Extra-articular distal radius fracture with dorsal angulation, typically from a fall on an outstretched hand.
Also known as: Colles fracture, distal radius fracture, DRF, broken wrist
Overview
Extra-articular fracture of the distal radius within 2-3 cm of the articular surface, with characteristic dorsal angulation, dorsal displacement, and radial shortening. Often accompanied by an ulnar styloid fracture. Named for Abraham Colles, who described the injury before the advent of radiography.
Epidemiology
Most common fracture of the upper extremity in adults. Bimodal distribution — high-energy injuries in young adults and low-energy fragility fractures in postmenopausal women. A distal radius fracture in a woman over 50 years is a sentinel osteoporotic fracture.
Try two board-style Colles Fracture questions
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Question 1MusculoskeletalEasy
A 68-year-old woman presents to urgent care after slipping on a wet floor and landing on her outstretched right hand. She has immediate, severe right wrist pain and cannot move the wrist. On examination there is swelling and a dorsally prominent "dinner-fork" deformity over the distal forearm, with tenderness over the distal radius. Distal pulses are intact and sensation in the median nerve distribution is normal. Which of the following is the most appropriate next diagnostic test?
AMRI scan of the wrist and forearm
BBedside ultrasound of the wrist
CCT scan of the wrist and forearm
DPlain radiographs of the wrist
Reveal answer & full explanation
Correct answer: D — Plain radiographs of the wrist
AMRI scan of the wrist and forearm
BBedside ultrasound of the wrist
CCT scan of the wrist and forearm
DPlain radiographs of the wrist✓
Why Plain radiographs of the wrist is correct
PA and lateral wrist radiographs are the initial and diagnostic study for a suspected distal radius (Colles) fracture, demonstrating the dorsal angulation, dorsal displacement, and radial shortening.
They allow measurement of the key alignment parameters that guide management: radial height (normal 10-13 mm), radial inclination (normal 21-25 degrees), and volar tilt (normal 10-12 degrees).
The classic dinner-fork deformity after a fall on the outstretched hand in an older woman is a Colles fracture until proven otherwise, and radiographs confirm it quickly and inexpensively.
Why the others are wrong
CT scan of the wrist and forearm is reserved for characterizing intra-articular involvement, comminution, and operative planning after plain films; it is not the first-line study.
MRI scan of the wrist and forearm is useful for occult fractures, such as a suspected scaphoid fracture with normal radiographs, or for ligamentous and soft-tissue injury, not for an obvious displaced distal radius fracture.
Bedside ultrasound of the wrist can detect cortical disruption but is operator-dependent and does not replace radiographs for fracture characterization and alignment measurement.
Question 2MusculoskeletalMedium
A 58-year-old woman returns to clinic 7 weeks after sustaining a minimally displaced distal radius fracture from a fall on her outstretched hand, which was treated nonoperatively in a short-arm cast. The cast was removed 1 week ago, and her pain and swelling had been steadily improving. This morning she suddenly noticed she can no longer lift her thumb away from the plane of her palm and cannot straighten the tip of her thumb. On exam, she is unable to extend the interphalangeal joint of the thumb, and there is tenderness just distal to Lister tubercle. Which of the following complications is most likely responsible for her new deficit?
AComplex regional pain syndrome type I
BAcute median nerve compression neuropathy
CExtensor pollicis longus tendon rupture
DMalunion of the distal radius fracture
Reveal answer & full explanation
Correct answer: C — Extensor pollicis longus tendon rupture
AComplex regional pain syndrome type I
BAcute median nerve compression neuropathy
CExtensor pollicis longus tendon rupture✓
DMalunion of the distal radius fracture
Why Extensor pollicis longus tendon rupture is correct
The EPL tendon hooks around Lister tubercle of the distal radius and is vulnerable to mechanical attrition and ischemic insult after a distal radius fracture, even when the fracture is nondisplaced or minimally displaced.
Delayed EPL rupture classically presents 6-8 weeks after the injury with sudden inability to extend the thumb interphalangeal joint (loss of retropulsion, lifting the thumb off a flat surface), often after the patient had otherwise been recovering well.
Tenderness localized just distal to Lister tubercle plus an abrupt, painless loss of active thumb IP extension at this time point are the hallmark, fitting this vignette.
Why the others are wrong
Acute median nerve compression neuropathy (acute carpal tunnel syndrome) occurs early, often at the time of injury or reduction, with paresthesias and pain across the thumb, index, and middle fingers, not a delayed isolated loss of thumb IP extension weeks later.
Malunion of the distal radius fracture is healing in poor alignment causing persistent deformity, reduced grip strength, and limited range of motion, but it does not cause a sudden isolated inability to extend the thumb IP joint.
Complex regional pain syndrome type I presents with disproportionate burning pain, allodynia, swelling, and vasomotor or sudomotor changes, not a discrete tendon-rupture motor deficit isolated to thumb extension.
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Postmenopausal women with osteoporosis or osteopenia
Fall on outstretched hand (FOOSH) with wrist extended
High-energy trauma in younger patients
Prior fragility fracture, low body weight, chronic steroid use
Pathophysiology
Axial load through a dorsiflexed wrist concentrates force at the metaphyseal-diaphyseal junction of the distal radius. Cortical bone fails in tension volarly and compresses dorsally, producing the characteristic apex-volar (dorsally angulated) fracture pattern.
Clinical presentation
Symptoms
Acute wrist pain after a fall
Visible deformity
Inability to use the wrist or hand
Numbness or tingling in median nerve distribution if neurapraxia
Signs / physical exam
Dinner-fork deformity on lateral view (dorsally displaced distal fragment)
Swelling, ecchymosis, and tenderness over the distal radius
Loss of normal volar tilt of the distal radius
Assess median nerve (thumb opposition, sensation over volar thumb and index finger) and check for compartment syndrome
Classic findings
Dinner-fork deformity in an older woman after a fall on the outstretched hand.
Differential diagnosis
Smith fracture (reverse Colles) — Volar angulation and displacement from fall on flexed wrist or direct dorsal blow; 'garden spade' deformity
Barton fracture — Intra-articular distal radius fracture with carpal subluxation (volar or dorsal)
Chauffeur fracture — Radial styloid fracture; often with scapholunate ligament injury
Scaphoid fracture — Snuffbox tenderness; may coexist with distal radius fracture
Wrist contusion / sprain — Diagnosis of exclusion after radiographs
Diagnostic workup
Diagnostic criteria
Acceptable radiographic alignment in adults: radial shortening <3 mm, dorsal tilt <10 degrees, intra-articular step-off <2 mm, radial inclination within 5 degrees of contralateral side. Failure to meet these parameters after reduction is an indication for operative fixation.
CT for intra-articular involvement, comminution, and operative planning
DEXA scan in patients over 50 with a fragility fracture — initial DRF often triggers osteoporosis workup
Diagnostic algorithm
Fracture
Mechanism
Deformity
Stability
Colles
FOOSH with wrist extended
Dorsal angulation / dinner fork
Often treatable closed
Smith (reverse Colles)
Fall on flexed wrist or dorsal blow
Volar angulation / garden spade
Unstable — usually operative
Barton
Shear force across articular surface
Carpal subluxation with rim fragment
Unstable — operative
Chauffeur
Direct radial blow (historic crank-start injury)
Radial styloid fragment
Often operative if displaced
Common distal radius fracture eponyms and their distinguishing features.
Treatment
First-line
Closed reduction under hematoma block, conscious sedation, or Bier block
Sugar-tong splint initially, transitioning to a short-arm cast at 1-2 weeks
Total immobilization 4-6 weeks with serial radiographs at weeks 1, 2, and 6 to monitor for loss of reduction
Calcium, vitamin D, and osteoporosis workup in adults over 50
Second-line / adjunct
Operative fixation indicated for: failure to achieve or maintain acceptable alignment, intra-articular displacement >2 mm, open fracture, neurovascular compromise, or bilateral injuries
Volar locking plate fixation is the most common surgical option
External fixation, percutaneous pinning, or intramedullary nail in select cases
Hand therapy for stiffness after immobilization or surgery
Complications
Malunion with persistent deformity and reduced grip strength
Median nerve injury — acute carpal tunnel syndrome may require urgent release
Extensor pollicis longus tendon rupture (classically 6-8 weeks post-injury from mechanical or ischemic insult at Lister tubercle)
Post-traumatic osteoarthritis of the radiocarpal joint
Complex regional pain syndrome
Compartment syndrome
PANCE pearls
A distal radius fracture in a woman over 50 is an osteoporotic fragility fracture — order DEXA and initiate treatment.
Delayed extensor pollicis longus rupture presents 6-8 weeks after a nondisplaced or minimally displaced fracture — patient suddenly cannot extend the thumb interphalangeal joint.
Smith and Barton fractures are unstable and almost always require operative fixation.
References
AAOS 2020 — American Academy of Orthopaedic Surgeons clinical practice guideline on the management of distal radius fractures
NOF — Bone Health and Osteoporosis Foundation (formerly NOF) Clinician's Guide to Prevention and Treatment of Osteoporosis
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