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VTE prophylaxis during lower-limb immobilisation after tibial plateau fracture — MSRA MCQ

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HardKnee InjuriesVTE prophylaxis during lower-limb immobilisation after tibial plateau fractureMSRA

A 72-year-old woman is reviewed on the day of discharge from an urgent treatment centre after a non-operatively managed lateral tibial plateau fracture sustained in a fall. She has been fitted with a hinged knee brace and instructed not to weight-bear for 6 weeks. She normally mobilises independently. She has metastatic breast cancer receiving systemic treatment and had a proximal DVT 4 years ago during previous chemotherapy. She has no active bleeding, thrombocytopenia, recent haemorrhagic stroke, peptic ulcer disease or planned surgery. Her Cockcroft–Gault creatinine clearance is 26 mL/min. She is not taking an anticoagulant. What is the most appropriate venous thromboembolism prophylaxis plan?

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Correct answer: D — Prescribe enoxaparin 20 mg subcutaneously once daily, with reassessment as mobility returns and consideration of stopping if immobilisation continues beyond 42 days

Explanation lettering: C = shown as A · A = shown as C · E = shown as D · D = shown as E

This patient has lower-limb immobilisation because her brace-management plan prevents normal weight-bearing. Her VTE risk is substantially increased by non-weight-bearing immobilisation, active metastatic cancer and previous DVT; there are no stated major bleeding contraindications. NICE therefore advises considering pharmacological prophylaxis with LMWH or fondaparinux when VTE risk outweighs bleeding risk, and considering stopping if immobilisation extends beyond 42 days. Enoxaparin is appropriate, but her creatinine clearance of 26 mL/min requires dose reduction. The enoxaparin SmPC specifies 20 mg subcutaneously once daily for VTE prophylaxis when creatinine clearance is 15–30 mL/min. A is insufficient because general measures do not address her markedly elevated thrombotic risk. B is plausible because NICE includes fondaparinux as an option, but the proposed standard 2.5 mg dose does not account for renal impairment; product-specific prescribing restrictions and doses must be checked. C is the usual prophylactic enoxaparin dose but risks accumulation and bleeding in severe renal impairment. D is attractive because oral anticoagulants are used for some orthopaedic indications, but apixaban is not the NICE-recommended pharmacological option for lower-limb immobilisation after injury.

Reference: NICE NG89: Venous thromboembolism in over 16s: reducing the risk of hospital-acquired deep vein thrombosis or pulmonary embolism — Lower limb immobilisation (2018; updated 2019) — https://www.nice.org.uk/guidance/ng89/chapter/Recommendations NICE NG89: Recommendations — Definitions (2018; updated 2019) — https://www.nice.org.uk/guidance/ng89/chapter/recommendations Clexane Multidose Vial Summary of Product Characteristics — Renal impairment (2022) — https://www.medicines.org.uk/emc/product/4498/smpc