In an active middle‑aged adult with gradual posterior heel pain 2–6 cm proximal to the calcaneal insertion, what are the key differential diagnoses and how should Achilles tendinitis be confirmed and managed conservatively?

Achilles Tendinitis: Differential Diagnosis and Management

For an active middle-aged adult with gradual posterior heel pain 2–6 cm proximal to the calcaneal insertion, the diagnosis is most likely Achilles tendinopathy (not tendinitis), confirmed by palpable tenderness and thickening in the mid-portion of the tendon, and managed primarily with eccentric strength training combined with stretching, heel lifts, activity modification, and NSAIDs for acute pain relief. 1, 2

Critical Terminology Clarification

• The condition should be labeled "tendinosis" or "tendinopathy" rather than "tendinitis" because approximately 80% of cases involve chronic degenerative changes with collagen disorganization and tenocyte proliferation rather than acute inflammation. 2, 3
• This distinction matters clinically because anti-inflammatory treatments provide only temporary relief without addressing the underlying degenerative pathology. 2

Key Differential Diagnoses for Posterior Heel Pain

Insertional Achilles Tendinopathy

• Pain and tenderness at or within 2 cm of the calcaneal insertion (not 2-6 cm proximal). 1
• Prominence appreciated medially and laterally to the Achilles tendon insertion with central or global tenderness. 1
• Radiographs often show spurring or erosion at the insertion site. 1
• Aggravated by shoe pressure; relieved when walking barefoot. 1

Retrocalcaneal Bursitis (Haglund's Deformity)

• Most common in women aged 20-30 years. 1
• Tenderness lateral to the Achilles tendon (not within the tendon itself) with posterior lateral bony prominence. 1
• Pain aggravated by shoe pressure, relieved barefoot. 1
• Prominence visible on radiographs. 1
• Corticosteroid injections may be considered for the bursa (avoiding the Achilles tendon). 1

Calcaneal Stress Fracture

• History of increased walking or running activity before symptom onset. 1
• Pain on compression of the calcaneus is highly suspicious. 1
• Tenderness at the lateral calcaneal wall, slightly posterior to the subtalar facet. 1
• Swelling and warmth may be present. 1
• Symptoms often precede radiographic findings; technetium bone scanning is helpful for early diagnosis. 1

Neurologic Heel Pain

• Nerve irritation or entrapment causing heel pain or sensory changes. 1
• Requires subspecialist referral for electromyography, nerve conduction studies, or MRI. 1

Traumatic Causes

• Acute calcaneal fracture from fall onto heel from height. 1
• Acute plantar fascia rupture (radiographs and bone scans may be negative). 1

Rare Causes

• Tumors (malignant or benign), infections (soft tissue or bone), vascular compromise. 1
• Calcaneal apophysitis in adolescents (most common cause of heel pain in this age group). 1

Clinical Confirmation of Achilles Tendinopathy

Physical Examination Findings

• Palpable thickening and tender nodules in the tendon 2-6 cm proximal to insertion. 1
• Pain with resisted plantar flexion. 1
• Morning stiffness and pain in the tendon area (high diagnostic accuracy). 3
• Assess for anatomic deformities: forefoot/heel varus, excessive pes planus, or foot hyperpronation. 1, 4

Imaging

• Diagnosis is clinical; imaging is not required for typical presentations. 5
• Ultrasound or MRI useful for differential diagnosis when presentation is atypical. 3, 5
• MRI provides slightly better sensitivity and specificity than ultrasound. 3

Conservative Management Algorithm

First-Line Treatment (0-8 Weeks)

Eccentric strength training is the most effective and popular treatment option with the highest evidence-based effectiveness. 1, 2, 3, 5

• Eccentric exercises: Load the tendon through controlled lengthening contractions. 1, 2, 5
• Stretching of gastrocnemius-soleus complex: Generally considered helpful. 1, 2
• Deep friction massage: Recommended to reduce pain. 1, 2
• Heel lift orthotics: Unload the tendon for pain relief. 1, 2
• Shoe orthotics: Correct overpronation or pes planus problems. 1, 2
• Activity modification: Relative rest of affected area. 2
• Cryotherapy: Ice application. 2, 4
• NSAIDs: For acute pain relief only (not long-term). 1, 2, 3
• Weight loss if indicated. 1

If No Improvement After 6-8 Weeks

• Refer to podiatric foot and ankle surgeon. 1, 2
• Continue initial treatments. 1, 2
• Consider immobilization cast or fixed-ankle walker device. 1, 2
• Extracorporeal shock wave therapy: Can achieve 60% pain reduction with 80% patient satisfaction. 6, 3, 5

Surgical Consideration

• Indicated only after 6 months of unsuccessful conservative therapy. 6, 5
• Open debridement has success rates over 70% but complication rates up to 40%. 6
• Approximately 80% of patients fully recover within 3-6 months with conservative treatment, making surgery rarely necessary. 2

Critical Pitfalls to Avoid

Never Inject Corticosteroids Into or Around the Achilles Tendon

• Local corticosteroid injections are specifically NOT recommended for Achilles tendinopathy due to significant risk of tendon rupture. 1, 2, 3
• This applies to both insertional and mid-portion tendinopathy. 1, 2

Do Not Rely on Anti-Inflammatory Treatments Alone

• The underlying pathology is degenerative, not inflammatory. 2
• NSAIDs and corticosteroids may provide short-term relief but are ineffective long-term. 3

Do Not Pursue Unproven Therapies as First-Line

• Platelet-rich plasma (PRP), dextrose prolotherapy, and polidocanol sclerotherapy cannot be recommended due to limited evidence. 6
• Therapeutic ultrasound should not be primary treatment when evidence-based options (eccentric exercises, stretching, orthotics) have proven efficacy. 2

Address Biomechanical Abnormalities

• Training errors (excessive mileage, hill running, hard surfaces, poor footwear) are frequently responsible for onset. 4
• Gastrocnemius-soleus weakness or inflexibility and hindfoot malalignment with hyperpronation predispose to recurrence. 4