Classification system
Frykman Classification
Frykman Classification of Distal Radius Fractures
The Frykman classification sorts distal radius fractures into eight types from two findings — whether the fracture enters the radiocarpal joint, the distal radioulnar joint, both or neither, and whether the ulnar styloid is fractured — with odd-numbered types having an intact styloid and even-numbered types a fractured one.
What the Frykman category means
Frykman categories describe different patterns, not increasing severity — a higher-lettered or higher-numbered category is not necessarily a worse problem. The groups below are descriptive.
- Extra-articular (types I–II)1–2
The joint surfaces are not involved; alignment, not congruity, is what has to be restored.
- Single joint involved (types III–VI)3–6
Articular involvement at one of the two joints. Measure step-off and gap directly rather than inferring severity from the type.
- Both joints involved (types VII–VIII)7–8
The most complex patterns in this system, though the type still says nothing about displacement or comminution.
Published criteria and reliability
The published cut-offs that define this instrument, and the measured agreement between observers using it. Each is reported with the population it was derived in.
| Type | Value | Subscale | Population | Follow-up | Source |
|---|---|---|---|---|---|
| Criterion | Odd-numbered types have no ulnar styloid fracture; each even-numbered type is the same pattern with one | — | Distal radius fractures on plain radiographs | — | Frykman G 1967 |
| Criterion | Interobserver reliability is poor and intraobserver reproducibility only moderate, comparable to the other descriptive distal radius classifications | — | Orthopaedic surgeons and hand surgeons classifying distal radius fractures from radiographs | — | Andersen DJ 1996 |
Criterion is a published cut-off, definition or performance figure belonging to a classification or decision rule — it is not a change score and should not be read as one.
How the score is calculated
Stated in full so the calculation can be independently checked, and reproduced by hand if needed.
Two findings generate the eight types. The first is joint involvement: extra-articular, intra-articular at the radiocarpal joint, intra-articular at the distal radioulnar joint, or intra-articular at both. The second is whether the ulnar styloid is fractured. Types I, III, V and VII have no ulnar styloid fracture; types II, IV, VI and VIII are the same four patterns with one. So type I is extra-articular with an intact styloid and type II the same fracture with a styloid fracture; types III and IV involve the radiocarpal joint; types V and VI involve the distal radioulnar joint; types VII and VIII involve both. The numbering is arithmetic rather than a graded severity scale, and the higher-numbered types are not uniformly the more serious injuries.
Instrument profile
- Developer
- Gören Frykman
- Institution
- University of Lund, Sweden
- First published
- 1967
- Items
- 2
- Response format
- Two radiographic findings
- Score range
- 1 to 8
- Direction
- Categories are not ranked by severity
- Completion time
- About 1 minutes
- Regions
- Wrist & Hand
- Conditions
- Distal radius fracture, Colles fracture, Ulnar styloid fracture, Distal radioulnar joint injury
- Procedures
- Closed reduction and casting, Volar plate fixation of the distal radius, External fixation of the wrist, Percutaneous pinning
- Validity
- Descriptive rather than prognostic. Frykman’s own series linked articular involvement to poorer results, but later work has found the type number to add little once displacement, radial shortening, articular step-off and patient age are accounted for.
- Reliability
- Reliability is poor, principally because articular involvement and small ulnar styloid fragments are hard to judge consistently on plain radiographs.
When to use the Frykman
Well suited to
- Recording which joint surfaces a distal radius fracture enters, in a shorthand most hand and orthopaedic surgeons still recognise.
- Reading and comparing older distal radius literature, much of which reports outcomes by Frykman type.
Limitations and poor fits
- Planning treatment. The type omits dorsal angulation, radial shortening, articular step-off and comminution, which is nearly everything that determines whether a fracture needs fixation.
- Predicting outcome for an individual patient — use the measured radiographic parameters and the patient’s age and demands instead.
- Assuming an ulnar styloid fracture mandates fixation: after the radius is stabilised, the question is whether the distal radioulnar joint is unstable on examination, not whether the styloid is broken.
- Reporting fracture severity in a trial, where the AO/OTA system or an explicit set of radiographic measurements carries more information.
Frykman compared with other instruments
Instruments measuring a related construct, with the practical difference between them.
| Instrument | Items | Range | What it adds |
|---|---|---|---|
| AO/OTA | 3 | 1–3 | The AO/OTA classification gives every fracture an alphanumeric code in which the first digit is the bone, the second the segment and the letter the fracture type — extra-articular, partial articular or complete articular in an end segment, and simple, wedge or multifragmentary in a shaft — so that 32-A is a simple femoral shaft fracture and 43-C a complete articular pilon fracture. |
| QuickDASH | 11 | 0–100 | The QuickDASH is an 11-item shortened form of the DASH that measures physical function and symptoms across the whole upper limb on a single 0 to 100 scale, where a higher score means greater disability. |
| Mason | 2 | 1–4 | The Mason classification sorts radial head fractures into four types — non-displaced (I), displaced partial articular (II), comminuted involving the whole head (III), and any radial head fracture accompanied by an elbow dislocation (IV) — and the type broadly separates fractures managed non-operatively from those needing fixation or replacement. |
Copyright and permitted use
Published openly because it is the question every clinician and researcher asks before using an instrument, and almost nobody answers it.
A published radiographic classification system. No licence is required.
References
- Frykman G. Fracture of the distal radius including sequelae — shoulder-hand-finger syndrome, disturbance in the distal radio-ulnar joint and impairment of nerve function: a clinical and experimental study. Acta Orthopaedica Scandinavica (Supplementum). 1967.
- Andersen DJ, Blair WF, Steyers CM Jr, Adams BD, El-Khouri GY, Brandser EA. Classification of distal radius fractures: an analysis of interobserver reliability and intraobserver reproducibility. Journal of Hand Surgery (American Volume). 1996.
Editorial status
This page has not yet been signed off by a named clinical reviewer. The scoring logic is stated in full above so it can be independently verified, and every threshold is traceable to its source. See our editorial methodology.