Summary

Rupture of the Achilles tendon (Tendo-Achilles) is the most common major tendon rupture in the lower limb. It typically occurs in "Weekend Warriors" (middle-aged men playing explosive sports) with a sensation of being "kicked in the back of the leg". The rupture usually occurs in the Watershed Zone (2-6cm proximal to insertion) where blood supply is poorest. Diagnosis is purely clinical using the Simmonds-Thompson Squeeze Test. Management has shifted towards Functional Rehabilitation (early weight-bearing in an equinus brace) which yields results comparable to surgery without the wound complications, though surgery is still preferred for high-level athletes to minimize re-rupture risk. [1,2]

Key Facts

• Mechanism: Explosive push-off (Tennis, Squash).
• Sensation: "Bang" / "I was kicked".
• Site: 2-6cm proximal to calcaneal insertion (Watershed).
• Key Sign: Simmonds-Thompson Test (Squeeze calf -> Foot does NOT plantarflex).
• Common Pitfall: Missed diagnosis (20%). The patient can still plantarflex using secondary muscles (FHL, FDL, Tib Post), tricking the examiner.
• Management: Functional Bracing (Vacoped) vs Surgery.
• Re-rupture Rate: Conservative 8-12%, Surgical 2-4%.

Clinical Pearls

"The Gap is Real": Within the first 24 hours, you can often feel a palpable gap (delle) in the tendon. Mark it with a pen. Once swelling sets in (edema/haematoma), the gap disappears.

"Don't Trust the Toe Raise": A patient with an Achilles rupture can sometimes perform a toe raise (weakly) using their accessory flexors (Tibialis Posterior, Peroneals, Flexor Hallucis Longus). Do not rely on active movement. Trust the Squeeze Test.

"The Fluoroquinolone Factor": Ask about antibiotics. Ciprofloxacin can cause spontaneous tendon rupture, often bilaterally. Steroids are also a multiplier.

"Treat the Soft Tissues": The skin over the Achilles is thin and precarious. Whether surgical or conservative, handle the skin like gold dust. A necrotic wound here is a plastic surgery disaster involving free flaps.

Anatomy

• Triceps Surae: Gastrocnemius (fast twitch, crosses knee + ankle) + Soleus (slow twitch, ankle only).
• Tendon: The strongest/thickest in the body. It spirals 90 degrees as it inserts into the calcaneus.
• Blood Supply:
  • Proximally: From muscle belly.
  • Distally: From bone insertion.
  • Watershed Zone: 2-6cm proximal to insertion. This area relies on diffusion from the paratenon and is prone to hypovascularity, degeneration and rupture.
• Paratenon: Unlike other tendons, the Achilles lacks a true synovial sheath. It has a vascular paratenon.

Mechanism

• Eccentric Loading: The muscle is maximally contracting while being forcibly lengthened (e.g., landing from a jump or pushing off to sprint).
• Failure: The load exceeds the tensile strength of the (often degenerated) tendon fibers.
• Histology: Usually shows prior Myxoid Degeneration (Angiofibroblastic dysplasia). A healthy tendon rarely snaps; a degenerated one does.

          ACHILLES RUPTURE CONFIRMED
                     ↓
        ASSESS GAP ON ULTRASOUND (DYNAMIC)
        DO ENDS MEET IN PLANTARFLEXION?
        ┌────────────┴────────────┐
       YES                        NO  (or >1cm Gap)
        ↓                         ↓
   FUNCTIONAL                CONSIDER SURGERY
   BRACING                   (Gap too big to heal)
   (Standard)                     ↓
        ↓                    PATIENT FACTORS?
  (Vacoped Boot)             (Athlete vs Sedentary)
        ↓                         │
    PROTOCOL                 ┌────┴────┐
  (Full WB in Equinus)      SURG      CONSERVATIVE
       ↓
  REHABILITATION

1. Functional Rehabilitation (Conservative) - "Accelerated Rehab"

• Concept: Bring the tendon ends together by pointing the foot down (Equinus) and holding it there. Use early weight bearing (proprioception) to stimulate collagen alignment.
• Device: Vacoped Boot (Gold standard - adjustable range) or Wedged Moon Boot.
• Protocol (Example):
  • 0-2 weeks: Full Equinus (30 deg). Non-weight bearing (or heel touch).
  • 2-4 weeks: Full Equinus. Weight bearing as tolerated.
  • 4-8 weeks: Gradually remove wedges/reduce angle (5 deg per week).
  • 8-10 weeks: Into shoes with heel lift.
• Success: Re-rupture rates are now similar to surgery (in specialized centers with strict protocols).
• Pros: No wound complications (0% infection).

2. Surgical Repair

• Indication:
  • Gap >1cm in full equinus (ends don't meet).
  • High-level athletes (need maximal push-off power).
  • Delayed presentation (>2 weeks).
  • Re-rupture.
• Technique:
  • Open Repair: Large incision. Strong Krackow sutures. High wound risk.
  • Percutaneous (Mini-Open): Jig systems (Achillon / PARS). Smaller scar, lower infection risk, higher Sural nerve injury risk.
• Pros: Lowest re-rupture rate (2-3%). Slightly better strength?
• Cons: Infection (Deep infection is disastrous). Sural nerve injury. DVT.

The Krackow Suture

• A "locking loop" stitch used for tendon repair.
• It grips the tendon fibers tightly and prevents pull-out.
• Usually 2-4 strands of heavy non-absorbable suture (Ethibond/Fiberwire/UltraBraid).

The Percutaneous Jig (Achillon / PARS)

• Instrument passed inside the paratenon.
• Needles passed blindly through skin/jig/tendon.
• Risk: Catching the Sural Nerve (which runs laterally).
• Prevention: Open the lateral side to see the nerve. Or ultrasound guidance.

Key Studies

1. Willits et al. (2010): Landmark RCT. Surgery vs Functional Rehab. Result: NO significant difference in re-rupture rate if functional rehab used. Revolutionised non-operative care.
2. Keating et al. (2011): Operative repair reduces re-rupture but increases complications significantly.
3. Olsson et al. (2013): Early weight bearing improves healing.

Guidelines

• AAOS: Moderate evidence to support non-operative treatment in general population.
• BOA (British Orthopaedic Association): Conservative management is the standard of care for most patients, provided ends appose.

Did my tendon snap?

Yes. It has pulled apart like two ends of a mop.

Can it heal without surgery?

Amazingly, yes. The tendon ends are sticky. If we point your toes down in a special boot, the ends touch. Nature will glue them back together over 8-10 weeks. This avoids the risks of surgery (wound infection).

Why would anyone have surgery?

Surgery stitches them tighter. For Olympic athletes, that 1% extra power might matter. Or if the gap is too big for the ends to touch. But for most people, the boot gives a result just as good without the risk of a nasty infection.

Can I drive?

No. Not while in the boot (Right leg especially). Insurance is void. Usually 10-12 weeks.

Rivaroxaban (Xarelto)

• Class: Direct Factor Xa Inhibitor (DOAC).
• Indication: VTE Prophylaxis in lower limb immobilisation.
• Dose: 10mg OD.
• Duration: Usually until fully weight bearing (6-8 weeks).
• Contraindications: Active bleeding, severe renal impairment.
• Why?: The combination of trauma + immobilisation makes Achilles rupture a VERY high risk for DVT/PE.

Enoxaparin (Clexane)

• Class: Low Molecular Weight Heparin (LMWH).
• Indication: Alternative to Rivaroxaban.
• Dose: 40mg SC OD.
• Downside: Daily injections (patients hate it).

Case 1: The Sedentary Diabetic

Scenario: 50-year-old male, diabetic, smoker. Steps off curb, feels pop. Gap palpable. Management: Conservative (Functional Rehab). Reasoning: High risk of wound infection/healing problems with surgery. Diabetes + Smoking = Surgical Disaster waiting to happen.

Case 2: The Professional Sprinter

Scenario: 24-year-old athlete. Rupture confirmed. Management: Surgical Repair. Reasoning: Needs guaranteed maximal tensioning for power. Accepts wound risk for performance gain. Low re-rupture risk priority.

Case 3: The Missed Diagnosis

Scenario: 40-year-old male. Injury 6 weeks ago. "Calf strain". Now complains of weakness walking up stairs. Diagnosis: Chronic Achilles Rupture. Management: Surgical Reconstruction (V-Y Plasty or FHL Transfer). Primary repair impossible as ends have retracted and scarred.

Phase 1: 0-2 Weeks

• Vacoped Boot locked at 30 degrees plantarflexion.
• Touch weight bearing with crutches.
• Rivaroxaban 10mg OD.
• Elevation.

Phase 2: 2-4 Weeks

• boot locked at 30 degrees.
• Full weight bearing as tolerated.
• Active plantarflexion allowed (protected). NO dorsiflexion past neutral.

Phase 3: 4-8 Weeks

• Reduce boot angle by 5 degrees per week (or remove wedges).
• Aim for neutral (0 degrees) by week 8.
• Proprioception exercises.

Phase 4: 8+ Weeks

• Wean out of boot into shoes with heel lift.
• Heel raises (Double leg -> Single leg).
• Plyometrics start at 3-4 months.

• Achilles: Greek hero. Dipped in the River Styx by his mother Thetis, held by his heel. His only vulnerable spot. Killed by an arrow from Paris to the heel.
• Simmonds (1957): Described the squeeze test.
• Thompson (1962): Independent description of the same test. Hence "Simmonds-Thompson".
• Hunter (1700s): John Hunter (famous surgeon) ruptured his own Achilles while dancing. He treated it conservatively by binding it up. Proof that conservative care has a long history!

(End of Topic)