Overview
Shoulder osteoarthritis is the gradual, mechanical wearing of the articular cartilage that lines your glenohumeral joint, the ball-and-socket joint where the round head of the upper arm bone (the humeral head) sits against the shallow socket of the shoulder blade (the glenoid). As that smooth surface thins and roughens, the bones no longer glide cleanly, and the joint becomes stiff and painful. It is less common than hip or knee arthritis, but when it sets in it can cause real pain and a steady loss of motion.
Some cases are primary, meaning the wear builds up over the years with no single cause. Others are secondary, following a prior fracture, a shoulder that has dislocated before, or a long-standing rotator cuff tear that gradually changed how the joint carries load.
The most characteristic pattern of shoulder OA is erosion of the back wall of the socket (posterior glenoid erosion). This gradually shifts where the ball sits inside the socket, and it is why internal rotation, reaching your arm behind your back, is usually the first motion you lose.
Symptoms
Shoulder osteoarthritis comes on slowly. The pain is typically a deep, diffuse ache that builds over months to years rather than a sudden injury. Early on it worsens with activity and eases with rest, though in advanced cases the shoulder can ache at night and disturb your sleep. Many patients also notice a grinding or crunching sensation, called crepitus, as they move the arm.
Alongside the pain, the shoulder gradually stiffens. The motion that goes first is usually rotating the arm inward to reach behind your back, and the joint tends to "lock up" after you have been sitting still for a while. As that range of motion narrows, overhead tasks become harder and the arm can feel weak, less because the muscles have failed than because the stiff, painful joint no longer lets them work through their full arc.
Diagnosis & Evaluation
exam first, imaging to confirmYour provider starts with an exam, looking for the diffuse aching, the grinding with motion, and the gradual loss of internal rotation that is characteristic of glenohumeral arthritis and distinguishes it from rotator cuff or bursitis problems. X-rays usually confirm the diagnosis, showing the joint space narrowing, the bone hardening underneath the worn cartilage (subchondral sclerosis), and bone spurs (osteophytes) around the joint. When a replacement is on the table, an MRI or CT is often added to show how worn the back of the socket is and whether the rotator cuff is intact, both of which shape the surgical plan.
How We Treat It
what we try first, in orderCartilage does not grow back, so non-surgical care aims to quiet the pain and keep the joint working, not to reverse the wear. Most patients start here, and many stay here for years. The treatments below are the ones we usually reach for first.
Activity Modification
Cutting back on heavy overhead lifting and high-impact activities that load the joint. You do not need to stop using your shoulder, just the specific things that spike the pain.
Physical Therapy
Therapy works to preserve the range of motion you still have and to strengthen the muscles around the shoulder blade and rotator cuff, so they take some of the load off the damaged joint surfaces.
Medication & Injections
An over-the-counter anti-inflammatory like ibuprofen or naproxen (an NSAID) helps with day-to-day pain and swelling. A corticosteroid injection placed into the joint can give meaningful short-term relief, often enough to make therapy more productive. Platelet-rich plasma (PRP) and gel injections (viscosupplementation) are sometimes considered only after the standard measures above have been tried. The evidence for either in shoulder arthritis is limited, and gel injections are FDA-approved for the knee only. PRP is not covered by insurance (self-pay). Gel injections are offered self-pay.
When Surgery Is Considered
Surgery becomes the right conversation when arthritis has progressed to the point that daily activities are significantly limited and non-operative care is no longer keeping the pain under control. For shoulder OA that point is usually shoulder replacement, and which type is right depends largely on the rotator cuff.
If the rotator cuff is intact, an anatomic total shoulder replacement resurfaces the worn ball and socket with metal and plastic components to relieve pain and restore motion. When the rotator cuff is torn or no longer able to power the joint, a reverse-geometry design switches the position of the ball and socket so the deltoid muscle can lift the arm in the cuff's place.
If non-operative care is not enough, these procedures can address this condition:
Providers Who Treat Shoulder Osteoarthritis
Frequently Asked
questions we hear in clinicWhat is the first motion I tend to lose?
Usually rotating the arm inward to reach behind your back. Shoulder osteoarthritis tends to erode the back wall of the socket, which shifts where the ball sits, so internal rotation is typically the first motion to go. The joint also tends to "lock up" after you have been sitting still for a while.
Will the cartilage grow back?
No. Cartilage has no blood supply, so once it is worn it does not regrow. Non-surgical care is aimed at quieting the pain and keeping the joint working, not at reversing the wear. Most patients start with that care, and many stay there for years.
Do I need an MRI or CT scan?
Not usually for the diagnosis itself. X-rays usually confirm shoulder arthritis, showing the joint space narrowing, bone hardening under the worn cartilage, and bone spurs around the joint. An MRI or CT is often added when a replacement is on the table, to show how worn the back of the socket is and whether the rotator cuff is intact.
When is surgery considered?
When the arthritis has progressed to the point that daily activities are significantly limited and non-operative care is no longer keeping the pain under control. For shoulder osteoarthritis that point is usually shoulder replacement.
Which type of shoulder replacement is right for me?
It depends largely on the rotator cuff. If the cuff is intact, an anatomic total shoulder replacement resurfaces the worn ball and socket with metal and plastic components to relieve pain and restore motion. When the cuff is torn or can no longer power the joint, a reverse-geometry design switches the position of the ball and socket so the deltoid muscle can lift the arm in the cuff's place.
Is this the same as rheumatoid arthritis?
No. Rheumatoid arthritis is a systemic inflammatory disease, distinct from the mechanical joint wear we treat with shoulder replacement.
Further Reading
authoritative sourcesExternal patient-education references and related OSI pages for additional background: