Frozen Shoulder (Adhesive Capsulitis) - A Detailed Overview

Definition

• Campbell's Operative Orthopaedics 15th Ed 2026, p. 2839
• Miller's Review of Orthopaedics 9th Edition, p. 403

Epidemiology

Pathophysiology

1. Synovial inflammation - an initial inflammatory synovitis triggered by an unknown event
2. Reactive capsular fibrosis - the capsule thickens and contracts, obliterating the axillary recess

• Cytokines, metalloproteinases 2 and 9, and TGF-β1 are implicated
• Alarmins (endogenous molecules released after tissue injury, e.g., HMGB1) are significantly elevated in frozen shoulder capsules - HMGB1 expression correlates with pain severity
• Neoinflammation and neoangiogenesis within the capsule likely explain the often severe pain
• Histologically: dense type III collagen matrix containing fibroblasts and myofibroblasts (resembling Dupuytren's disease)
• The coracohumeral ligament (CHL) and the rotator interval capsule form the essential lesion

Classification

Risk Factors (Box 51.6)

• Female sex
• Age > 49 years
• Diabetes mellitus (5x increased risk)
• Cervical disc disease
• Prolonged immobilization
• Hyperthyroidism
• Stroke
• Myocardial infarction
• Autoimmune diseases
• Trauma, chest/breast surgery
• Hyperlipidemia (proposed, needs further research)

Stages of Disease (Arthroscopic Classification - Table 51.7)

Clinical Presentation

• Insidious onset of diffuse shoulder pain, especially at night
• Pain aggravated by lying on the affected side
• Progressive loss of motion - internal and external rotation are lost first, then flexion, then abduction
• Typical findings: internal rotation only to sacrum, 50% loss of external rotation, <90° abduction
• Both active AND passive ROM are equally restricted (pathognomonic)
• Tenderness to palpation over the shoulder
• Usually affects the non-dominant side more frequently

Diagnosis

• Equal restriction of active and passive ROM
• No other structural cause on imaging

• Plain radiograph - usually normal; rules out glenohumeral OA, fracture, or locked posterior dislocation
• Arthrography - loss of the normal axillary recess; reduced joint volume (classic finding)
• MRI - thickening of glenohumeral capsule along axillary pouch, thickening of CHL, obliteration of subcoracoid fat triangle, rotator interval synovitis (none are pathognomonic)
• Ultrasound - used to rule out rotator cuff pathology and guide injections

• Glenohumeral osteoarthritis
• Locked posterior shoulder dislocation
• Rotator cuff tear
• Cervical radiculopathy

Prognosis

• Traditionally considered self-limiting: 12-18 months without long-term sequelae
• A 10-year follow-up study: 94% recovered to normal function/motion; however, only ~30-51% were fully pain-free
• Approximately 10% of patients have long-term problems
• Diabetic patients fare worse: full ROM achieved in only 71% vs. 90% in non-diabetics
• Earlier presentation correlates with faster recovery

Physiotherapy Treatment

Stage-Based Physiotherapy Approach

Stage 1-2 (Inflammatory/Pain-Dominant Phase)

• Gentle range-of-motion exercises within pain-free limits
• Pendulum (Codman) exercises - gravity-assisted arm swinging to distract and gently mobilize the glenohumeral joint
• Cryotherapy - ice packs post-exercise to reduce inflammation
• TENS (Transcutaneous Electrical Nerve Stimulation) - shown to provide some benefit when combined with passive and active ROM exercises
• Therapeutic ultrasound - adjunct for pain and tissue extensibility
• Avoid aggressive stretching and overhead work (can worsen inflammation)
• Patient education: explain the self-limiting nature, stages, activity modification

Stage 3-4 (Fibrotic/Frozen Phase)

A. Stretching Exercises

• Cross-body stretch - adduction stretch for the posterior capsule
• Doorway stretch (pectoral stretch) - external rotation and flexion
• Sleeper stretch - internal rotation of the posterior capsule
• Towel stretch behind the back - internal rotation
• Supine external rotation stretch using a stick/wand
• Pendulum exercises with progressive arc
• All stretches should be held 30 seconds, performed 3-5 times daily, at the edge of discomfort (not sharp pain)

B. Manual Therapy

• Maitland joint mobilization - Grades I-II for pain relief (acute), Grades III-IV for ROM in fibrotic stage
• Kaltenborn traction - sustained joint traction to stretch the inferior capsule
• Posterior glides (anterior-posterior mobilization) - most effective for regaining external rotation
• Inferior glides - for regaining abduction
• End-range mobilization - sustained stretch at joint end-range

C. Strengthening Exercises (Thawing Phase)

• Rotator cuff strengthening - isometric initially, then isotonic with resistance bands
  • External rotation with band
  • Internal rotation with band
  • Scapular stabilization exercises (serratus anterior, lower trapezius)
• Shoulder shrugs, retraction, and rows for periscapular muscles
• Progress to overhead strengthening when pain and motion allow

D. Electrophysical Modalities (Adjuncts)

Stage 5 (Thawing Phase)

• Progressive strengthening
• Proprioception and neuromuscular re-education
• Functional task-specific training
• Return-to-work and sporting activity programs

Combined Non-operative Management Protocol (Campbell's, 2026)

1. Ultrasound-guided glenohumeral injection - local anesthetic + corticosteroid + ~20 mL saline (hydrodilation/hydrodistension) to expand the joint space
2. Manipulation under anesthesia (MUA) - shoulder manipulated supine using the FEAR sequence (Flexion, Extension, Abduction/Adduction, External/Internal Rotation) after anesthesia
3. Supervised physical therapy starts the day after MUA - daily sessions for at least 2-4 weeks to maintain motion gains
4. Second hydrodilation if needed at 4-8 weeks
5. Only ~5% eventually require arthroscopic capsular release

Intraarticular Corticosteroid Injection + Physiotherapy

• Corticosteroid injections provide more rapid pain relief, better functional outcomes, and higher patient satisfaction than other nonoperative modalities
• Site of injection (subacromial, intraarticular, rotator interval) does not significantly affect outcomes
• Most beneficial in phase 1 or early phase 2
• When combined with physiotherapy: faster symptom resolution than either treatment alone
• Hyaluronate injections: similar efficacy to steroids with fewer side effects

Summary: Treatment Algorithm

Frozen Shoulder
      |
      ├─ Stages 1-2 (Pain phase)
      │    ├─ NSAIDs / analgesics
      │    ├─ Corticosteroid injection (especially early)
      │    ├─ Gentle PT: pendulums, patient education, TENS
      │    └─ Avoid aggressive ROM
      │
      ├─ Stages 3-4 (Frozen phase)
      │    ├─ Manual therapy (Maitland, Kaltenborn, MET)
      │    ├─ Stretching programme (posterior/inferior capsule)
      │    ├─ Electrophysical modalities (ESWT, ultrasound, laser)
      │    └─ Hydrodistension ± MUA if refractory
      │
      └─ Stage 5 (Thawing phase)
           ├─ Progressive strengthening
           ├─ Proprioception training
           └─ Functional rehabilitation

Key Points

• ~90% of frozen shoulder responds to physiotherapy, corticosteroid injection, and NSAIDs
• Physiotherapy is most effective when stage-matched (gentle mobilization early, aggressive stretching in fibrotic phase)
• Manual therapy combined with exercise has the best evidence base
• Diabetic patients require more aggressive and prolonged management
• Post-manipulation supervised physiotherapy is critical to prevent recurrence
• Prevention (early mobilization after shoulder injury, surgery, MI) is the best strategy