---

Colles' Fracture: Structural Impairment and Clinical Reasoning

1. Definition and Anatomy

• The distal radius normally has a volar (palmar) tilt of 10-15° and an ulnar inclination of 20-25°
• The radial styloid is normally 9-12 mm longer than the ulnar articular surface (negative ulnar variance)
• A Colles' fracture disrupts all three of these radiologic parameters

---

2. Mechanism of Injury

• Axial compressive forces drive the distal fragment dorsally and proximally
• Compression forces on the dorsal cortex create dorsal comminution
• Approximately 90% of wrist falls result in this extension-type fracture pattern
• The remaining 10% produce flexion fractures (Smith's fracture, the "reverse Colles'")
• Predominantly affects postmenopausal women due to osteoporosis (nearly 80% of women over 50 have at least one)

---

3. Structural Impairments

3a. Bony Deformity

3b. Associated Injuries

• Ulnar styloid fracture - present in a large proportion of cases; represents avulsion by the triangular fibrocartilage complex (TFCC) and indicates distal radioulnar joint (DRUJ) disruption. This is a frequent source of long-term morbidity (pain, rotational loss, instability).
• Carpal instability - can occur with significant displacement
• TFCC tear - when ulnar styloid is avulsed at its base
• Triangular fibrocartilage complex injury - disrupts the ulnocarpal disk

3c. Neurovascular Impairments

• Acute contusion or traction at time of injury
• Compression from displaced fragments
• Nerve injury after closed reduction
• Cast or splint pressure
• Secondary acute carpal tunnel syndrome (ACTS)

Clinical pearl: Neurologic function must be assessed both before and after fracture reduction and splint application.

---

4. Classification Systems

Gartland and Werley (1951)

Frykman (1967)

---

5. Clinical Features (Presentation)

• Dinner fork deformity - the classic dorsal bump on lateral wrist profile (from dorsal displacement)
• Pain, swelling, tenderness over the distal radius (within 2-2.5 cm of the wrist)
• Wrist deviated toward the radial side (prominence of the ulnar head medially)
• Restricted wrist and forearm movement
• Palmar paresthesias (median nerve compression in the carpal tunnel)
• Crepitus on palpation/movement

Undisplaced and minimally displaced fractures may show no obvious deformity - the dinner-fork sign is not always present.

---

6. Radiologic Evaluation

PA (Posteroanterior) View

• Assess radial length/shortening - if radius is not equal to or longer than ulna, reduction is indicated
• Evaluate ulnar inclination angle loss
• Identify intra-articular extension into radiocarpal or radioulnar joints
• Detect ulnar styloid fracture
• Measure intraarticular step-off

Lateral View

• Best for assessing dorsal angulation and displacement
• Loss of normal volar tilt (0° or dorsal tilt = abnormal)
• Defines the classic dinner fork profile

CT Scan

---

7. Stability Assessment

• Dorsal angulation >20 degrees
• Intra-articular involvement
• Marked comminution
• Radial shortening >1 cm
• Associated DRUJ instability or radiocarpal instability patterns

• Loss of reduction after closed treatment
• DRUJ instability
• Radiocarpal instability patterns
• Subsequent post-traumatic arthritis

---

8. Clinical Reasoning - Management

8a. Indications for Reduction

• Lateral X-ray shows articular surface tilted dorsally beyond neutral
• Dorsal angulation >20°
• Radial shortening (radius shorter than ulna on AP view)
• Significant dorsal or radial displacement

8b. Anesthesia for Reduction

1. Hematoma block - 10 mL of 1% lidocaine injected into the fracture hematoma via a dorsal approach (22-gauge needle); most practical for ED
2. Bier block (IV regional anesthesia) - effective, requires IV and cuff
3. Nerve blocks - median, radial, ulnar, or brachial plexus approaches
4. Procedural sedation - for complex or very painful reductions

8c. Reduction Technique

1. Apply finger traps to index and middle fingers - axial traction relaxes deforming muscle forces, may accomplish reduction alone
2. While traction is applied, push the distal fragment distally (to restore length) and palmarly (to restore volar tilt)
3. Firmly hold the forearm proximally as a counter-force
4. Confirm reduction radiographically

8d. Immobilization

• Double sugar-tong splint (initial 3-5 days) - extends from elbow to wrist with a second component from elbow to axilla; immobilizes wrist but allows finger movement
• Short-arm cast - applied after swelling subsides (4-6 weeks total immobilization)
• Avoid circumferential casting in the first 24 hours - edema may cause neurovascular compromise
• Bivalve any cast applied acutely

8e. Indications for Surgery

---

9. Complications

Early

Late

---

10. Special Populations

• Postmenopausal women: Most common demographic; osteoporotic bone increases comminution risk and reduces ability to maintain reduction. Consider DEXA and osteoporosis treatment.
• Children: The analogous injury is a distal radial physeal injury (Salter-Harris fracture of the radial growth plate) - only severe displacement requires reduction; classified differently from adult Colles' fracture.
• High-demand / younger patients: Volar tilt restoration is especially important; surgery more often required for anatomic reduction.

---

Summary: Key Clinical Reasoning Points

---

• Rosen's Emergency Medicine, Chap. 43, p. 612
• Tintinalli's Emergency Medicine, Chap. 269, p. 1847
• Pfenninger & Fowler's Procedures for Primary Care, Chap. 190, p. 1321
• Pye's Surgical Handicraft, 22nd Ed., p. 189
• Campbell's Operative Orthopaedics, 15th Ed., p. 3639 (Table 62.14)
• THIEME Atlas of General Anatomy and Musculoskeletal System, p. 277