Unfortunately, it is challenging to find out if someone has suffered a grade 3, 4 or 5 ac joint separation. Look at the situation that Trevor Siemian, QB for the Denver Broncos, experienced. Instead of the initial diagnosis that he sustained a grade 3 ac separation of his non-throwing arm, a further detailed evaluation discovered ligaments torn in the areas where the scapula, clavicle, and AC joint connect. Instead of a grade 3 ac separation Trevor Siemian actually had a more severe grade 5 ac joint separation. This resulted in not just an “optional surgery” rather operation was required.

“A grade 3 ac joint separation and a grade 5 ac separation are both determined by the amount of vertical movement of the clavicle relative to the coracoid bone. Via x-rays the injured side must be compared to the non-injured side in order to determine the grade. If the distance between the two bones is at least 25% increased relative to the normal side, but less than 100% (double the distance) then the injury is considered to be a grade 3. If the distance is more than that it is a grade 5. A grade 4 ac joint separation is one where there is significant posterior movement of the clavicle relative to the acromion”, explains Steven Struhl, MD who is a world renowned AC Joint Specialist.

AC Joint Separation Grading

“If this grading scheme seems complicated, unwieldy and somewhat unreliable it’s because it is. Numerous studies have demonstrated that when groups of experienced orthopedic surgeons were asked to grade AC joint separation injuries based on standard x-rays there was considerable differences of opinion. Even when 3 dimensional CT scan imaging was utilized there were still significant differences of opinion about the severity of injury. This has powerful clinical significance because the decision for surgical versus a non-surgical initial treatment approach is highly dependent on the initial grading.”, shares Dr. Struhl.

How to accurately determine AC joint injury grade

In order to determine the grade of an ac joint injury it is essential that both the normal and the abnormal side be imaged. This involves both the standard “Zanca” view (for vertical movement) as well as an axillary view to determine horizontal movement. Accuracy is significantly improved when the measurements are done through digital analysis of the x-rays.

Unless someone is being evaluated by an AC Joint Specialist, your initial ac joint separation grading might be different than initially thought.

Posted on behalf of Steven Struhl MD