There is more than one joint in the shoulder. What you choose to do about your shoulder arthritis really depends on where the arthritis is in your shoulder and how severe it is. Below is a typical case of severe arthritis in the ball and socket portion of the shoulder joint.
Arthritis is actually relatively uncommon in this joint. But when it occurs it tends to show a distinct pattern. The hallmark of arthritis at the ball and socket shoulder joint is joint space narrowing bone spurs at the bottom of the ball portion of the joint.
The patient in this case had greater than 10 years of shoulder pain and was in his late 50’s when he presented for surgery. At this point he was unable to tolerate the pain and had significant difficulty sleeping and using the arm for daily activities. Conservative treatments like medications and injections were not helping.
The final x-rays demonstrate an anatomic shoulder replacement. Another term for this is shoulder arthroplasty. What you notice is there is a new metal ball and a plastic socket, which has replaced the previously worn joint. The metal ball is attached to a metal stem, which is press fit into the canal of the humerus. The upper stem has a lightly roughened surface that allows it to bond to the bone in the top of the humerus. The metal ball is made of cobalt chrome (an alloy) and the stem is made of titanium.
The new socket implant is made of a plastic called polyethylene. Four small holes are drilled into the bone socket and then filled with cement. The implant is then pressed into the holes and the cement dries and bonds the plastic socket to the bone. The plastic does not show up on x-ray but you will notice that there is a small metallic fragment in the socket implant. This is solely for the purpose of making the plastic implant visible on x-ray. This allows the surgeon to monitor your implants over time. If the implant ever shifts then this marker can be helpful for identifying that.
The goal of the operation is to create a new, smooth, well balanced surface for the joint. As you can see the components are similar in size and shape to the normal shoulder. And there is now a space between the ball and the bone socket. The patient is now pain-free and has full range of motion for the first time in 10 years.