What is Shoulder Arthritis?
- Shoulder arthritis, specifically osteoarthritis (OA), is caused by the wear and tear of the articular cartilage in the shoulder joint. This degenerative process leads to pain, stiffness, and functional impairment. The two primary joints within the shoulder that can be affected are the acromioclavicular (AC) joint, where the clavicle meets the acromion, and the glenohumeral (GH) joint, where the ball of the humerus meets the glenoid fossa of the scapula [Khazzam et al, 2020; Millett et al, 2008].
- Anatomical Description:
- Glenohumeral (GH) Joint: This ball-and-socket joint is formed by the head of the humerus (upper arm bone) and the glenoid fossa of the scapula (shoulder blade).
- Osteoarthritis in this joint is characterized by the loss of cartilage, formation of osteophytes, and changes in the subchondral bone, leading to pain and reduced range of motion [Michener et al, 2021; Khazzam et al, 2020; Khazzam et al, 2020].
- Causes:
- Primary Osteoarthritis: This occurs due to the natural aging process and the degenerative changes in the joint cartilage without any specific underlying cause [Michener et al, 2021; Khazzam et al, 2020].
- Secondary Osteoarthritis: This can result from prior injuries, such as fractures, shoulder instability, rotator cuff tears, or joint infections, which accelerate the degenerative process [Michener et al, 2021].
- Prevalence: Osteoarthritis of the shoulder affects approximately 20% of adults over the age of 65. The prevalence of glenohumeral osteoarthritis has been reported to be between 17% and 20% in adults over 65 years of age in various population studies [Michener et al, 2021].
What are the early symptoms of shoulder arthritis?
- The early symptoms of shoulder arthritis, specifically osteoarthritis
- Gradual onset of deep shoulder pain: This pain typically worsens with activity and may be more pronounced at night [Khazzam et al, 2020; Kibler et al, 2010].
- Decreased range of motion (ROM): Patients often experience a progressive loss of shoulder motion, particularly in external rotation and abduction [Michener et al, 2021].
- Crepitus: A sensation of grinding or popping within the joint during movement [Kibler et al, 2010].
- Stiffness: Morning stiffness or stiffness after periods of inactivity is common [Khazzam et al, 2020].
Differences between AC joint and GH joint arthritis?
- Acromioclavicular
(AC) joint arthritis and glenohumeral (GH) joint arthritis are both
forms of shoulder arthritis but differ in their anatomical locations,
clinical presentations, and management strategies.Anatomical Location:
- AC Joint Arthritis:
This involves the small joint between the acromion of the scapula and
the clavicle. It is a planar diarthrodial joint stabilized by the
acromioclavicular and coracoclavicular ligaments [Flores et al, 2020].
- Diagnosis is based on clinical history, physical examination, and imaging studies such as plain radiographs and MRI. Diagnostic local anesthetic injection into the AC joint can help confirm the diagnosis [Buttaci et al, 2004; Mall et al, 2013].
- GH Joint Arthritis:
This affects the ball-and-socket joint formed by the humeral head and
the glenoid cavity of the scapula. It is a larger joint with a wide
range of motion, stabilized by the rotator cuff muscles and the joint
capsule [Menge et al, 2014].
- Diagnosis involves a combination of clinical evaluation, radiographs showing joint space narrowing, osteophytes, and subchondral sclerosis. MRI can be used to assess the extent of cartilage loss and associated soft tissue involvement [Khazzam et al, 2020; Michener et al, 2021].
What imaging modalities are effective for diagnosing shoulder osteoarthritis?
- Effective imaging modalities for diagnosing shoulder osteoarthritis, specifically for glenohumeral (GH) joint arthritis, include:
- Radiography: This is the first-line imaging modality for both AC and GH joint arthritis. It is useful for assessing bony structures, joint space narrowing, osteophytes, and subchondral sclerosis. The American Medical Society for Sports Medicine recommends routine radiographs as part of the initial assessment [Park et al, 2023; Demehri et al, 2015; Herring et al, 2024].
- Magnetic Resonance Imaging (MRI): MRI is highly effective for detailed evaluation of both AC and GH joint
arthritis. It provides comprehensive information about cartilage damage, bone marrow edema, synovitis, and soft tissue abnormalities. MRI is particularly useful for detecting early osteoarthritis and assessing the severity and progression of the disease. The American Physical Therapy Association highlights the utility of MRI for confirming the diagnosis of GH joint osteoarthritis [Park et al, 2023; Veen et al, 2018; Michener et al, 2021]. - Computed Tomography (CT): CT is beneficial for assessing detailed osseous structures and biomechanical abnormalities. It is particularly useful in cases where precise bone detail is required, such as preoperative planning for shoulder arthroplasty [Park et al, 2023; Demehri et al, 2015; Silva et al, 2023].
- Ultrasound: High-resolution ultrasound is effective for evaluating the AC joint, rotator cuff, and other soft tissue structures, but has limited visualization of the GH joint [Park et al, 2023; Wengert et al, 2019].
What are the treatment options for shoulder osteoarthritis?
- Traditional Conservative Treatments: The goal of treatment is to control the pain using medications and a cortisone injection.
- Pharmacological Treatments:
- Nonsteroidal Anti-Inflammatory Drugs (NSAIDs): These are commonly used to reduce pain and inflammation in both AC and GH joint arthritis [Michener et al, 2021;.[1-2]
- Acetaminophen: Preferred for pain management, especially in patients who may not tolerate NSAIDs.[3]
- Physical Therapy: Physical therapy focusing on ROM and strength-training exercises is effective in managing GH joint arthritis [Michener et al, 2021]. Emphasis on rotator cuff and scapular stabilizer strengthening to improve function and reduce pain [Michener et al, 2021; Kibler et al, 2010; Menge et al, 2014]. Adjusting activities to reduce stress on the shoulder joint is also recommended Kibler et al, 2010; Menge et al, 2014].
- Intra-Articular Injections:
- Corticosteroid Injections: Steroid injections can be effective for short-term symptom relief of GH joint arthritis pain, but the benefit typically wears off in a few months.
- A
study by Metzger et al. demonstrated that a single, image-guided
corticosteroid injection resulted in statistically and clinically
significant improvements in shoulder function and pain, with benefits
lasting up to 4 months [Metzger et al, 2021].
- Another study by Fritz et al. found that 74% of patients reported
clinically relevant pain reduction 1 month after the injection [Fritz et al, 2019].
- Associated Risks of corticosteroid
injections, including
infection, post-injection flare, and, with repeated use, potential joint
damage and systemic effects such as hyperglycemia.
- The American Academy of Orthopaedic Surgeons (AAOS) notes that while
corticosteroid injections are widely used, there is insufficient
evidence to definitively recommend for or against their use in GH joint
osteoarthritis [Izquierdo et al, 2010].
- Hyaluronic Acid (HA) Injections: These have shown efficacy in pain relief and functional improvement in GH joint arthritis.
- A
systematic review and meta-analysis by Familiari et al. found that HA
injections significantly improved pain scores compared to baseline and
corticosteroid injections, with an overall effect size of 4.43
(p=0.00006) [Familiari et al, 2023].
- Another meta-analysis by Zhang et al. reported a reduction in visual
analog scale (VAS) pain scores by 26.2 mm at 3 months and 29.5 mm at 6
months [Zhang et al, 2019].
- Blaine et al. demonstrated significant pain relief at multiple time points up to 26 weeks [Blaine et al, 2008].
- Duration of Symptom Improvement: The duration of symptom improvement varies among studies. Familiari et al. reported significant pain relief lasting up to 6 months [Familiari et al, 2023]. Zhang et al. noted improvements in pain and function at 3 and 6 months [Zhang et al, 2019]. Blaine et al. observed significant pain relief at 7, 17, and 26 weeks [Blaine et al, 2008].
- HA injections are generally well-tolerated. Common adverse events include mild pain and swelling at the injection site, local effusion, lethargy, and face rash [Zhang et al, 2019]. Blaine et al. reported no serious adverse events related to the treatment [Blaine et al, 2008].
Kwon et al. found comparable rates of adverse events between HA and
placebo groups, with no serious treatment-related adverse events [Kwon et al, 2013].
- Recently in January of 2024, CMS has approved the use of viscosupplementation injections for the treatment of shoulder impingement and glenohumeral arthritis. Learn more about viscosupplementation here.
- Surgical Management
- When conservative treatments fail, glenohumeral arthritis can be treated surgically with a shoulder replacement surgery. Surgical management options for glenohumeral osteoarthritis (GH OA) include both joint-preserving procedures and arthroplasty, each with distinct outcomes and complications.
- Arthroscopic Management: Comprehensive Arthroscopic Management (CAM)is a joint-preserving procedure that includes arthroscopy, chondroplasty, synovectomy, loose body removal, microfracture, capsular release, humeral osteoplasty, axillary nerve neurolysis, subacromial decompression, and biceps tenodesis. This approach is particularly beneficial for young, active patients. Outcomes show significant improvements in pain and function, with a 63% survival rate at 10 years. Complications are minimal, but predictors of failure include joint space <2 mm and severe humeral head incongruity [Arner et al, 2021; Arner et al, 2022].
- Total Shoulder Arthroplasty (TSA):TSA involves replacing both the humeral head and the glenoid with prosthetic components. It is indicated for advanced GH OA with significant joint degeneration. TSA provides superior pain relief and functional improvement compared to hemiarthroplasty (HA), with better outcomes in terms of range of motion and patient satisfaction [Kirsh et al, 2022; Singh et al, 2010]. Complications include infection, prosthetic loosening, and periprosthetic fractures, with a revision rate of approximately 1.5% [Kirsh et al, 2022].
- Reverse Shoulder Arthroplasty (RSA):RSA is increasingly used for GH OA, especially in patients with rotator cuff deficiency. It provides similar pain relief and functional outcomes to TSA but with better stability in cases of rotator cuff pathology. RSA has a lower rate of glenoid loosening but may result in reduced range of motion compared to TSA [Kirsh et al, 2022].
