DCO, or Distal Clavicular Osteolysis, is a rather bad shoulder condition that all too many athletes suffer from.
DCO occurs when we have damage to our AC (acromioclavicular) joint and it goes unattended to for a period of time. More-so than that, additional damage is done with further activity and the bones that make up the joint get significant damage.
The AC joint is made up of where the distal clavicle bone meets the acromion process of the scapula (see photo below). A sprain of the AC joint tends to involve a macrotrauma (one significant injury) such as a bad fall or other form of side shoulder impact. The AC joint tends to get hypermobile (or move too much) easily as it is not a very stable joint to begin with. When the joint is injured, or sprained, care is needed to stabilize the joint and allow for it to heal. In-office treatments can significantly reduce recovery time and this is important as a healing AC joint sprain is susceptible to further injury.
Let’s say that someone has an AC joint injury that is not, should we say, cared for properly and it does not heal well. Top that with continued weight training and/or other shoulder heavy activities and guess what?…that person will very likely end up with DCO.
Although DCO takes some time to develop, once it does, it takes quite a long time for it to settle down, if it ever does. In fact, there are surgical procedures to remove the distal part of the clavicle (ouch!) and rebuild the AC joint. Does that sound good? I hope not! This injury, if identified early, has a great prognosis with conservative intervention. However, if it goes on for too long, the damage is irreversible.
You see, with DCO, the distal clavicle (where it meets the AC joint), due to continual irritation and damage, starts to get reabsorbed by the body. Yes, you read properly. The bone starts to get eaten away. The longer the condition lasts, the more bone gets reabsorbed, until the condition is permanent.
If the person gets conservative care early enough from a practitioner who has specialized training in extremity/sports injuries, the condition can be resolved. The most important thing to do is properly identify the injury and quickly work to eliminate what is causing the problem. Once this is achieved, therapy will help with the healing process.
On examination, an AC joint sprain and DCO will look very similar. One thing to consider is how long the condition has been in play. This means that a long-standing AC joint sprain, or one that is not healing, will likely progress to DCO. Once this occurs, the timeframe for recovery tends to be much greater. Simply put, the longer the condition is present, the longer it takes for it to recover.
There is no single orthopedic test for DCO. In fact, you would test the region as you would for an AC joint sprain. The best imaging test to identify DCO is MRI. We need to see inside the bone to see how inflamed it is and also to see if there is erosion of the distal clavicle. Although an x-ray will show damage and resorption after it has been there for a long period of time, a MRI is preferred as it can see inside the bone and pick up resorption much sooner…and the key to this condition is identifying it early!
Once the injury is properly identified, change in activity is needed along with dietary changes and proper conservative care. When the inflammation in the area stops and the body heals, the person will likely get a callous like ‘bump’ at the AC joint region, but at least the process is stopped. As previously mentioned, if the condition is not dealt with in an appropriate fashion in an early enough timeframe, then a surgeon can rebuild the AC joint.
The general advice with your shoulder or any other musculoskeletal injury is to give it 7-10 days to see if it recovers on its own. If you have an injury that does not resolve in this timeframe, it’s likely an injury that needs professional attention. Failure to do so can lead to more significant problems down the road and some can be quite unforgiving!