Landing hard on the point of your shoulder, whether in a tackle, a fall or a spill off the bike, can leave you with pain and a tender bump right on top of the shoulder. This is often an AC joint injury, also known as a shoulder separation, and it is one of the most common shoulder injuries in contact sport.
There is a lot of uncertainty about whether a shoulder separation needs a scan or surgery. Here is what an AC joint injury actually is, how it is graded, what the evidence says helps, and when it is worth seeing a physio.
In this article
What is an AC joint injury?
The AC joint, or acromioclavicular joint, is where the end of your collarbone meets the tip of your shoulder blade at the top of the shoulder. Ligaments hold this joint together, and an AC joint injury is a sprain or tear of those ligaments. It usually causes pain right on top of the shoulder, tenderness over the joint, and sometimes a visible step or bump if the ligaments are more badly injured.
In the general population
AC joint sprains account for roughly 3 to 9 percent of all shoulder girdle injuries, so they are far more common in contact and collision sport.
What causes a shoulder separation?
It is usually a direct force. Common causes include:
- A fall onto the point of the shoulder
- A heavy tackle or collision in contact sport
- Coming off a bike or a fall in other sports
The amount of force and the direction of the knock help determine how badly the ligaments are injured.
How are AC joint injuries graded?
AC joint injuries are graded by severity, commonly using the Rockwood system from grade I through to grade VI. Lower grades involve a sprain or partial injury to the ligaments, while higher grades involve more complete tears and greater separation of the joint. The grade guides the plan, which is why an assessment matters rather than guessing from the outside.
Do I need surgery for a shoulder separation?
For most people, no. The evidence and clinical consensus is that lower-grade injuries, generally Rockwood grades I to III, are managed conservatively without surgery, while higher-grade injuries, grades IV to VI, are usually referred for a surgical opinion. Most lower-grade separations settle with a period of relative rest and a graded rehabilitation programme, so surgery is the exception rather than the rule.
What actually helps an AC joint injury?
For lower-grade injuries, a staged plan works well. A typical approach includes:
- Early protection and relative rest to settle pain, sometimes with a sling for comfort
- Restoring comfortable shoulder movement
- Progressive strengthening for the shoulder blade and shoulder
- A staged return to training, contact and sport
Many people return to their sport with a structured programme tailored to their shoulder and goals, and a physio can guide the timing so you do not go back too soon.
When should you see a physio or specialist?
See a physio if your shoulder pain is limiting your sport, work or daily life, or you want a clear plan to recover and return to contact with confidence.
Seek prompt assessment if
There is an obvious large step or deformity at the top of the shoulder, severe pain, or you cannot move the arm. These may point to a higher-grade injury that needs a specialist opinion, so it is worth getting checked rather than pushing on.
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Helping You Perform at Your Best
At ACE Sports Medicine in Upper Mount Gravatt, our physiotherapists provide personalised care for shoulder injuries and AC joint injuries across Brisbane's southside, from settling symptoms to a graded return to contact sport. Your first appointment includes an assessment and a plan matched to your shoulder and goals.