Complete Achilles tendon tear

Complete Achilles tendon tear (rupture) is one of the most common and debilitating tendon injuries in adults, occurring at an incidence of 11–37 per 100,000 per year in Australia and increasing due to a more active ageing population. The Achilles tendon, the largest and strongest tendon in the body, is the confluent insertion of the gastrocnemius and soleus muscles into the calcaneal tuberosity. Complete rupture most frequently occurs in the hypovascular "critical zone" 2–6 cm proximal to the calcaneal insertion. The classic presentation is a middle-aged recreational athlete (the "weekend warrior") who experiences sudden sharp posterior heel or calf pain during explosive push-off, often describing hearing or feeling a "pop," followed by immediate loss of plantar flexion strength. Management options include surgical repair and non-operative functional rehabilitation; contemporary high-quality evidence supports non-operative management with functional rehabilitation achieving equivalent re-rupture rates and functional outcomes to surgery in most patients.

Complete Achilles tendon rupture results from a sudden overload of a tendon that has been progressively weakened by degenerative changes (tendinosis). Acute traumatic rupture in an otherwise normal tendon is uncommon.

Mechanical and Degenerative Mechanisms

• Tendinosis as a precursor — the majority of complete ruptures occur in tendons with pre-existing degenerative change (tendinosis); tendinosis involves disorganised collagen fibres, mucoid degeneration, neovascularisation, and absence of inflammatory cells; the tendon is mechanically weakened and susceptible to sudden failure under high load; this explains why many patients report no prior symptoms before rupture
• Critical zone ischaemia — the zone 2–6 cm proximal to the calcaneal insertion is the region of poorest vascular supply; this watershed zone is the most common site of both chronic tendinopathy and acute rupture; relative ischaemia impairs collagen remodelling and repair capacity
• Mechanism of acute rupture — explosive concentric or eccentric loading generates tensile forces exceeding tendon failure threshold; common mechanisms include sudden push-off in court sports (basketball, squash), unexpected dorsiflexion (falling, stepping in a hole), and sudden sprinting from rest
• Risk factor accumulation — male sex (5–10× higher risk), age 30–50 years, fluoroquinolone antibiotics (ciprofloxacin, levofloxacin), corticosteroid injections into or adjacent to the tendon, systemic corticosteroids, gout, rheumatoid arthritis, renal disease, and hyperlipidaemia all contribute to tendon vulnerability; fluoroquinolone-associated rupture can occur at low-load activity and within weeks of prescription

Complete Achilles tendon rupture has a characteristic clinical presentation. The diagnosis is clinical in the majority of cases; ultrasound is confirmatory when clinical findings are equivocal. The injury is missed in 20–25% of initial presentations, most commonly when local swelling masks the palpable gap and the Thompson test is not performed.

History

• Sudden posterior heel or calf pain — abrupt onset during activity; often explosive in nature; patient commonly describes hearing or feeling a loud "pop" or "snap"; many report being struck or kicked in the back of the calf (though no contact occurred); immediate inability to push off or stand on tiptoe
• Mechanism — most commonly explosive push-off in racquet sports, basketball, or football; also step-off from a kerb or uneven surface causing sudden dorsiflexion; less commonly direct trauma; up to 25% have no prior Achilles symptoms; inquire about fluoroquinolone use in the preceding 6 months
• Functional deficits — difficulty walking (though many can walk with a limp by recruiting peroneal plantarflexion); inability to stand on tiptoe on the affected leg; loss of push-off during gait; stair climbing difficulty

Examination Findings

• Thompson test (Simmonds test) — patient prone with foot hanging free; squeeze the calf at its widest point; normal result: plantar flexion of foot; positive (abnormal) result: no plantar flexion, indicating complete rupture; sensitivity 96%, specificity 93%; must be performed in all patients with suspected Achilles injury
• Palpable gap — a palpable defect or step in the tendon 2–6 cm proximal to the calcaneal insertion; present in most acute ruptures before swelling develops; swelling and haematoma in delayed presentations can mask the gap; palpate the full length of the tendon
• Resting equinus angle — with patient prone, the injured foot rests in less equinus (more dorsiflexed) than the contralateral side; this reflects loss of resting tendon tension; a useful confirmatory sign when present
• Single heel raise test — inability to perform a single-leg heel raise on the affected side; note that some patients can plantarflex weakly (using tibialis posterior and peroneal muscles) — this does not exclude complete Achilles rupture

The diagnosis of complete Achilles tendon rupture is primarily clinical. Imaging is used to confirm the diagnosis when clinical findings are equivocal, exclude bony avulsion fracture, and assess rupture characteristics to guide management decisions.

• Essential
  X-ray ankle (AP and lateral)

  Mandatory first-line investigation to exclude calcaneal avulsion fracture or associated bony injury. Achilles rupture itself is not visible on plain X-ray. Look for: loss of Kager triangle (pre-Achilles fat pad opacity), calcaneal avulsion fragment. Avulsion fractures require orthopaedic referral and different management to midsubstance rupture. Item 57706.
• Recommended
  Ultrasound Achilles tendon

  Confirmatory imaging for clinically suspected complete rupture; differentiates complete from partial tear; characterises gap length, tendon end apposition (important for non-operative management decisions), and associated tendinopathy. Dynamic ultrasound assesses whether plantarflexion restores tendon apposition (critical for functional rehabilitation). Sensitivity 94–100%, specificity 83–100% for complete rupture. Item 55054 (ultrasound soft tissue).
• Specialised
  MRI Achilles tendon

  Gold standard for characterising rupture extent, tendon end quality, and associated pathology. Used in equivocal ultrasound cases, prior tendinopathy where differentiation from partial tear is difficult, planning surgical approach, or pre-operative assessment. Item 63560 (MRI lower limb). Not required for straightforward acute complete rupture with positive Thompson test and palpable gap.

Management pathway selection (operative vs non-operative functional rehabilitation) is guided by patient age, activity level, gap characteristics on imaging, time from injury, and patient preference.

Pharmacological management in Achilles tendon rupture is supportive. Analgesia for acute pain and venous thromboembolism (VTE) prophylaxis during immobilisation are the primary pharmacological considerations.

The primary treatment decision is operative versus non-operative management, to be made in consultation with an orthopaedic surgeon or sports medicine physician. The GP role is immediate immobilisation, analgesia, imaging, and urgent referral.

Immediate GP Management

• Immobilise in equinus — apply a below-knee back-slab or equinus boot with heel wedges (plantarflexion 20–30 degrees) immediately on diagnosis; this approximates the tendon ends and prevents further retraction; the foot must NOT be immobilised in neutral or dorsiflexion — this risks tendon gap and compromises healing
• Non-weight bearing initially — provide crutches; non-weight bearing until specialist review; early weight-bearing protocols are used in rehabilitation but should be guided by specialist
• Urgent referral — refer to orthopaedic surgery or sports medicine within 1–3 days; the decision between operative and non-operative management should be made within the first 1–2 weeks; delay beyond 4 weeks results in tendon end fibrosis and retraction, making conservative management less effective and surgical repair more complex

Non-Operative Functional Rehabilitation

• Modern functional rehabilitation protocol — initial immobilisation in equinus boot at 30 degrees plantarflexion; early graduated weight-bearing from 2 weeks; heel wedge reduction over 6–8 weeks progressively moving to neutral; physiotherapy-directed rehabilitation from 6 weeks; return to running 12–16 weeks; return to sport 6–9 months; re-rupture rate 2–4%
• Evidence base — RCT evidence (UKSTAR trial, Willits et al) demonstrates that non-operative management with early functional rehabilitation achieves equivalent functional outcomes, patient-reported scores, and re-rupture rates to operative repair, with fewer wound complications; the Achilles Tendon Total Rupture Score (ATRS) is the preferred patient-reported outcome measure

Surgical Repair

• Open surgical repair — primary end-to-end repair; traditionally open approach; lower re-rupture rate than older non-operative cast immobilisation protocols (but equivalent to modern functional rehabilitation); higher risk of wound infection (2–10%), sural nerve injury, and scar tenderness; preferred for elite athletes, large gap injuries, and patient preference
• Minimally invasive and percutaneous repair — comparable outcomes to open repair with lower wound complication rates; increasingly used in suitable candidates; same post-operative rehabilitation protocol as non-operative management

Non-pharmacological management encompasses immobilisation, physiotherapy-directed rehabilitation, and patient education about realistic recovery expectations.

Physiotherapy Rehabilitation

• Early phase (0–6 weeks) — protected weight-bearing in boot; ankle range of motion exercises within boot; oedema management (elevation, compression); commence isometric calf contractions when pain allows; gait training with crutches progressing to full weight-bearing in boot
• Intermediate phase (6–12 weeks) — progressive heel raise exercises (bilateral progressing to unilateral); transition from boot to shoe with heel raise; proprioception and balance training; swimming and cycling for cardiovascular fitness; progressive resistance strengthening of calf complex
• Late phase (12–24 weeks) — single-leg heel raise endurance (target 25 repetitions); hopping and plyometric loading progressing to running; sports-specific drills; return to running from approximately 12–16 weeks with structured run-walk program; return to full training and sport 6–9 months
• Criteria-based return to sport — return to sport should be criteria-based not time-based; criteria include: single-leg heel raise >25 repetitions; limb symmetry index >90% for strength and power; hop tests; psychological readiness; most patients require 9–12 months for full sporting return

VTE Prevention

• Non-pharmacological VTE prevention — ankle pump exercises in the boot; elevate limb when at rest; graduated compression stockings on contralateral leg; early mobilisation as soon as clinically appropriate; pharmacological prophylaxis as per risk assessment (see pharmacological section)

Monitoring focuses on rehabilitation progress, detection of re-rupture or complications, and safe return to sport.

Indications for Specialist Referral

• Orthopaedic surgery — all acute complete Achilles tendon ruptures; avulsion fractures; chronic or neglected ruptures; re-rupture after prior repair
• Sports medicine — return-to-sport planning; elite athletes; recalcitrant tendinopathy co-existing with rupture; ongoing functional deficits beyond 6 months
• Vascular surgery — suspected vascular injury; severe limb ischaemia

Special considerations apply to elderly patients, patients on fluoroquinolones, and athletes with elite sporting demands.

Elderly and High Surgical Risk Patients

• Non-operative management is strongly preferred in elderly patients and those with high surgical risk (diabetes, peripheral vascular disease, immunosuppression, prior wound complications); tendon healing capacity is reduced but functional outcomes with modern rehabilitation protocols are acceptable; focus on safe mobilisation and VTE prevention; walking stick or frame support during early rehabilitation

Fluoroquinolone-Associated Rupture

• Fluoroquinolone antibiotics (ciprofloxacin, norfloxacin, levofloxacin) are associated with a 3–4-fold increased risk of Achilles tendon rupture; risk is highest in patients older than 60 years, those on concurrent corticosteroids, and renal transplant recipients; fluoroquinolone-associated ruptures may be bilateral and can occur at low activity levels or with minimal trauma; prescribers should counsel patients about tendon rupture risk and advise cessation of the antibiotic and rest if tendon pain develops; bilateral simultaneous rupture warrants urgent orthopaedic review

Elite and Competitive Athletes

• Elite athletes typically prefer surgical repair to minimise re-rupture risk and maximise return to high-level competition; return to professional sport after Achilles tendon rupture typically requires 9–12 months; criteria-based return to sport protocols are essential; psychological readiness and kinesiophobia (fear of re-injury) are important components of rehabilitation; sports psychologist involvement is valuable in high-level athletes

Stewardship in Achilles tendon rupture focuses on accurate diagnosis to avoid missed injury, appropriate antibiotic prescribing (avoiding fluoroquinolones where possible), judicious use of VTE prophylaxis, and avoiding prolonged NSAID use during tendon healing.

GP Role

• Diagnose accurately — perform Thompson test; palpate for gap; X-ray to exclude avulsion fracture; ultrasound to confirm if clinical doubt
• Immobilise immediately — equinus boot or back-slab; non-weight bearing; do not leave in neutral or dorsiflexion; provide crutches
• Refer urgently — orthopaedic or sports medicine referral within 1–3 days; document time of injury; delay worsens outcomes
• Prescribe VTE prophylaxis — assess VTE risk; prescribe rivaroxaban or enoxaparin for duration of immobilisation
• Avoid fluoroquinolones — in patients with Achilles tendon pathology; counsel patients receiving fluoroquinolones about rupture risk

Follow-up is milestone-based and coordinated with orthopaedic or sports medicine and physiotherapy. Full recovery and return to sport typically requires 9–12 months. Prevention of re-rupture and contralateral rupture is a key long-term goal.

• Lantto I et al. — Epidemiology of Achilles tendon ruptures: increasing incidence over a 33-year period; Scand J Med Sci Sports 2015
• Wilkins R, Bisson LJ — Operative versus nonoperative management of acute Achilles tendon ruptures: a quantitative systematic review; Am J Sports Med 2012
• Maffulli N et al. — Early weightbearing and functional exercises accelerate recovery after Achilles tendon rupture; Br J Sports Med 2003
• UKSTAR trial — UK trial of operative versus non-operative management of Achilles tendon ruptures; Lancet 2020
• van der Eng DM et al. — Effectiveness of non-surgical treatment compared to surgical treatment for Achilles tendon ruptures; PLoS ONE 2013
• Australian and New Zealand Venous Thromboembolism Guidelines — Lower limb immobilisation and VTE risk; NHMRC 2019
• Therapeutic Guidelines: Musculoskeletal — Achilles tendon injuries; available via eTG complete
• TGA — Fluoroquinolone antibiotic safety review and tendon risk advisory; TGA.gov.au