Pectoralis Major Tendon Transfer

What is Pectoralis Major Tendon Transfer?

Tendons are bands of connective tissue fibers that connect muscle to bone. Pectoralis major tendon transfer is a surgical procedure to treat a massive anterosuperior rotator cuff tear or isolated irreparable subscapularis tear in the shoulder. The procedure involves transferring a healthy pectoralis major tendon to replace the damaged tendon and restore the normal movement of the shoulder.

The shoulder joint, also referred to as the glenohumeral joint, is a ball-and-socket joint made up of three bones, namely the humerus (upper arm bone), scapula (shoulder blade), and clavicle. The head of the humerus articulates with the socket of the scapula called the glenoid cavity. The clavicle bone or collarbone is an S-shaped bone that connects the scapula to the sternum or breastbone. A group of four tendons and muscles called the rotator cuff maintain the stability of the shoulder joint, preventing the humerus from sliding out of the socket bone (dislocation). The rotator cuff attaches the humerus to the shoulder blade and helps to lift and rotate your arm. The rotator cuff consists of supraspinatus, infraspinatus, subscapularis, and teres minor. The subscapularis muscle is the largest and most powerful of all the muscles.

Rotator cuff tears typically involve the supraspinatus tendon. However, anterosuperior rotator cuff tears are characterized by a total rupture of the subscapularis with either the supraspinatus alone or the supraspinatus and infraspinatus. These massive tears are not always responsive to repair due to the gravity of the defect, muscular atrophy, tendon retraction, and fatty degeneration of the cuff remnant, necessitating a pectoralis major tendon transfer.

Anatomy of the Pectoralis Major Muscle

The pectoralis muscle is a large fan-shaped muscle comprised of the pectoralis major and pectoralis minor muscles that stretch from the armpit to the collarbone and down across the lower chest region on both sides of the chest. The two sides of the chest connect at the breastbone or sternum. The pectoralis major is a powerful muscle that aids in rotating the arm inward and move it closer to the body. The pectoralis muscles connect the chest wall with the humerus (upper arm bone) and shoulder. The pectoralis major moves each shoulder joint in four distinct directions and also keeps the arms attached to the body. 

Indications for Pectoralis Major Tendon Transfer

Your surgeon may recommend pectoralis major tendon transfer for chronic irreparable anterosuperior rotator cuff tear associated with subscapularis tear that is not amenable to conservative treatment.  Other indications include:

• Persistent pain and shoulder dysfunction with limitations in elevation and external rotation
• Weakness and pain on activities that require pulling objects or pushing across the front of the body, such as gripping and lifting a heavy weight in front of you
• Muscle atrophy (wasting or loss of muscle tissue in the shoulder joint) 
• Intact and functional posterior cuff (infraspinatus and teres minor)

Preparation for Pectoralis Major Tendon Transfer

Preparation for pectoralis major tendon transfer may involve the following steps:

• A review of your medical history and a physical examination is performed by your doctor to check for any medical issues that need to be addressed prior to surgery.
• Diagnostic tests such as routine blood work to help detect any abnormalities that could compromise the safety of the procedure. MRI scan is also performed to assess the size of the tear, retraction of the tendons, degenerative status of the attached muscles, and quality of the shoulder joint. It also reveals the bulk and quality of the pec major muscle to be transferred.
• You will be asked if you have allergies to medications, anesthesia, or latex.
• You should disclose your current medications or supplements you are taking or any current illnesses or conditions you have such as heart or lung disease.
• You may be asked to stop taking certain medications, such as blood thinners, anti-inflammatories, aspirin, or other supplements for a week or two.
• You should refrain from alcohol and tobacco at least a few days prior to surgery and several weeks after, as it can hinder the healing process.
• You should not consume solids or liquids at least 8 hours before surgery.
• You should arrange for someone to drive you home after surgery.
• A signed informed consent form will be obtained from you after the pros and cons of the surgery have been explained.

Procedure for Pectoralis Major Tendon Transfer

Pectoralis major tendon transfer surgery is usually performed under general anesthesia with you lying either in a beach chair or lateral decubitus position. An incision is made along the section of the affected shoulder and the damaged rotator cuff muscle is exposed and removed. Attention is then turned towards obtaining the pectoralis major tendon from its attachment site on the humerus. The pectoralis major muscle and tendon is located just below and in front of the subscapularis muscle. It also has a very broad tendon; therefore, a section of it can be transferred without significantly affecting loss of strength. Typically, one-half to two-thirds of the pec major tendon is detached and mobilized. It is then moved as high up the humerus as possible to exert a downward and internal rotation force on the shoulder, compensating for the subscapularis and supraspinatus muscles. The transferred tendon is fixed to the bone with multiple strong suture anchors. A final shoulder assessment is performed to confirm satisfactory repair. Finally, instruments are withdrawn, and the soft tissues and incision are closed with sutures and covered with a sterile bandage.

Post-Operative Care and Recovery

In general, postoperative care and recovery after pectoralis major tendon transfer will involve the following steps:

• You will be transferred to the recovery area where your nurse will closely observe you for any allergic/anesthetic reactions and monitor your vital signs as you recover from the effects of anesthesia.
• Your arm will be placed in a shoulder sling for 2 to 4 weeks to rest the shoulder and promote healing.
• You may experience pain, swelling, and discomfort in the shoulder area. Pain and anti-inflammatory medications are provided as needed to address these. You may also apply ice packs to the treatment area to help reduce swelling and pain.
• Antibiotics may also be prescribed to address the risk of surgery-related infection.
• You are encouraged to walk as frequently as possible with assistance to prevent the risk of blood clot formation.
• Instructions on incision site care and bathing will be provided to keep the wound clean and dry.
• Refrain from strenuous activities and lifting heavy weights for at least a couple of months. A gradual increase in activities is recommended.
• An individualized physical therapy protocol will be designed once you are off the sling to help strengthen your shoulder muscles and optimize shoulder function.
• You should be able to resume your normal daily activities in 3 to 4 weeks but with certain activity restrictions. Return to sports may take 6 months or longer.
• Refrain from driving until you are fully fit and receive your doctor’s consent.
• A periodic follow-up appointment will be scheduled to monitor your progress.

Risks and Complications

As with all surgeries, pectoralis major tendon transfer surgery may be associated with certain risks and complications, such as:

• Infection
• Bleeding or hematoma
• Blood clot formation
• Shoulder stiffness
• Damage to adjacent blood vessels and nerves
• Non-healing, rupture, or loosening of the tendon
• Failure of the transfer
• Weakness of the biceps muscle
• Anesthesia-related risks