Growth Plate Injuries in Youth Baseball Athletes

This post was written by Terry Phillips, DPT. Terry is a full time physical therapist working at Driveline Baseball.

Growth plate injuries are among the most commonly reported injuries for youth and teenage athletes. Also referred to as Little League Elbow and Shoulder, these injuries occur to an area of the body that is responsible for roughly 80% of growth to the humerus, the bone running between the elbow and shoulder. Despite the common name, growth plate injuries not limited to young athletes and can also become an issue in 16 or 17 year olds.

As with any injury, the severity can vary with each individual. Being able to know the risk factors associated with growth plate injuries as well as the signs and symptoms can play an important role in reducing the likelihood that these types of injuries can have a major effect on an athlete’s playing career.

First, we must understand what the growth plate is and how it can become injured. The growth plate, also known as the epiphyseal plate or the physis, is an area of cartilage at the end of a bone where new bone is made. There are two growth plates in the humerus; one near the shoulder, and one by the elbow. In adults, these areas close and bone is no longer growing. In children and teenagers, this area is open. Because these areas are open zones of soft cartilage, they are actually one of the weakest spots in the upper arm; weaker even than the attaching ligaments and muscles, including the UCL (the ligament needing repair in Tommy John surgeries).

Because throwing puts high amounts of distraction, or pulling, forces on the shoulder and the elbow, the growth plates can can be susceptible to small, microtrauma with each throw. Overtime, this trauma can lead to inflammation, adaptive bony changes, such as widening of the growth plate, or in more extreme cases, fragmentation or avulsion fractures, where the attaching soft tissues can rip off a small piece of the bone.

Early detection is very important to help reduce the risk of a mild injury turning into a more severe injury that could require several months removed from competition. Pain, in the shoulder or elbow, is the most obvious indicator that something may be happening at the level of the growth plate of an athlete. In the shoulder, pain is most commonly present in the front and lateral portion of the shoulder. In addition, there may be swelling present, tenderness to touch to the area, loss of range of motion that may or may not include pain, and weakness, pain or both with resistance to shoulder external rotation.

In the elbow, pain will most likely be present around the medial epicondyle, the bony prominence of the inner elbow. There may also be swelling, tenderness to touch around the medial epicondyle, pain with bending or straightening the elbow, and decreased grip strength, with or without pain. From a performance perspective, an athlete could demonstrate a decrease in throwing velocity, and in some instances may also have decreased accuracy due to a loss of grip strength.

Knowing the risk factors associated with growth plate injuries is also beneficial for both parents and coaches to help reduce the risk of occurrence. Among the biggest risk factors is the amount of throwing an athlete does throughout the calendar year. USA Baseball has developed the Pitch Smart program that governs how many pitches a pitcher is allowed to throw and also the number of days rest following a pitching outing. Pitch Smart also makes recommendations to reduce the amount of throws a pitcher does in a 12 month period, depending on the athlete’s age. This includes not throwing a baseball for 2-3 months. While Little League and most youth leagues enforce the pitch count guidelines, there is not enforcement of the amount of throwing an athlete can do throughout the year. With travel teams and tournaments on top of year-round practice, it becomes very easy for these recommendations to be neglected and for young arms to amass a lot of throws throughout the year. In addition to excessive throwing, other risk factors include muscle tightness that can occur with growth spurts, muscle weakness and/or poor body control, poor throwing mechanics, and joint hypermobility, which is another way of saying an athlete is too flexible.

Diagnosis of a growth plate injury can only be done by a medical professional. To fully understand the severity of an injury, imaging will have to be done to see if there is only inflammation versus some type of widening or fracture of the actual growth plate. Even if there is no fracture or widening present, rest for 4-6 weeks may still be recommended to allow the inflammation to decrease. During this time the athlete should work with a rehab professional to improve the strength and range of motion in the area, along with other areas of the body including the scapula, spine, and hips. If left untreated, the injury can progress to a fracture, which in many instances can result in the athlete needing surgery to repair the area. In these cases, the athlete will be splinted for several weeks, will need physical therapy for 4-6 months, and will be unable to throw a baseball for upwards of 6 months.

Injuries to the growth plate are not completely preventable. However, the likelihood of an injury happening can certainly be reduced. The most important guideline to follow is to limit the amount of throwing an athlete does throughout the year. While this does mean adhering to the Pitch Smart guidelines, it also includes avoiding playing other positions that require a high amount of throwing such as catcher, outfield, or shortstop, if that athlete is pitching regularly. Additionally, athletes should not be throwing year round. It is widely recommended that youth athletes take at least 4 months off from competitive pitching as well as 2-3 months off from throwing a baseball at all. When athletes are throwing, it is very important that participate in a proper warm-up and recovery protocol to ensure the tissues around the shoulder and elbow are ready to take on the stress of throwing. Finally, if an athlete is doing a considerable amount of throwing throughout the year, they should work with a rehab or strength and conditioning professional to address any weaknesses and mobility restrictions that may be present which could lead to increased stresses being placed on the elbow or shoulder during the throwing motion.

Growth plate injuries continue to be one of the leading injuries that youth baseball players endure at some point in their playing career. Identifying possible risks, knowing the signs, and making the appropriate modifications are extremely important when it comes to limiting the risk sustaining a significant injury. As coaches and parents a lot of this task relies on us. Following the appropriate recommendations can help keep your young ball player on the field throughout the course of a long, hard season.

Terry Phillips graduated with his Doctorate of Physical Therapy from Ithaca College in 2009. He then spent the next 7 years working in an outpatient orthopedic setting. In 2016, he began working on a part-time basis at Driveline Baseball. In 2017 he moved into a full-time role. He is the author of several articles regarding injuries commonly seen in youth baseball and softball players.


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