. The most important treatment for thrower’s and little league elbow is to avoid throwing for a period of time to rest the injured structures and allow them to heal. This may take several weeks, but it is important to allow complete healing to prevent recurrent symptoms. It is also important to maintain range of motion during the rest period. During the resting period, treatment and therapies are necessary for proper and adequate healing. Once an athlete begins to throw again, it is important that he or she resume throwing in a gradual controlled manner.