First and second year — the floor first, then every step
Describe it the way it will be fixed: location, pattern, fragment count, then the six numbers — displacement, angulation, rotation, shortening, gap and joint extension — each measured in a defined way and in two planes.
Orient first
Describe position of the DISTAL fragment relative to the proximal — that is the convention for displacement and angulation.
Angulation is measured in both the AP (varus/valgus) and lateral (procurvatum/recurvatum) planes; a radiograph in one plane can make a badly angulated fracture look aligned.
Rotation cannot be seen reliably on radiographs; it is measured clinically or by CT torsion comparison with the other side.
Acquire the study
Full-length AP and lateral of the whole bone, including the joint above and below; a single long cassette or stitched images.
The manoeuvre
Location: proximal, middle or distal third of the shaft (or metaphyseal/diaphyseal junction), measured in cm from a joint line.
Pattern: transverse, oblique, spiral, segmental, or wedge (butterfly) — and the number of fragments.
DISPLACEMENT: translation of the distal fragment in mm or as a percentage of the shaft width, on AP and lateral separately.
ANGULATION: the angle between the long axes of the proximal and distal fragments on AP (varus/valgus) and lateral (apex anterior/posterior), in degrees.
SHORTENING: the overlap of the fragments in mm, or the length difference against the contralateral bone on a calibrated long-leg film.
GAP (distraction) between the main fragments in mm.
EXTENSION into a joint or the metaphysis; the fibula (with the tibia) or the femoral neck (with the femur).
Soft tissue: gas in the soft tissues (open fracture or skin breach), foreign bodies.
What confirms it
Two orthogonal views including both joints.
What licenses you to exclude it
A single-plane radiograph cannot exclude significant angulation or displacement.
The classic misread
Measuring angulation on one view only.
Missing an ipsilateral femoral neck fracture with a femoral shaft fracture because the hip was not included.
Missing a proximal fibular fracture with a distal tibial spiral fracture (or vice versa).
Reporting the injury
Classification to use
AO/OTA: femur 32 (diaphysis) and tibia 42 — A simple (spiral, oblique, transverse), B wedge (intact or fragmented wedge), C multifragmentary (intact or fragmented segmental). Gustilo–Anderson grades an OPEN fracture but is a surgical classification; the radiologist reports signs of an open fracture.
Measurements — and how to take them
Displacement: translation of the distal fragment in mm or % of shaft width, on each view.
Angulation: in degrees on AP and lateral, named by direction (varus/valgus; apex anterior/posterior).
Rotation: side-to-side difference in femoral anteversion or tibial torsion on CT, in degrees.
Shortening / vertical height: fragment overlap in mm, or length difference to the contralateral bone on calibrated imaging.
Gap: distance between the main fragment ends in mm.
Articular step-off and gap, in mm, when the fracture extends into a joint; the number of fragments.
What to report
Bone, side, location, pattern, fragment count, AO/OTA code if your centre uses it.
Displacement, angulation in both planes, shortening, gap, rotation if measured, joint extension.
Associated fracture of the paired bone or the proximal/distal joint; soft-tissue gas and foreign bodies.
How to report it
X-ray: "Comminuted fracture of the mid-shaft of the right tibia with a butterfly fragment (AO/OTA 42B). The distal fragment is displaced 8 mm laterally (about half the shaft width) and angulated 12° into valgus and 6° apex anterior, with 10 mm of shortening. No extension into the knee or ankle. Associated proximal third fibular fracture. Gas in the anterior soft tissues."
CT: "Torsion comparison: tibial external torsion 42° on the injured side against 28° on the normal side — 14° excess external rotation."
What not to report
Do not write "in satisfactory alignment" — give the numbers; acceptability is the treating surgeon's judgement.
Signs of an open fracture (gas, foreign body) — antibiotics and debridement.
Joint extension and articular step-off — changes fixation (plate versus nail).
An ipsilateral femoral neck fracture — changes the implant and the order of fixation.
Reference values
Each value carries the caveat that keeps it from being misused. Normal limits and diagnostic criteria are kept apart on purpose: a disease cut-off read as a normal range is the more dangerous mistake.
Diagnostic criteria
Fracture (union) · Union versus delayed union — qualitative
bridging callus on a named number of cortices is the taught union look-for; published time-to-union is bone- and site-specific — do not invent a universal “united by week X”
A scaphoid and a tibia do not share a calendar. Name the bone and the cortices.
X-ray · CT
See it on real cases
Direct links to Radiopaedia — the reference article and worked cases with their images. Each opens on Radiopaedia.