(858) 554-7980
Contact
Shoulder

AC Joint Injuries

The acromioclavicular (AC) joint is a small joint located at the top of the shoulder where the collarbone (clavicle) meets the highest point of the shoulder blade (acromion). This joint plays a crucial role in the movement and stability of the shoulder, enabling a wide range of arm and shoulder motions, such as lifting, rotating, and moving the arm across the body. Despite its small size, it is an important component in shoulder mechanics and is susceptible to injuries, especially from direct impacts or falls.

The AC joint is supported by a group of ligaments:

  • Acromioclavicular Ligaments: These ligaments connect the clavicle to the acromion, providing stability to the joint.
  • Coracoclavicular (CC) Ligaments: Comprising the conoid and trapezoid ligaments, these attach the clavicle to another part of the scapula called the coracoid process, further stabilizing the joint.

An acromioclavicular joint injury occurs when there is damage to the ligaments that hold the clavicle (collarbone) to the scapula (shoulder blade). Injuries to the AC joint are common in athletes, particularly those involved in contact sports, and can also result from falls or accidents.

AC joint injuries are classified based on severity, ranging from a mild sprain to complete separation. They are typically graded on a scale of I to VI:

  1. Grade I: Mild sprain of the AC ligament without significant displacement.
  2. Grade II: Partial tearing of the AC ligament with slight displacement of the collarbone.
  3. Grade III: Complete tearing of the AC and coracoclavicular (CC) ligaments, resulting in noticeable elevation of the collarbone.
  4. Grades IV-VI: Severe dislocations involving damage to surrounding structures and a more pronounced separation of the collarbone from the shoulder blade.

The symptoms vary depending on the severity of the injury but commonly include:

  • Pain: Sharp pain at the top of the shoulder, especially when moving the arm across the body.
  • Swelling: Swelling and tenderness around the joint.
  • Bruising: Bruising may occur in the affected area.
  • Visible Deformity: In more severe cases (Grades III-VI), a visible bump or elevation of the collarbone can be seen.
  • Limited Range of Motion: Difficulty lifting the arm or performing overhead activities.

The most common causes of AC joint injuries include:

  • Direct Trauma: A direct blow to the shoulder, such as during contact sports (football, rugby) or a fall onto the shoulder.
  • Falling on an Outstretched Hand: This indirect mechanism can transmit force up the arm to the shoulder joint, resulting in injury.
  • Overuse: Repetitive overhead movements, especially in athletes like weightlifters or baseball players, can lead to chronic stress and eventual injury to the AC joint.

Diagnosis involves a combination of medical history, physical examination, and imaging studies. Dr. Cinque will review your medical history including any shoulder injuries and inquire about your symptoms. He will inspect the shoulder for signs of deformity, swelling, and tenderness. He may also perform specific tests, such as the cross-body adduction test, where the arm is moved across the chest to assess pain levels in the AC joint.

Dr. Cinque will order X-rays to confirm the diagnosis and assess the extent of the injury. In more complex cases, an MRI or ultrasound may be used to evaluate ligament damage.

Treatment depends on the severity of the injury and can range from conservative management to surgical intervention:

Non-Surgical Treatments (Grades I-III):

  • Rest: Avoid activities that aggravate the shoulder, allowing time for the ligaments to heal.
  • Ice: Applying ice packs to the shoulder reduces swelling and alleviates pain.
  • Sling: Using a sling can immobilize the shoulder, promoting healing.
  • Medications: Over-the-counter pain relievers, such as NSAIDs (ibuprofen or naproxen), help manage pain and inflammation.
  • Physical Therapy: Gradual exercises to restore strength and mobility are crucial in the rehabilitation process. A physical therapist can guide patients through a tailored program to regain full function.

Surgical Treatments (Grades IV-VI or Chronic Instability):

  • Surgical Repair: In cases of severe displacement or ongoing pain and instability, surgery may be necessary. The procedure typically involves realigning the collarbone and fixing it in place using screws, plates, or sutures.
  • Rehabilitation: Post-surgery, patients undergo physical therapy to regain strength and range of motion. Recovery time varies depending on the injury’s severity and the surgical method used.

Most individuals with mild to moderate AC joint injuries (Grades I-III) recover well with conservative treatment. Full recovery can take several weeks to months, depending on the injury’s severity. For severe injuries requiring surgery, recovery can extend to several months and return to full activity may take longer. Proper rehabilitation is essential to restore shoulder function and prevent future injuries.

Contact Dr. Mark Cinque at Scripps to schedule a consultation to learn more about your shoulder injuries and receive personalized care.

At a Glance

Mark Cinque, MD

  • Board-certified, fellowship-trained orthopedic surgeon
  • Orthopedic Residency: Stanford University, Fellowship: The Steadman Clinic
  • Authored over 100 peer-reviewed publications
  • Learn more
Call • (858) 554-7980
Request an Appointment

Schedule Consult