Shoulder problems in athletes occur for various reasons. In most cases, a careful history and exam will reveal the underlying cause. This article will review the main causes of shoulder pain in both pediatric and adult athletes and briefly discuss treatment options.
Young athletes who develop shoulder pain without associated injury can usually be categorized into one of three groups: patients with excessive joint laxity, poor shoulder posture or irritation of the growth plates of the humerus (arm bone).
Most commonly, young athletes presenting to the physician’s office with shoulder pain have extra looseness, or laxity, of the joint, either from birth, or acquired through the repetitive use of the shoulder. Athletes with laxity from birth usually have joint looseness in all directions. This is termed multidirectional instability or MDI. MDI is not so much a medical condition as it is a description of normal variation. Most people with joint laxity never develop shoulder pain. In cases where an athlete with MDI participates in a sport involving repetitive overhead motion, however, problems can arise when the forces placed across the shoulder cause the arm to shift excessively in the joint. When this happens, the muscles that cross the joint are forced to contract more often and more forcefully in an attempt to minimize this extra movement. Over time, muscle strain and tendonitis can develop. Acquired laxity develops over time in relation to the pattern of use of the shoulder, and can also lead to problems, though a full discussion of these patterns is beyond the scope of this article.
Athletes who have a slouched posture or who have over-developed chest muscles related to weight training (with inadequate attention to the back) often acquire a forward drift of the shoulder blades around the chest wall or an abnormal tilt of the shoulder blade due to the pull of tight anterior chest muscles. This is important because the rotator cuff (the common tendon of a group of muscles arising from the shoulder blade) has to pass underneath a portion of the shoulder blade in order to get to its attachment on the humerus. When the shoulder blade, or scapula, is positioned normally on the back, there is ample room for the tendon to pass underneath this bony arch. When the scapula is positioned excessively forward or tilted, however, the space surrounding the rotator cuff is restricted. This is termed “impingement,” and is often a predisposing factor in the development of rotator cuff problems. This decrease in operating space around the rotator cuff is magnified when the arm is brought over the head – a motion common in sports such as baseball, volleyball, or swimming.
Some young athletes present to the office with shoulder pain that arises from irritation of the growth plate of the humerus. Growth plates are the cartilage zones in long bones where new bone is laid down so that bones can lengthen. Children between the ages of eleven and fourteen are most susceptible to this. At this age, movements in sport are starting to become more adult-like, and the volume and intensity of sport participation is also increasing, at a time that the growth plates in the long bones are still open and susceptible to injury. Athletes who throw excessively can traumatize this growth plate and present with aching pain related to the injury.
Active adults who present for the first time with shoulder pain may have laxity as the cause (particularly people who are new to a particular sport) but usually are experiencing impingement-related pain. This can be postural, as with young people, or can be associated with the shape of the acromion – the bony shelf over the rotator cuff that is part of the shoulder blade. When the acromion is shaped in such a way that the space under it is maximized, the likelihood of developing shoulder pain is decreased. On the other hand, when the acromion drops down into this space, the likelihood of shoulder problems increase. Impingement can also occur when the joint between the collarbone (clavicle) and acromion (the acromioclavicular, or AC joint) enlarges into the space under the acromion. Finally, impingement can occur when the arm entraps against enlarged ligaments in the shoulder girdle. Over time in athletes who chronically impinge, the rotator cuff can start to deteriorate, thicken and even tear, which itself causes pain.
Although also beyond the scope of this article, some adults presenting with shoulder pain are experiencing pain related to arthritis, either at the primary shoulder (glenohumeral) joint or AC joint.
The management of a patient with shoulder pain varies according to the underlying cause, making proper evaluation vital to successful treatment. In many instances, the patient must relearn proper shoulder mechanics and correct postural changes that have developed over long periods of time. Most of the time, when properly directed, patients can eliminate their pain with the use of a home rehab program. In other instances, supervision in physical therapy is necessary. Factors that determine the need for physical therapy include the complexity of the problem, the age of the patient, or the speed with which the patient is needing to get the problem under control (problems that develop in-season are more likely to be dealt with in a supervised setting than problems that develop in the off-season). In all instances, when dealing with an athlete, rehab should end, not when pain control is achieved, but when the patient can demonstrate mastery of the movement patterns required of them by their sport, at a frequency that approaches the requirements of the sport, and tolerate this without pain.
The shoulder is a wonderfully complex joint, and proper evaluation searches for root causes in order to prevent recurrent problems down the road. In most, but not all cases of shoulder pain, home rehabilitation is successful. If you are experiencing shoulder problems, call (515)221-1102 to schedule a sports medicine physician appointment. We’ll do what’s necessary to get you back to pain-free activity again.