How can I differentiate tendinitis from bursitis?

Differentiating Tendinitis from Bursitis

The key to distinguishing tendinitis from bursitis is through precise palpation: tendinitis produces well-localized tenderness directly over the tendon that reproduces the patient's activity-related pain, while bursitis causes more diffuse tenderness over the bursa with pain that is less specifically related to tendon loading maneuvers 1.

Clinical Examination Approach

Location of Tenderness

• Tendinitis: Palpation elicits well-localized tenderness that is similar in quality and location to the pain experienced during activity 1
• Bursitis: Tenderness is typically more diffuse and located over the bursa itself rather than along the tendon 2

Pain with Tendon Loading

This is the most discriminating feature:

• Tendinitis: Physical maneuvers that simulate tendon loading predictably reproduce the patient's pain 1
• Bursitis: Pain is present but not specifically reproduced by tendon loading maneuvers; instead, pain occurs with direct pressure over the bursa or with movements that compress the bursa 2

Pain Pattern

• Tendinitis:

  • Insidious onset of load-related localized pain coinciding with increased activity 1
  • Pain described as "sharp" or "stabbing" 1
  • Early stages: pain during activity that may subside after warm-up
  • Later stages: pain at rest 1

• Bursitis: Pain is more related to direct pressure on the bursa and positions that compress it 2

Physical Examination Findings

Inspection

Both conditions may show:

• Swelling and asymmetry 1
• Erythema (though this suggests septic bursitis if present in bursitis) 2

Critical distinction: Joint effusions are uncommon with tendinopathy and suggest intra-articular pathology instead 1

Range of Motion

• Tendinitis: Range-of-motion testing is often limited on the symptomatic side 1
• Bursitis: May have full range of motion unless severe inflammation is present

Imaging When Diagnosis Unclear

Reserve imaging for unclear diagnoses, recalcitrant pain, or preoperative evaluation 1:

Ultrasound

• Tendinopathy: Shows tendon thickening, heterogeneous echogenicity, and calcification 1
  • Sensitivity for tendinopathy: 67-93%, specificity: 88-100% 3
• Bursitis: Shows bursal fluid collection and thickening 3
  • Sensitivity for subacromial bursitis: 79-81%, specificity: 94-98% 3

MRI

• Tendinopathy: Demonstrates degenerative thickening, fibrovascular proliferation, mucoid degeneration 1
• Bursitis: Shows bursal fluid and inflammation 1

Site-Specific Considerations

Retrocalcaneal Area (Achilles)

• Retrocalcaneal bursitis: Characterized by increased bursal pressure (mean 30.5 mmHg unloaded vs. -9.9 mmHg in Achilles tendinopathy) 4
• This is a measurable distinction if invasive pressure measurement is available

Shoulder

• Subacromial bursitis: In polymyalgia rheumatica, bilateral bursitis >3mm thickness has 96.3% specificity for differentiating from rotator cuff tendinopathy 5

Common Pitfall

Do not assume all overuse injuries are inflammatory "tendonitis" 1. Most patients presenting to primary care have chronic degenerative tendinopathy (tendinosus), not acute inflammation. True inflammatory conditions exist but are less common in the primary care setting 1.

The presence of multiple symptomatic tendons should alert you to consider rheumatic disease rather than simple overuse tendinopathy 1.