Glenohumeral osteoarthritis is a degenerative joint disease affecting the main ball-and-socket joint of the shoulder, characterized by the progressive loss of articular cartilage, joint space narrowing, and the formation of bone spurs. It is less common than hip or knee arthritis but can cause significant pain and disability.
Glenohumeral osteoarthritis often develops in the setting of prior shoulder pathology. Longstanding rotator cuff tears can lead to superior migration of the humeral head and accelerated cartilage wear — a pattern called cuff tear arthropathy. Recurrent shoulder dislocations and prior Bankart repairs are established risk factors for secondary arthritis, as is chronic subacromial impingement that has gone untreated. Understanding these upstream contributors is essential when evaluating a patient with shoulder joint degeneration.
Causes
Primary osteoarthritis.
In most cases, glenohumeral osteoarthritis develops as part of the normal aging process without a specific identifiable cause. Genetic predisposition, joint mechanics, and the cumulative effects of a lifetime of shoulder use all contribute to progressive cartilage breakdown. The posterior glenoid is disproportionately affected in many patients, leading to the characteristic posterior glenoid wear pattern and posterior humeral head subluxation seen on imaging.
Secondary osteoarthritis.
Secondary glenohumeral arthritis develops as a consequence of prior shoulder injury or disease. Previous shoulder dislocations, massive rotator cuff tears leading to superior humeral migration (cuff tear arthropathy), fractures involving the joint surface, prior shoulder surgery — including over-tightened instability repairs — avascular necrosis of the humeral head, and inflammatory arthritis such as rheumatoid arthritis can all substantially accelerate the degenerative process. In these secondary cases, arthritis may develop at a younger age and progress more rapidly than primary osteoarthritis.
Symptoms
The hallmark symptom is a deep, aching pain within the shoulder joint that worsens with activity and is relieved by rest, at least in the early stages. Stiffness and progressive loss of range of motion — particularly internal rotation and cross-body reaching — are characteristic features that distinguish glenohumeral arthritis from subacromial pathology. A grinding or crackling (crepitus) sensation with shoulder movement is common, caused by roughened cartilage surfaces moving against one another. As the disease advances, pain may occur at rest and at night, and activities of daily living including dressing, reaching overhead, and lifting become increasingly difficult. Significant loss of external rotation with the arm at the side is a particularly reliable clinical indicator of glenohumeral joint involvement.
Diagnosis
A physical exam by a doctor assesses range of motion deficits — especially the loss of external rotation — crepitus, and localized joint line tenderness. X-rays are the primary imaging tool, revealing joint space narrowing, osteophyte (bone spur) formation, subchondral sclerosis, and humeral head flattening or posterior subluxation. An MRI provides critical additional information that X-rays cannot: cartilage thickness and quality throughout the joint, the condition and reparability of the rotator cuff (essential for determining which type of shoulder replacement is appropriate), labral status, bone marrow edema, and the presence of subchondral cysts. The rotator cuff assessment on MRI is arguably the most important factor in surgical planning — an intact cuff supports total shoulder arthroplasty, while a deficient cuff directs the surgeon toward reverse total shoulder arthroplasty. MRI also identifies concurrent acromioclavicular joint arthritis, which may need to be addressed at the same operative sitting.
Arthritis severity (Samilson-Prieto)
Doctors use a grade to indicate the severity of glenohumeral osteoarthritis based on the size of inferior osteophytes and the degree of joint space narrowing.
- Mild: Small bone spurs (less than 3 mm) with minimal joint space narrowing. Symptoms are often manageable with conservative treatment at this stage.
- Moderate: Bone spurs 3–7 mm with mild to moderate joint space narrowing and irregularity of the joint surface. Conservative care may still provide meaningful relief, though injections play a more prominent role.
- Severe: Bone spurs greater than 7 mm with marked joint space narrowing, significant joint surface irregularity, subchondral cyst formation, and often posterior humeral head subluxation. Surgical intervention is frequently required for adequate symptom control.
Treatments
Treatment plans depend on the severity of arthritis, patient age, activity level, and — critically — the condition of the surrounding rotator cuff.
Initial management includes activity modification, application of ice or heat, and anti-inflammatory medications to reduce pain and swelling.
Mild to moderate arthritis: Physical therapy to maintain range of motion and preserve rotator cuff strength slows functional decline and may reduce mechanical stress on the joint surface. Intra-articular corticosteroid injections provide meaningful short-term pain relief and are most effective when the joint still retains some cartilage. Hyaluronic acid (viscosupplementation) injections are used in some patients, though evidence for their efficacy in the shoulder is more limited than in the knee.
Severe arthritis with intact rotator cuff
Total shoulder arthroplasty — replacing both the humeral head with a stemmed metal implant and the glenoid surface with a polyethylene component — is the gold standard for patients with advanced glenohumeral arthritis and a functioning rotator cuff. It provides excellent, durable pain relief and functional restoration and is one of the most successful joint replacement procedures performed. MRI confirmation of rotator cuff integrity prior to surgery is a critical step in the preoperative workup. After surgery, a thorough physical therapy program is essential to recovering strength and range of motion.
Severe arthritis with rotator cuff deficiency
When the rotator cuff is severely compromised or irreparable — as in cuff tear arthropathy — a reverse total shoulder arthroplasty is preferred. By reversing the ball-and-socket configuration of the joint and placing the center of rotation more medially, this implant allows the deltoid muscle to power arm elevation independently, bypassing the need for a functioning rotator cuff. Outcomes for reverse arthroplasty have improved substantially in recent years and it is now the most commonly performed shoulder replacement in the United States.
Severe arthritis in younger, active patients
Younger patients — typically those under 55 — may be candidates for joint-preserving options aimed at delaying formal replacement. Arthroscopic debridement with capsular release, removal of loose bodies, and biologic augmentation can provide a window of pain relief, though results are generally less predictable than arthroplasty. Shoulder resurfacing — replacing only the humeral head surface without a full stem — is an option in select younger patients with well-preserved glenoid cartilage, preserving bone stock for a potential future conversion to total shoulder replacement.
Get an MRI to Confirm Your Diagnosis
Before surgical planning or starting treatment, a clear MRI diagnosis ensures the right path forward. First Look MRI offers self-pay Shoulder MRI scans — no doctor's order or insurance required — at our locations in Georgia, Texas, and Colorado.