AC Joint Reconstruction

What is the Acromioclavicular (AC) Joint?

The acromioclavicular (AC) joint is one of the joints present within your shoulder. It is formed between a bony projection at the top of the shoulder blade (acromion) and the outer end of the clavicle (collarbone). The joint is enclosed by a capsule and supported by ligaments.

The AC joint is stabilized by the following structures:

• Capsular ligaments: These ligaments are called the acromioclavicular ligaments. They have superior and inferior components and resist separation of the joint in the horizontal direction.
• Extracapsular stabilizers: These are ligaments extending from a bony process of the scapula called the coracoid process to the clavicle (coracoclavicular ligaments) and the acromion (coracoacromial ligaments). These ligaments resist vertical forces from separating the joint.
• Muscular attachments: The deltoid muscle on the outside of the shoulder and the trapezius muscle in the upper back and neck also help stabilize the acromioclavicular joint.

An injury to the AC joint, particularly the ligaments, can result in instability or separation of the AC joint (shoulder separation) causing pain and discomfort and limiting shoulder function.

What is Acromioclavicular Joint Reconstruction?

Shoulder separation can usually be managed by non-surgical treatments. In cases of a severe separation of the AC joint, your surgeon may perform a surgical repair or use a tissue graft to reconstruct the damaged ligaments. An autograft (from your own body) or allograft (from a donor) of the anterior tibia or hamstring may be used. Your surgeon might also suggest artificial non-absorbable material to graft the damaged ligaments.

The goals of surgery include:

• Relief from pain
• Improved shoulder movement
• Improved strength and function
• Faster recovery in cases of athletes

Anatomic reconstruction of the AC joint helps ensures static and safe fixation with stable joint function.

Procedure for Acromioclavicular (AC) Joint Reconstruction

Acromioclavicular joint reconstruction involves the following steps:

• The procedure is performed under general anesthesia and regional anesthesia.
• A diagnostic arthroscopy may be performed to visualize the position of the tear and extent of the damage.
• An incision is made to expose the AC joint and any damaged tissue is trimmed.
• Tissue is dissected to expose the coracoid process.
• The graft is passed from under the coracoid process to a hole drilled into the clavicle and the displaced clavicle is reduced.
• Sutures are used to close the wound.
• Alternatively, a ligament extending from the coracoid process to the acromion (coracoacromial ligament) may be transferred to the end of the clavicle to reduce it in position. 
• The graft ends are secured to the bone.

Following surgery, your arm is placed in a sling and your shoulder will be immobilized for a period of 6 weeks. You will then require rehabilitation to regain strength and movement of the shoulder joint and can return to your regular activities in about 6 months. 

What is AC Joint Stabilization?

Acromioclavicular (AC) joint stabilization is a surgical procedure employed to treat severe cases of AC joint dislocation.

AC joint dislocation is the separation of the collar bone or clavicle from the acromion (the top portion of the shoulder blade or scapula at the outer edge of the shoulder) due to severe trauma. AC joint dislocation usually occurs as a result of a direct fall on to the top of the shoulder which causes the shoulder blade to be forced downwards and the collarbone to pop up. It is most commonly seen in individuals involved in sports such as mountain biking, rugby, football, snowboarding, motocross, and horse riding.

AC joint stabilization surgery involves repairing the torn tendons and ligaments or replacing them with either natural tissue grafts obtained from your own body (autograft) or donor (allograft) from the anterior tibia/hamstring or by using an artificial synthetic graft, which helps to hold the AC joint firmly in its position and prevent recurrent pain and instability.

Anatomy of the AC Joint

The AC joint is located at the highest point of the shoulder. It acts as a junction between the acromion of the shoulder blade and collarbone. The joint is easily identified as a slight bump that you feel when you move your hands over the top of your shoulder. The AC joint is supported and stabilized by the capsule of the joint and two ligaments known as the coracoclavicular ligaments that attach the collarbone with the front portion of the shoulder blade (coracoid process). The joint enables you to lift your arms overhead and functions by passing the intensity from your arm to the skeleton. If the joint is damaged, it becomes displaced and unstable requiring stabilization surgery.

Indication for AC Joint Stabilization

A total AC joint dislocation that exhibits persistent symptoms of pain, loss of motion, and weakness in the arm and shoulder for about 3 to 6 months despite undergoing conservative treatment measures is usually an indication for AC joint stabilization surgery. 

Preparation for AC Joint Stabilization

Pre-procedure preparation for AC joint stabilization will involve the following steps:

• A thorough examination by your doctor is performed to check for any medical issues that need to be addressed prior to surgery.
• Depending on your medical history, social history, and age, you may need to undergo tests such as blood work and imaging to help detect any abnormalities that could threaten the safety of the procedure.
• You will be asked if you have allergies to medications, anesthesia, or latex.
• You should inform your doctor of any medications, vitamins, or supplements that you are taking.
• You should refrain from medications or supplements such as blood thinners, aspirin, or anti-inflammatory medicines for 1 to 2 weeks prior to surgery.
• You should refrain from alcohol or tobacco at least 24 hours prior to surgery.
• You should not consume any solids or liquids at least 8 hours prior to surgery.
• Arrange for someone to drive you home as you will not be able to drive yourself after surgery.
• A written consent will be obtained from you after the surgical procedure has been explained in detail.

Procedure for AC Joint Stabilization

AC joint stabilization surgery, in general, involves the following steps:

• The procedure is performed under general or regional anesthesia.
• A diagnostic arthroscopy may be performed to visualize the position of the dislocation and the extent of the damage.
• An incision is made over the top of the shoulder to expose the AC joint and any damaged tissue is trimmed.
• Tissue is dissected to expose the coracoid process.
• A graft is passed from under the coracoid process to a hole drilled into the clavicle and the displaced clavicle is reduced.
• Alternatively, a ligament extending from the coracoid process to the acromion (coracoacromial ligament) may be transferred to the end of the clavicle to reduce it in position.
• The graft ends are secured to the bone with screws.
• The incision is closed with sutures and sterile dressings are applied.

Postoperative Care and Recovery

In general, postoperative care instructions and recovery after AC joint stabilization will involve the following steps:

• Post surgery, your arm is placed in a sling and your shoulder will be immobilized for a few weeks.
• You will be transferred to the recovery area to be monitored until you are awake from the anesthesia.
• Your nurse will monitor your blood oxygen level and other vital signs as you recover.
• You may notice some pain, swelling, and discomfort in the shoulder area. Pain and anti-inflammatory medications are provided as needed.
• Medications will also be prescribed as needed for symptoms associated with anesthesia, such as vomiting and nausea.
• Antibiotics are prescribed to address the risk of surgery-related infection.
• It is important to keep the surgical site clean and dry. Instructions on surgical site care and bathing will be provided.
• Refrain from smoking for a specific period of time as it can negatively affect the healing process.
• Eating a healthy diet rich in vitamin D is strongly advised to promote healing and a faster recovery.
• Refrain from strenuous activities and lifting heavy weights for the first couple of months. Gradual increase in activities over a period of time is recommended.
• An individualized physiotherapy protocol will be designed to help strengthen your shoulder muscles and optimize shoulder function.
• You will be able to resume your normal activities in a couple of months; however, return to sports may take 4 to 6 months or longer.
• A periodic follow-up appointment will be scheduled to monitor your progress.

Risks and Complications of AC Joint Stabilization

AC joint stabilization surgery is a relatively safe procedure; however, as with any surgery, some risks and complications may occur, such as:

• Infection
• Blood clots
• Injury to nerves and vessels
• Bleeding
• Anesthetic/allergic reaction
• Shoulder stiffness
• Graft failure
• Hardware failure
• The need for revision surgery to address the failure of joint stabilization