A 58-year-old woman with osteoporosis falls on her outstretched hand and presents with wrist pain and deformity. Plain radiographs show a fracture of the distal radius with dorsal angulation and shortening. The fracture line extends into the radiocarpal joint. Which investigation is most specific for determining the exact fracture pattern classification (Barton vs. Colles vs. Smith) and articular involvement?

Explanation

## Investigation of Choice for Distal Radius Fracture Classification ### Why CT with Multiplanar Reconstruction is Essential **Key Point:** CT with coronal and sagittal reconstructions is the most specific investigation for: - Precise fracture line orientation and extension - Degree of articular surface involvement - Comminution pattern and fragment displacement - Differentiation between Barton (intra-articular with dislocation), Colles (dorsal angulation, extra-articular or minimally intra-articular), and Smith (volar angulation) patterns ### Fracture Pattern Differentiation | Fracture Type | Location | Angulation | Articular Involvement | Imaging Finding on CT | |---|---|---|---|---| | **Colles** | Distal radius metaphysis | Dorsal | Minimal/none | Dorsal cortical comminution | | **Smith** | Distal radius metaphysis | Volar | Minimal/none | Volar cortical comminution | | **Barton** | Distal radius articular surface | Dorsal or volar | Significant (intra-articular) | Fracture line crosses radiocarpal joint with fragment displacement | ### Clinical Pearl **High-Yield:** Plain radiographs may show dorsal angulation and shortening but cannot reliably assess: - Exact degree of articular surface involvement - Comminution pattern in the coronal plane - Occult fracture lines extending into the joint - Precise classification needed for surgical vs. conservative management CT provides: 1. **Coronal images** — assess radial styloid involvement and ulnar-sided comminution 2. **Sagittal images** — determine volar vs. dorsal angulation and articular extension 3. **Axial images** — evaluate intra-articular fragment displacement ### Why This Case Requires CT The presence of **dorsal angulation + shortening + intra-articular extension** requires precise classification because: - **Colles fractures** (dorsal, minimal articular involvement) → typically conservative or percutaneous pinning - **Barton fractures** (dorsal, significant articular involvement) → surgical fixation (volar or dorsal plate) - The exact degree of articular involvement determines surgical approach and prognosis **Mnemonic: DART** — **D**istal radius fractures need **A**dvanced imaging; **R**econstruction (multiplanar); **T**ype classification. [cite:Rockwood & Green's Fractures in Adults Ch 11]