Achilles tendon rupture is one of the most common musculoskeletal injuries, with an annual incidence of 5–50 per 100,000 persons, predominantly affecting males in their 30s–50s who participate in intermittent recreational sports. [1] Up to 20% are initially misdiagnosed, most commonly as an ankle sprain. [2] The diagnosis is primarily clinical; physical examination is more sensitive than MRI. [3]
1. History
- Mechanism: Sudden forced plantar flexion, unexpected dorsiflexion, or violent dorsiflexion of a plantar-flexed foot (e.g., pushing off during basketball, tennis, or sprinting; fall from height) [4]
- Classic complaint: Audible "pop" or "snap" with a sensation of being kicked or struck in the back of the leg [5]
- Acute severe posterior ankle/calf pain that may subside quickly — patients sometimes walk into the ED [6]
- Inability to push off, stand on toes, or run; difficulty with stairs [5]
- Cramping or muscle spasms in the proximal calf [6]
- Important negatives: Painful Achilles tendons rarely rupture — most ruptures occur in previously asymptomatic tendons with minimal prodromal symptoms [5]
- Ask about timing (critical: diagnosis within 72 hours optimizes nonoperative management), activity level, and functional demands [7]
2. Alarm Features
- Open wound over the posterior ankle (open rupture — rare but requires urgent surgical evaluation)
- Signs of compartment syndrome (severe pain out of proportion, pain with passive stretch, tense compartment)
- Neurovascular compromise distally
- Bilateral rupture (consider systemic etiology: fluoroquinolones, corticosteroids, connective tissue disease)
- Associated fracture (calcaneal avulsion)
- Signs of DVT/PE during immobilization period (calf swelling, dyspnea) — VTE rate after ATR is 3.6–6.4%, which is 6.5× higher than other foot/ankle injuries [8-10]
3. Medications
- Culprit medications:
- Fluoroquinolones (levofloxacin, ciprofloxacin, moxifloxacin): OR 2.52 for ATR; risk persists for months after completion of therapy [11-12]
- Corticosteroids (systemic): Concomitant use with fluoroquinolones dramatically increases risk (OR 6.64) [13]
- Local corticosteroid injections to the Achilles tendon
- Risk amplifiers: Age >60, renal failure, organ transplant recipients, prior tendon disorders [11]
- Acute treatment: NSAIDs and acetaminophen for pain; avoid opioids if possible
- VTE prophylaxis: ACCP suggests no routine pharmacologic thromboprophylaxis for isolated lower-leg injuries (Grade 2C), but the TRiP(cast) score can identify high-risk patients who warrant LMWH. Aspirin alone does not appear to reduce VTE incidence in this population [8][14-15]
4. Diet
- No specific dietary triggers or restrictions
- Adequate protein intake and hydration support tendon healing
- Ensure adequate vitamin C and vitamin D for collagen synthesis and musculoskeletal health
- Smoking cessation is critical — impairs wound healing and tendon repair
5. Review of Systems
- MSK: Prior Achilles pain, contralateral Achilles symptoms, history of tendinopathy, other tendon injuries
- Vascular: Calf swelling, warmth, dyspnea (DVT/PE risk during immobilization)
- Rheumatologic: Joint pain, stiffness, rashes (rheumatoid arthritis, connective tissue disorders)
- Endocrine: Diabetes, thyroid disease (associated with tendinopathy)
- Medications: Fluoroquinolone or corticosteroid use (current or recent)
- Infectious: Recent febrile illness treated with antibiotics (fluoroquinolone exposure)
6. Collateral History and Family History
- Prior episodes of tendon rupture or tendinopathy (personal or family)
- Family history of VTE — independently associated with post-ATR VTE (aOR 20.9) [9]
- Personal history of VTE/thrombophilia (aOR 6.1 for post-ATR VTE) [9]
- Connective tissue disorders (Ehlers-Danlos, Marfan syndrome)
- Activity level and occupational demands (critical for surgical vs. nonoperative decision-making)
7. Risk Factors
- Age: 30s–50s for rupture; highest tendinopathy-to-rupture conversion at ages 40–59 [6]
- Sex: Male predominance; left tendon more commonly ruptured than right [4]
- Activity: Intermittent recreational athletes ("weekend warriors"); sudden eccentric loading [4]
- Medications: Fluoroquinolones (OR 2.52), systemic corticosteroids, local steroid injections [12-13]
- Comorbidities: Renal failure, organ transplant, rheumatoid arthritis, obesity [11][16]
- Prior tendinopathy: ~4% progress to rupture [6]
- Other: Decreased tendon fibril size (moderate evidence), urban living [16]
8. Differential Diagnosis
- Ankle sprain (most common misdiagnosis — up to 20% of ATR initially misdiagnosed as sprain) [2]
- Gastrocnemius/soleus muscle tear ("tennis leg") — pain more proximal, no palpable Achilles gap, negative Thompson test
- Partial Achilles tendon tear — may have equivocal Thompson test; ultrasound helpful
- Calcaneal avulsion fracture — bony tenderness at insertion; visible on plain radiograph
- Retrocalcaneal bursitis — pain anterior to the Achilles insertion, positive two-finger squeeze test [7]
- Plantaris tendon rupture — medial calf pain, intact Achilles function
- Deep vein thrombosis — posterior calf pain/swelling without traumatic mechanism
- Posterior tibial tendon dysfunction — medial ankle pain, difficulty with single-leg heel raise
9. Past Medical History
- Prior Achilles tendinopathy or rupture (contralateral or ipsilateral)
- Previous tendon injuries at any site
- Rheumatoid arthritis or other inflammatory arthropathies
- Diabetes, chronic kidney disease, thyroid disorders
- Organ transplant history
- History of VTE or known thrombophilia
- Recent or chronic fluoroquinolone/corticosteroid use
10. Physical Exam
- Thompson (Simmonds) test: Patient prone, foot off table edge; squeeze the calf — absence of plantar flexion is diagnostic (sensitivity 96%, specificity 93%) [6-7]
- Palpable gap/defect: Loss of continuity in the tendon 2–6 cm proximal to insertion (sensitivity 73%, specificity 89%) [7]
- Increased passive dorsiflexion: Compared to the uninjured side
- Decreased resting tension: Affected foot rests in more dorsiflexion than the contralateral side when prone
- Inability to perform single-leg heel raise on the affected side
- Bruising/ecchymosis at the posterior ankle [6]
- All three clinical findings (abnormal Thompson test, decreased resting tension, palpable defect) together have 100% sensitivity for complete rupture [3]
11. Lab Studies
- No routine labs required for diagnosis
- If surgical repair planned: standard preoperative labs (CBC, BMP, coagulation studies)
- Consider D-dimer if concern for DVT during immobilization period
- If bilateral or atraumatic rupture: consider rheumatologic workup (ESR, CRP, RF, ANA), renal function, and medication review
12. Imaging
- First-line: Clinical diagnosis is sufficient in most cases — MRI is unnecessary for diagnosing acute complete ruptures when clinical findings are clear [3]
- Point-of-care ultrasound (POCUS): Excellent ED adjunct when exam is limited by pain/swelling; sensitivity 94.8%, specificity 98.7% for complete rupture. The RAUT test (real-time Achilles ultrasound Thompson) combines ultrasound with the Thompson test for improved diagnostic accuracy even by novice users [2][17-18]
- Plain radiographs: Useful to rule out calcaneal avulsion fracture; may show insertional calcific tendinopathy [7]
- MRI: Reserved for ambiguous presentations, partial tears, chronic/subacute injuries, or preoperative planning. Sensitivity ~91%, specificity ~100% [3][19]
- Key ultrasound finding: Gap measurement ≥5 mm during dorsiflexion in active patients or ≥10 mm in sedentary patients should prompt surgical evaluation [7]
13. Special Tests
- Thompson (calf squeeze) test: The single most important bedside test [20]
- Matles test: Patient prone, knees flexed to 90° — affected foot falls into neutral/dorsiflexion (normally rests in slight plantar flexion)
- O'Brien needle test: 25-gauge needle inserted through skin into tendon 10 cm proximal to insertion; passive dorsiflexion of the ankle causes needle to tilt if tendon is intact
- RAUT test: Ultrasound-augmented Thompson test — sensitivity 86–87%, specificity 81–92% [18]
- Copeland sphygmomanometer test: BP cuff around calf inflated to 100 mmHg; dorsiflexion of the foot should increase pressure to ~140 mmHg if tendon is intact
14. ECG
- Not routinely indicated for Achilles tendon rupture
- Consider ECG if:
- Preoperative evaluation for surgical repair
- Concern for PE during immobilization (tachycardia, right heart strain pattern — S1Q3T3, right axis deviation, T-wave inversions in V1–V4)
- Patient with cardiac risk factors undergoing anesthesia
15. Assessment
- Typical presentation: Middle-aged male recreational athlete with sudden "pop" during explosive movement, posterior ankle pain, palpable gap, and positive Thompson test [5-6]
- Atypical presentations: Pain may subside quickly, leading patients to delay presentation; partial tears may have equivocal exam findings; delayed presentations show calf atrophy and thickened tendon [5]
- Severity stratification: Complete vs. partial rupture; acute (<72 hours) vs. subacute/chronic; gap size on ultrasound
- Complications: Rerupture (2.3% surgical vs. 3.9–6.2% nonoperative), DVT/PE (3.6–6.4%), wound infection (surgical), sural nerve injury (minimally invasive surgery 5.2%), prolonged calf weakness, gait abnormalities [1][9-10][21]
16. Treatment Plan
Initial ED management
- Posterior splint in gravity equinus (slight plantar flexion) with ace wrap
- Non-weight-bearing with crutches
- Ice, elevation, analgesia (NSAIDs/acetaminophen)
- Urgent orthopedic referral (ideally within 72 hours of injury) [7]
Definitive management — shared decision-making
- NEJM 2022 trial[1]
- The UKSTAR trial (n=540) validated functional bracing as equivalent to plaster casting for nonoperative management [22]
- Early mobilization and functional rehabilitation are critical regardless of treatment strategy [21][25]
17. Disposition
- Discharge from ED: The vast majority of patients — splinted in equinus, non-weight-bearing, with orthopedic follow-up within 48–72 hours [26]
- Admission criteria: Rare; consider for open rupture, associated fracture requiring fixation, polytrauma, or inability to safely mobilize at home
- Orthopedic consultation triggers: All confirmed or suspected complete ruptures; partial tears with significant gap (≥5 mm active, ≥10 mm sedentary); young/high-demand athletes [7]
- VTE risk assessment: Use the TRiP(cast) score — Achilles tendon rupture is classified as a "high-risk trauma" (3 points); patients scoring ≥7 warrant pharmacologic thromboprophylaxis. Age ≥50, personal/family VTE history are independent risk factors [9][15]
18. Follow Up / Return Precautions
- Follow-up: Orthopedic evaluation within 48–72 hours for definitive treatment planning; if nonoperative, serial follow-up for functional bracing and rehabilitation progression [26]
- Return precautions — seek immediate care for:
- Increasing calf swelling, warmth, or pain (DVT)
- Chest pain, shortness of breath (PE)
- Numbness/tingling in the foot (nerve compression from splint)
- Worsening pain or skin breakdown under splint
- Expected recovery: Return to work ~6–12 weeks (faster with surgery by ~19 days on average); return to sport typically 6–12 months; surgical patients demonstrate 18% greater strength recovery at 18 months [21]
- Patient counseling: Rerupture risk is low regardless of treatment strategy; early mobilization improves outcomes; full recovery of calf strength may take 12–18 months; contralateral rupture risk exists
References
1. Nonoperative or Surgical Treatment of Acute Achilles’ Tendon Rupture. — Myhrvold SB, Brouwer EF, Andresen TKM, et al. The New England Journal of Medicine. 2022.
2. Diagnosing Achilles Tendon Rupture With Ultrasound in Patients Treated Surgically: A Systematic Review and Meta-Analysis. — Aminlari A, Stone J, McKee R, et al. The Journal of Emergency Medicine. 2021.
3. MRI Is Unnecessary for Diagnosing Acute Achilles Tendon Ruptures: Clinical Diagnostic Criteria. — Garras DN, Raikin SM, Bhat SB, Taweel N, Karanjia H. Clinical Orthopaedics and Related Research. 2012.
4. Surgical Interventions for Treating Acute Achilles Tendon Ruptures. — Khan RJ, Carey Smith RL. The Cochrane Database of Systematic Reviews. 2010.
5. Selected Issues for the Master Athlete and the Team Physician: A Consensus Statement. — Kibler WB, Putukian M. Medicine and Science in Sports and Exercise. 2010.
6. Common Painful Foot and Ankle Conditions: A Review. — Cooper MT. The Journal of the American Medical Association. 2023.
7. Heel Pain: Diagnosis and Management. — Morancie NA, Irvin L, Rayala BZ. American Family Physician. 2025.
8. Venous Thromboembolism Rates in Patients With Lower Limb Immobilization After Achilles Tendon Injury Are Unchanged After the Introduction of Prophylactic Aspirin: Audit. — Braithwaite I, Dunbar L, Eathorne A, Weatherall M, Beasley R. Journal of Thrombosis and Haemostasis : JTH. 2016.
9. Age, Personal and Family History Are Independently Associated With Venous Thromboembolism Following Acute Achilles Tendon Rupture. — Oliver WM, Mackenzie SA, Lenart L, et al. Injury. 2022.
10. Incidence of Venous Thromboembolism Following Achilles Tendon Rupture. Data From the UK Foot and Ankle Thrombo-Embolism (UK-FATE) Audit. — Solan M, Briggs-Price S, Houchen-Wolloff L, et al. Injury. 2025.
11. FDA Drug Label. — Updated date: 2024-09-27. Food and Drug Administration.
12. Fluoroquinolones and the Risk of Tendon Injury: A Systematic Review and Meta-Analysis. — Alves C, Mendes D, Marques FB. European Journal of Clinical Pharmacology. 2019.
13. Clinical Implications of the Association Between Fluoroquinolones and Tendon Rupture: The Magnitude of the Effect With and Without Corticosteroids. — Persson R, Jick S. British Journal of Clinical Pharmacology. 2019.
14. Prevention of VTE in Orthopedic Surgery Patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th Ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. — Falck-Ytter Y, Francis CW, Johanson NA, et al. Chest. 2012.
15. Targeted Prophylactic Anticoagulation Based on the TRiP(cast) Score in Patients With Lower Limb Immobilisation: A Multicentre, Stepped Wedge, Randomised Implementation Trial. — Douillet D, Penaloza A, Viglino D, et al. Lancet. 2024.
16. Predictors of Primary Achilles Tendon Ruptures. — Claessen FM, de Vos RJ, Reijman M, Meuffels DE. Sports Medicine. 2014.
17. Point-of-Care Ultrasound Diagnosis of Acute Achilles Tendon Rupture in the ED. — Adhikari S, Marx J, Crum T. The American Journal of Emergency Medicine. 2012.
18. Realtime Achilles Ultrasound Thompson (RAUT) Test for the Evaluation and Diagnosis of Acute Achilles Tendon Ruptures. — Griffin MJ, Olson K, Heckmann N, Charlton TP. Foot & Ankle International. 2017.
19. Imaging Modalities in the Diagnosis and Monitoring of Achilles Tendon Ruptures: A Systematic Review. — Dams OC, Reininga IHF, Gielen JL, van den Akker-Scheek I, Zwerver J. Injury. 2017.
20. The Utility of Clinical Measures for the Diagnosis of Achilles Tendon Injuries: A Systematic Review With Meta-Analysis. — Reiman M, Burgi C, Strube E, et al. Journal of Athletic Training. 2014.
21. Achilles Tendon Ruptures: Nonsurgical Versus Surgical Treatment. — Saggar R, Mullen J, Mangone PG, Hogan MV. Arthroscopy : The Journal of Arthroscopic & Related Surgery : Official Publication of the Arthroscopy Association of North America and the International Arthroscopy Association. 2025.
22. Plaster Cast Versus Functional Brace for Non-Surgical Treatment of Achilles Tendon Rupture (UKSTAR): A Multicentre Randomised Controlled Trial and Economic Evaluation. — Costa ML, Achten J, Marian IR, et al. Lancet. 2020.
23. Open Surgical Repair as Gold Standard for Acute Achilles Tendon Ruptures: Systematic Review and Network Meta-Analysis. — Pisano A, Boxler M, Gambuti E, et al. Knee Surgery, Sports Traumatology, Arthroscopy : Official Journal of the ESSKA. 2025.
24. What Is the Best Evidence to Guide Management of Acute Achilles Tendon Ruptures? A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials. — Meulenkamp B, Woolnough T, Cheng W, et al. Clinical Orthopaedics and Related Research. 2021.
25. Acute Achilles Tendon Ruptures: An Update on Current Management Strategies. — Dold AP. The Journal of the American Academy of Orthopaedic Surgeons. 2024.
26. Audit of a Revised Pathway Aimed at Expediting Diagnosis and Treatment for Suspected Achilles Tendon Rupture. — Cole K, Moosa A, Rhodes A, et al. The Journal of Foot and Ankle Surgery : Official Publication of the American College of Foot and Ankle Surgeons. 2023.