Weight Lifter's Shoulder and AC Separation

The Acromioclavicular joint is a joint between the end of the collar bone and the tip of the wing bone. It forms an apex at the top part of the shoulder.

It is an important connection between a free hanging mobile limb and the rest of the skeleton.



The ligaments that hold the joint together can be damaged, often from direct trauma such as a fall onto the point of the shoulder.

A grade 1 injury involves the ligaments of the AC joint and is stable, grade 2 involves additional disruption to the ligaments that hold the collarbone from lifting.

A grade 3 injury is complete disruption of these ligaments, and the joint can become unstable.

Most of these injuries do not require surgery but they can lead to long-term problems with shoulder function and individual assessment is recommended to guide best management1,2

In some cases, the disc inside the joint that normally cushions it will degrade and the joint will become arthritic with loss of cartilage, formation of bone spurs and these bone spurs can lead to rotator cuff wear and pain

Depending on their activities, most people with AC joint osteoarthritis won’t have significant symptoms because it is quite a stable joint 3.

One recent study showed that 90% of patients with asymptomatic AC OA seen incidentally on MRI for other shoulder issues, remained symptom free for 7 years follow-up 4.

Weight Lifter's Shoulder

A condition that tends to be quite consistently painful and can be very debilitating is AC joint osteolysis, otherwise known as Weight Lifter's shoulder.

This is where the end of the collar bone becomes painful, and the inner structure of the bone starts to break down.

It is a kind of bone stress injury that happens in people who overload their shoulder in the horizontal pushing/pulling plane.