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Suspected septic arthritis of a prosthetic hip — MSRA MCQ

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ModerateHip and GroinSuspected septic arthritis of a prosthetic hipMSRA

A 69-year-old man presents with a 16-hour history of rapidly worsening left groin pain. He had a left total hip replacement 4 years ago and had been pain-free and independently mobile until yesterday. He now cannot weight-bear and feels feverish. He takes adalimumab and prednisolone 5 mg daily for rheumatoid arthritis. His temperature is 38.1°C, pulse 106 beats/min and blood pressure 132/74 mmHg. The hip is held flexed and any passive movement causes severe pain. The surgical scar is intact, with no discharge or erythema. There has been no fall. What is the most appropriate immediate management in primary care?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: C — Arrange emergency hospital assessment and discuss urgently with the on-call orthopaedic team

Explanation lettering: C = shown as A · A = shown as B · B = shown as C

This presentation requires emergency assessment for suspected septic arthritis/prosthetic joint infection. The decisive features are abrupt onset of severe pain in a previously well-functioning prosthetic hip, inability to weight-bear, fever, marked pain on passive movement and immunosuppression. A normal-looking scar does not exclude a deep prosthetic joint infection. This is time-critical because urgent orthopaedic assessment, joint aspiration and possible operative drainage are required; antimicrobial treatment should not delay appropriate sampling or source control unless the patient is clinically septic. A is inappropriate because oral antibiotics in primary care may delay definitive assessment and reduce microbiological yield. C is plausible because inflammatory markers and radiography may contribute to hospital assessment, but they must not delay emergency referral in suspected septic arthritis. D would be appropriate for gradual mechanical symptoms without acute systemic features; aseptic loosening typically does not produce fever and abrupt severe pain. E is a potential differential for acute monoarthritis, but the prosthetic hip, systemic features and severe movement-related pain require septic arthritis to be excluded urgently rather than a therapeutic trial.

Reference: Rheumatology and bone disease | Borders Ref Help Toolkit (Crawled May 2026) — https://www.rightdecisions.scot.nhs.uk/borders-ref-help-toolkit/rheumatology-and-bone-disease/rheumatology-and-bone-disease/ Septic Arthritis/Osteomyelitis | NHS Grampian, Orkney and Shetland antimicrobial prescribing guidance (Crawled May 2026) — https://www.rightdecisions.scot.nhs.uk/antimicrobial-prescribing-nhs-grampian-orkney-shetland/hospital-guidance-for-adults/musculoskeletal-joint/septic-arthritisosteomyelitis/