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- Components: Shaft, Radial Styloid, and Dorsal Medial and Palmar Medial Parts;

- Type I:
    - colles frx equiv: undisplaced and minimally comminuted;

- Type II:
    - die punch frx: unstable w/ moderate to severe displacement;
    - similar to Mayo class II: displaced frx involving radioscaphoid joint;
    - radioscaphoid joint frx: involves more than radial styloid (Chauffeur frx) fracture) and has significant dorsal angulation and radial shortening;
    - requires stabilization provided by external fixators, along w/ percutaneous pins, to maintain an accurate reduction;

- Type IIb (irreducible)
    - this is a double die punch frx which is an irreducible injury;
           - dorsal medial component fragmentation;
           - persistent radiocarpal incongruity > than 2 mm;
           - radial shortening > 3 - 5 mm;
           - dorsal tilting & displacement > of 10 deg
           - radiocarpal step off > 5 mm (on a lateral view);
    - requires open treatment for restoration of articular congruity;
    - requires ORIF of radiocarpal articular surface, supplementary external fixation, and iliac bone grafting;

- Type III:
    - is die punch or lunate load fracture, and is often irreducible by traction alone;
    - involves additional frx from shaft of radius that projects into flexor compartment;
    - Mayo equivolent: are displaced involving the radiolunate joint;
    - this may require fixation w/ small screws or wires  in conjunction with closed or limited open articular surgery;

- Type IV:
    - transverse split of articular surfaces w/ rotational displacement;
    - Mayo eqivolent is a displaced frx involving both radioscaphoid & lunate joints, and the sigmoid fossa of the distal radius;
          - is often a more comminuted frx involving all of major joint articular surfaces, & almost always includes frx component into distal radioulnar joint

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Intra-articular fractures of the distal end of the radius in young adults.

Distal radius fractures: patterns of articular fragmentation.