Acromioclavicular (AC) joint injury occurs on the top part of the shoulder where the collarbone attaches to the front side of the shoulder. The injury can be caused in different ways such as repetitive use of the shoulder or a fall. AC injuries are common to more men than women aged below 35 years. This is majorly because most of these individuals are much likely to engage in high-risk activities such as sports, or even work-related tasks like roofing. AC joint can be handled effectively by an experienced therapist without necessarily involving surgical procedures.


What are AC joint injuries?


The four ligaments that hold the acromion and the clavicle link up the two bones of the shoulder. Hence, the AC joint injury occurs when the four ligaments get stressed causing some level of joint separation. The two types of injuries that cause an AC joint injury are traumatic and overuse.

Traumatic AC joint injury often occurs to people who sustain injuries when they fall, such as sportsmen and manual laborers. It occurs when the ligaments holding the two bones of the shoulder get damaged. This type of AC joint injury is referred to as a shoulder separation and involves the shoulder’s ball-and-socket joint. Depending on the degree of separation, the injury will be graded as mild or severe. A physical therapist can easily treat a mild case of AC joint injury, but a severe case of AC injury may require a surgical procedure that will be followed by sessions of physical therapy.

Overuse AC joint injury, on the other hand, occurs when repeated stress is exerted on the shoulder. There is a cartilage at end of the two shoulder bones that is meant to protect the joint from wear and tear. If excessive stress is exerted on this cartilage, it begins to fail enduring leading to the injury. If it wears out significantly, the condition will be called arthritis. Individuals who execute duties that require constant lifting of the hands over the head and weightlifting often suffer from this type of AC injury.


How does it feel?


An AC injury victim may experience the following:

  • General pain and swelling on the shoulder
  • Tenderness and swelling on the joint
  • Loss of strength on the shoulder
  • A bump on the shoulder that is visible
  • Loss of motion on the shoulder
  • Discomfort when lifting objects above the head or carrying them on the side
  • A popping sound when moving the shoulder

How is AC injury Diagnosed?


I thought about this: it’s very critical that the physical therapist understands the medical history of the patient including asking questions about when the AC injury began and what relieves or aggravates it. The therapist should assess various details such as the shoulder’s flexibility, motion, swelling, and even sensation.


He or she should also examine different structures of the shoulder as well. The other parts of your body that ought to be examined to determine whether they contribute to the shoulder AC joint injury include the neck and upper back. Besides examination, the physical therapist can also utilize other diagnostic imaging such as MRI, ultrasound or x-ray.

A Guide to Acromioclavicular (AC) Joint Injury