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← Musculoskeletal medicine and orthopaedics indexChapter sections
Role and principlesAssessment and patient selectionBaseline assessmentInterventionsMedicines and treatment safetyTargets, monitoring and follow-upSpecial situationsCommon pitfallsQuestionsSources
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Educational draft · awaiting clinical reviewThe full textbook explains uncertainty but does not replace live national or local guidance, specialist advice, or current prescribing information.

Venous-thromboembolism prevention after lower-limb surgery

Musculoskeletal medicine and orthopaedics · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

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Suspected postoperative pulmonary embolism

New unexplained hypoxia, pleuritic pain, tachycardia, haemoptysis, syncope or haemodynamic instability after lower-limb surgery may be pulmonary embolism despite prophylaxis.

Action: Use ABCDE, summon urgent senior help, provide oxygen when indicated and follow the acute PE diagnostic and treatment pathway; prophylactic dosing is not adequate treatment for confirmed VTE.

Role and principles

Select, time and continue mechanical and pharmacological thromboprophylaxis after lower-limb surgery while actively balancing thrombosis, bleeding, renal and neuraxial-anaesthesia risks.

Lower-limb surgery creates venous stasis through immobility, endothelial injury from operation or trauma and a transient hypercoagulable response. Risk increases with previous VTE, thrombophilia, cancer, age, obesity, oestrogen exposure, major trauma, prolonged anaesthesia, dehydration and markedly reduced mobility. Bleeding risk rises with active bleeding, coagulopathy, thrombocytopenia, severe liver or renal disease, uncontrolled hypertension, recent neuraxial intervention and interacting antithrombotics. Document both sides of the balance rather than writing only a VTE score.

Classify the operation correctly because NICE regimens differ. Elective hip and knee replacement, hip or proximal-femoral fragility fracture, arthroscopy, other knee surgery, foot and ankle surgery and isolated immobilisation are not interchangeable. Establish baseline and anticipated mobility, anaesthetic plan, renal function, weight, platelet count, existing antiplatelet or anticoagulant indication, and whether the patient can self-administer injections. Reassess after postoperative bleeding, return to theatre or an unexpected period of immobility.

Practice

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Musculoskeletal medicine and orthopaedicsOriginal SBA

Elective hip prophylaxis sequence

A patient undergoes uncomplicated elective total hip replacement and has acceptable bleeding risk. Which regimen is one of the NICE-listed first choices for thromboprophylaxis?

Choose one answer, then submit
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Sources and review status4 sources · checked 27 Aug 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.

  • NICE NG89 VTE Prevention RecommendationsRisk assessment and procedure-specific orthopaedic pharmacological and mechanical prophylaxis.
  • Clexane Prefilled Syringes SmPCEnoxaparin prophylactic dosing, duration, renal, bleeding and neuraxial safety.
  • Xarelto Ten Milligram SmPCLicensed rivaroxaban regimen after elective hip or knee replacement.
  • NICE NG158 VTE Diagnosis and ManagementDiagnostic and treatment pathways when DVT or PE is suspected despite prophylaxis.

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateComplete draftClinical stateAwaiting reviewJurisdictionUnited Kingdom

Use mechanical prevention when indicated and safe. Intermittent pneumatic compression is useful from admission in hip-fracture patients when pharmacological prophylaxis is contraindicated, continuing until mobility is no longer significantly reduced. Anti-embolism stockings require measurement, fitting and daily removal for hygiene and skin inspection; they are not the same as compression stockings used for venous disease. Document peripheral perfusion and avoid devices that compromise a cast, wound or neuropathic skin.

Select one guideline-supported pharmacological regimen and write the agent, dose, first administration time, duration and discharge supply. LMWH is widely used but accumulates in renal impairment and interacts with neuraxial procedures. Aspirin is a specific NICE option after elective replacement, not a universal substitute for every lower-limb operation. Rivaroxaban is licensed after elective hip or knee replacement when haemostasis is established. Fondaparinux needs adequate renal function and a low bleeding risk when started after fragility-fracture surgery.

Before discharge, teach injection or tablet use, missed-dose action, bleeding signs and DVT or PE symptoms. Confirm who supplies and administers remaining doses and communicate the stop date to primary care. If acute VTE is suspected, switch from prevention thinking to diagnostic and therapeutic pathways; do not give extra prophylactic doses as improvised treatment. If bleeding occurs, stabilise first, identify last doses and renal clearance, involve surgery and haematology as required and reintroduce prophylaxis when the balance becomes favourable.

Key points

  • Assess VTE and bleeding risk on admission, at consultant review and whenever surgery, mobility, renal function, bleeding or clinical condition changes.
  • Combine early mobilisation and hydration with procedure-specific prophylaxis; walking is beneficial but does not substitute for indicated anticoagulant or mechanical prevention.
  • NICE first-line elective hip options are LMWH for 10 days then aspirin 75 mg or 150 mg daily for 28 days, LMWH for 28 days with stockings until discharge, or rivaroxaban.
  • NICE first-line elective knee options are aspirin 75 mg or 150 mg daily for 14 days, LMWH for 14 days with stockings until discharge, or rivaroxaban.
  • For fragility fractures of pelvis, hip or proximal femur, offer prophylaxis for one month when VTE risk outweighs bleeding risk: LMWH 6 to 12 hours after surgery or fondaparinux 6 hours after surgery when bleeding risk is low.
  • Consider LMWH or fondaparinux during lower-limb immobilisation when thrombosis risk exceeds bleeding risk, and consider stopping if immobilisation continues beyond 42 days.
  • Mechanical devices require correct fit, skin and perfusion checks; avoid anti-embolism stockings in severe peripheral arterial disease or other listed contraindications.
  • Coordinate every anticoagulant dose with spinal or epidural insertion and removal, renal function and haemostasis; local neuraxial timing protocols and product information are mandatory.

Assessment and patient selection

High thrombosis burden

Hip fracture, replacement surgery, previous VTE, cancer and prolonged immobility can combine to justify extended pharmacological prevention.

High bleeding burden

Active bleeding, expanding haematoma, low platelets, renal accumulation and recent neuraxial procedures can make routine dosing unsafe.

Probable postoperative DVT

New asymmetric swelling and tenderness after surgery requires objective assessment because pain and oedema are otherwise common postoperatively.

Possible pulmonary embolism

Unexplained tachycardia, hypoxia, pleuritic pain, syncope or shock remains concerning even when prophylaxis was correctly administered.

Mechanical-device injury

Pressure marks, blistering, numbness, cool toes or worsening pain suggests poor fit or impaired perfusion and needs immediate removal and reassessment.

Post-discharge prevention gap

An incomplete supply, absent training or unclear stop date commonly interrupts an intended extended prophylaxis course.

Red flags requiring action

  • Sudden breathlessness, chest pain, syncope, shock or an increasing oxygen requirement requires immediate assessment for pulmonary embolism and competing postoperative emergencies.
  • New unilateral calf or whole-leg swelling, tenderness or venous distension requires a DVT pathway rather than simply extending prophylaxis without diagnosis.

Baseline assessment

  1. 01
    First-line VTE and bleeding risk assessmentFirst stepFirst line
    Why
    Determine whether and how to combine pharmacological and mechanical prevention for the exact procedure and patient.
    Interpretation and limitations
    Repeat after consultant review and any material clinical change; a previous score is invalid if bleeding, mobility or renal function changes.
  2. 02
    Baseline FBC and renal function
    Why
    Identify anaemia, thrombocytopenia and impaired clearance before selecting and dosing an anticoagulant.
    Interpretation and limitations
    Use creatinine clearance where the medicine requires it; eGFR alone may misclassify dosing in extremes of age, weight or muscle mass.
  3. 03
    Compression ultrasonography for suspected DVT
    Why
    Objectively assess new postoperative leg symptoms rather than inferring thrombosis from swelling alone.
    Interpretation and limitations
    Follow the acute VTE diagnostic pathway, including repeat imaging when indicated; do not use screening ultrasound routinely in asymptomatic patients.
  4. 04
    CT pulmonary angiography or alternative PE imaging
    Why
    Confirm or exclude pulmonary embolism in a clinically appropriate patient after initial probability assessment.
    Interpretation and limitations

Interventions

01Admission and operationChoose procedure-specific preventionFirst stepA patient is admitted for lower-limb surgery, fracture care or immobilisation.+
  1. 1Assess individual VTE and bleeding risks, renal function, platelets, mobility and existing antithrombotic treatment.
  2. 2Identify the exact NICE procedure category and select a supported pharmacological and mechanical strategy.
  3. 3Coordinate first and last doses with surgery, haemostasis and neuraxial anaesthesia using the local anticoagulation protocol.
  4. 4Document the agent, dose, timing, duration, mechanical-device plan and responsible prescriber.
02Postoperative reviewRebalance after clinical changeBleeding, renal deterioration, delayed mobilisation or further surgery changes the original plan.+
  1. 1Assess haemodynamics, wound, haemoglobin, platelets, renal clearance and the time of every antithrombotic dose.

Medicines and treatment safety

Provides LMWH thromboprophylaxis for major lower-limb surgery and fragility-fracture pathways when bleeding risk is acceptable.

Enoxaparin surgical prophylaxis

For a high-risk adult, give 4,000 IU anti-Xa activity, equivalent to 40 mg, by subcutaneous injection once daily; align the first dose and total duration with the NICE procedure pathway and neuraxial plan.

Adjust or avoid according to creatinine clearance, weight and product guidance; check bleeding, platelets and concomitant antithrombotics and observe mandatory neuraxial timing intervals.

Offers a NICE-listed oral prophylaxis option in the specified elective knee or sequential hip replacement pathways.

Aspirin after elective joint replacement

After elective knee replacement use 75 mg or 150 mg orally once daily for 14 days; after elective hip replacement, NICE permits the same daily dose for 28 days after 10 days of LMWH.

Do not generalise it to hip fracture or every immobilised limb; assess active bleeding, ulcer disease, aspirin-sensitive asthma, allergy and interacting antiplatelet or anticoagulant therapy.

Provides a licensed NICE-supported oral option for VTE prevention after elective hip or knee replacement.

Rivaroxaban after elective hip or knee replacement

Give 10 mg orally once daily, starting 6 to 10 hours after surgery once haemostasis is established; continue for 5 weeks after major hip surgery or 2 weeks after major knee surgery.

Targets, monitoring and follow-up

  • Review wound bleeding, bruising, haemoglobin trend and haemodynamics after surgery and after any unplanned procedure.
  • Recalculate renal function when acute illness, dehydration or kidney injury could cause anticoagulant accumulation.
  • Inspect skin under stockings or compression devices daily and reassess distal warmth, colour, sensation and capillary refill.
  • Track each administered and omitted dose, including the reason and the senior decision about restart.
  • Reassess mobility relative to baseline because this influences mechanical endpoints and some ongoing-risk decisions.
  • At discharge, verify supply, administration ability, stop date and understanding of bleeding and thrombotic warning features.

Special situations

Prophylaxis does not exclude VTE

No preventive regimen is completely effective, so new hypoxia or unilateral swelling still requires objective assessment.

Aspirin is pathway specific

Its NICE role after elective replacement cannot be copied automatically to fragility fractures or other immobilised limbs.

Renal change alters exposure

A dose appropriate before surgery may accumulate after dehydration or acute kidney injury and needs active review.

Neuraxial timing is procedural safety

Insertion and removal of spinal or epidural devices must be coordinated around exact anticoagulant doses, not merely the calendar day.

The discharge dose still matters

Extended courses fail when supply, teaching or responsibility is unclear even though the inpatient prescription was correct.

Common pitfalls

  1. 01

    Using one prophylaxis regimen for every form of lower-limb surgery or immobilisation.

  2. 02

    Calling a patient mobile after one transfer without comparing function with their normal or anticipated mobility.

  3. 03

    Prescribing LMWH without reviewing renal function, weight, platelets or the neuraxial plan.

  4. 04

    Assuming aspirin alone is appropriate after a hip fragility fracture because it is an option after elective knee replacement.

  5. 05

    Leaving the discharge stop date as an unspecified community decision.

  6. 06

    Treating suspected PE with an extra prophylactic dose instead of activating the acute diagnostic pathway.

  • Active major bleeding, expanding wound haematoma, haemodynamic decline or a substantial haemoglobin fall requires urgent review and temporary antithrombotic decisions by the responsible team.
  • New back pain, weakness, numbness or sphincter dysfunction after neuraxial anaesthesia while anticoagulated raises concern for spinal haematoma and needs emergency anaesthetic and spinal assessment.
  • A platelet fall with new thrombosis after heparin exposure may represent heparin-induced thrombocytopenia; stop all heparin products and obtain urgent specialist advice.
  • Failure to prescribe or administer post-discharge prophylaxis for the intended duration creates a preventable gap when thrombotic risk remains elevated.
    • Choose imaging around haemodynamic stability, contrast risk and pregnancy; a negative study must still be reconciled with the clinical picture.
  • 05
    Platelet trend for suspected heparin-induced thrombocytopenia
    Why
    Recognise a clinically important platelet fall or new thrombosis temporally related to heparin exposure.
    Interpretation and limitations
    Use a validated pretest score and specialist testing; stop heparin immediately when probability warrants rather than awaiting laboratory confirmation.
    • 2
    Pause, change or restart pharmacological prophylaxis through senior surgical and anaesthetic review rather than informal omission.
  • 3Use safe mechanical prevention while anticoagulation is contraindicated and inspect skin and perfusion regularly.
  • 4Reassess daily until the intended regimen and mobility endpoint are again explicit.
    • 03DischargeComplete the intended courseThe patient leaves hospital before prophylaxis is due to finish.+
    1. 1Reconcile the inpatient doses and calculate the exact remaining number and stop date.
    2. 2Supply the full course or confirm community provision and demonstrate injection technique when relevant.
    3. 3Explain bleeding, DVT and PE warning symptoms and what to do after a missed dose.
    4. 4Send the regimen, indication, last dose and stop date to the GP, community team and patient.
    04Suspected eventMove from prevention to acute careNew leg, respiratory or haemodynamic features suggest VTE or major bleeding.+
    1. 1Use ABCDE and obtain immediate senior support for instability, significant bleeding or possible pulmonary embolism.
    2. 2Identify prophylaxis and antithrombotic doses but do not assume they exclude thrombosis.
    3. 3Follow the diagnostic pathway and start therapeutic anticoagulation only when the acute risk-benefit decision supports it.
    4. 4EscalationCoordinate reversal, surgery or escalation with haematology, anaesthesia and the operating team when bleeding or neuraxial complications are possible.

    Review renal and hepatic function, active bleeding, interacting medicines and neuraxial timing; this prophylactic dose is not the acute DVT or PE treatment regimen.