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BOAST Guidelines
BOFAS / BOA Consensus (SpecS Pathway)
Foot and Ankle

Management of Acute Achilles Tendon Rupture

Evidence-based standard on the rapid identification, immobilisation in equinus, structured specialist review, and protocolised functional rehabilitation for acute Achilles tendon ruptures.

Key standards

  • ›Diagnose acute Achilles tendon ruptures primarily via clinical assessment using Simmonds triad and the Thompson calf squeeze test.
  • ›Do not delay immobilisation for routine imaging; reserve ultrasonography or MRI for equivocal cases or dynamic apposition assessment.
  • ›Apply immediate initial immobilisation in resting equinus (plantarflexion) to prevent tendon distraction.
  • ›Refer all acute ruptures urgently to a specialist orthopaedic service / acute tendon clinic.
  • ›Formally assess venous thromboembolism (VTE) risk according to NICE guidelines and offer thromboprophylaxis where indicated.
  • ›Employ shared decision-making between non-operative functional bracing and operative repair, highlighting equivalent long-term functional scores.
  • ›Utilise early functional weight-bearing protocols in a protected orthosis with gradual reduction of equinus over 8–10 weeks.
  • ›Reserve operative repair predominantly for high-demand athletes, delayed presentations, dynamic end separation, or re-ruptures.
  • ›Ensure structured physiotherapy supervision focusing on calf muscle endurance, gait retraining, and avoiding forced passive dorsiflexion.

Introduction

Acute Achilles tendon rupture is a common soft tissue injury predominantly affecting active individuals in the third to fifth decades of life. The BOA and the British Orthopaedic Foot & Ankle Society (BOFAS) provide definitive national guidance to minimise misdiagnosis, prevent delayed presentation, and standardize functional rehabilitation whether managed operatively or non-operatively.

Initial Assessment and Diagnosis

  • Acute ruptures should be evaluated clinically without relying routinely on advanced imaging.
  • Clinical diagnosis relies on classic features, specifically evaluating for the Simmonds triad:
    • Positive Simmonds / Thompson calf squeeze test (loss of passive plantarflexion).
    • Palpable gap along the tendon substance (most frequently 2–6 cm proximal to the calcaneal insertion).
    • Altered resting angle of the ankle (loss of physiological equinus compared to the contralateral limb).
  • Radiographs should be reserved for ruling out bony avulsion fractures (calcaneal sleeve or avulsion fractures). Ultrasound or MRI is indicated only when clinical examination is equivocal, in delayed presentations, or to assess dynamic tendon apposition.

Acute Management and Immobilisation

  • Immediately upon clinical suspicion, the ankle must be immobilised in gravity equinus (plantarflexion) using a rigid splint/plaster backslab or dedicated orthosis with heel wedges to prevent tendon gap elongation.
  • Patients must be kept strictly non-weight-bearing initially and referred urgently to a specialist foot and ankle service or dedicated acute rupture clinic.
  • Venous thromboembolism (VTE) risk assessment must be performed according to NICE guidelines (NG89), and thromboprophylaxis considered for the duration of rigid or restricted lower limb immobilisation.

Definitive Treatment Selection

  • The choice between operative repair (open or minimally invasive/percutaneous) and non-operative management must involve shared decision-making.
  • Both strategies demonstrate equivalent patient-reported functional outcomes when combined with an early, structured functional rehabilitation protocol.
  • Non-operative functional management is generally the first-line standard for the majority of patients, eliminating surgical wound breakdown, infection, and sural nerve injury risks.
  • Operative repair should be considered for patients with delayed presentation (>2–3 weeks), high-performance athletes, re-ruptures, or where dynamic imaging shows failure of tendon end apposition in equinus.

Functional Rehabilitation Protocol

  • Standard care mandates protocolised functional rehabilitation, typically in an adjustable rigid walking orthosis with wedges:
    • Weeks 0–2: Immobilisation in fixed equinus (e.g., 30° plantarflexion or 3 wedges), protected weight-bearing.
    • Weeks 2–8: Progressive sequential reduction of equinus (removal of wedges typically every 2 weeks) with guided full weight-bearing.
    • Weeks 8–12+: Transition to normal footwear with heel raise, active plantarflexion strengthening, and physical therapy avoiding sudden passive dorsiflexion stretching.

Exam-tested points

  • ›Simmonds triad consists of: (1) positive calf squeeze (Thompson's test), (2) altered resting angle/angle of declination, and (3) palpable tendon gap.
  • ›Plantaris tendon integrity and intact long toe flexors (FHL/FDL) can produce active non-weightbearing plantarflexion despite a complete rupture, leading to false-negative exams if strength alone is tested.
  • ›Major landmark trials (e.g., Willits et al., UK STAR trial) demonstrated that functional non-operative treatment with early mobilisation achieves re-rupture rates comparable to surgical repair (~5-8%) without operative complications.
  • ›Surgical complications include wound breakdown, deep infection, and sural nerve entrapment/injury (particularly relevant in percutaneous techniques).
  • ›Dynamic ultrasound assessment evaluates whether tendon ends appose within 20-30 degrees of plantarflexion; a persistent large gap (>1 cm in equinus) may be an indication for surgical intervention.
  • ›Temporary lower limb immobilisation and reduced mobility pose a significant VTE risk requiring strict adherence to NICE NG89 thromboprophylaxis assessment.
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