An A/C joint sprain is damage to the ligaments that supports the acromioclavicular joint. If you have suffered an acromioclavicular sprain, you have damaged the strong fibrous ligaments that hold the end of your collarbone to the front tip of your shoulder blade. Another term sometimes used to describe this injury is “shoulder separation.” 40-50% of all athletic shoulder injuries involve the acromioclavicular (AC) joint. AC injuries are common in adolescents and young adults who participate in contact sports, like hockey and football. Shoulder separation may be confused with shoulder dislocation, yet the injuries are quite different.
Classification of Separated Shoulder
Injuries may range from mild fraying of a single ligament to complete rupture of all three of the supporting ligaments. Significant tears can allow your collarbone to move upward, out of its normal position. This creates a raised bump under your skin knows as a “step deformity.” AC joint injuries are categorized (Grade 1-Grade 6) based upon the amount of damage.
- Grade 1 injuries are tender without joint separation.
- Grade 2 injuries may be accompanied by a slight separation of the joint.
- Grade 3 and above will show significant joint separation.
Mechanism of A/C joint sprain
Injuries typically occur following a fall onto the point of your shoulder, while your arm is at your side. This drives the shoulder girdle down and away from the collarbone. Also, separation injuries occur by falling onto your outstretched hand, driving the shoulder girdle up. You will most likely feel pain and swelling on the very top of your shoulder. More significant injuries may produce bruising or a visible “bump” beneath the skin. Moving your shoulder will be painfully limited for a while.
Treatment for Acromioclavicular Sprain
Your treatment will vary, depending upon the severity of your injury. Grade 1, 2, and most Grade 3 injuries can be treated conservatively with rehabilitation. A sling may help to control painful movements. Initially, you will need to limit activity, especially reaching overhead, behind your back, or across your body. Your doctor will prescribe exercises as an important part of your rehab. Consistency with a rehab plan avoids long-term problems. Initially, using an ice pack for 10-15 minutes each hour may help to limit swelling and pain.
Some mild separations will heal by themselves within a week or two. More significant injuries can take longer. Your limited shoulder ability ranges between one and eight weeks. Also, patients who have suffered a significant amount of ligament damage may have a permanent bump on their shoulder, regardless of treatment. Yet this bump does not usually cause ongoing problems.