Diagnosis: Insertional Achilles Tendinopathy
The most likely diagnosis is insertional Achilles tendinopathy, given the posterior-superior heel location, mild swelling, erythema, and warmth in a 55-year-old male. 1
Clinical Reasoning
The key diagnostic features that point to insertional Achilles tendinopathy include:
- Location specificity: Pain at the posterior-superior heel directly corresponds to the Achilles tendon insertion site on the calcaneus 1
- Age and presentation: This condition commonly presents with insidious onset of chronic posterior heel pain and swelling, which fits the clinical picture 1
- Inflammatory signs: The presence of mild swelling, redness, and warmth indicates active inflammation at the insertion site 2, 3
Physical Examination Findings to Confirm
On examination, you should specifically assess for:
- Tenderness centrally or globally at the Achilles insertion, with possible prominence appreciated medially and laterally to the tendon insertion 1
- Pain aggravated by increased activity and pressure from shoes 1
- Relief of pain when walking barefoot (this distinguishes it from plantar fasciitis) 1, 4
Alternative Diagnoses to Consider
While insertional Achilles tendinopathy is most likely, the differential includes:
- Retrocalcaneal bursitis: Presents with similar posterior heel pain but tenderness localizes to the retrocalcaneal recess between the anterior Achilles tendon and posterosuperior calcaneus 5
- Haglund's deformity with bursitis: More common in younger women (20-30 years), with tenderness lateral to the Achilles tendon and a visible posterior lateral prominence 1
- Superficial calcaneal bursitis: Inflammation between the skin and Achilles tendon/calcaneal prominence 5
Diagnostic Workup
Obtain weight-bearing radiographs of the foot and ankle to identify:
- Spurring or erosion at the Achilles tendon insertion (commonly seen in insertional tendinopathy) 1
- Prominent posterior superior calcaneus (Haglund's deformity) 1, 4
- Rule out calcaneal stress fracture or other bony pathology 4
If radiographs are negative but symptoms persist beyond 1 week, MRI without contrast or ultrasound can confirm tendon pathology and assess for associated bursitis 4, 6
Critical Pitfall to Avoid
Never inject corticosteroids near or into the Achilles tendon insertion due to high risk of tendon rupture 1, 7, 8. If considering injection therapy, it must be directed into the retrocalcaneal bursa only, carefully avoiding the tendon itself 1.