Shoulder injury in a young athlete is usually a result of overuse, barred a distinct traumatic event. One of the types of overuse shoulder injuries that results in severe shoulder pain is called acromial apophysiolysis. Pediatricians often diagnose the condition in young baseball pitchers.

Incomplete fusion and tenderness of the acromion is responsible for the shoulder injury, according to the Radiological Society of North America. The acromion forms the bone at the top of the shoulder. It actually consists of four bones that join during a person’s teen years.

In its online journal “Radiology,” the RSNA described the results of a study which found that “young baseball pitchers who throw more than 100 pitches per week are at risk” of suffering acromial apophysiolysis. Some sustain rotator cuff tears and other shoulder injuries, as well.

Another study, also posted at pubs.rna.org, concluded that acromial apophysiolysis is characterized in part by edema (too much watery fluid accumulating in body cavities or tissues).

Patients 25 years of age and younger were found to be most susceptible to “superior” shoulder pain  due to the shoulder injury. Researchers confirmed that pitching “is a risk factor (because) it predisposes the patient to the development of an osacromiale and rotator cuff tears after age 25 years.”

The study is titled “Acromial Apophysiolysis: Superior Shoulder Pain and Acromial Nonfusion in the Young Throwing Athlete.” The authors were Johannes B. Roedl, MD, PhD; William B. Morrison, MD; Michael G. Ciccotti, MD; and Adam C. Zoga, MD.

“We kept seeing this injury over and over again in young athletes who come to the hospital at the end of the baseball season with shoulder pain and edema at the acromion, but no other imaging findings,” Roedl, a radiologist, said in a news release. “We believe that, as a result of overuse, edema develops and the acromion bone does not fuse normally.”

The research took place at Thomas Jefferson University Hospital’s Department of Radiology in Philadelphia. It involved 2,372 patients between 15 and 25 years of age who had undergone MRIs to diagnose the cause of their shoulder pain. The imaging tests detected edema of the acromial apophyses in 61 (2.6 percent) of the cases.

“Association of acromial edema with incomplete fusion, pitching and clinical findings was determined in the study group, and in an age- and sex-matched control group,” the researchers wrote.

The patients included men and women, most of whom were baseball pitchers. Roedl said they were chosen for the study because “among high school athletes, pitching is the most common reason for shoulder injury.”

Forty percent of one group of study participants had thrown more than 100 pitches per week, compared with 8 percent in the other group. All the patients were diagnosed with acromial apophysiolysis.

According to sportswithoutinjury.com, baseball pitchers are not the only athletes at risk. The shoulder injury also happens to those who play softball, tennis, golf, handball, volleyball and other sports that require throwing or hitting an object. Even weight lifters and yoga practitioners are vulnerable.

The best advice for avoiding acromial apophysiolysis and other overuse shoulder injuries is to practice moderation. The shoulder joint needs time to rest and heal. When the arm starts to hurt, it is time to take a break.

The American Academy of Orthopedic Surgeons recommends that pitchers reduce the number of times they throw a ball in a game. The organization supports pitch-count limits set by the USA Baseball Medical Safety Advisory Committee.

Strengthening exercises, and stretching and warming up before workouts, are helpful. Ice and anti-inflammatory medication reduce swelling and discomfort.

If you or your child are faced with unabating shoulder pain, contact our nationally recognized sports medicine physicians at Orthopedic Surgery San Diego.