AC Sprain
Acromioclavicular (AC) Joint Anatomy
The acromioclavicular (AC) joint is formed between the acromion and the collar bone, or clavicle. Of importance, the AC joint is held together by a thick joint capsule circumferentially, and an AC ligament. The coracoclavicular (CC) ligaments are formed by two ligaments that attach from the coracoid to the clavicle. The outer (or lateral) ligament is shaped like a trapezoid, and hence its name. The inner (medial) ligament is shaped like a cone, so it is called the conoid. These ligaments and structures are important for the stability of the AC joint.
Grade I Sprain
A grade I sprain involves only partial tearing of the AC ligament. The CC ligaments are not affected.
Grade II Sprain
A grade II sprain involves near complete tearing of the AC ligament and only partial tearing of the CC ligaments.
Grade III Sprain
A grade III sprain involves complete tearing of both the AC and CC ligaments.
Higher Grade Injuries (IV-VI)
Higher grade AC joint injuries also involve complete tearing of the AC and CC ligaments.
A grade IV separation is a complete separation when the end of the clavicle gets pushed backwards (posterior) into the trapezius muscle.
A grade V separation is a complete separation when the end of the clavicle gets pushed more than 100% of its height vertically (superior) towards the head.
A grade VI separation is a complete separation when the end of the clavicle gets pushed down below the level of the coracoid.
Treatment
Grade I and II Sprains: These injuries are treated (nonoperatively) without surgery. You can expect a 2-3 week course in a sling, used only for comfort. Ice, rest, and non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or naprosyn can also be used as needed for pain.
Grade III Sprain: Though this type of injury is currently controversial, the vast majority of these injuries can be treated without surgery. Recent studies have suggested in active laborers and elite athletes, surgical fixation may be superior to nonoperative treatment.
Higher Grade Injuries (IV-VI): In general, most higher grade injuries are treated surgically.
Surgical Options
Surgery can involve repairing or reconstructing the ligaments. Depending on when the injury occurred, your surgeon may elect to use manufactured products, autograft (your own tissue), or allograft (cadaver) tissue to repair your ligaments. Chronic injuries require a biologic component to have the best possible outcomes.