Arthroscopic Anatomic Glenoid Reconstruction

The shoulder joint allows for more movement than any other joint in the body, but that flexibility also makes it easier to dislocate. Over time, repeated dislocations or injuries can damage the socket of the shoulder, called the glenoid. When too much bone is lost, standard repairs may not be enough to keep the shoulder stable, i.e. keeping the head of the upper arm bone or, “humerus”, in its socket.

Arthroscopic anatomic glenoid reconstruction is an innovative and novel procedure that rebuilds the damaged part of the socket (glenoid) using a small piece of bone, called a graft (typically a distal tibial allograft). The surgery is done arthroscopically, through tiny incisions with a camera and special tools. By replacing the loss bone in the front of the socket, the procedure creates a more secure fit for the ball of the shoulder joint, reducing the chance of future dislocations.

Historically, shoulder instability could be treated either with an all-soft tissue repair or bone augmentation. Soft-tissue repairs include repair of the labrum tissue in the front of the shoulder to restore a bumper to prevent the ball coming out of the socket and potentially a remplissage procedure, which fills a defect in the back of the humerus. Bone augmentation procedures include placing additional bone in the front of the socket to restore the lost bone from the dislocations. Most commonly, this includes a Latarjet procedure, where your coracoid (bony prominence on the front of your shoulder) is harvested and moved to the socket.

All soft-tissue repairs are safe, minimally-invasive procedures with little risk to neurovascular structures. While outcomes are generally acceptable, the success rate (avoiding re-dislocation) at 5 years may be as low as 80%. Traditional open bony augmentation procedures generally have much higher rates durable stability (90-95%), but are more invasive and carry risks to important neurovascular structures that help you move your arm (notably the musculocutaneous nerve). Additionally, the bone block is placed through the subscapularis muscle belly (one of the rotator cuff tendons). This is theoretically safe, but does still result in violation of that tendon.

AAGR (arthroscopic distal tibial allograft) procedures combined the best elements of both traditional approaches. AAGR is arthroscopic and minimally invasive, without risk to the surrounding nerves (unlike open bone block procedures, where there is always a risk). During the AAGR, bone is restored via the distal tibial allograft. Additionally, because the procedure is arthroscopic, in conjunction with adding the bone, the labrum can be repaired and the remplissage can be performed, providing 3 points of stability. This is done without any violation of the subscapularis tendon. This means the AAGR can provide the stability of open bone block procedures, but maintain the safety of arthroscopic all-soft tissue procedures.

People at highest risk for repeated shoulder dislocations and subluxations include

• Young athletes who play contact sports such as football, basketball, Rugby, swimming, baseball, and volley ball that puts repeated stress on the shoulder making it more likely to dislocate the shoulder again after the first injury.
• People with a prior history of dislocation. Once the shoulder has been dislocated, the soft tissues and ligaments that normally hold the joint in place are stretched or torn. This makes the shoulder more prone to slipping out again. The risk is particularly high after the first dislocation occurs at a younger age. that increases the risk of repeated instability.
• Patients with significant bone or soft tissue damage. Damage to the glenoid socket (bone loss) or the humeral head (the ball of the joint) significantly increases the likelihood of repeat instability. This is often seen in patients who have had multiple dislocations or high-energy trauma.
• People with naturally loose ligaments.
• Patients who failed prior shoulder surgery or the joint sustained additional trauma after surgery.
• Older adults with rotator cuff injuries. When the rotator cuff muscles are weakened or torn, the joint lacks an important stabilizing force, increasing the chance of repeated episodes.

Dr. Kaplan carefully reviews each case to decide if this procedure is the best option for long-term success.