Frozen Shoulder: Assessment, Phases, and Differential Diagnosis

How to Assess Frozen Shoulder?

Assessing frozen shoulder, medically known as adhesive capsulitis, requires a comprehensive evaluation integrating patient history, symptom presentation, and a detailed physical examination that specifically identifies global, painful restrictions in both active and passive range of motion, particularly in a capsular pattern.

Understanding Frozen Shoulder (Adhesive Capsulitis)

Frozen shoulder is a common, often debilitating condition characterized by pain and a progressive, significant loss of both active and passive range of motion (ROM) in the glenohumeral (shoulder) joint. It results from inflammation and subsequent fibrosis (scar tissue formation) within the joint capsule, causing it to thicken, contract, and adhere to the humeral head. This restricts the normal gliding and rolling movements essential for full shoulder mobility.

Key Characteristics:

• Pain: Often deep, aching, and worsens with movement or at night.
• Stiffness: A profound and global limitation in movement.
• Global ROM Loss: Affects all planes of movement (flexion, abduction, rotation).

The Three Phases of Frozen Shoulder

Understanding the distinct phases of frozen shoulder is crucial for accurate assessment and management, as symptoms evolve over time:

• Freezing (Painful) Stage: This initial phase typically lasts from 2 to 9 months. It is characterized by the gradual onset of pain, often without a specific injury, which progressively worsens. Pain is frequently severe, especially at night and with movement, and is accompanied by a slow, progressive loss of shoulder motion.
• Frozen (Stiffening) Stage: Lasting 4 to 12 months, this phase sees a reduction in pain intensity compared to the freezing stage, but the stiffness becomes the predominant and most debilitating symptom. The shoulder's range of motion is severely restricted, impacting daily activities significantly.
• Thawing (Resolution) Stage: This final phase can last from 5 months to 2 years, or even longer. During this period, the shoulder's range of motion gradually improves. While full recovery is common, some individuals may experience residual stiffness or discomfort.

Subjective Assessment: Patient History and Symptom Presentation

A thorough subjective assessment provides critical clues for diagnosing frozen shoulder. Engage the patient in a detailed discussion about their symptoms and medical background:

• Pain Characteristics:
  • Location: Often diffuse, deep within the shoulder.
  • Intensity: How severe is the pain, especially at its worst?
  • Aggravating/Alleviating Factors: What makes the pain worse or better? (e.g., movement, specific positions, rest).
  • Night Pain: Is pain waking them from sleep or making it difficult to find a comfortable position? This is a common feature in the freezing phase.
• Onset and Duration:
  • Was the onset gradual or sudden? Frozen shoulder typically develops gradually, often without a specific injury.
  • How long have they experienced symptoms? This helps determine the phase.
• Impact on Daily Activities:
  • What functional limitations are present? (e.g., difficulty reaching overhead, behind the back, dressing, washing hair, fastening a seatbelt).
  • How has the condition affected their work, hobbies, or quality of life?
• Medical History:
  • Associated Conditions: Inquire about systemic conditions known to increase the risk of frozen shoulder, such as diabetes mellitus (most common association), thyroid disorders (hypo- or hyperthyroidism), Parkinson's disease, and cardiac disease.
  • Previous Trauma or Surgery: While frozen shoulder can be primary (idiopathic), it can also be secondary to shoulder trauma, surgery, or prolonged immobilization.

Objective Assessment: Physical Examination

The physical examination is the cornerstone of diagnosing frozen shoulder, focusing on observing movement patterns and assessing range of motion.

• Observation:
  • Posture: Note any protective posturing or guarding of the affected arm.
  • Muscle Atrophy: In later stages, disuse can lead to visible atrophy of shoulder girdle muscles.
• Palpation:
  • Gently palpate around the shoulder joint (deltoid, rotator cuff tendons, bicipital groove, AC joint) to identify areas of tenderness or muscle spasm. While not diagnostic for frozen shoulder, it helps rule out other conditions.
• Active Range of Motion (AROM) Assessment:
  • Ask the patient to actively move their arm through various planes. Observe the quality, smoothness, and total range of movement.
  • Movements to Assess:
    • Flexion: Lifting the arm straight forward and overhead.
    • Abduction: Lifting the arm out to the side and overhead.
    • External Rotation: With the elbow bent at 90 degrees and tucked into the side, rotate the forearm outwards.
    • Internal Rotation: Reach behind the back as if tucking in a shirt (measure by which spinal level the thumb reaches).
  • Key Indicator: In frozen shoulder, AROM will be significantly limited and painful, particularly at the end ranges, in all planes.
• Passive Range of Motion (PROM) Assessment:
  • This is the most critical component. Gently move the patient's arm through the same planes of motion while they relax.
  • Crucial Finding: In frozen shoulder, PROM will be significantly restricted and painful at the end range, mirroring the limitations seen in AROM. This "global restriction of both active and passive motion" is the hallmark differentiating frozen shoulder from many other shoulder conditions where passive motion might be relatively preserved.
  • Capsular Pattern: The characteristic pattern of restriction in frozen shoulder is typically:
    1. Greatest loss of External Rotation
    2. Significant loss of Abduction
    3. Lesser (but still significant) loss of Internal Rotation and Flexion
  • This specific pattern helps confirm the diagnosis.
• Special Tests (Differentiation):
  • While there are no specific "frozen shoulder" special tests, performing tests for other conditions helps rule them out:
    • Rotator Cuff Integrity Tests (e.g., Empty Can, External Rotation Lag Sign, Lift-off Test): These are typically negative or show less pronounced weakness in true frozen shoulder, as the primary issue is capsular restriction, not tendon pathology.
    • Impingement Tests (e.g., Neer's, Hawkins-Kennedy): May elicit pain due to secondary impingement from altered mechanics, but are not primary diagnostic for frozen shoulder.
    • Acromioclavicular (AC) Joint Tests (e.g., Cross-Body Adduction): To rule out AC joint pathology.
• Neurological Screen:
  • Assess sensation (dermatomes), muscle strength (myotomes), and reflexes to rule out cervical radiculopathy, which can mimic shoulder pain.
• Strength Testing:
  • Manual muscle testing will likely be limited and painful due to restricted ROM, but can help identify specific muscle weaknesses if a patient can isolate movement.

Key Diagnostic Indicators for Frozen Shoulder

Based on the assessment, the following are the strongest indicators:

• Global Restriction of Both Active and Passive Range of Motion: This is the most defining feature, differentiating it from conditions like rotator cuff tears where passive ROM might be preserved.
• Capsular Pattern of Restriction: External rotation is most limited, followed by abduction, then internal rotation/flexion.
• Gradual Onset of Pain and Stiffness: Often without a specific traumatic event.
• Night Pain: Especially prominent in the freezing phase.
• Absence of Significant Instability or Specific Rotator Cuff Tear: Helps rule out primary mechanical issues.

Differentiating Frozen Shoulder from Other Conditions

It's crucial to distinguish frozen shoulder from conditions with similar symptoms:

• Rotator Cuff Tendinopathy/Tear: Often presents with pain on specific movements (e.g., overhead reaching) and weakness, but passive range of motion is usually preserved or less globally restricted.
• Shoulder Impingement Syndrome: Pain with overhead movements, but typically full passive range of motion is maintained.
• Glenohumeral Osteoarthritis: While it causes pain and stiffness, it usually has a slower progression, crepitus, and X-ray evidence of joint space narrowing. Restriction may not always follow a pure capsular pattern initially.
• Cervical Radiculopathy: Pain and neurological symptoms (numbness, tingling, weakness) radiate down the arm in a dermatomal or myotomal pattern, originating from the neck. Shoulder ROM may be full or limited only secondarily due to pain.

When to Seek Professional Medical Advice

While fitness professionals can identify potential signs of frozen shoulder, a definitive diagnosis and treatment plan require medical expertise. Advise individuals to seek professional medical advice if they experience:

• Persistent or worsening shoulder pain and stiffness.
• Significant loss of shoulder function impacting daily life.
• Any uncertainty about the cause of their shoulder symptoms.
• Symptoms that do not improve with conservative management or worsen over time.

Conclusion

A comprehensive assessment of frozen shoulder demands a meticulous approach, combining a detailed patient history with a thorough physical examination. The unique characteristics of global and painful restriction in both active and passive range of motion, particularly in a capsular pattern, are the definitive indicators distinguishing adhesive capsulitis from other shoulder pathologies. For fitness professionals, recognizing these signs is vital for appropriate client guidance and referral, ensuring individuals receive timely and effective medical care to navigate the challenging course of frozen shoulder.