Adhesive capsulitis is a condition characterized by spontaneous onset of pain and a progressive, global loss of both active and passive glenohumeral range of motion. Unlike rotator cuff tears, where passive motion is often preserved, adhesive capsulitis involves a primary contracture of the joint capsule. For the board-certified physician, success depends on recognizing the clinical stages and selecting interventions that match the biological state of the joint.

1. Epidemiology and Risk Factors

Adhesive capsulitis typically affects patients between the ages of 40 and 60 and is more common in women.

• Primary (Idiopathic): No identifiable cause.
• Secondary: Associated with systemic or local factors.
  • Diabetes Mellitus: The strongest association; diabetics have a 10–20% lifetime risk, and their cases are often more refractory to treatment.
  • Thyroid Disease: Both hyper- and hypothyroidism are linked to increased incidence.
  • Prolonged Immobilization: Common after surgery or stroke.

2. The Three Clinical Stages

The boards often test your ability to determine a patient’s current stage based on the “pain vs. stiffness” ratio.

• Stage 1: The “Freezing” (Painful) Phase (0–9 months): Characterized by gradual onset of diffuse, severe shoulder pain that is often worse at night. The pain precedes the loss of motion.
• Stage 2: The “Frozen” (Adhesive) Phase (4–12 months): Pain begins to subside, but the shoulder becomes significantly stiff. There is a global loss of range of motion, with external rotation typically being the most limited.
• Stage 3: The “Thawing” (Recovery) Phase (12–42 months): A gradual improvement in range of motion. While many consider this a self-limiting condition, recent evidence suggests that without intervention, some permanent loss of motion may persist.

3. Pathophysiology: The Coracohumeral Ligament

The underlying pathology involves an inflammatory contracture of the glenohumeral joint capsule, particularly the rotator interval.

• Rotator Interval: The space between the supraspinatus and subscapularis tendons.
• Coracohumeral Ligament (CHL): This ligament becomes thickened and fibrotic, acting as a “tether” that restricts external rotation.
• Histology: Studies show an abundance of fibroblasts and myofibroblasts, similar to the pathology found in Dupuytren’s contracture.

4. Physical Exam: The “Capsular Pattern”

The hallmark of adhesive capsulitis is the capsular pattern of restriction.

• Active vs. Passive: In adhesive capsulitis, both active and passive range of motion are restricted. This is the primary way to differentiate it from a large rotator cuff tear (where passive motion is generally intact).
• Specific Deficits: External rotation is the first and most severely limited motion, followed by abduction and then internal rotation.
• Firm End-Feel: On passive range of motion, the clinician will feel a “leathery” or firm end-feel rather than the soft-tissue approximation felt in a healthy joint.

5. Interventional Management

Treatment is tailored to the clinical stage of the disease.

Stage 1 Interventions

In the painful “Freezing” phase, the goal is inflammation control.

• Intra-articular Corticosteroid Injection (IACI): High-yield board evidence shows that IACIs are most effective when given early in the disease process to shorten the painful phase.
• Suprascapular Nerve Block (SSNB): Effective for refractory night pain, providing a “window” for the patient to engage in gentle stretching.

Stage 2 Interventions

In the stiff “Frozen” phase, the goal is to break down adhesions.

• Hydrodilatation (High-Volume Distension): A procedure where a large volume of saline (20–40 mL), corticosteroid, and local anesthetic is injected into the joint under pressure to manually stretch and “burst” the capsule.
• Manipulation Under Anesthesia (MUA): A more aggressive surgical option where the surgeon manually moves the shoulder through its full range to break adhesions while the patient is sedated.

6. “No Pain, No Gain” is a Myth

Overly aggressive stretching in the “Freezing” phase can actually exacerbate the inflammatory process and worsen the condition.

• Stage 1 Therapy: Focuses on pain-free, active-assisted range of motion and pendulums (Codman’s exercises).
• Stage 2/3 Therapy: Transition to more aggressive stretching and eccentric strengthening to regain the functional kinetic chain.
• Kinetic Chain Compensation: Patients often develop excessive scapular-thoracic movement to compensate for the lack of glenohumeral motion. Rehab must address the secondary trigger points in the upper trapezius and levator scapulae.

---

High-Yield Board “Fast Facts”

• Diabetes and Adhesive Capsulitis: Higher risk, more severe stiffness, and poorer response to IACI.
• External Rotation: Typically the most limited plane of motion.
• The “capsular pattern”: ER > Abduction > IR.
• Differential Diagnosis: Always rule out Posterior Shoulder Dislocation, which also presents with a sudden loss of external rotation but usually has a history of trauma or seizure.