Summary

Achilles tendon rupture is a common injury affecting the strongest tendon in the human body. It typically occurs in middle-aged "weekend warriors" during activities involving sudden push-off or landing (e.g., tennis, squash, basketball). The rupture usually occurs at the "watershed zone" 2-6cm above the calcaneal insertion where blood supply is poorest. Most ruptures occur on a background of chronic tendinopathy. Diagnosis is clinical using Simmonds-Thompson test. Modern evidence supports functional rehabilitation (non-operative) for most patients, with surgery reserved for elite athletes, delayed presentations, or re-ruptures.

Key Facts

• Incidence: 18-37 per 100,000 per year (increasing)
• Peak age: 30-50 years ("weekend warrior")
• Sex ratio: Male:Female 10:1
• Rupture site: 2-6cm above calcaneal insertion (watershed zone)
• Missed diagnosis rate: 20-25% initially misdiagnosed as "ankle sprain"
• Key test: Simmonds-Thompson (calf squeeze) test
• Treatment trend: Functional rehabilitation now first-line for most patients

Clinical Pearls

"Someone Kicked Me": Patients classically describe feeling like they were kicked or struck in the back of the leg. This is pathognomonic history for Achilles rupture.

They CAN Still Walk: Do not be fooled! Patients can walk and even weakly plantarflex (using tibialis posterior and peronei). The Simmonds test is mandatory for all posterior ankle pain.

Equinus Position: Initial immobilization MUST be in full plantarflexion (equinus) to approximate tendon ends. Casting at 90 degrees leaves a gap and prevents healing.

Why This Matters Clinically

Achilles rupture is commonly missed in emergency departments. Delayed diagnosis leads to worse outcomes despite treatment. Understanding the clinical examination and avoiding the trap of preserved ambulation prevents missed injuries. The shift towards non-operative management has reduced surgical complications while maintaining comparable outcomes.

Structured Approach

General:

• Gait assessment (limping, difficulty pushing off)
• Compare both sides

Inspection:

• Swelling posterior ankle
• Bruising (may be extensive)
• Gap visible in tendon (if swelling permits)
• Altered resting ankle position

Palpation:

• Palpable defect/gap 2-6cm above insertion
• Tenderness at rupture site

Special Tests

Natural History

• Untreated complete rupture will not heal spontaneously with functional recovery
• Chronic neglected ruptures develop muscle shortening and scarring

Outcomes with Treatment

Prognostic Factors

Good Prognosis:

• Early diagnosis (less than 2 weeks)
• Appropriate initial immobilization (equinus)
• Compliance with rehabilitation
• Younger age
• No prior tendinopathy

Poor Prognosis:

• Delayed diagnosis (greater than 4 weeks)
• Re-rupture
• Poor compliance
• Continued quinolone/steroid use
• Significant comorbidities

Key Guidelines

1. BOAST 13 (2019) — British Orthopaedic Association Standards for Trauma. Supports functional rehabilitation as first-line; emphasizes VTE prophylaxis. BOA BOAST
2. AAOS Clinical Practice Guideline (2010) — American Academy of Orthopaedic Surgeons. Non-operative management acceptable for most patients.

Landmark Trials

Willits et al. (2010) — Surgery vs Non-Operative with Functional Rehabilitation

• 144 patients randomised
• Key finding: No significant difference in re-rupture rate (3.5% surgical vs 4.6% non-op)
• Key finding: Higher complication rate in surgical group (16% vs 1%)
• Clinical Impact: Shifted practice globally towards non-operative management

Lantto et al. (2016) — Long-term Outcomes

• Prospective randomised trial
• Key finding: At 18 months, no difference in functional outcomes
• Clinical Impact: Confirmed durability of non-operative approach

Metz et al. (2008) — Minimally Invasive vs Open Surgery

• Key finding: Lower wound complication rate with minimally invasive techniques
• Clinical Impact: If surgery chosen, consider minimally invasive approach

Evidence Strength

What has happened?

Your Achilles tendon — the strong cord at the back of your ankle connecting your calf muscle to your heel — has snapped (ruptured). This is like a rope that has frayed over time finally breaking when put under sudden strain. It is a common injury, especially in active people in their 30s-50s.

Why did it happen?

In most cases, the tendon had already weakened over time (a process called tendinopathy) without causing any symptoms. When you suddenly pushed off or changed direction, the tendon could not cope and snapped. Certain medications (like ciprofloxacin) and steroids can weaken tendons and increase this risk.

How is it treated?

Good news: in the past, everyone had surgery. We now know that for most people, healing in a special boot works just as well and avoids surgical risks.

1. Boot treatment (functional rehabilitation): You will wear a boot with your foot pointed down (like a ballerina). We gradually flatten your foot over 8-10 weeks while the tendon heals. You will work with a physiotherapist.
2. Surgery: This may be recommended if you are a professional athlete, if the diagnosis was delayed, or if the tendon re-ruptures. Surgery stitches the tendon together but carries risks of wound problems.

What to expect

• You will be in a boot for about 10 weeks
• You can start putting weight on the leg after 2-4 weeks (in the boot)
• It takes 6-9 months before you can return to running or sports
• Your calf muscle may remain slightly smaller on that side permanently

When to seek help

Contact your doctor or return to hospital if:

• Increasing pain or swelling in the leg (DVT risk)
• Problems with the boot or cast (rubbing, pressure sores)
• You hear or feel another "pop" (re-rupture)
• Signs of infection if you had surgery (redness, pus, fever)

The "Simmonds" Station

1. Inspect (Prone Position)

• Ask patient to kneel on chair or lie prone on couch with feet hanging off edge.
• Look:
  • Swelling: Loss of definition of the tendon.
  • The Angle of Dangle (Matles Test): The normal foot rests in slight plantarflexion (gravity). The ruptured foot hangs vertically (neutral/dorsiflexed) because the "guy rope" is cut.
  • Gap: Visible defect?

2. Palpate

• Feel the tendon defect. It is usually 2-6cm proximal to the calcaneus.
• Tenderness.

3. The Special Test (Simmonds-Thompson)

• Action: Squeeze the calf muscle belly (Gastrocnemius).
• Normal Response: The foot plantarflexes (points down). (The tendon pulls the heel up).
• Abnormal Response: The foot stays still. (The connection is broken).
• Note: This is the ONLY test that matters.

Viva Questions:

• Q: Can a patient walk with a ruptured Achilles?
  • A: YES. They can use Tibialis Posterior and Peroneals towards the floor. Do not rule out rupture based on ability to walk.
• Q: Why do we treat in Equinus (Plantarflexion)?
  • A: To approximate the tendon ends. Treating in neutral leaves a gap -> lengthened tendon -> functional failure.
• Q: What is the main risk of surgery?
  • A: Wound Breakdown. The skin is tenuous. Infection here often leads to disastrous consequences (exposed tendon).
• Q: What nerve is at risk?
  • A: Sural Nerve (runs lateral to the tendon).

Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Consult an orthopaedic surgeon for Achilles tendon rupture management.