Colles Fracture is Characterized by Dorsal Angulation, Not Ventral Angulation
No, a Colles fracture is characterized by dorsal angulation (posterior displacement), not ventral angulation. The classic Colles fracture involves dorsal displacement and angulation of the distal radius fragment.
Characteristics of Colles Fracture
Colles fracture is defined by specific radiographic features:
- Dorsal (posterior) angulation of the distal radius fragment
- Dorsal displacement of the distal fragment
- Radial shortening
- Loss of radial inclination
- Often includes dorsal cortex comminution
Radiographic Evidence and Predictors
Research shows that dorsal angulation is a key feature in Colles fractures and has significant implications for treatment outcomes:
- Dorsal angulation >10 degrees correlates with poorer functional outcomes 1
- Dorsal cortex comminution, patient age, and sex are predictors of final dorsal tilt angulation at the end of immobilization 2
- The degree of dorsal angulation at final follow-up correlates with loss of wrist flexion 3
Treatment Considerations
When treating Colles fractures, the position of immobilization is critical:
- Traditional immobilization with the forearm in pronation may contribute to recurrence of dorsal angulation deformity 4
- Immobilization with the forearm in supination may help reduce the deforming force of the brachioradialis muscle on the distal fragment 4
- Closed reduction becomes particularly challenging when axial compression is present along with dorsal angulation 5
Acceptable Parameters for Conservative Treatment
For extra-articular Colles fractures treated conservatively, the following parameters are associated with good functional outcomes:
- Dorsal angulation ≤9 degrees
- Loss of radial inclination ≤3 degrees
- Radial shortening ≤2 mm 1
Common Pitfalls
Misidentifying fracture type: Confusing Colles fracture (dorsal angulation) with Smith fracture (volar/ventral angulation)
Inadequate reduction: Failing to correct dorsal angulation sufficiently, which can lead to functional limitations, particularly in wrist flexion
Improper immobilization position: Using traditional pronation position may contribute to recurrence of deformity
Focusing solely on radiographic parameters: Despite the correlation between anatomical and functional results, some patients with poor radiographic outcomes may still achieve acceptable functional results 3
Understanding the correct angulation pattern in Colles fracture is essential for proper diagnosis, treatment planning, and outcome prediction. The dorsal angulation is the hallmark feature that distinguishes it from other distal radius fractures.