A torus fracture, also called a buckle fracture, is an incomplete compression fracture of the metaphysis of a growing bone in which the cortex bulges outwards but never breaks. It is the single most common fracture of childhood, and the distal radius is by far the most common site. On radiographs you see a small step, angle or wrinkle in the cortical outline a short distance proximal to the physis, with no lucent fracture line, no cortical discontinuity and no displacement.
The imaging is easy. The decision that follows it is where the value lies: a true torus fracture is inherently stable, and the current evidence, including the 965-child FORCE randomised trial and NICE NG38, says these children need a soft bandage or removable splint and discharge, not a rigid cast, not a clinic appointment and not a repeat radiograph. Calling the fracture correctly is therefore the whole job, because the label determines the pathway.
| At a glance | |
|---|---|
| Definition | Incomplete metaphyseal compression fracture with cortical buckling and an intact cortex |
| Most common site | Distal radius metaphysis, with or without the distal ulna |
| Typical age | School-age children and early adolescents; occurs from toddler age up to physeal closure |
| Mechanism | Fall on an outstretched hand (FOOSH) producing axial load through the wrist |
| First-line imaging | PA and lateral radiographs of the wrist; point-of-care ultrasound is a validated alternative |
| Key stability rule | Cortical buckling only. Any cortical breach, lucent line, angulation or physeal involvement means it is not a torus fracture |
| Treatment | Soft bandage or removable wrist splint for about 3 weeks, then self-directed return to activity |
| Follow-up imaging | Not required for a confirmed torus fracture |
| Union | Clinically healed by 3 to 4 weeks; complications are rare |
Quiz
Which of the following is a feature of this pathology?
- Spiral fracture pattern
- Transverse fracture pattern
- Oblique fracture pattern
- Stable, rounded bump or protrusion on the bone
What is a torus (buckle) fracture?
A torus fracture is a failure of bone in compression rather than in tension. Axial load is transmitted up the hand and carpus into the distal radial metaphysis, the trabeculae there impact, and the thin metaphyseal cortex is pushed outwards into a low bulge. Because the cortex is deformed and not torn, the periosteal sleeve remains completely intact, and it is that intact sleeve which makes the injury stable and self-splinting.
The terms torus fracture and buckle fracture are used interchangeably in the literature and in every current guideline. Some older texts try to divide them by the number of cortices involved, reserving “buckle” for a single cortex and “torus” for a circumferential bulge. No standard classification endorses that split, radiologists do not report it, and it does not alter management, so treat the two words as synonyms. What matters instead is the distinction from the other incomplete paediatric fracture patterns.
| Pattern | Mode of failure | Cortical integrity | Typical location | Stability |
|---|---|---|---|---|
| Torus / buckle | Pure compression | Both cortices intact; one or both buckled outwards | Metaphysis (distal radius most often) | Inherently stable |
| Greenstick | Bending, tension on the convex side | Complete break of one cortex, plastic deformity of the other | Diaphysis or metadiaphysis | Potentially unstable, may angulate |
| Plastic (bowing) deformation | Sub-failure bending load | Both cortices intact, no visible fracture line | Diaphysis, classically the ulna or fibula | Deformity persists, may block reduction of the paired bone |
| Complete metaphyseal fracture | Compression plus tension | Both cortices breached | Metaphysis | Unstable, can displace |
| Salter-Harris injury | Shear or avulsion through the growth plate | Physeal lucency with or without metaphyseal or epiphyseal fragment | Physis | Needs follow-up; growth-arrest risk |
Why children buckle where adults break
- Immature bone is more porous, more richly vascularised and has a lower mineral content than adult bone, so it yields plastically instead of shattering. The pores blunt propagation of a crack but make the bone easier to crush.
- The metaphysis is the weak link. Its cortex is thin and its underlying trabecular bone is soft, unlike the thick diaphyseal cortex a few centimetres proximally, so an axial load fails at the metaphyseal-diaphyseal junction.
- A thick, strong and osteogenic periosteum stays intact across the buckle. This is why the fracture cannot displace and why it heals so quickly.
- The distal radius takes the load. Roughly one child in 25 sustains a distal radius buckle fracture, and these account for about half of all paediatric wrist fractures.
Torus fractures are essentially confined to the growing skeleton, and they are metaphyseal, not a flat-bone injury. Beyond the distal radius, look for the same buckled cortex at the following sites.
| Site | Typical mechanism | Where to look |
|---|---|---|
| Distal radius, with or without distal ulna | FOOSH | Dorsal cortex on the lateral view, 1 to 2 cm proximal to the physis |
| Distal tibia and fibula | Axial load from a jump or fall, low-energy ankle twist | Anterior or posterior distal tibial metaphyseal cortex on the lateral view |
| Distal femur | Axial load, often a fall from height | Supracondylar metaphyseal cortex |
| Proximal humerus | Fall onto the shoulder or an outstretched arm | Surgical neck metaphysis |
| Metacarpals and phalanges | Direct axial blow to a digit | Metaphyseal cortex adjacent to the physis |
X-ray findings of a torus fracture
Primary signs
| Sign | What you see | Pearl |
|---|---|---|
| Cortical buckle | A focal outward bulge, step or sharp angle in the cortical margin of the metaphysis | Follow the cortical line from diaphysis to physis on every view. The abnormality is a change in contour, not a lucency |
| Intact cortex | The cortical white line is continuous across the bulge | If the line is broken anywhere, this is not a torus fracture |
| No fracture lucency | No lucent line traversing the metaphysis | A lucent line means a complete or greenstick fracture |
| Trabecular condensation | Subtle band of increased density behind the buckle from impacted trabeculae | Often the only clue when the cortical bulge is borderline |
| Distance from the physis | The buckle sits about 1 to 2 cm proximal to the growth plate | A metaphyseal abnormality abutting the physis should raise suspicion of a Salter-Harris II injury |
| Soft-tissue swelling | Local dorsal soft-tissue fullness over the distal radius | Supports the diagnosis but is neither sensitive nor specific |
Two features that are often listed in older sources deserve correction. Callus is not a presenting finding. Periosteal new bone appears at roughly two to three weeks and is a sign of a healing fracture on a follow-up film, not something you look for on the injury radiograph. And a displaced pronator quadratus fat pad is a soft sign only. It is neither sensitive nor specific enough to diagnose or exclude an occult distal radial fracture, and it should never override the cortical assessment.
The commonest pitfalls
- Reading a single view. A purely dorsal buckle can be invisible on the PA film and obvious on the lateral, and the reverse is true for a radial-sided buckle. Two orthogonal views are the minimum.
- Mistaking the normal metaphyseal flare for a buckle. The normal distal radial metaphysis widens smoothly and symmetrically. A torus is a focal, asymmetric, angular interruption of that smooth flare.
- Missing the paired ulna. A distal ulnar buckle or plastic deformity accompanies the radial injury in a substantial minority. Assess the ulna separately.
- Over-calling on an obliqued film. Rotation projects the cortex tangentially and can simulate a step. If the finding is present on only one poorly positioned view, repeat the view before committing.
- Routinely imaging the opposite wrist. Contralateral comparison views are occasionally useful for suspected plastic bowing but should not be a reflex, as they double the radiation dose for a diagnosis that is usually resolvable on the injured side.
Imaging protocol: radiographs, and where ultrasound now fits
PA and lateral radiographs of the wrist remain the standard initial investigation and are all that a torus fracture requires. No CT, no MRI, no oblique views. The genuinely new development since this article was first written is the evidence base for point-of-care ultrasound (POCUS) as the first-line imaging modality in children with a clinically non-deformed distal forearm injury.
| Trial | Design and population | Primary outcome | Result |
|---|---|---|---|
| BUCKLED (Snelling et al., NEJM 2023) | Open-label non-inferiority RCT, 270 children aged 5 to 15 with an isolated distal forearm injury without visible deformity, randomised to initial POCUS or radiography | Physical function of the arm at 4 weeks (PROMIS upper-extremity score, non-inferiority margin 5 points) | POCUS non-inferior: 36.4 vs 36.3 points, mean difference 0.1 (95% CI -1.3 to 1.4). No clinically important fracture was missed in either arm |
| Diagnostic-accuracy analysis of the same cohort (Snelling et al., Ann Emerg Med 2024) | Same 270 participants; treating clinician classified the imaging as no fracture, buckle fracture or other fracture, against an expert-panel reference standard | Diagnostic accuracy of the treating clinician | Correct diagnosis in 97.8% with POCUS vs 83.0% with radiographs, absolute difference 14.8% (95% CI 8.0 to 21.6). Accuracy was better with POCUS specifically for buckle fractures (difference 18.5%) |
The practical reading: in a child with wrist pain after a fall and no clinical deformity, a trained clinician using a high-frequency linear probe over the six-view distal forearm protocol can diagnose a buckle fracture at least as reliably as a radiograph, with no ionising radiation and no imaging queue. This does not replace radiography where deformity is visible, where the examination is inconclusive, or where the operator is untrained, and radiographs remain the reference standard for anything that is not a clean buckle.
Is it really a buckle? Separating stable from unstable
Because the management pathways now diverge so sharply, misclassifying a potentially unstable distal radius fracture as a torus fracture matters more than it used to. Three pieces of published work help.
The 1-cm rule
Iles and colleagues (Pediatric Radiology, 2019) measured fracture-to-physis distance in 203 children with closed distal radius fractures and proposed a simple screening measurement.
| Finding | Value |
|---|---|
| Cohort | 203 children with closed distal radius fractures; 148 buckle (73%), 55 potentially unstable (27%) |
| Children aged 7 to 16 | Fracture-to-physis distance was under 1 cm in only 1 of 106 buckle fractures on the PA view and none on the lateral |
| Proposed rule | In a child 7 years or older, an isolated distal radius fracture whose distance from the physis is under 1 cm is unlikely to be a buckle fracture |
| Best accuracy | 82% using cut-offs of 14 mm on PA and 13 mm on lateral |
| Children aged 3 to 6 | Accuracy was low at every distance tested, so the rule should not be applied to this age group |
Volar and bicortical buckles
About a quarter of distal radius buckle fractures involve the volar rather than the dorsal cortex, and volar buckles have historically been treated more cautiously. A 333-fracture series from Nationwide Children’s Hospital (Pediatric Emergency Care, 2024) found 254 dorsal (76%) and 79 volar (24%) buckles, and reported that when the volar fracture met the same strict criteria used for dorsal ones, namely cortical buckling with no cortical breach and no physeal involvement, removable brace and home management was safe. Only one of the 79 volar cases returned for persistent pain. The caveat is in the phrase “strict criteria”: if you cannot convince yourself the volar cortex is unbroken, do not call it a buckle.
The angled buckle controversy
A subset described as “angled” buckle fractures, thought to result from an off-centre compressive force, has been proposed to harbour occult intraphyseal extension and therefore to behave as an unstable Salter-Harris injury. A 2022 review concluded that the radiographic evidence for or against this entity is limited, that misdiagnosis is common in the absence of universal diagnostic criteria, and that complication rates nevertheless remain low. The defensible position for the reporting radiologist is to describe what is present, state explicitly whether the cortex is intact and whether the physis is spared, and avoid the label “buckle” for anything angulated.
Differential diagnosis
| Diagnosis | Discriminating feature | Why it matters |
|---|---|---|
| Greenstick fracture | Metadiaphyseal or diaphyseal, with a complete break in one cortex and bowing of the other, usually with angulation | May angulate further; needs reduction if angulated and a cast, so cannot be discharged as a buckle |
| Plastic (bowing) deformation | Smooth abnormal curvature of the whole shaft with no cortical break and no buckle; classically the ulna accompanying a radial injury | Can block reduction of the paired bone; contralateral comparison views are genuinely helpful here |
| Salter-Harris type II fracture of the distal radius | Lucency through the physis with a metaphyseal (Thurston Holland) fragment; the abnormality abuts rather than sits proximal to the growth plate | Requires follow-up for displacement and growth disturbance |
| Complete metaphyseal fracture | Lucent line crossing both cortices | Unstable, may displace in cast; needs orthopaedic review |
| Normal metaphyseal flare or nutrient groove | Smooth, symmetrical widening or a fine oblique lucency with sclerotic margins traversing the cortex obliquely | The commonest over-call; check the contour is smooth and the finding is reproducible on the second view |
| Distal radial physeal stress injury (gymnast wrist) | Widened, irregular physis with metaphyseal sclerosis in a repetitive-loading athlete, no acute buckle | Chronic overuse rather than acute trauma; managed by activity modification |
What to put in the report
A torus fracture report is short, but because it drives a discharge decision every element earns its place. Cover these six points.
- Bone and side, and whether the ulna is also involved.
- The pattern: state “torus (buckle) fracture” explicitly, and state that the cortex is intact and there is no lucent fracture line.
- Which cortex buckles (dorsal, volar, radial or ulnar) and on which view it is seen.
- Distance from the physis, at least qualitatively, and an explicit statement that the physis and epiphysis are normal.
- Alignment: confirm there is no angulation, displacement or shortening.
- Soft tissues and any second injury in the imaged field.
A worked example: “Buckling of the dorsal and radial cortices of the distal radial metaphysis approximately 15 mm proximal to the physis, with an intact cortex, no lucent fracture line and no angulation. The distal radial physis and epiphysis are normal. The distal ulna is intact. Appearances are those of a torus (buckle) fracture, a stable injury.” The final clause is the one the emergency clinician acts on.
Treatment: what the evidence actually says
The management of torus fractures has changed more than the imaging has. Rigid casting with clinic review and repeat films, still common practice in many departments, is no longer supported.
| Evidence | What it tested | Finding |
|---|---|---|
| FORCE trial (Perry et al., Lancet 2022) | Randomised equivalence trial, 965 children aged 4 to 15 with a distal radius torus fracture across 23 UK hospitals; offer of a soft bandage with immediate discharge versus rigid immobilisation with follow-up | Pain at 3 days was equivalent (3.21 vs 3.14 on the Wong-Baker FACES scale; adjusted difference -0.10, 95% CI -0.37 to 0.17, against a prespecified margin of 1.0). No difference in pain or function over 6 weeks |
| FORCE cost-effectiveness analysis (Perry et al., Bone Joint J 2024) | Within-trial economic evaluation from the NHS and societal perspective | The offer of a bandage saved GBP 12.55 per patient with equivalent quality-adjusted life years, and had a 95% probability of being cost-effective. Small per child, large across a health system |
| Systematic review and meta-analysis (Pakarinen et al., Sci Rep 2024) | Seven RCTs, 1,550 patients, comparing bandage, splint and cast | Splint gave slightly higher pain scores than cast at 3 days and 1 week but faster return to activities at 3 and 4 weeks. Bandage gave a marginally higher pain score on day 1 only. All torus fractures healed clinically within 3 to 4 weeks. Soft bandage or removable splint is the optimal first-line treatment |
| Earlier systematic review (Hill, Masters and Perry, J Pediatr Orthop B 2016) | Eight RCTs of alternative splinting versus complete plaster cast | Splinting was superior for function, cost and convenience with no excess pain or complications |
What the guideline says
NICE guideline NG38 on non-complex fractures, published in February 2016 and last reviewed in June 2025, makes two recommendations specific to this injury:
- 1.3.3 Do not use a rigid cast for torus fractures of the distal radius.
- 1.3.4 Discharge children with torus fractures after first assessment and advise parents and carers that further review is not usually needed.
In practice that means a soft bandage or an off-the-shelf removable wrist splint worn for comfort for about three weeks, simple analgesia, written advice, and self-directed return to normal activity as pain settles. A cast is reasonable only when the child or family strongly prefers one after shared decision-making, or when the diagnosis of a pure buckle is in doubt. Formal activity restriction is not required, and the child does not need to be kept off the playground until a follow-up appointment that is not going to happen.
Follow-up imaging and healing
Repeat radiographs are the most common unnecessary investigation in this injury. A torus fracture cannot displace, so a follow-up film cannot change management, and audit work has shown that half of these children still receive more than one radiograph series. Reserve imaging for the child whose pain is escalating rather than settling, or in whom the original diagnosis is being reconsidered.
| Time from injury | Expected clinical state | Imaging |
|---|---|---|
| Day 0 | Local pain, swelling, reduced range of motion | PA and lateral radiographs (or POCUS) to make the diagnosis |
| Days 1 to 3 | Pain at its peak, roughly 3 out of 10 on a paediatric faces scale in both bandage and cast groups | None |
| Week 1 to 2 | Pain settling; child using the hand for light activity | None |
| Week 3 | Bandage or splint discarded; most children back to normal activity | None |
| Weeks 3 to 4 | Clinically united in essentially all cases | None |
| Beyond 4 weeks | Persistent or worsening pain is the exception | Re-image and reconsider the original diagnosis |
Refracture, malunion, growth disturbance and compartment syndrome are not features of this injury. If any of them appears to be developing, the original diagnosis was probably wrong.
Etymology and synonyms
The word torus comes from the Latin for a swelling, bulge or protuberance. In classical architecture the torus is the large convex moulding at the base of a column, and the buckled metaphyseal cortex reproduces exactly that profile, which is where the fracture got its name.
Synonyms in current use are buckle fracture, torus fracture and incomplete compression fracture of the metaphysis. In the emergency-medicine and orthopaedic literature the abbreviation DRBF (distal radius buckle fracture) is common.
Frequently asked questions
References
Single best review article
Key trials and guidelines
- Perry DC, Achten J, Knight R, et al. Immobilisation of torus fractures of the wrist in children (FORCE): a randomised controlled equivalence trial in the UK. Lancet. 2022;400(10345):39-47. PMID: 35780790.
- National Institute for Health and Care Excellence. Fractures (non-complex): assessment and management. NICE guideline NG38. Published February 2016, last reviewed June 2025. nice.org.uk/guidance/ng38.
- Snelling PJ, Jones P, Bade D, et al. Ultrasonography or radiography for suspected pediatric distal forearm fractures. N Engl J Med. 2023;388(22):2049-2057. PMID: 37256975.
- Snelling PJ, Jones P, Bade D, et al. Diagnostic accuracy of point-of-care ultrasound versus radiographic imaging for pediatric distal forearm fractures: a randomized controlled trial. Ann Emerg Med. 2024;83(3):198-207. PMID: 37999655.
- Iles BW, Samora JB, Singh S, Ruess L. Differentiating stable buckle fractures from other distal radius fractures: the 1-cm rule. Pediatr Radiol. 2019;49(3):358-364. PMID: 30547221.
- Nandigam M, Chmil M, Thompson BP, Samora JB, Ruess L. Volar distal radius buckle fractures: is bracing and home management safe? Pediatr Emerg Care. 2024;40(8):e159-e163. PMID: 38713845.
- Pakarinen O, Saarinen AJ, Ponkilainen VT, Uimonen M, Helenius I, Kuitunen I. Soft bandage, splint or cast as the treatment of distal forearm torus fracture in children: a systematic review and meta-analysis. Sci Rep. 2024;14(1):21052. PMID: 39251716.
- Perry DC, Dritsaki M, Achten J, et al. Cost-effectiveness analysis of soft bandage and immediate discharge versus rigid immobilization in children with distal radius torus fractures. Bone Joint J. 2024;106-B(6):623-630. PMID: 38821496.
- Gonzalez N, Lucas JP, Winegar A, Den Haese J, Danahy P. A review of pediatric distal radius buckle fractures and the current understanding of angled buckle fractures. Cureus. 2022;14(5):e24943. PMID: 35706760.
- Hill CE, Masters JP, Perry DC. A systematic review of alternative splinting versus complete plaster casts for the management of childhood buckle fractures of the wrist. J Pediatr Orthop B. 2016;25(2):183-190. PMID: 26523533.
- Ben-Yakov M, Boutis K. Buckle fractures of the distal radius in children. CMAJ. 2016;188(7):527. PMID: 26976961.
- Davidson JS, Brown DJ, Barnes SN, Bruce CE. Simple treatment for torus fractures of the distal radius. J Bone Joint Surg Br. 2001;83(8):1173-1175. PMID: 11764434.
Related reading on RadioGyan: Colles fracture, Smith fracture and triquetral avulsion fracture cover the adult distal radius and carpal counterparts of this injury.
Done by – Dr Gauri / edited by Mansi. Updated and expanded 2026.
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