Common Fractures & Orthopedic Injuries
A high-yield Step 2 CK review of common fractures and orthopedic injuries — classic eponyms, fracture-associated nerve/vessel injuries, and the "next best step" for board emergencies including occult scaphoid fracture, compartment syndrome, open fracture, and fat embolism.
Approach: pattern + next best step
Fractures are tested as pattern recognition plus the correct next step. For any injury, work a disciplined sequence: (1) mechanism (FOOSH, high-energy, punch, seizure/electrocution), (2) focused exam with a documented neurovascular check distal to the injury, (3) imaging (plain films in two views; CT for complex/intra-articular; MRI for occult fractures), then (4) management.
Describe every fracture by location, pattern (transverse, oblique, spiral, comminuted, greenstick), displacement/angulation, and open vs closed (skin breach). Open fractures and neurovascular compromise are emergencies.
General principles: reduce, immobilize, analgesia, then definitive fixation. Most isolated, minimally displaced fractures are splinted; displaced, intra-articular, or unstable patterns need ORIF. On boards, always ask three questions that drive the highest-yield answers: Is it open? Is there compartment syndrome? Is a named nerve or vessel at risk?
- Colles — distal radius, dorsal angulation, "dinner-fork" deformity; FOOSH in an osteoporotic elderly woman
- Smith — distal radius, volar angulation ("reverse Colles"); fall onto a flexed wrist
- Scaphoid — FOOSH + anatomic snuffbox tenderness; initial film often normal → AVN/nonunion risk
- Boxer's — 5th metacarpal neck, punching a hard surface; check for malrotation
- Clavicle — middle third most common; sling, heals nonoperatively
- Jones — metaphyseal–diaphyseal junction of the 5th metatarsal; watershed blood supply → nonunion. Distinguish from the proximal tuberosity avulsion (pseudo-Jones), which heals well
- Femoral neck — shortened, externally rotated leg; intracapsular → AVN of femoral head (contrast extracapsular intertrochanteric, which rarely causes AVN)
- Stress fracture — overuse, X-ray normal early → MRI; think female athlete triad
- Salter-Harris — any pediatric fracture through the growth plate (physis)
Named fractures — mechanism, hallmark, complication, management
| Fracture | Mechanism / buzzword | Hallmark | Key complication | Management |
|---|---|---|---|---|
| Colles | FOOSH, elderly | Dorsal angulation, dinner-fork | Acute median nerve, malunion | Closed reduction + splint; ORIF if unstable |
| Smith | Fall on flexed wrist | Volar angulation | Median nerve | Reduction; often ORIF (unstable) |
| Scaphoid | FOOSH, snuffbox tender | Occult on early film | AVN (proximal pole), nonunion | Thumb-spica even if X-ray negative; repeat film/MRI |
| Boxer's | Punch | 5th MC neck, malrotation | Malunion, "fight-bite" infection | Reduction, ulnar-gutter splint |
| Femoral neck | Elderly fall | Short, ext. rotated leg | AVN, nonunion | Young/nondisplaced: urgent internal fixation; elderly displaced: arthroplasty |
| Jones | 5th MT overuse/inversion | Meta-diaphyseal junction (not tuberosity) | Nonunion | Non-weight-bearing cast; ORIF in athletes |
Vignette: A 22-year-old falls onto an outstretched hand. He has tenderness in the anatomic snuffbox and pain on axial loading of the thumb. Wrist radiographs are read as normal.
Diagnosis: Clinically suspected (occult) scaphoid fracture — up to ~20–30% are radiographically invisible in the first days.
Next best step: Immobilize in a thumb-spica splint and treat as a fracture, then repeat radiographs in 10–14 days or obtain MRI for early definitive diagnosis. Do not discharge as a "sprain."
Why it matters: The scaphoid's blood supply enters distally and runs retrograde, so proximal-pole fractures risk avascular necrosis and nonunion. A missed scaphoid fracture is a classic board (and malpractice) trap.
Vignette: Six hours after a tibial shaft fracture, a patient has pain out of proportion to exam and severe pain on passive stretch of the toes. The compartment feels tense; distal pulses are present.
Diagnosis: Acute compartment syndrome. Pain on passive stretch is the earliest, most sensitive sign; pulselessness and pallor are late. A normal pulse does not exclude it.
Next best step: Remove/bivalve any cast or tight dressing, keep the limb at heart level (do not elevate), and get emergent surgery for fasciotomy. Diagnosis is clinical; if measured, delta pressure (diastolic − compartment) <30 mmHg (or absolute pressure >30 mmHg) supports it.
Pitfall: Waiting for the full "6 Ps" or for pulses to vanish delays fasciotomy → irreversible muscle necrosis and Volkmann contracture.
- Open fracture → emergency: early IV antibiotics (cefazolin; add an aminoglycoside for grossly contaminated/Gustilo III, add penicillin for farm/fecal soiling), tetanus prophylaxis, urgent irrigation & debridement
- Compartment syndrome → pain on passive stretch; fasciotomy — do not wait for pulselessness
- Fat embolism syndrome → long-bone/femur fracture, 24–72 h later: hypoxemia, confusion, petechiae (axilla/conjunctiva); supportive care, early fixation prevents it
- Avascular necrosis → scaphoid (proximal pole), femoral neck, talus (retrograde/tenuous supply)
- Femoral shaft → high-energy, can lose 1–1.5 L of blood; look for associated injuries
- VTE → hip/pelvic/lower-limb fractures need DVT prophylaxis
- Nonunion → scaphoid, Jones (5th MT), tibia — poorly vascularized "watershed" sites
Fracture site → nerve/vessel at risk
| Injury site | Structure at risk | Deficit |
|---|---|---|
| Surgical neck of humerus / anterior shoulder dislocation | Axillary n. | Deltoid weakness, "regimental-badge" numbness |
| Midshaft humerus (spiral groove) | Radial n. | Wrist drop, dorsal hand numbness |
| Supracondylar humerus (child) | Median n. / AIN, brachial a. | Can't make "OK" sign; pink pulseless hand |
| Medial epicondyle | Ulnar n. | Clawing, weak grip, medial hand numbness |
| Posterior hip dislocation | Sciatic n. | Foot drop, posterior leg numbness |
| Fibular neck | Common peroneal n. | Foot drop, dorsal foot numbness |
| Knee dislocation | Popliteal a. | Limb ischemia — check ABI/CT angiography |
SALTR — Salter-Harris physeal (growth-plate) fractures, types I–V:
- S = I: Slipped — through the physis only (may look normal on X-ray)
- A = II: Above — physis + metaphysis (most common)
- L = III: Lower — physis + epiphysis (intra-articular)
- T = IV: Through — metaphysis + physis + epiphysis
- R = V: Ruptured / cRush — compression of the physis (worst prognosis)
Higher type → higher risk of growth arrest; type V is often recognized only in retrospect.
Forearm fracture-dislocations — "MUGR":
- Monteggia = proximal Ulna fracture + radial head dislocation
- Galeazzi = distal Radius fracture + distal radioulnar joint (DRUJ) dislocation
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