Part 3: - What’s a joint like this doing in a nice person like you?

I hope you have been saving these past few articles on joint replacement because it would make a nice little “manual” if you will, for references if the day ever comes when you might face the need for one of these procedures.

So far, we’ve touched upon the knee and the hip (and there is still more to discuss there as well). There are several variations of hip and knee replacements, and I will start on those once we’ve gone through the most commonly performed procedures.

Shoulder replacement surgery is usually performed for the primary purpose of pain control.

Let’s talk about the shoulder. The shoulder joint is the third most commonly replaced joint behind the hip and knee. Even at that, shoulder “arthroplasty” (another term for replacement) follows at a distant third (approximately 23,000 per year) when compared to the more than 700,000 hip and knee replacements performed each year in the U.S.

For discussion purposes, I’ll limit this column to the “total shoulder” variation.

Shoulder joint replacement is typically performed for the same reason as that of hips and knees; end-stage, painful arthritis. These procedures are usually arrived at after all lesser treatment forms – oral medications, therapy, cortisone injections and even shoulder arthroscopy, have been undertaken and found ineffective.

What makes up the shoulder joint?

The two major bone structures that comprise the shoulder joint are the humeral head (ball of the upper arm) and the glenoid (socket). Unlike the knee and hip, the shoulder joint is a non-weight-bearing joint and is stabilized and kept in socket mainly by soft tissue tension from muscles, tendons and ligaments. In instances of degenerative arthritis, the joint surface degeneration can affect either the humerus, glenoid or both.

There are a number of supportive structures that help allow for motion and stability – the deltoid muscles, shoulder “capsule” and the rotator cuff. In fact, the rotator cuff is the principal structure that determines what type of replacement implants can be used. The rotator cuff must be intact in order to utilize a standard total shoulder configuration. A chronically torn and/or absent cuff necessitates the use of another prosthetic type, called the Reverse Shoulder Replacement, which we will discuss further in subsequent issues.

What position will I be in?

Typically, this procedure is performed in what is called the “Beach Chair” position, similar to how one sits in a lounging chair at the beach or in a Lazy Boy recliner.

General anesthesia is the anesthetic of choice for airway safety reasons and most patients receive a special anesthetic “block” either before or immediately after the surgery that dramatically reduces post-operative pain. The incision is typically placed along the front-most aspect of the shoulder and upper arm, which permits maximum access to the shoulder joint.

The ball of the upper arm, or humeral head, is treated much the same way in surgical preparation as the ball of the hip joint. The diseased head is removed, the humeral bone canal prepared to accept a prosthetic “stem” on which an artificial ball or “head” is inserted. The stem can be either press-fit or cemented into place using special bone cement.

Preparation of the glenoid, or socket, is a bit different primarily because of its shape, but in general, the steps and final products are quite similar. The glenoid is a very shallow socket, thus making it inherently less stable than other joints. The diseased, arthritis surface is shaved off and the underlying bone is prepared to accept either a cemented or press-fit implant.

In either case, a plastic “spacer” is snapped into position after the metallic plate has been properly inserted to act as a stabilizer as well as a low-friction interface with the artificial ball (head).

Is total replacement necessary all the time?

Actually, the answer is ‘no.’ There are instances where only the humeral head (ball) is diseased and degenerated, but the glenoid (socket) is normal and intact. Therefore, only the ball needs replaced. This procedure is known as a hemi-arthroplasty (half-replacement). This procedure type is most frequently performed in trauma cases, i.e. shoulder fractures, where the broken ball is replaced rather than attempting to “fix” it and the glenoid is left alone. This is typically not considered the “procedure-of-choice” in an elective replacement scenario for arthritis.

What to expect after surgery
A special arm sling is used after surgery to support the arm, wrist and hand, as well as restrict shoulder motion. Over time, your surgeon will increase the amount of time you can spend out of the sling as therapy and healing progress. Many patients are free of restrictive slings, etc. by four to six weeks after surgery.

One of the most important things about shoulder replacement surgery, and this also differs from hip and knee replacement, is that the procedure is usually performed for the primary purpose of pain control, with less emphasis placed upon range of motion. That being said, restoration and improvement of mobility is still a very important goal, but pain relief is the overriding motivation for the procedure. It is critically important to have a clear understanding of your expectations of the procedure, as well as your surgeon’s.

Shoulder replacement surgery can be as gratifying a procedures as the hip and knee replacement, especially if you are suffering from the debilitating pain and limited mobility that severe, end-stage arthritis can inflict.

The brain operates on the same amount of power as 10-watt light bulb. (The cartoon image of a light bulb over your head when a great thought occurs isn’t too far off the mark. Your brain generates as much energy as a small light bulb even when you’re sleeping). Ahh…that explains it…

Have questions? Want more information? Contact Compass Care Management LLC to see how they can help (www.healthcare-advocates.org), and visit www.bone-and-joint-pain.com

Chisholm’s expertise in nursing, orthopedics and surgery spans more than 30 years. For more information on orthopedic-related topics, visit www.bone-and-joint-pain.com. Submit questions or comments to Ken at This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Shoulder replacement surgery is usually performed for the primary purpose of pain control, with less emphasis placed upon range of motion.

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