What Is the Magnuson-Stack Procedure?

What is the Magnuson-Stack procedure?

Magnuson-Stack procedure is a surgical procedures that corrects shoulder instability.
Magnuson-Stack procedure is a surgical procedures that corrects shoulder instability.

Magnuson-Stack procedure is one of the surgical procedures performed to correct shoulder instability. It is named after the two surgeons who first performed the technique, Paul B. Magnuson and James K. Stack, in 1943. 

This surgery involves tightening of the ligament and capsule of the shoulder joint and altering the insertion site of the ligament. This surgery has a good success rate, but a complete range of motion may not be possible and may not be ideal for athletes or laborers.

The anatomy of the shoulder joint

The shoulder joint (glenohumeral joint) is a ball and socket joint. It is formed between the scapula (shoulder blade) and the humerus (the upper arm bone). 

The outer end on the scapula (shoulder blades) is called the glenoid; it meets the head of the humerus (the upper arm bone) to form the glenohumeral cavity. This functions as a flexible ball and socket joint. It is surrounded by a fibrous capsule. 

The joint is stabilized by a ring of cartilage called the labrum. The capsule is reinforced by the rotator cuff (a group of muscles and tendons that surround the shoulder joint) and ligaments. 

Shoulder dislocation occurs when the head of the humerus separates from the scapula at the shoulder joint. The shoulder joint has a rich blood and nerve supply.

What are the causes of shoulder instability?

Patients with shoulder instability present with pain and an abnormal range of motion of the joint. Some common causes of shoulder instability are:

  • Extraordinary range of motion of the shoulder 
  • Shallow glenoid
  • Injury to the upper limb or shoulder joint 
  • Underlying conditions causing ligament or muscle laxity
  • Medical conditions such as seizures or electric shock

How is the Magnuson-Stack procedure performed?

Before the surgery

Prior to the surgery, the surgeon performs a complete physical assessment. In addition, the surgeon performs X-ray, computed tomography (CT), and magnetic resonance imaging (MRI) to assess the joint status. A complete blood analysis is done, and consent for surgery is obtained.

During the surgery

The surgery is performed under general anesthesia. It is an open surgery. During the surgery, the anterior capsular and muscular wall is tightened by advancing the capsule and tendon in the shoulder joint. This provides a “sling effect.” The surgeon carefully preserves the nerve and blood supply.

After the surgery

The surgeon administers painkillers and antibiotics. The patient is usually discharged 24 to 72 hours after the surgery. Immobilization is necessary immediately following the surgery and is continued for three to six weeks. 

Rehabilitation follows immobilization, but complete rotation is limited for four to six weeks following the surgery. Pain, swelling, and bruising is expected in the postoperative period and usually resolves within two weeks.

What are the complications of the Magnuson-Stack procedure?

Complications that are possible with this procedure include the following:

  • Loss of functional abilities due to a significant loss of external rotation
  • Recurrence of instability
  • Injury to nerves and blood vessels
  • Bleeding
  • Infection
  • Secondary osteoarthritis 
  • Hematoma (blood clot)
  • Seroma (collection of fluid)


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