Scapular notching ...PO Day 118

                  Scapular notching explained ... The best I can which may not be perfectly correct.
                                              
I finally asked my surgeon to explain scapular notching and tell me how to avoid it. I was pleased to learn the burden falls on the surgeon's shoulders and there is nothing the patient can do about it.

Scapular notching was a bigger problem in the earlier days of rTSA but remains a bugaboo, for surgeons and device manufacturers.  As the operated arm moves up and down, the  metallic socket (or cup) at the top of the humerus pivots on the glenosphere (the metal ball) separated only by a polypropylene liner, like the one in the photo above.  (Except without the damaged area.) A common problem has been that the socket/cup, in some arm positions, extended beyond the circumference of the glenosphere (the ball) and wore away at the exposed scapula to which the glenosphere is attached. This created a groove in the scapula and erosion on the poly liner. Actually the poly liner seemed to have endured the worst of it. See photo above. There is some question about the effect of plastic particulates from liner sluffing off into the blood but so far it has not been identified as a major problem. Gradual notching of the scapula does not appear to cause pain or discomfort. So what is the big concern? As a chronic condition there is some conjecture that it causes a loosening of the glenoid but so far this is unproven.

Surgical technique and evolutionary design changes in the prosthetic devices have improved the situation. Lateralizing it (that's making the glenosphere stick out farther, to you and me) and inferiorizing it (dropping it down a little lower so it is a little off-center) and using as large a glenosphere as possible are techniques used to prevent scapular notching. At least that is the approach used by my surgeon and the company whose product he chooses to use. I can imagine there are as many opinions of what to do as there are manufacturers of the artificial shoulder joints and surgeons to install them.

I am just glad to know there is at least one possible glitch that I can leave for someone else to fret about.





Archive timeline: 2014: May and June - preparing for surgery, July - surgery and post op problems, August - recovery and physical therapy, September - thinking medically, October--