Acromioclavicular separations or sprains can vary in severity, depending on the extent of injury to the stabilizing ligaments and capsule. Depending on the severity of the blow causing the injury, most of the time only a partial tear of the acromioclavicular ligament will occur.
If this is the case then only a first- degree injury is produced. A second-degree injury occurs when the acromioclavicular ligament is completely tom, but the coracoclavicular ligament remains intact. This can also include subluxation or partial displacement.
The subluxation isn't always noticeable upon examination, but can be confirmed on x-ray. If the force is enough than it tears the acromioclavicular ligament, the coraclavicular ligament, and the capsule, it is known as a third-degree injury. A third degree injury is obvious on examination, and can be confirmed on x-ray.
Athletes are the most likely candidates for AC injuries, more specifically football players and hockey players. These being the sports that usually put lots of stress on the shoulders in general. An athlete who has an AC injury will often leave the field/ice holding his/her arm close to the side.
It's very important to find out the exact happenings of the injury, that is did the athlete fall on the outstretched arm, or receive a severe blow to the arm (Acromial area). It is important when examining the area to rule out pain from the contusion by manipulating the clavicle at midshaft. Sometimes there's an obvious deformity or easily detected motion at the AC joint which makes it easier to diagnose the injury. The more difficult to diagnose is the less severe injury. Often times the athlete will be put through a variety of motion tests to get the proper diagnosis promptly.
Treatment of these injuries depends on the severity, first and second degree sprains of the AC joint can often be treated successfully with a sling for 2 to 4 weeks, when pain is alleviated. This is usually followed up with some physical therapy to restore normal range of motion and to strengthen the upper extremities. The treatment of third-degree sprains of complete dislocations varies.
Some doctors think it best to be aggressive and perform an open reduction (surgery). Other doctors feel that they should be treated non- surgically because people tend to do well and can function with complete dislocations. When surgery is performed, it is usually directed at reconstruction of the conoid and trapezoid ligaments (coraclavicular ligaments).
Return to Activity
It is important that the athlete not return to sport until they have full range of nonpainful motion, no tenderness upon direct palpation of the acromioclavicular joint, and no pain when manual traction is applied.
The prognosis of these injuries is very good, obviously better for the lower grade injuries (first and second degree). However, even third degree injuries will do well if the appropriate treatment is applied and enough rehabilitation and rest is allowed.