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Traumatic knee lipohaemarthrosis suggesting occult intra-articular fracture — MSRA MCQ

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ModerateKnee InjuriesTraumatic knee lipohaemarthrosis suggesting occult intra-articular fractureMSRA

A 46-year-old man attends a GP-led urgent treatment centre 2 hours after falling directly onto his flexed right knee while carrying a heavy box downstairs. He has immediate pain, a large effusion and cannot comfortably weight-bear. He can perform a straight-leg raise. There is no deformity, no focal patellar tenderness, no ligamentous laxity and no neurovascular deficit. Anteroposterior and lateral knee radiographs show no definite fracture. However, the horizontal-beam lateral view shows a fat-fluid level in the suprapatellar pouch, reported as lipohaemarthrosis. What is the most appropriate management today?

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

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Correct answer: D — Make the patient non-weight-bearing, apply a temporary knee splint as needed and arrange urgent trauma service assessment

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

Lipohaemarthrosis after knee trauma is a fat-fluid level caused by marrow fat entering the joint, and is a highly specific radiographic marker of an intra-articular fracture. A fracture may be occult on initial plain radiographs. This patient therefore requires management as a possible intra-articular knee fracture: non-weight-bearing, temporary splintage if required for pain or instability, and urgent trauma/orthopaedic assessment for further investigation and definitive planning. A is appropriate for a stable soft-tissue knee injury without features suggesting fracture. B may temporarily relieve a tense haemarthrosis but does not address the likely occult intra-articular fracture and is not the priority in a neurovascularly intact patient. D recognises that further imaging may be needed, but allowing partial weight-bearing before fracture assessment is inappropriate. E underestimates the urgency and does not protect the knee adequately while an occult articular fracture is being evaluated.

Reference: ED/MIU Adult (>16 yrs): Orthopaedic referral pathway (2025) — https://rightdecisions.scot.nhs.uk/media/t1uki5fm/orthopaedic-referral-pathway.pdf Lipohaemarthrosis in knee trauma: an experience of 907 cases (1994) — https://pubmed.ncbi.nlm.nih.gov/8034349/