Justin Fields missed the Chicago Bears vs NY Jets game on Sunday due to an AC joint separation. Fields said he was dealing with a separated shoulder “basically an AC joint” injury after he landed on his left side when he was tackled on the Bears’ final drive against Atlanta.  The AC joint is the joint on the top of the shoulder between the shoulder blade and the collar bone or what is medically called the acromion and the clavicle making it the acromioclavicular joint.   

A review of AC joint injuries published in 2013 in the American Journal of Sports Medicine shows that this is a very common injury in these athletes.  In this study, which reviewed all injuries in the NFL from 2000 to 2011, 8% of the injuries involved the shoulder and almost a third of these involved an injury to the AC joint.  Quarterbacks had the highest incidence rates of AC joint injuries essentially being 20 injuries per 100 players.  Luckily the time lost from this is not bad.  The mean time missed from playing from an AC joint injury was only 9.8 days and only 1.7% of the AC joint injuries required surgery.  

The AC joint can be injured when tackling another player hitting them with the corner of the shoulder and the shoulder blade is depressed from the collar bone tearing the supporting ligaments.  This can also be injured when one lands directly on the shoulder again depressing the shoulder blade away from the clavicle.  Most of the injuries involve only partial tears of the ligaments between the clavicle and the shoulder blade and the recovery is quick.  More extensive injuries with complete tears of the ligaments and displacement of the shoulder blade away from the clavicle can cause chronic pain and shoulder disability making surgery necessary in up to 50%.  In rare cases the clavicle can dislocate posteriorly or inferiorly making surgery necessary in a more urgent manner.  Luckily for Justin Fields it looks like he has a minor sprain and should be ready to play in the next week.