Adhesive Capsulitis (Frozen Shoulder)

Description

• Frozen shoulder or adhesive capsulitis (AC):
  • Presents as progressive painful restriction in range of movement of the glenohumeral (GH) joint (1)
  • Resolution ranges from complete to varying degrees of limitation for active and passive shoulder movements (1).
  • Unlike early disease (typically painful), late AC can present as pain-free restricted motion.
• Subtypes:
  • Primary AC:
    • Idiopathic
    • Usually associated with diabetes mellitus (DM) (1)
    • Typically resolves in 9 to 18 months (2)
  • Secondary AC:
    • Typically due to prolonged immobilization
    • Most commonly as complication of rotator cuff impingement syndrome (rotator cuff tendonitis) that remains incompletely treated
    • Sometimes called “shoulder-hand-syndrome” which is a complex regional pain syndrome (or reflex sympathetic dystrophy), if it is characterized by shoulder pain, diffuse swelling, and decreased range of motion (ROM) (2)
• Clinical course:
  • Phase 1 (2 to 9 months): painful phase. Pain is constant. Diagnosis may be difficult if restricted movement is not present in early disease.
  • Phase 2 (4 to 12 months): stiffening or freezing phase. Movement becomes restricted, especially during external rotation.
  • Phase 3 (12 to 42 months): resolution or thawing phase; gradual return to normal shoulder mobility (2)

Epidemiology

• Incidence: 2.4/1,000 people per year (2)
• Prevalence: 2–5% in the general population, 10–20% among diabetics (2)

Etiology and Pathophysiology

Underlying fundamental processes:

• Idiopathic
• Inflammation: Mast cells, T cells, B cells, and macrophages have been identified histologically, suggesting an inflammatory process.
• Angiogenesis
• Scarring: Fibroblasts and myofibroblasts have been identified histologically. Capsular contracture reduces the joint volume to 3 to 4 mL compared to the normal 10 to 15 mL.

Genetics
No predisposition identified

Risk Factors

• Shoulder immobilization; often due to impingement syndrome (most significant risk factor)
• Increasing age (1)
• Female gender (1)
• Diabetes (1)
• Thyroid disease (1)
• Atherosclerotic cardiovascular disease (ASCVD): cerebrovascular accident (CVA)/myocardial infarction (MI)/hyperlipidemia (2)
• Antiretroviral medication use
• Parkinson disease
• Trauma/surgery (1)
• Prior history of AC in contralateral shoulder

General Prevention

• Active lifestyle, while avoiding shoulder injury
• Control of diabetes, atherosclerotic disease, thyroid, and autoimmune conditions

Commonly Associated Conditions

DM, autoimmune disorders, Parkinson disease, highly active antiretroviral therapy (HAART) use, CVA/MI, cervical disc disease, hyperthyroidism (1)

History

• Identify possible risk factors.
• Progressive and worsening stiffness of the GH joint
• Majority will have diffuse shoulder pain, especially at the beginning of the disease.
• On the late phase of the disease, stiffness becomes predominant.

Physical Exam

• Limitation in both active and passive ROM
• Capsular pattern of restriction is demonstrated, with external rotation most affected, followed by abduction, and then flexion (1).
• Pain with rotator cuff impingement tests
• Inability to reach overhead or back pocket
• Scapular substitution frequently accompanies active shoulder movement.
• Injection test can be helpful in differentiating AC from subacromial pathologies such as rotator cuff tendinopathy (which should improve with injection of local anesthetics, in contrast to AC). This should only be done if the diagnosis is still uncertain after a thorough history and physical.

Differential Diagnosis

• Rotator cuff strain/tear/impingement syndrome
• GH or acromioclavicular joint osteoarthritis (OA)
• Cervical strain/radiculopathy/OA
• Subacromial bursitis
• Parsonage-Turner syndrome: brachial plexus inflammation secondary to a trigger, such as an infection, trauma, or autoimmune condition
• Myofascial pain syndrome
• Calcific tendonitis
• Fracture
• Shoulder subluxation/dislocation
• Bony neoplasm/metastasis

Diagnostic Tests & Interpretation

• No labs are required for idiopathic AC. Blood tests can be used to check for associated/related conditions, such as diabetes, thyroid disease, a stroke, autoimmune diseases, and, in rare cases, Parkinson disease (e.g., thyroid-stimulating hormone, hemoglobin A1C, erythrocyte sedimentation rate).
• Imaging
  • Plain radiographs of the affected shoulder (posteroanterior, external rotation, axillary, and supraspinatus outlet views)
    • Preferred initial tests
    • In most cases, will be negative
    • Used primarily to rule out other pathologies such as GH OA, fractures, dislocation, or tumors (2)
  • Magnetic resonance imaging (MRI)
    • Not indicated unless there is a concomitant pathology in the shoulder or neurologic deficit
    • May show thickening of the joint capsule and the coracohumeral ligament along with edema and increased joint fluid (2)
  • Ultrasound (US)
    • Indications similar to those for MRI
    • Selection depends on individual cases and clinician’s preference.
    • Can also reveal joint capsule thickening and increased joint fluid
    • Doppler can show increased vascularity around the intra-articular portion of the biceps tendon and coracohumeral ligament.

Medication

• Pain management
  • Acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs) are first line of treatment.
• Glucocorticoid injections:
  • Can be beneficial especially when administered at the beginning of the disease
  • A short course of physical therapy after an injection, for 4 to 6 weeks, can improve pain and ROM (3).
  • Injection may be diluted with a local anesthetic like lidocaine. Triamcinolone 20 to 40 mg or methylprednisolone 20 to 40 mg can be used.

Additional Therapies

• Exercise and physical therapy:
  • Gentle ROM exercises should be offered to every patient.
  • Exercises should be performed daily and as tolerated. A structured plan should be given to the patient (4).
  • Physical therapy has been found to be beneficial especially in phases 2 and 3 of AC. Best data supports its use in conjunction with other treatment, like corticosteroids (5).
• Laser has been suggested as a possible treatment, particularly for pain relief; not enough evidence for support

Surgery/Other Procedures

• Should be reserved for patients who do not respond to conservative measures for at least 1 year
• Some of the most common procedures include manipulation under anesthesia, arthroscopic capsular release, distension arthrogram, among others (2).

Follow-up Recommendations

• After establishing a diagnosis, assess the need for pain control and start the patient on NSAIDs, in combination with a gentle exercise program.
• Follow up in 3 to 4 weeks: if no significant improvement, may consider intra-articular corticosteroid injections (5)
• Physical therapy should also be considered because it can hasten the rate of recovery and increase ROM (5).
• For secondary AC, consider evaluation by a multidisciplinary team.
• If no improvement, consider surgical intervention (2).

Patient Education

• Patient education is important; explain prognosis and ensure compliance with treatment.
• Climbing the wall: Face a wall and place the hand from the affected shoulder flat on the surface of the wall; use the fingers to “climb” the wall; pause 30 seconds every few inches. Repeat the exercise after turning the torso 90 degrees to wall (abduction).
• In case of secondary AC, address the importance of treating underlying causes.

Prognosis

• Recovery is dependent on onset of treatment, symptoms, and comorbidities in patient.
• Variable duration, lasting 1 to 3 years without intervention (1)
• Patients with idiopathic frozen shoulder have a good rate of recovery (6).

ICD-10

• M75.00 Adhesive capsulitis of unspecified shoulder
• M75.01 Adhesive capsulitis of right shoulder
• M75.02 Adhesive capsulitis of left shoulder

ICD-9

• 726.0 Adhesive capsulitis of shoulder

SNOMED

• 15635961000119100 Bilateral adhesive capsulitis of shoulders (disorder)
• 301971000119109 Adhesive capsulitis of right shoulder (disorder)
• 301981000119107 Adhesive capsulitis of left shoulder (disorder)
• 399114005 adhesive capsulitis of shoulder (disorder)
• 430474001 Secondary adhesive capsulitis (disorder)