Frozen shoulder

Frozen shoulder, also known as adhesive capsulitis, is a condition characterized by stiffness and pain in the shoulder joint. It can significantly impair daily activities and quality of life. Early recognition and appropriate management are crucial for improving outcomes.

Definition and Terminology

Definition

Frozen shoulder is defined as a condition marked by progressive pain and restriction of both active and passive range of motion in the glenohumeral joint, without evidence of significant structural abnormalities. It typically develops gradually and may resolve over months to years.

Alternative Names

• Adhesive capsulitis: Refers to the presence of adhesions and fibrosis in the shoulder joint capsule.
• Periarthritis of the shoulder: An older term describing inflammation of the tissues surrounding the shoulder joint.

Epidemiology

Incidence and Prevalence

Frozen shoulder affects approximately 2 to 5 percent of the general population. It is more commonly diagnosed in individuals aged 40 to 60 years and can occur in both shoulders, either sequentially or simultaneously.

Age and Gender Distribution

The condition is most prevalent among middle-aged adults. Women are slightly more affected than men, and hormonal or metabolic factors may contribute to this disparity.

Risk Factors

• Diabetes mellitus, especially type 1 and type 2
• Thyroid disorders, both hypo- and hyperthyroidism
• Previous shoulder injury, surgery, or prolonged immobilization
• Cardiopulmonary conditions and other systemic diseases

Pathophysiology

Capsular Inflammation and Fibrosis

Frozen shoulder involves chronic inflammation of the joint capsule, leading to thickening, fibrosis, and contracture. This results in a progressive reduction of the joint space and restricted movement.

Immunological and Biochemical Factors

Studies suggest that immune-mediated processes contribute to the development of adhesive capsulitis. Increased levels of inflammatory cytokines and growth factors in the synovium promote fibrosis and tissue remodeling.

Changes in Joint Capsule and Synovium

The anterior and inferior portions of the glenohumeral capsule are most commonly affected. Synovial adhesions and contractures limit both active and passive range of motion, particularly in external rotation and abduction.

Clinical Presentation

Stages of Frozen Shoulder

Frozen shoulder typically progresses through three stages:

• Freezing stage: Gradual onset of shoulder pain, worsening at night, with increasing stiffness. This stage can last 6 to 9 months.
• Frozen stage: Pain may stabilize or decrease, but stiffness persists, limiting shoulder movement. Duration is usually 4 to 12 months.
• Thawing stage: Gradual recovery of range of motion occurs over 6 to 24 months.

Symptoms

• Pain localized to the shoulder, often worse at night
• Restricted active and passive range of motion, especially external rotation
• Functional limitations affecting daily activities such as dressing, reaching overhead, or lifting objects

Diagnosis

History and Physical Examination

Diagnosis of frozen shoulder is primarily clinical, based on patient history and a detailed physical examination. Key features include progressive shoulder pain, stiffness, and limitation of both active and passive movements.

• Assessment of onset, duration, and progression of symptoms
• Evaluation of pain characteristics, including nocturnal worsening
• Measurement of range of motion in all planes, particularly external rotation and abduction

Imaging Studies

Imaging is used to rule out other shoulder pathologies rather than confirm frozen shoulder:

• X-ray: Typically normal, used to exclude osteoarthritis or fractures
• MRI: May show capsular thickening or synovial changes
• Ultrasound: Can assess rotator cuff integrity and capsular abnormalities

Differential Diagnosis

• Rotator cuff tear
• Shoulder osteoarthritis
• Shoulder impingement syndrome
• Bicipital tendinitis or labral tears

Management

Non-Operative Management

Most cases of frozen shoulder respond to conservative measures:

• Physical therapy focusing on stretching, range of motion exercises, and strengthening
• Pharmacological treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) or analgesics
• Activity modification to minimize pain while maintaining mobility

Interventional Procedures

• Corticosteroid injections: Reduce inflammation and provide short-term pain relief
• Hydrodilatation: Injection of saline or contrast into the joint to stretch the capsule and improve mobility

Surgical Management

• Manipulation under anesthesia: Performed when conservative measures fail, to break capsular adhesions
• Arthroscopic capsular release: Minimally invasive surgery to release tight capsule and improve range of motion

Complications and Prognosis

Potential Complications

• Chronic pain persisting beyond the typical recovery period
• Long-term stiffness and restricted range of motion
• Recurrence in the same or contralateral shoulder
• Secondary shoulder dysfunction due to compensatory movements

Prognosis and Recovery Timeline

Frozen shoulder is generally self-limiting, with most patients achieving significant improvement within 1 to 3 years. Early diagnosis and consistent rehabilitation improve outcomes, while delayed management can prolong the course of the condition.

Prevention

Primary Prevention

• Early mobilization of the shoulder after injury or surgery
• Regular stretching and range of motion exercises for at-risk populations
• Education on maintaining shoulder mobility and avoiding prolonged immobilization

Secondary Prevention

• Monitoring for early signs of stiffness or pain in patients with risk factors
• Prompt initiation of physical therapy or medical interventions to prevent progression
• Regular follow-up for individuals with diabetes, thyroid disorders, or prior shoulder injuries

References

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2. Hand C, Clipsham K, Rees JL, Carr AJ. Long-term outcome of frozen shoulder. J Shoulder Elbow Surg. 2008;17(2):231-236.
3. Shaffer B, Tibone JE, Kerlan RK. Frozen shoulder. A long-term follow-up. J Bone Joint Surg Am. 1992;74(5):738-746.
4. Carette S, Moffet H, Tardif J, Bessette L, Morin F, Frémont P, et al. Intra-articular corticosteroids, supervised physiotherapy, or a combination of the two in the treatment of adhesive capsulitis of the shoulder: A randomized trial. Arthritis Rheum. 2003;48(3):829-838.
5. Le Lievre HM, Murrell GA. Long-term outcomes of manipulation under anesthesia for frozen shoulder. J Shoulder Elbow Surg. 2006;15(3):279-282.
6. American Academy of Orthopaedic Surgeons. AAOS clinical practice guideline: Management of frozen shoulder. Rosemont, IL: AAOS; 2019.
7. Wolfe SW, Pedowitz RA. Shoulder disorders: Current concepts and controversies. J Hand Surg Am. 2010;35(10):1631-1641.
8. Zuckerman JD, Rokito A. Frozen shoulder: A consensus definition. J Shoulder Elbow Surg. 2011;20(2):322-325.
9. Ranalletta M, Rossi LA, Sirio D, Bruchmann G, Maignon G. Arthroscopic capsular release for frozen shoulder: Clinical results and prognostic factors. J Shoulder Elbow Surg. 2011;20(6):922-928.