In an athlete with acute calf pain and a popping sensation after jumping, how should I evaluate for calf muscle strain versus Achilles tendon rupture and what is the appropriate treatment?

Assessment and Treatment of Acute Calf Pain with Popping Sensation in Athletes

Immediately perform the Thompson test, assess for a palpable gap in the Achilles tendon, and evaluate ankle plantar flexion strength—if two or more of these tests are positive, you are dealing with an Achilles tendon rupture requiring urgent orthopedic referral, not a simple calf strain. 1, 2

Initial Clinical Evaluation

The key to managing this athlete is distinguishing between a calf muscle strain (gastrocnemius/soleus injury) and complete Achilles tendon rupture, as the popping sensation can occur with both conditions but the treatment pathways diverge dramatically.

Critical Physical Examination Maneuvers

Perform at least two of the following diagnostic tests to establish the diagnosis:

• Thompson/Simmonds squeeze test: Squeeze the calf while the patient is prone with feet hanging off the table—absence of plantar flexion indicates complete Achilles rupture 1, 2
• Palpable gap assessment: Run your fingers along the Achilles tendon to detect a defect, typically 2-6 cm proximal to the calcaneal insertion 1
• Plantar flexion strength testing: Have the patient attempt single-leg heel raise—inability to perform this indicates complete rupture 1, 2
• Passive ankle dorsiflexion: Increased dorsiflexion compared to the uninjured side suggests rupture 1

Location-Specific Tenderness Patterns

• Mid-calf tenderness (gastrocnemius/soleus belly): Suggests muscle strain 3, 4
• Musculotendinous junction tenderness (distal calf): Can be either severe strain or partial Achilles injury 3
• Achilles tendon body tenderness with gap: Indicates complete rupture 1, 2

Critical pitfall: Excessive swelling and pain can mask the diagnosis in the first 48 hours after injury—if clinical examination is equivocal, re-examine the patient at 3-5 days or proceed directly to imaging 5, 1

Diagnostic Imaging Strategy

For Suspected Achilles Tendon Rupture

• Initial imaging: Obtain anteroposterior and lateral radiographs of the ankle to rule out avulsion fractures and assess for soft tissue swelling 5
• Confirmatory imaging when diagnosis is uncertain: MRI without IV contrast is the reference standard, with 95% sensitivity and specificity for detecting complete ruptures, partial tears, and chronic degenerative changes 1
• Alternative confirmatory imaging: Ultrasound can demonstrate tendon discontinuity and is useful when MRI is unavailable, though it is operator-dependent 1, 2

For Suspected Calf Muscle Strain

• When clinical diagnosis is clear: Imaging is not routinely necessary for grade I-II strains 3
• When diagnosis is uncertain or severe injury suspected: MRI or ultrasound confirms the location and grade of muscle injury, which is valuable for prognosis and return-to-play planning 3

Treatment Pathways

For Achilles Tendon Rupture

Non-surgical management is the preferred approach for most patients, including athletes, as it provides similar functional outcomes to surgery with lower complication rates, particularly wound-related issues. 2

Non-Surgical Protocol

• Immediate immobilization: Place the ankle in equinus (plantar flexed) position in a cast or boot 2
• Early mobilization: Begin protected weight-bearing within 2 weeks and transition to a protective device that limits dorsiflexion 2
• Progressive rehabilitation: Start mobilization by 2-4 weeks using a protective boot, with gradual progression to full weight-bearing 2

Critical consideration: Patient compliance is crucial to prevent rerupture—athletes must understand that non-surgical treatment requires strict adherence to the rehabilitation protocol 2

Surgical Consideration

• Rarely indicated: Reserve surgery for grade III ruptures with significant retraction, reruptures, or cases where non-surgical treatment has failed 6
• Minimally invasive techniques: When surgery is chosen, minimally invasive repair offers acceptable functional outcomes with lower wound complication rates than open repair, though sural nerve injury risk exists 6

For Calf Muscle Strain

Acute Phase (First 72 Hours)

• RICE protocol: Rest, ice (cryotherapy), compression, and elevation 7
• Protected weight-bearing: Use crutches if unable to walk without limping 3
• NSAIDs: Consider for pain control and inflammation reduction 8

Rehabilitation Phase (After 72 Hours)

• Progressive exercise: Begin with passive range of motion, advance to active stretching, then eccentric strengthening 7, 3
• Massage and manual therapy: Can facilitate recovery when combined with exercise 7
• Gradual return to activity: Grade I-II strains typically require 2-4 weeks; grade III strains may take up to 6 weeks before return to training 7, 3

Important prognostic factor: History of previous calf strain is the strongest risk factor for reinjury—athletes with prior strains require more conservative return-to-play timelines 3

Key Differentiating Features

Finding	Achilles Rupture	Calf Strain
Thompson test	Positive (no plantar flexion) [1]	Negative [1]
Palpable gap	Present [1]	Absent [3]
Single-leg heel raise	Unable to perform [1]	Painful but possible (grades I-II) [3]
Location of maximal tenderness	Achilles tendon body [1]	Muscle belly [3,4]

Common Pitfalls to Avoid

• Assuming a "pop" always means rupture: Both complete Achilles ruptures and severe gastrocnemius strains can present with an audible pop 3, 4
• Missing partial Achilles tears: These can have negative Thompson test but still show weakness and require modified treatment 1
• Premature return to sport after calf strain: Reinjury rates are high when athletes return before achieving full strength and flexibility 3
• Overlooking plantaris rupture: This can mimic gastrocnemius strain but typically has a more benign course 4