In a 21-year-old male with Achilles pain and difficulty walking one week after a fall and a negative Thompson test, what are the likely diagnoses and recommended initial management?

Achilles Tendinopathy, Not Rupture

This patient most likely has Achilles tendinopathy rather than a complete rupture, given the negative Thompson test, and should be managed conservatively with eccentric exercise as the primary treatment.

Diagnostic Reasoning

The negative Thompson test effectively rules out complete Achilles tendon rupture 1. The Thompson (calf-squeeze) test has the highest sensitivity (0.96) and specificity (0.93) for detecting Achilles rupture, with a negative likelihood ratio of only 0.04 1. When this test is negative, the probability of complete rupture drops dramatically.

Given the clinical presentation of:

• Achilles pain after trauma (fall)
• Difficulty walking
• One week duration
• Negative Thompson test

The differential diagnosis narrows to:

Most Likely: Achilles Tendinopathy

• Pain, swelling, and reduced performance exacerbated by activity 2
• Can present acutely after trauma in previously asymptomatic tendons
• Morning stiffness and pain on palpation are the most useful clinical diagnostic features 1

Less Likely Alternatives:

• Partial Achilles tear (would still show some Thompson test abnormality)
• Paratendinitis
• Retrocalcaneal bursitis

Initial Management Algorithm

Step 1: Confirm Diagnosis Clinically

Assess for:

• Morning stiffness (high sensitivity for tendinopathy) 1
• Tenderness on palpation of the tendon (sensitivity 0.64, specificity 0.81) 1
• Achilles tendon thickening on examination 2

Step 2: Imaging (If Diagnosis Uncertain)

• Ultrasound is first-line for confirming tendinopathy and assessing for partial tears 2, 3
• MRI provides slightly better sensitivity/specificity but is more expensive 2
• Imaging can identify neovascularization and structural changes 3

Step 3: Conservative Treatment Protocol

Primary Treatment: Eccentric Exercise

• This has the highest evidence-based effectiveness for Achilles tendinopathy 2
• Should be the cornerstone of management
• Typically involves heel-drop exercises performed daily

Adjunctive Measures:

• Shock wave therapy (second-highest evidence for effectiveness) 2
• Activity modification (reduce running/jumping temporarily)
• Consider orthotics or heel lifts to reduce strain

Step 4: Avoid Ineffective Treatments

Do NOT use:

• NSAIDs beyond short-term pain relief (ineffective long-term) 2
• Corticosteroid injections (provide only short-term relief, no long-term benefit) 2

Consider only if conservative treatment fails after 3-6 months:

• Platelet-rich plasma injections 2
• Glyceryl trinitrate patches 2
• Ultrasound-guided prolotherapy with paratenon stripping (emerging option for refractory cases) 3

Critical Pitfalls to Avoid

1. Missing a partial tear: If pain is severe or patient cannot perform single-leg heel raise, obtain ultrasound to rule out partial rupture
2. Premature return to activity: Tendinopathy requires gradual progressive loading; rushing back increases chronicity risk
3. Over-relying on imaging: Diagnosis is primarily clinical; imaging abnormalities often don't correlate with symptoms 2
4. Using corticosteroids: These may provide temporary relief but don't address pathophysiology and may weaken tendon further 2

Expected Timeline

• Most patients improve with conservative treatment over 3-6 months 2, 4
• Eccentric exercise programs typically require 12 weeks minimum for benefit
• If no improvement after 6 months of appropriate conservative care, consider advanced interventions or surgical consultation 4