The acromioclavicular, or AC, joint is part of the shoulder girdle (the collar bone and shoulder blade that support the shoulder joint). An AC joint injury describes an injury to the top of the shoulder. It occurs where the front of the shoulder blade (acromion) attaches to the collarbone (clavicle). Most often, trauma, such as a fall directly on the outside of the shoulder, causes an AC joint injury. Overuse (repeated lifting of heavy weights or objects overhead with poor mechanics) also can result in an AC joint injury.
AC joint injuries are most common in people younger than age 35. Males sustain five times more traumatic AC joint injuries than females. Younger athletes who take part in activities like football, biking, skiing, and hockey have the highest risk for this injury.
Physical therapists can identify and effectively treat AC joint injuries, often avoiding the need for surgery.
Physical therapists are movement experts. They improve quality of life through hands-on care, patient education, and prescribed movement. You can contact a physical therapist directly for an evaluation. To find a physical therapist in your area, visit Find a PT.
There are four ligaments that hold the two bones of the AC joint together. When an AC joint injury occurs, these ligaments are stressed. This stress results in some degree of joint separation. There are two types of injuries of the AC joint: traumatic and overuse injuries.
Traumatic AC joint injury. This type of injury occurs when the joint is disrupted. The ligaments that hold the two bones of the joint together get stretched too far. This is called a shoulder separation. It is different from a shoulder dislocation, which involves the ball-and-socket joint.
Traumatic AC joint injuries are most common in people who fall and land on the outside of the shoulder or hand. Examples include a:
Traumatic AC joint injuries can range from a mild to severe grade. Grading is based on the amount of joint separation involved. Mild cases can be treated by a physical therapist. More severe cases may require surgery followed by physical therapy.
Overuse AC joint injury. This type of injury occurs over time due to repeated and too much stress on the joint. Cartilage at the end of the acromion and clavicle bones protects the joint from daily wear and tear. Over time, the demand placed on this cartilage may be more than it can endure. The result is an overuse injury that can lead to major wearing of the cartilage and arthritis. Overuse AC joint injury is most common in people who do repeated tasks. Examples include:
A physical therapist will conduct a full evaluation, including measuring the wound area and inspecting the surrounding skin. Range of motion, mobility, and strength also will be assessed, as these can contribute to the wound problem, and may assist in the healing process. Your physical therapist also may perform specific testing related to circulation and sensation; you may need additional testing from a doctor as well.
With an AC joint injury, you may experience:
Physical therapists can diagnose an AC joint injury through a shoulder exam. Your physical therapist will conduct a full evaluation to find out the degree of your injury and identify all the factors that may contribute to it.
They will begin by interviewing you to learn about your health history. They may be helped by forms you fill out before your first session. The interview will become more specific to the condition of your shoulder. Your physical therapist may ask you questions such as:
This information allows the physical therapist to better understand what you are going through. It also helps determine the course of your physical exam.
The physical exam will vary depending on your interview. Most often it will begin with observing the region of your symptoms and any movements or positions that cause pain. Your physical therapist also may examine other areas of your body that may have changed due to problems with your shoulder function. They may:
Your physical therapist will discuss their findings with you. They will work with you to develop a program for your specific needs and goals and to help you heal.
In some cases, your physical therapist may refer you for diagnostic imaging. Ultrasound, X-ray, or MRI can help to confirm the diagnosis and find out how severe the injury is.
Your physical therapist will design a treatment plan to help you safely return to your desired activities. Your treatment plan may include:
Accidents happen and it can be difficult to prevent many traumatic AC joint injuries. However, much can be done to prevent the string of events that lead to overuse injuries. Physical therapists can help reduce overuse injuries by:
Consult a physical therapist as soon as possible if you have persistent constant or worsening symptoms.
All physical therapists are prepared through education and clinical experience to treat a variety of conditions or injuries. You may want to consider:
You can find physical therapists who have these and other credentials by using Find a PT, the online tool built by the American Physical Therapy Association. This tool can help you search for physical therapists with specific clinical expertise in your area.
General tips when you’re looking for a physical therapist (or any other health care provider):
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