Pelvic Fracture
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Direct answer
A fractured pelvis is a haemorrhage problem wearing an orthopaedic costume: the ring's cancellous bone and rich venous plexus bleed hundreds of millilitres after high-energy disruption, so the unstable patient with a pelvic fracture is resuscitated with a pelvic binder centred on the greater trochanters closing the open book, blood products, and rapid decisions — external fixation or C-clamp, preperitoneal packing, and angioembolisation for arterial bleeding. Mechanism sorts the patterns: lateral compression (the commonest, from side impacts), anteroposterior compression opening the symphysis like a book, and vertical shear (Malgaigne) unstable in all planes — the Young-Burgess system — while Tile grades stability as A (stable), B (rotationally unstable, vertically stable) and C (unstable in both). Blood at the meatus, a high-riding prostate or perineal bruising in a male mandates a retrograde urethrogram before any catheter attempt.
What you must remember
- Classification pairs: Young-Burgess types by mechanism — lateral compression, anteropostercer compression (open book), vertical shear, combined — and Tile by stability: A stable, B rotationally unstable (open-book or lateral compression injury of the ring), C vertically and rotationally unstable.
- Haemorrhage source order: venous plexus and cancellous bone bleeding account for most blood loss (which is why mechanical closure works), with arterial bleeding (superior gluteal, internal iliac branches) in a minority that needs angioembolisation; the retroperitoneum can conceal litres.
- Resuscitation sequence for the unstable pelvis: pelvic binder at the level of the trochanters, permissive hypotension until control, balanced transfusion, then external fixation or anterior C-clamp, preperitoneal pelvic packing, and angiography when bleeding continues or a blush is seen on CT.
- Urological red flags: blood at the external meatus, perineal or scrotal haematoma, high-riding or impalpable prostate, inability to void — posterior urethral injury until a retrograde urethrogram says otherwise; a bladder rupture accompanies both blunt ring disruption and straddle injuries; do not pass a catheter blindly when these signs exist.
- Associated injuries to hunt: head injury, intra-abdominal solid organ injury (FAST then CT), vaginal laceration making it an open fracture, sciatic and lumbosacral plexus injury, and death from haemorrhage in the vertically unstable elderly.
- Special patterns: straddle fracture (all four pubic rami) with urethral and bladder injury; Malgaigne fracture — vertical shear through the ring (historically through rami plus sacroiliac joint) with limb shortening; open-book with symphyseal diastasis over about 2.5 cm meaning torn sacrotuberous and sacrospinous ligaments.
- Stable injuries: isolated pubic ramus fractures in the elderly after a fall and avulsion injuries are treated conservatively with analgesia and early mobilisation; the exam contrast is always conservative ramus versus operated open-book or vertical shear.
- Fixation hardware: symphyseal plating and sacroiliac screws for definitive stabilization; the binder must be removed within about 24 hours to avoid pressure necrosis once stability is achieved.
A worked trauma pathway
A 30-year-old falls from a height of six metres onto his left side, arriving with a blood pressure of 90/60, a pulse of 120, and pain over the pelvis; compression of the iliac wings reproduces pain and the left leg appears shortened and externally rotated. Reasoning in order: trauma team activation, pelvic binder applied at the trochanters before any log-roll manipulation, two units of blood ordered early under a massive transfusion protocol, FAST negative for intraperitoneal fluid. Because the mechanism is vertical shear and he remains unstable after binder and products, the pathway runs to CT if he stabilises — showing sacroiliac disruption with a contrast blush — followed by angioembolisation of the bleeding internal iliac branch and definitive sacroiliac screw fixation. Blood is noticed at his meatus during catheter preparation, so the retrograde urethrogram precedes catheterisation: a partial posterior urethral injury allows a gentle single attempt, otherwise a suprapubic catheter is placed. Had the same mechanism produced a stable lateral compression injury with normal vitals, the treatment would have been analgesia and mobilisation — the exam's favourite stability-based fork.
How the exam frames it
Three question shapes repeat. First, classification: match the mechanism to the pattern (side impact to lateral compression, head-on to open book, fall from height to vertical shear) and the pattern to stability. Second, the urology trap: catheter first versus retrograde urethrogram first — meatal blood, perineal haematoma or high-riding prostate always earns the urethrogram; passing a catheter through a torn urethra converts partial injury to complete. Third, the resuscitation order: binder, then products, then fixation or packing or embolisation — with the tested fact that most pelvic bleeding is venous, which is why closing the ring, not opening the abdomen, stops it.
Frequently asked questions
How are pelvic fractures classified by stability?
Tile type A are stable, type B rotationally unstable but vertically stable (open-book and lateral compression patterns), and type C unstable in rotation and vertical planes; Young-Burgess classifies by mechanism into lateral compression, anteropostercer compression and vertical shear.
Why is a pelvic binder applied in the unstable patient?
Because most pelvic haemorrhage is venous and from cancellous bone, mechanically closing the open-book deformity reduces pelvic volume and tamponades the bleeding alongside resuscitation.
What is the role of angioembolisation in pelvic fracture?
It treats persistent arterial bleeding — typically from internal iliac branches such as the superior gluteal artery — suspected by continued instability despite binder and fixation or a contrast blush on CT.
What signs suggest urethral injury before catheterisation?
Blood at the external meatus, perineal or scrotal haematoma, a high-riding or impalpable prostate, and inability to void; a retrograde urethrogram is performed before any catheter attempt.
What is a straddle fracture and what does it injure?
Fractures of all four pubic rami from a direct fall onto the perineum, carrying a high association with bladder and urethral injury.