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What is Partial Shoulder Replacement?

Partial shoulder replacement, also called shoulder hemiarthroplasty, is a surgical procedure during which the upper bone in the arm (humerus) is replaced with a prosthetic metal implant, whereas the other half of the shoulder joint (glenoid or socket) is left intact.

The shoulder joint (glenohumeral joint) is a ball and socket joint where the head of the humerus (upper arm bone) articulates with the socket of the scapula (shoulder blade), which is called the glenoid. The two articulating surfaces of the bones are covered by a smooth tissue called articular cartilage, which allows the bones to slide over each other without friction, enabling smooth movement. The cartilage is lubricated by synovial fluid. Tendons and ligaments around the shoulder joint provide strength and stability to the joint.

Indications for Partial Shoulder Replacement

Partial shoulder replacement is usually indicated for a severe fracture or arthritic conditions of the shoulder, in which only the humeral head or ball of the joint is damaged and the glenoid socket is normal or intact. Arthritis is a degenerative condition in which the cartilage that allows smooth movement in the joints wears away causing the adjacent bones to rub against each other resulting in pain and stiffness. In such conditions, replacement of the damaged portion of the humerus will reduce the friction as bone-ends can no longer come in contact and thus relieve pain.

Surgery remains as a sole treatment option when all possible conservative means of treatment such as rest, anti-inflammatory medications, and physical therapy have been ineffective in resolving your symptoms.

Preparation for Partial Shoulder Replacement

In general, preoperative preparation for partial shoulder replacement will involve the following steps:

  • A thorough examination is performed by your doctor 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 bloodwork and imaging to screen for 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 supplements or medications 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 a week before surgery.
  • You should not consume solids or liquids at least 8 hours prior to surgery.
  • Arrange for someone to drive you home after surgery.
  • A written consent will be obtained from you after the surgical procedure has been explained in detail.

Procedure for Partial Shoulder Replacement

In general, partial shoulder replacement surgery will involve the following steps:

  • You will lie on your back on the operating table under regional or general anesthesia.
  • An incision is made over the affected shoulder and the underlying muscles are separated to expose the shoulder joint.
  • The surgery may be performed as an open surgery, where a large incision is made, or minimally invasive, where small incisions are made to insert an arthroscope (a thin tube with a camera and light source) and surgical tools.
  • The upper arm bone (humerus) is separated from the glenoid socket of the shoulder bone.
  • The arthritic or damaged potions of the humeral head is removed and replaced with a metal ball that is attached to a stem that extends into the humerus.
  • Next, your surgeon may use special tools to smooth and reshape the socket to provide a stable surface for the new humeral head to rotate and fit appropriately.
  • The shoulder joint is then tested through its range of motion, and the entire joint is irrigated and cleaned with a sterile solution.
  • Upon completion, the incision is closed with absorbable sutures and covered with a sterile bandage.

Postoperative Care and Instructions

In general, postoperative care instructions and recovery after partial shoulder replacement 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.
  • You may need to stay in the hospital for 2 to 3 days before discharge to home.
  • You may notice some pain, swelling, and discomfort in the shoulder area. Pain and anti-inflammatory medications are provided as needed.
  • Antibiotics are also prescribed to address the risk of surgery-related infection.
  • Your arm may be secured with assistive devices such as a sling or a cast for the first few weeks to facilitate healing with instructions on restricted weight-bearing.
  • Keep the surgical site clean and dry. Instructions on surgical site care and bathing will be provided.
  • Refrain from smoking as it can hinder the healing process.
  • Refrain from strenuous activities for the first few months and lifting heavy weights for at least 6 months. Gradual increase in activities over a period of time is recommended.
  • An individualized physical therapy protocol will be designed to help strengthen shoulder muscles and optimize shoulder function.
  • You will be able to resume your normal activities in a month or two after surgery; however, return to sports may take at least 6 months or longer.
  • A periodic follow-up appointment will be scheduled to monitor your progress.

Risks and Complications

Partial shoulder replacement is a relatively safe procedure; however, as with any surgery, some risks and complications may occur, such as the following: 

  • Infection
  • Bleeding
  • Postoperative pain
  • Damage to nerves and vessels
  • Shoulder stiffness
  • Thromboembolism or blood clots
  • Anesthetic/allergic reactions