Distal Radius Fractures

Distal radius fractures are the commonest fractures of the upper limb and among the most frequently encountered fractures in any casualty. They have a classic bimodal age distribution — low-energy fragility fractures in elderly osteoporotic women and high-energy injuries in young adults. The eponyms (Colles, Smith, Barton, chauffeur, Hutchinson) are a perennial favourite in NEET PG, and you must be able to instantly map each name to its mechanism, displacement, and deformity.

Definition & relevant anatomy

A distal radius fracture is any fracture occurring within the metaphyseal region of the distal radius, conventionally defined as the zone within 3 cm proximal to the radiocarpal joint. The distal radius bears roughly 80% of the axial load transmitted across the wrist (the ulna bears ~20%), which is why it fails first on a fall.

Three radiological parameters must be on your fingertips because both reduction adequacy and exam questions hinge on them.

Parameter	Normal value	What it measures
Radial inclination (radial angle)	22°–23° (≈ 20–25°)	Slope of the radial articular surface in the AP/coronal plane
Volar (palmar) tilt	11°–12° (≈ 10–12°)	Tilt of the articular surface in the lateral/sagittal plane (faces volarly)
Radial height (length)	11–12 mm	Distance from radial styloid tip to ulnar articular surface of distal radius

High-yield: Radial inclination ≈ 22°, volar tilt ≈ 11°, radial height ≈ 11–12 mm. The styloid of the radius normally projects ~12 mm distal to the ulnar styloid. Loss of these is the radiological hallmark of a displaced Colles fracture.

Classification — the eponyms (most tested)

This is the single most important section for the exam. Learn the mechanism → deformity link, not just the names.

Fracture	Direction of displacement	Mechanism	Clinical deformity
Colles	Dorsal (posterior) displacement + dorsal angulation	Fall on out-stretched hand (FOOSH), wrist extended	Dinner-fork / bayonet deformity
Smith (reverse Colles)	Volar (anterior/palmar) displacement + volar angulation	Fall on flexed wrist / back of hand	Garden-spade deformity
Barton	Intra-articular fracture-dislocation of dorsal or volar rim, carpus subluxes with fragment	High-energy shearing	Unstable; volar Barton commoner
Chauffeur (Hutchinson)	Intra-articular fracture of the radial styloid	Direct radial-side impact / crank-handle recoil	Often associated with scapholunate injury

High-yield: Colles = dorsal; Smith = volar. The fastest way to remember: "CoLLes" has the L's standing up like a fork raised — dinner-fork deformity, dorsal angulation. Smith goes the other way (volar/garden-spade).

High-yield: Volar Barton is the most common Barton variant and is inherently unstable because the carpus follows the displaced volar fragment — it almost always needs a volar buttress (locking) plate, never a cast alone.

Mnemonic for the eponyms: "Colles Drops a Dinner fork Dorsally; Smith Shoves it Straight to the palm."

Abraham Colles (1814)

The original Colles description was an extra-articular fracture about 2.5 cm (1 inch) proximal to the wrist in the elderly. Six classic components of displacement are examined frequently:

1. Dorsal displacement of the distal fragment →
2. Dorsal angulation (loss/reversal of volar tilt) →
3. Radial displacement →
4. Radial angulation (loss of radial inclination) →
5. Impaction / shortening (loss of radial height) →
6. Supination of the distal fragment.

High-yield: A fracture in a child at the same site that mimics a Colles is usually a greenstick or buckle (torus) fracture, or a Salter-Harris type II physeal injury — not a true Colles. NEET PG loves this distractor.

Etiology & pathophysiology

• Elderly (low energy): trivial fall on outstretched hand; osteoporosis is the dominant risk factor. A distal radius fracture is often the sentinel/index fragility fracture that should trigger a DEXA scan and osteoporosis workup — it precedes hip and vertebral fractures.
• Young adults (high energy): road-traffic accidents, sports, falls from height; usually comminuted and intra-articular with greater soft-tissue and median-nerve involvement.
• Force vector: axial load through a hyperextended (Colles) or flexed (Smith) wrist, with the radius failing in tension dorsally/volarly and compression on the opposite cortex.

Clinical features

• Pain, swelling, and tenderness around the wrist after a fall.
• Dinner-fork deformity (lateral profile: dorsal prominence proximal, volar dip) in displaced Colles; garden-spade in Smith.
• Restricted, painful wrist and forearm rotation.
• Always document distal neurovascular status — specifically the median nerve (test sensation over the volar tip of the index finger / radial 3½ digits and thumb abduction).

High-yield: Acute carpal tunnel syndrome (median nerve compression) is the most important early complication to look for — paraesthesiae in the thumb, index, middle, and radial half of the ring finger. Increasing pain and median paraesthesia after reduction is an indication for urgent carpal tunnel release.

Diagnosis & investigation of choice

• Investigation of choice: Plain radiograph — PA and lateral views of the wrist (with the elbow at 90°). This confirms the diagnosis and lets you measure inclination, tilt, and height.
• Oblique views help delineate intra-articular extension and styloid fractures.
• CT scan is the investigation of choice to characterise intra-articular comminution and step-off and to plan fixation in complex/young patients.
• MRI is reserved for suspected associated soft-tissue injury — TFCC (triangular fibrocartilage complex) tears, scapholunate ligament rupture, or occult fracture.

Stepwise diagnostic approach: History (mechanism: extended vs flexed wrist) → inspect for dinner-fork/garden-spade deformity → examine median nerve & vascularity → PA + lateral X-ray → measure inclination/tilt/height & look for intra-articular step → CT if intra-articular comminution suspected.

High-yield: On the X-ray, a key marker of an unstable fracture is dorsal comminution, intra-articular involvement, initial dorsal angulation > 20°, radial shortening > 5 mm, or an associated ulnar styloid fracture. These predict failure of conservative treatment.

Management & implant of choice

Treatment depends on stability, articular congruity, and patient profile.

Non-operative (closed reduction + immobilisation)

• Indicated for stable, extra-articular, minimally/non-displaced fractures and many elderly low-demand patients.
• Closed reduction under haematoma block / regional anaesthesia, then a below-elbow cast.
• The reduction manoeuvre for a Colles: traction → disimpaction → palmar flexion + ulnar deviation + pronation of the distal fragment, then immobilise in slight flexion and ulnar deviation (the Cotton-Loder position).

High-yield: The Cotton-Loder position (extreme palmar flexion + ulnar deviation) holds the reduction but, if used in full extreme, predisposes to median nerve compression and finger stiffness — so only slight flexion is now recommended. This is a classic two-edged exam point.

Operative

Pattern	Preferred fixation
Stable extra-articular	Cast (closed reduction)
Unstable extra-articular / metaphyseal	Percutaneous K-wires ± cast, or external fixator
Displaced intra-articular / comminuted (young, high-demand)	Open reduction & internal fixation with a volar locking plate (current gold standard)
Volar Barton	Volar buttress plate
Highly comminuted, ligamentotaxis needed	External fixator (spanning) ± bone grafting

High-yield: The volar locking compression plate (volar LCP) is the implant of choice for most displaced and intra-articular distal radius fractures today, allowing early mobilisation and reliable maintenance of volar tilt.

Acceptable reduction criteria (when to accept a closed result):

• Radial shortening < 5 mm
• Dorsal tilt < 5–10° (some accept up to neutral; dorsal angulation should not exceed ~10°)
• Intra-articular step-off < 2 mm
• Radial inclination loss < 5°

If these cannot be achieved or maintained, operate.

Complications

Divide them into early and late — examiners love this split.

Early	Late
Acute median nerve compression (carpal tunnel)	Malunion (commonest late complication) → dinner-fork residual, dorsal tilt
Compartment syndrome (rare)	Sudeck's osteodystrophy / Complex Regional Pain Syndrome (CRPS Type I)
Loss of reduction / re-displacement in cast	Extensor pollicis longus (EPL) rupture
Vascular injury	Stiffness, shoulder-hand syndrome, secondary OA, mal/nonunion

High-yield: EPL (extensor pollicis longus) rupture typically occurs weeks after a minimally displaced/undisplaced Colles treated conservatively, due to attritional ischaemia of the tendon at Lister's tubercle (not at the fracture displacement site). Treatment is extensor indicis proprius (EIP) tendon transfer, not direct repair. This is one of the most repeated single-best-answer facts in this topic.

High-yield: Sudeck's osteodystrophy (now CRPS type I / reflex sympathetic dystrophy) presents with disproportionate pain, swelling, vasomotor instability, stiffness, and patchy ("spotty") osteopenia on X-ray. Management is aggressive physiotherapy, analgesia, vitamin C prophylaxis, and sometimes sympathetic blocks.

High-yield: Malunion is the most common late complication overall, leading to cosmetic deformity, weak grip, reduced rotation, and mid-carpal/ulnar-sided wrist pain (positive ulnar variance → ulnar impaction).

Key differentials

• Scaphoid fracture — tenderness in the anatomical snuffbox, FOOSH mechanism, normal initial X-ray possible; missing it risks avascular necrosis. Always palpate the snuffbox in any "wrist sprain".
• Galeazzi fracture — fracture of the distal radial shaft with distal radioulnar joint (DRUJ) dislocation ("fracture of necessity," needs ORIF). Distinguish from a true distal radius metaphyseal fracture.
• Monteggia — proximal ulna fracture + radial head dislocation (the reverse "GR-MU" rule).
• Carpal dislocations — perilunate / lunate dislocation (look for the "spilled teacup" / "piece of pie" sign on X-ray).
• Wrist sprain / TFCC tear — ulnar-sided wrist pain with normal bony architecture.

Mnemonic — GRIMUS / "GR-MU": Galeazzi = Radius fracture; Monteggia = Ulna fracture. (Each pairs with dislocation of the other bone's joint.)

Recently asked / exam angle

• Eponym ↔ deformity matching is the bread-and-butter MCQ: Colles → dinner-fork/dorsal; Smith → garden-spade/volar; volar Barton → most common Barton, unstable.
• Normal radiological values (radial inclination 22°, volar tilt 11°, radial height 11–12 mm) appear as direct single-fact questions and as "which is lost in Colles?" stems.
• EPL rupture after undisplaced Colles → EIP transfer — very high-frequency single-best-answer.
• Implant of choice = volar locking plate for displaced intra-articular fractures.
• Acute carpal tunnel / median nerve as the immediate complication needing urgent decompression.
• Cotton-Loder position and its risk of median nerve compression / stiffness.
• A distal radius fragility fracture should prompt osteoporosis evaluation (DEXA) — a public-health/orthogeriatrics angle increasingly tested.
• Greenstick/torus and Salter-Harris II as the paediatric equivalents — distractor in "child fell on hand" stems.

Rapid revision

1. Distal radius bears 80% of axial wrist load; fracture site is within 3 cm of the joint.
2. Colles = dorsal displacement, dinner-fork deformity, FOOSH on extended wrist.
3. Smith = volar displacement, garden-spade deformity, fall on flexed wrist (reverse Colles).
4. Volar Barton is the commonest Barton, is unstable, and needs a volar buttress plate.
5. Chauffeur (Hutchinson) fracture = intra-articular radial styloid fracture.
6. Normal values: radial inclination ~22°, volar tilt ~11°, radial height ~12 mm; radial styloid lies ~12 mm distal to ulnar styloid.
7. Investigation of choice = PA + lateral X-ray; CT for intra-articular step/comminution; MRI for TFCC/ligament.
8. Implant of choice for displaced intra-articular = volar locking plate; K-wires/ex-fix for comminuted metaphyseal.
9. Acceptable reduction: shortening <5 mm, articular step <2 mm, dorsal tilt <10°.
10. EPL rupture follows an undisplaced Colles (attrition at Lister's tubercle) → treat with EIP transfer.
11. Malunion is the commonest late complication; CRPS / Sudeck's shows spotty osteopenia.
12. A fragility distal radius fracture is a sentinel event — order a DEXA and treat osteoporosis.