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Throwing Injuries


Throwing Injuries

David M. Lintner MD
Medical Director, Houston Astros
Team Physician, Houston Texans
Chief of Sports Medicine, Methodist Sports Medicine

The throwing motion is one of the most stressful activities for a shoulder. This is the fastest human motion ever recorded, with the shoulder moving at more than 7000 degrees per second. To throw hard, the athlete must rotate his/her shoulder externally greater than 90° with the arm in the overhead and extended position. This puts a tremendous strain on the ligaments and rotator cuff muscles that stabilize the shoulder. As a result of this strain, athletes who throw repeatedly (such as baseball pitchers) will often damage their rotator cuff or the ligaments in the shoulder. It all starts with a “Catch 22”: To throw hard, the athlete’s shoulder must be loose enough to externally rotate and hyperextend more than normal, but shoulders that are loose enough to do so often become unstable.

The stability of the shoulder depends primarily on the ligaments (which act like cables between the bones) and the rotator cuff muscles which pull the humeral head (ball) into the center of the glenoid (socket) during shoulder motion. If the ligaments are loose, the rotator cuff must do extra work to keep the shoulder centered. If the rotator cuff is damaged, painful, or weak, the shoulder is more dependent upon the ligaments. So, if the rotator cuff is damaged in a loose shoulder, the joint becomes unstable.

The labrum is also very important in providing shoulder stability. It acts like a rubber ring or bumper surrounding the socket, helping to keep the ball centered. The ligaments, capsule, and the bicep tendon all attach to the labrum, each contributing to the stability of the shoulder joint. If the labrum is damaged, the attachment of these important shoulder stabilizers is often damaged, causing instability and pain.

Elite throwers often have very flexible and sometimes loose shoulders but have extraordinarily strong and coordinated rotator cuffs that allow them to take advantage of the looseness in their shoulder to generate tremendous torque while throwing the ball.


If their rotator cuff becomes inflamed or damaged, they will be unable to stabilize their shoulder and will suffer pain and a decrease in throwing performance. Recreational or less experienced throwers are more prone to developing these same problems, often because of poor mechanics or less attention to rotator cuff strengthening.

When a shoulder is unstable, excessive stress is placed on the rotator cuff leading to inflammation and tendinitis of the rotator cuff. This weakens the rotator cuff, making it less able to stabilize the shoulder so a vicious cycle is created. This is when a thrower will typically lose velocity and control, and may require time off of
throwing. If it progresses, a partial tear in the rotator cuff may occur.


Throwing athletes will often develop tendinitis in their shoulder or elbow. Tendinitis means that the tendons that connect the muscles to the bones are inflamed. In the shoulder, this most often involves the rotator cuff or bicep tendons. The tendon is not torn, but is inflamed and swollen.

Causes for tendinitis can include high or intense usage. In competitive throwers at any level, tendinitis will be perceived as pain in the shoulder, typically worse when cocking the arm or during the early acceleration phase of the throw. Generally, it improves during warm up, but worsens if the athlete keeps throwing. It may awaken the athlete from sleep. Doing routine activities such as reaching up to a shelf, fastening a seat belt or tucking in a shirt can often become painful. In a competitive thrower, velocity will often decrease. If the shoulder is loose jointed to begin with, the rotator cuff may have trouble stabilizing the shoulder and some symptomatic instability may develop. Diagnosis of tendonitis is made by physical examination and often MRI scan.

The athlete is often relieved that the problem is tendonitis and not “a tear”, but treatment is still required. The treatment of tendonitis consists of ice, relative rest (i.e. decreasing workload, but not necessarily stopping throwing), stretching and strengthening of the affected muscles and tendons and using anti-inflammatory medication. Surgery is usually not required, unless the tendonitis does not respond to treatment or worsens. In severe cases, the inflammation can cause the deterioration of the tendon and eventually partial tearing. Intervention is needed to prevent this, and the healing process must be monitored by following the relief of pain. Tendonitis of the rotator cuff that does not respond to non-operative treatment may be due to underlying instability. Sometimes, it is the instability that requires surgery, rather than the tendonitis itself.

Rotator Cuff Tears

If the rotator cuff is stressed beyond its ability, it will tear. In a thrower this typically incremental, similar to a rope fraying. The body can sometimes heal these partial tears if they are not too severe. Mechanisms of injury include repetitive throwing with a loose shoulder, fall onto an outstretched arm, or rarely on one throw. Most experienced pitchers have some minor damage to their rotator cuffs visible on MRI scan, but are able to compensate. If the ligaments stretch further, or the cuff tears further, they may lose this ability to compensate and develop pain with throwing. Treatment requires stretching and strengthening of the affected muscles and tendons and using anti-inflammatory medication, but if the tear is severe this will be fruitless. Then surgery becomes necessary. Surgery to stabilize the shoulder may protect the rotator cuff, but if the cuff is torn it will require suturing too. Suturing the rotator cuff often leads to some stiffness afterwards, which is well tolerated by the average person but can be debilitating to an athlete who depends on an unusually flexible joint to throw. Thus, newer techniques are always being developed to try to repair the rotator cuff without causing stiffness. More and more of the cuff tears can be repaired with the arthroscope, so more and more throwers are returning to their sport.

Partial Tears of the Rotator Cuff

Labral Tears

The labrum is a rubbery cartilage ring much like a washer or gasket that surrounds the socket (glenoid) of the shoulder. The labrum is a critical structure because it acts as a stabilizer of the shoulder as well as an attachment point for many of the ligaments around the shoulder. The biceps tendon also attaches to the superior labrum. If the labrum is torn or detached from the glenoid, the ligaments or tendons that attach to it are thereby detached making the shoulder unstable, painful, or both.

In addition, if a piece of the labrum is torn loose, it will often get caught between the ball and socket and cause a sensation of grinding, popping, and pain. This is typically most noticeable with rotational movements of the arm such as throwing, reaching overhead, etc.

Detached Superior Labrum (Before  Repair to Glenoid)

SLAP Tears

SLAP stands for superior labrum-anterior and posterior to the biceps tendon. The biceps attaches to the labrum on the upper (“superior”) glenoid If the labrum is detached in this region, the biceps tendon is no longer firmly attached to the socket. This will often cause pain with throwing, reaching to the front or side, or trying to lift objects to or above shoulder level. The most common causes of this injury are repeated strain on the biceps tendon (for example, throwing, repetitive overhead usage of the arm) or a sudden trauma such as falling on an outstretched hand and jamming the shoulder. Pain and popping is frequently noted. The pain is often in the back of the shoulder. Those that throw or use their arms overhead are often unable to continue doing so.

Diagnosis of a SLAP tear is achieved by a careful history and a thorough physical examination. However, other injuries can imitate a SLAP tear, therefore an MRI scan is often necessary to confirm the diagnosis. This scan should be done with some dye injected into the shoulder and often with the arm positioned into the overhead or cocked position. Injecting the dye and scanning the shoulder with the arm in this position are quite helpful in demonstrating these tears.

In general, SLAP tears do not heal by themselves. For successful treatment, the labrum must be reattached to the glenoid. This is done arthroscopically using suture anchors implanted into the bone, which are then used to suture the labrum back into place. The arm must be kept in a sling postoperatively to protect the sutures while the labrum heals. Some limited range of motion is possible but only within these limits! If the arm is moved too vigorously too soon, the sutures will fail and the repair will separate.

Physical therapy will usually begin within the first week after the surgery. We will check you approximately one week postoperatively followed by checks every few weeks until your recovery is advanced. Typical return to deskwork is within a few days after the surgery, reaching overhead approximately 6 weeks after the surgery, and return to throwing approximately 3 months after the surgery. A return to competition for throwers is usually between 4 and 6 months postoperatively. Supervised physical therapy is usually necessary for the first 2-3 months at least.

Bankart Tears

A Bankart lesion is when the labrum becomes detached from the front of the glenoid socket. In this area, the labrum serves as the attachment point for the main ligaments that stabilize the shoulder (the inferior glenohumeral ligament). If the shoulder has dislocated, the labrum is often detached causing the inferior glenohumeral ligament to lose its attachment to the glenoid. This typically does not heal and recurrent dislocations can recur.

This is diagnosed by a careful history and thorough physical examination looking for signs and symptoms of persistent instability in the shoulder. A sensation of looseness, popping out, instability, or locking of the shoulder can be associated with this. The Bankart lesions typically do not heal on their own and require surgical repair. In fact, an active male athlete who has had a dislocation of his dominant shoulder will have an approximately 80-90% chance of having repeat episodes if he does not have surgical treatment and continues his usual activities. Most athletes prefer to have this repaired. This can often be done arthroscopically, but in collision athletes (such as football players) open repair may be preferred. The repair technique involves reattachment of the labrum to the glenoid using suture anchors embedded in the glenoid which are then used to tie the labrum back to its normal position. This serves to reattach the ligaments to the socket and restore stability to the shoulder. Rehabilitation takes approximately 3-4 months to return to full sports, but you would be able to begin moving your shoulder within the first few weeks after the surgery. The timing of this depends upon the exact nature of the repair. Supervised physical therapy is necessary to assure satisfactory progression of motion and strength without putting undue stress on the repair.


The difference between laxity (joint looseness) and instability is key. Throwers will have laxity in their shoulders, some with an astonishing amount. However, until it becomes a problem, this is considered “normal” for that individual and a preventive “Pitchers’ Exercise Program” for the rotator cuff and muscles around the shoulder blade is all that is necessary. However, if the athlete’s rotator cuff is unable to control the laxity (often due to inflammation) and the athlete develops pain due to the laxity, then the shoulder is deemed “functionally unstable”. This may occur gradually over time or with an acute injury, but usually the former.

When functional instability develops, rehabilitation is critical. In professional throwers, some time off and an aggressive strengthening program for the rotator cuff and muscles that rotate the scapula is usually successful. If not, the thrower will need surgery – not on the rotator cuff, but on the ligaments. Remember, if the ligaments are loose, the rotator cuff must bear the additional burden to stabilize the shoulder. The surgery is to tighten the ligaments and capsule, either with sutures or with the heat probe (Thermal Shrinkage). The goal is to tighten the shoulder just enough to stabilize the joint without losing range of motion. In most surgeons’ hands, arthroscopic techniques are more effective than open. For high level throwers, the surgeon’s experience is critical to gaining a successful result and return to full activities. However, even in the most experienced hands, about 85% of professional throwers will make it back to their pre-injury level after needing this surgery. The odds are lower for those at lower levels of competition.

Throwers Program

After a thrower sustains a shoulder or elbow injury and has recovered enough to resume throwing, an organized and gradual return to throwing is needed. A pitcher cannot immediately resume competitive throwing once the pain subsides without a high risk of re-injury. Some time is needed to recondition the arm. David LaBossiere, the Head Athletic Trainer with the Astros for 19 years has developed an effective throwing program to guide the injured thrower during their return to competition. Obviously, the schedule does not strictly apply to every athlete, but serves as a useful framework that can be modified as the individual’s situation requires.

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