JHS - 2026-03-16 - Journal Article
A Classification of Extra-articular Distal Radius Fractures With Associated Injuries.
Hegazy G, Seddik M, El-Sadek RE, Mansour T, Shaheen E, El-Sebaey I, Alnahas M, Elhalawany M, Elzoghby A, Abdelaziz M, Darweash A
Topics
Key Takeaway
A new 4-type, 8-subtype classification for extra-articular distal radius fractures achieved Cohen's kappa of 0.75–0.88 across all subtypes in multicenter reliability testing.
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Summary
This multicenter study across three university-affiliated centers developed a hierarchical classification for extra-articular DRFs integrating four radiographic domains: fracture instability, distal ulnar fracture morphology, DRUJ disruption, and carpal involvement. Six trained observers independently classified a stratified random sample of 80 cases (10 per subtype). Cohen's kappa ranged from 0.81–0.88 for Types IA, IB, IIA, and IIIA, and 0.75–0.79 for the more complex subtypes IIB, IIIB, IVA, and IVB, indicating substantial to near-perfect agreement across all categories.
Key Limitation
The classification has no demonstrated correlation with treatment selection, surgical outcomes, or complication rates, limiting its current utility beyond descriptive and research purposes.
Original Abstract
PURPOSE
To develop a classification system for extra-articular distal radius fractures (DRFs) integrating radiographic parameters of instability, ulnar fractures, distal radioulnar (DRU) joint disruption, and carpal involvement and to evaluate its reliability.
METHODS
A multicenter study across three university-affiliated orthopedic centers identified 1,239 extra-articular DRFs from 3,784 radiographs. Radiographic features were categorized into four domains: (1) DRF instability (radial inclination <15°, radial height loss ≥5 mm, dorsal angulation >15° in dorsally displaced fractures or volar tilt >15° in volarly displaced fractures, or metaphyseal comminution); (2) distal ulnar fractures (simple vs comminuted); (3) DRU joint disruption (bony vs soft tissue); and (4) carpal involvement. A hierarchical classification system with four types and eight subtypes was developed: Type I (isolated DRFs: IA stable, IB unstable), type II (ulnar fracture: IIA simple, IIB comminuted), type III (DRU joint disruption: IIIA bony, IIIB soft tissue), and type IV (carpal involvement: IVA isolated, IVB with DRU joint disruption). Reliability was assessed using a stratified random sample of 80 cases (10 per subtype) independently reviewed by six trained observers (two per center). Reliability was determined using Cohen's kappa with 95% confidence intervals.
RESULTS
Reliability testing of the classification system across centers demonstrated mean k values ranging from 0.81 to 0.88 for Type I (IA and IB), Type IIA (simple ulnar), and Type IIIA (bony DRU joint) subtypes and mean k values ranging from 0.75 to 0.79 for Types IIB (comminuted ulnar), IIIB (soft tissue DRU joint), IVA (carpal only), and IVB (carpal + DRU joint).
CONCLUSIONS
This classification system provides reliable and reproducible classification of extra-articular DRFs with meaningful inter- and intraobserver reliability across all fracture types.
CLINICAL RELEVANCE
This proposed classification may improve comparability across studies and assist in clinical management and evidence synthesis for extra-articular DRFs.