Arthritis is a painful, inflammatory condition that affects the slick, white cartilage on the ends of bones. As we age, the limited number of cartilage-producing cells declines, and the articular cartilage begins to wear thin. While non-operative treatments such as injections and NSAID’s can effectively treat the symptoms, the only curative treatment is a shoulder arthroplasty.
During this procedure, the physician will replace the arthritic humeral head with a metal ball and the arthritic glenoid with a plastic cup. For a video of this procedure, click this link.
As discussed on our Total Shoulder Arthroplasty page, the hardware used in these cases varies tremendously. Traditional long stem components have recently given way to short stem or completely stemless components like the one shown below from our Fort Sanders West clinic in Knoxville, TN.
As you can see, the bright white “ball” at the end of the humerus (arm bone) does not have a stem extending down the shaft of the humerus. Instead, the component is press-fitted into the softer cancellous bone at the top of the bone. This allows the surgeon to place the component more precisely, as the stem no longer dictates where the prosthesis can be placed.
Also note the thin space between the metal head and the bony “cup” (glenoid). This space is actually filled with a special plastic infused with vitamin E, dramatically increasing the wear characteristics and prolonging the life of the implant. Dr. Spencer worked on the design team for this new cutting edge material, and the results have shown the plastic can last upwards of 20 years. The reason this shows up as clear on x rays is that it is considerably less dense than the surrounding bone.
When implanted correctly and precisely, a total shoulder arthroplasty can make a world of difference regarding pain and function. The procedure essentially replaces the raw, painful bone with painless metal and plastic, allowing most patients to progress through surgery with minimal narcotic use.
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