Postoperative Care — Investigating Late Postoperative Fever
A 68-year-old woman is on postoperative day 7 after dynamic hip screw fixation of a right intertrochanteric fracture. Her temperature is 38.1 °C. The incision is dry and clean, the chest is clear and oxygen saturation is 97% on room air. Her urinary catheter was removed on day 2 and urinalysis is normal. The left calf is 3 cm larger than the right. Which investigation is most appropriate next?
- A.Swab of the surgical wound for culture
- B.Compression duplex ultrasound of the left legCorrect
- C.Two sets of peripheral blood cultures
- D.Computed tomography pulmonary angiography
Explanation
Fever beyond the first few postoperative days needs a source-directed search, and by the end of the first week the usual causes are wound infection, urinary infection, intravenous line infection and venous thromboembolism. Here the wound, chest and urine are unremarkable, while the contralateral calf is clearly swollen after hip fracture surgery, one of the highest-risk settings for deep vein thrombosis. Deep vein thrombosis commonly produces low-grade fever, and compression duplex ultrasound is the first-line, non-invasive test to confirm it before full-dose anticoagulation. Blood cultures are reasonable when fever is high or the patient looks septic, but they will not identify the likely source in a stable patient with a localising leg sign. A wound swab from a clean, dry incision only grows skin colonisers and should not drive treatment. Pulmonary angiography is reserved for suspected pulmonary embolism, which needs symptoms such as dyspnoea, pleuritic pain, tachycardia or hypoxaemia. A calf circumference at least 3 cm greater than the other side scores a point on the Wells criteria. Thromboprophylaxis reduces but does not abolish the risk, so a patient receiving low-molecular-weight heparin can still develop a clot.
Why each option
- A.
- A clean, dry incision gives no indication for culture, and a swab would only grow skin flora of no clinical significance.
- B.
- Correct. A unilaterally swollen calf after hip fracture surgery suggests deep vein thrombosis, and compression duplex ultrasound is the first-line confirmatory test.
- C.
- Blood cultures suit a septic or high-fever picture but do not address the localising leg finding in this stable patient.
- D.
- Pulmonary angiography is for suspected embolism, and she has no dyspnoea, chest pain, tachycardia or hypoxaemia to justify contrast and radiation.
Reference: NICE NG89 Venous thromboembolism in over 16s 2018 (updated 2019); NICE NG158 Venous thromboembolic diseases 2020 (updated 2023); UpToDate — Fever in the surgical patient
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