Musculoskeletal & Integumentary · Topic 2 of 11

Fractures, Dislocations & Fat Embolism

Musculoskeletal · orthopedic trauma

Fractures, Dislocations & Fat Embolism

Check the limb's nerves and pulses, give open fractures antibiotics within the hour, and fix older adults' hip fractures within 24–48 hours.

Key numbers

Open fracture: IV antibiotics within 60 minutesAntibiotics ≤ 60 min

Hip fracture: surgery within 24–48 hoursSurgery ≤ 24–48 h

Fat embolism: hypoxemia, confusion and petechiae24–48 h after injury

Reduce a hip dislocation within 6 hoursReduce ≤ 6 h

01 · DoHip fracture: surgery within 24–48 hours

Operate on hip fractures in older adults within 24–48 hours of admission (AAOS 2021, strong); early surgery and mobilization avoid the DVT, pressure injury, pneumonia, deconditioning and death that prolonged bed rest brings.

02 · DoOpen fracture: IV antibiotics within 60 minutes

Treat any fracture with a nearby wound as open: sterile dressing, tetanus prophylaxis, IV antibiotics within 60 minutes of arrival, and urgent operative irrigation and debridement.

03 · Watch forFat embolism: hypoxemia, confusion and petechiae

Fat embolism syndrome follows long-bone (especially femoral) or pelvic fractures, usually within 24–48 hours: respiratory distress and hypoxemia, then confusion or coma and a petechial rash on the upper body and axillae.

Presentation

What you'll see

Pain out of proportion suggests compartment syndromePain out of proportion to the injury, or pain that steadily worsens over hours, suggests compartment syndrome or ischemia; risk is highest with tibial shaft, tibial plateau and both-bone forearm fractures and crush injuries.

Hip fracture: shortened, externally rotated legHip fracture causes groin pain and inability to walk; a displaced fracture leaves the leg shortened and externally rotated. Pain may be referred to the knee, and an impacted fracture may still allow walking.

Diagnosis & monitoring

Work-up

Gustilo-Anderson grades open fractures I–IIICGustilo-Anderson: I = wound < 1 cm, clean; II = wound > 1 cm, moderate soft-tissue damage; III = extensive damage — IIIA adequate coverage, IIIB inadequate coverage, IIIC arterial injury needing repair.

Gurd: two major, or one major plus four minorGurd and Wilson: 2 major, or 1 major plus 4 minor. Major: respiratory distress, cerebral signs without head injury, petechial rash. Minor: tachycardia > 110, fever > 38.5 °C, retinal changes, jaundice, falling hemoglobin or platelets.

Do right now

In this order

First moves

Check distal pulses, sensation and motor function

→

Open fracture: IV antibiotics within 60 minutesAntibiotics ≤ 60 min

→

Reduce and splint deformed or unstable fractures promptly

→

Hip fracture: surgery within 24–48 hoursSurgery ≤ 24–48 h

Why each step

Check distal pulses, sensation and motor functionExamine every injured limb at once for open wounds, distal neurovascular injury (pulses, perfusion, sensation, motor function) and compartment syndrome, and examine the joints above and below the injury.

Open fracture: IV antibiotics within 60 minutesTreat any fracture with a nearby wound as open: sterile dressing, tetanus prophylaxis, IV antibiotics within 60 minutes of arrival, and urgent operative irrigation and debridement.

Reduce and splint deformed or unstable fractures promptlyReduce and splint grossly unstable or deformed fractures early, especially with skin tenting, to relieve pain and protect soft tissue; splinting long-bone fractures may help prevent fat embolism.

Hip fracture: surgery within 24–48 hoursOperate on hip fractures in older adults within 24–48 hours of admission (AAOS 2021, strong); early surgery and mobilization avoid the DVT, pressure injury, pneumonia, deconditioning and death that prolonged bed rest brings.

Management

Orders

Cefazolin for type I–II; ceftriaxone for type IIIGustilo I–II: cefazolin 2 g IV every 8 hours (3 g if > 120 kg). Type III: add gram-negative coverage — ceftriaxone 2 g IV daily, or cefazolin plus an aminoglycoside.

Negative x-ray, suspected hip fracture: get MRIImage a suspected hip fracture with an AP pelvis and cross-table lateral film; if radiographs are normal but suspicion persists, MRI is the next study — more sensitive than CT for occult fractures.

Fascia iliaca or femoral nerve block for painFor an isolated hip fracture in an older adult, a fascia iliaca compartment or femoral nerve block gives 6–8 hours of analgesia and spares opioids; coagulopathy and bleeding disorders are contraindications.

Displaced femoral neck: arthroplasty; intertrochanteric: ORIFDisplaced femoral neck fractures in older adults get hemiarthroplasty or total hip arthroplasty because the fracture often cuts the femoral head's blood supply (osteonecrosis); intertrochanteric fractures are fixed with ORIF.

VTE prophylaxis, LMWH preferred, 10–14 days minimumAfter hip fracture surgery give pharmacologic thromboprophylaxis — LMWH preferred, UFH an alternative — for at least 10–14 days, up to 35 days; DOACs are approved for elective arthroplasty, not hip fracture.

FES: supportive care; early fixation prevents itTreat fat embolism syndrome supportively — oxygen and ventilation as for ARDS, hemodynamic support. Early long-bone stabilization (within 24 hours) is the best prevention; corticosteroids are not routinely recommended.

Reduce a hip dislocation within 6 hoursMost hip dislocations are posterior (leg shortened, adducted, internally rotated); reduce as soon as possible, preferably within 6 hours, because delay raises osteonecrosis risk. Check the sciatic nerve and get CT after reduction.

Knee dislocation: ABI and CT angiographyKnee dislocation often injures the popliteal artery despite normal pulses: reduce immediately, measure the ankle-brachial index (≤ 0.9 suggests vascular injury), get CT angiography and call vascular surgery; repair within 8 hours.

Hip fracture or posterior hip dislocation?

Commonly confused

Typical injury	Older adult, ground-level fall
Leg position	Shortened and externally rotated
Time target	Surgery within 24–48 hours
Definitive care	ORIF or arthroplasty
Key complication	Femoral head osteonecrosis (displaced neck), VTE

More detail

Reference

Show 7 reference facts

Pulmonary embolism is the most common fatal complication of serious hip and pelvic fractures; pelvic and femoral fractures can also bleed enough to cause hemorrhagic shock.

The peroneal nerve is the nerve most often injured in knee dislocation (foot drop); any sensory or motor deficit needs immediate orthopedic consultation.

Begin interdisciplinary (orthogeriatric) co-management at admission for every hip fracture; it lowers complications and mortality and helps get patients to surgery within 24–48 hours.

A hip fracture from a fall from standing height is a fragility fracture that establishes osteoporosis; start osteoporosis evaluation and treatment rather than waiting for a DXA scan.

Cerebral fat embolism shows a diffusion-weighted MRI 'starfield' pattern of scattered small lesions; it is non-specific and most visible early.

In severely injured, unstable polytrauma patients, damage-control orthopedics (temporary external fixation, definitive fixation later) may be safer than early total care.

Fractures prone to osteonecrosis include displaced femoral neck, scaphoid and displaced talar neck fractures; after hip fracture, nonunion and osteoarthritis are also common.

Pearl

A long-bone fracture, then breathless, confused and petechial a day or two later — that is fat embolism until proven otherwise.

Sources · Merck Manual Professional — Overview of Fractures · Merck Manual Professional — Hip Fractures (reviewed Mar 2025) · AAOS — Updated Clinical Practice Guideline for Management of Hip Fractures in Older Adults (Dec 2021): surgery within 24–48 hours, interdisciplinary care · Ryder Trauma Center (Jackson Health) — Practice Guidelines for Open Fracture (antibiotics within 60 minutes; regimens by Gustilo type; summarizes EAST 2011 and SIS guidelines) · Merck Manual Professional — Hip Dislocations (Feb 2026) · Merck Manual Professional — Knee (Tibiofemoral) Dislocations · Miyake T et al. Advances and uncertainties in fat embolism syndrome: a review. Trauma Surg Acute Care Open 2026;11:e001913 · Timon C et al. Fat Embolism Syndrome — a qualitative review of its incidence, presentation, pathogenesis and management. Malays Orthop J 2021;15:1–11 · Falck-Ytter Y et al. Prevention of VTE in orthopedic surgery patients: ACCP Antithrombotic Therapy guidelines, 9th ed. Chest 2012;141(2 Suppl):e278S–e325S · Merck Manual Professional — Overview of Dislocations · Merck Manual Professional — Osteoporosis · Anderson DR et al. American Society of Hematology 2019 guidelines for management of VTE: prevention of VTE in surgical hospitalized patients. Blood Adv 2019;3:3898–3944 · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).