Instead of cortisone, which rarely helps inflammation, see if your doctor will inject lidocaine, or a similar local pain killer, directly into your joint, and, after a few minutes, test your articulation. If you find that you have a greater range of motion under the the influence of the pain killer, then your are more likely suffering from inflammation, rather than any physical deformity that would require surgery.
There are lifestyle changes one can make to ease the consequences of joint inflammation, via dietary changes and gentle but steady articulation exercises.
There is a family of plants that have built into their DNA a herbicide that causes an allergic reaction in some folks - this reaction usually causes aggravation in joints and connective tissue. The herbicide generated in these plants serves as nature's way to ward off insects from eating the fruit of the plants before procreation can occur, but, for those humans with low tolerance to minute amounts of this herbicide, aching joints and painful articulation can be the result. These plants are known as Night Shades, which include potatoes, tomatoes, bell peppers, egg-plants, and others (look it up on the web). I learned about this from extensive reading on the web about arthritis, and, for the last two months I have abstained from all night shades and my former intolerable pain in my left shoulder has calmed down to where I am hopeful to finally regain my full articulation. Prior to this, I could not articulate my left elbow more than 45 degrees from my ribcage (a negative result from "impingement" surgery).
There is a spice, called Turmeric, which contains a substance known as Curcumin, which is believed to reduce inflammation. Statistical analysis of nations like India and Pakistan, where turmeric is widely used in their popular spice, Curry, suggest the anti-inflammatory benefits of adding liberal quantities of turmeric to the diets of those susceptible to arthritis. I take 4 to 8 heaping teaspoons of turmeric daily for the last two months.
Bragg's apple cider vinegar (with mother) is a foul tasting potion that also has anti-inflammatory benefits when swallowed. I mix it with stevia and grapefruit juice to overcome the foul smell and taste, and take about 4 to 8 tablespoons daily.
This is just to suggest ways for potential surgical prospects to maybe avoid submitting to the invasive surgery, which carries unpredictable consequences that might not help at all with the joint pain, if the root problem is inflammation all the time. Study the web for articles about inflammation - there is a wealth of helpful information out there.
There is little profit for the medical profession in teaching the public how to adjust lifestyles to avoid inflammation. But, if one is diligent, searching the web can be very instructive and one can find inexpensive ways to make changes so as to reduce, or hopefully ELIMINATE, inflammation.
If you find that your joint pain is aggravated by an oncoming rain storm (or any lowering of barometric pressure), then you might consider seriously that your shoulder has become a focal point in your body for inflammation resulting from allergies to something in your diet or a lack of needed nutrients, along with frequent body motions that put undue pressure on your shoulder. For example, the old time favorite exercise with weights, known as a "military press", which consists of pushing a heavily weighted bar up over your head, has been determined to be destructively harmful to healthy shoulder joints - likewise for the popular "bench press". These exercises should be avoided and this kind of movement should be limited to light, or NO, weights, and limited repetitions.
You can gently exercise articulation of your shoulder by holding onto a door knob with one hand, leaning forward so that the other shoulder is at, or slightly below, waist level, and then letting your free hand dangle downwards towards the floor,swinging it around in a circle, figure 8, and like a pendulum so as to engage higher angles of articulation from the ribcage. You can adjust the angle as per the pain you experience, but, four or five times per week of this activity, along with sensible dietary adjustments, could result in regaining your full articulation
without surgery. Worth a try.