What type of tendonitis causes pain in the posterior shoulder joint?

Posterior Shoulder Tendonitis: Causes and Management

Infraspinatus and teres minor tendonitis are the primary causes of posterior shoulder joint pain, with the infraspinatus being the most commonly affected tendon in this region. 1

Anatomy and Pathophysiology

The rotator cuff is composed of four muscles:

• Subscapularis (anterior)
• Supraspinatus (superior)
• Infraspinatus and teres minor (posterior)

When the posterior components of the rotator cuff develop tendonitis, patients experience pain in the posterior aspect of the shoulder joint. This commonly occurs due to:

• Repetitive throwing motions in athletes 1
• Overhead work activities 1
• Improper functioning and muscle weakness allowing superior humeral head migration 1
• Repetitive microtrauma to the tendon tissue 2

Clinical Presentation

Patients with posterior shoulder tendonitis typically present with:

• Pain during the deceleration and follow-through phases of throwing 1
• Decreased velocity and precision in throwing athletes 1
• Focal weakness with decreased range of motion during abduction with external or internal rotation 1
• Pain exacerbated by specific arm positions or movements

Diagnosis

Physical examination findings suggestive of posterior rotator cuff tendonitis include:

• Pain with resisted external rotation (tests infraspinatus function)
• Pain with arm positioned in abduction and internal rotation 1
• Scapular dyskinesis (abnormal scapular movement patterns) 1
• Weakness in external rotation

Imaging

Standard shoulder radiographs should include:

• Anteroposterior views in internal and external rotation
• Axillary or scapula-Y view 1

MRI is the preferred advanced imaging modality for evaluating rotator cuff pathology when conservative treatment fails 3.

Treatment Approach

Initial Management

1. Rest from aggravating activities until asymptomatic 1
2. NSAIDs as first-line medication for pain management 3
3. Physical therapy focusing on:
   • Pain control measures
   • Gentle range of motion exercises
   • Proper positioning education 3

Progressive Rehabilitation

1. Rotator cuff and scapular stabilizer strengthening 1, 3
2. Eccentric training which may have beneficial effects for tendinopathy 4
3. Technique modification for athletes and manual laborers to minimize repetitive stress 1

Advanced Treatment Options

• Corticosteroid injections can be used selectively in resistant cases, but should be limited (typically no more than 3-4 per year) to avoid potential tendon weakening 3, 5
• Therapeutic modalities such as ultrasound, extracorporeal shock wave therapy (ESWT), and iontophoresis have limited and contradictory evidence 1, 4

Surgical Consideration

If pain persists despite a well-managed 3-month conservative treatment trial, referral to an orthopedic surgeon for surgical evaluation may be warranted. Surgical techniques typically include excision of abnormal tendon tissue and performance of longitudinal tenotomies to release areas of scarring and fibrosis 1.

Return to Activity Protocol

1. Complete rest until asymptomatic
2. Begin rehabilitation with rotator cuff and scapular stabilizer strengthening
3. Implement a progressive throwing program emphasizing proper mechanics over 1-3 months (depending on injury severity)
4. Return to competition only after completing a functional, progressive throwing program without symptoms 1

Common Pitfalls to Avoid

• Misdiagnosis: Posterior shoulder pain can be mistaken for other conditions like labral tears or glenohumeral instability
• Inadequate rest: Returning to activity too soon can lead to chronic tendinopathy
• Overreliance on passive treatments: Active rehabilitation is essential for recovery
• Neglecting scapular stabilizers: Focus should include both rotator cuff and scapular muscle strengthening
• Improper technique correction: Addressing biomechanical factors is crucial to prevent recurrence

Proper diagnosis and comprehensive rehabilitation focusing on the posterior rotator cuff muscles are essential for effective management of posterior shoulder tendonitis.