Thursday, August 4, 2016

Non-operative treatment of shoulder arthritis with posterior decentering (subluxation)

Today this email came in:

"We met several months ago. Dr. X had recently completed a cortisone procedure on my left and arthritic shoulder. As I recall when you analyzed my x-ray you noted that my humerus bone was posterior in the socket and as a consequence mobility was restricted and plenty of crepitus based on the the bone moving in the unintended part of the socket. Irrespective of the type of initial dislocation you explained that the bone is mis-placed and remains there (due If guess to the composite if all existing forced from damaged/weak muscles, tendons, etc). You offered to try to respond by email to follow-up questions that I might have.

I'd like to learn exactly which physical exercises might rebuild or retrain my physiology in such a way that the bone would find a new and better equilibrium in its socket (that enables improved mobility and less bone-on-bone wear that is undoubtedly taking place). I would like your advice or referral of a therapist with solid experience relating to shoulder anatomy and damage. For the most part I've only encountered PTs who described standard exercises that offered negligible value. They had no regard to exact status of my condition and had no ability to develop a treatment trajectory that would be optimal.

I look forward to your thoughts."

Comment: Posterior humeral decentering (subluxation) is a common feature of glenohumeral osteoarthritis

Once the glenoid develops a pathologic posterior concavity, the humeral head tends to fall into it when the arm is elevated to a functional position as shown in the three 'truth views' above. The deeper the posterior concavity, the less likely it is that exercises can help.

For early stages of arthritis, we recommend avoiding pushups, bench presses and other pushing exercises while focusing on external rotator strengthening so that the posterior rotator cuff muscles can help resist the tendency for the shoulder to slide out of the back of the joint. See below

as well as stretching exercises to minimize stiffness (see this link). We do not use steroid or other injections into the shoulder joint.