Paediatric Distal Radius, Buckle and Physeal Wrist Fractures

Paediatric distal radius injuries are among the most common fractures in childhood, usually after a fall on an outstretched hand. They range from a stable compression injury to a displaced fracture involving both cortices or the distal radial physis. The clinical skill is matching the amount of treatment to the true stability of the injury.

A buckle fracture is a compression bulge in the cortex. It is stable because there is no complete cortical disruption. It should not be treated like a displaced fracture. Conversely, a complete metaphyseal fracture or displaced physeal injury should not be softened into the word "buckle" just because the child is young.

Remodelling potential is excellent near the distal radial physis, especially in younger children and sagittal-plane deformity. It is less reliable in adolescents, coronal deformity, rotational deformity, unstable complete fractures and injuries close to skeletal maturity. Distal ulna physeal injury deserves special attention because growth disturbance can create ulnar variance and distal radioulnar joint problems.

The goals are simple: identify the pattern, protect the skin and nerves, avoid unnecessary follow-up for stable buckle fractures, reduce unacceptable deformity gently, use a well-moulded non-tight cast when needed, and give families clear cast and swelling return advice.

• A buckle fracture occurs when compressive force crumples one cortex without full structural failure.
• Greenstick fractures fail on the tension side while the opposite cortex bends.
• Complete fractures disrupt both cortices and can shorten or angulate.
• The distal radial physis is weaker than ligament attachments, so falls can produce Salter-Harris injuries.
• The thick periosteum can maintain partial stability but also hide displacement. Remodelling depends on age, plane of deformity and proximity to the distal radial physis. Younger children have more growth remaining. Sagittal-plane deformity remodels more predictably than rotational deformity. Rotation does not remodel reliably. Bayonet apposition may be acceptable in selected young children, but this is not a rule for older children near maturity.

Median nerve symptoms can occur from swelling, deformity or a tight cast. Distal ulna physeal injury carries growth-disturbance risk and should not be forgotten when the radius fracture dominates the X-ray.

History

The history should define mechanism, energy, pain location and nerve symptoms.

• Mechanism: FOOSH, sport, fall from height, trampoline, scooter, bike or direct blow.
• Pain onset: immediate pain and refusal to use the wrist supports fracture.
• Location: distal radius, distal ulna, snuffbox, forearm or elbow.
• Neurological symptoms: paraesthesia or altered sensation in thumb, index and middle fingers suggests median nerve concern.
• Current immobilisation: increasing pain, swelling, numbness or tightness after splint or cast is a safety issue.
• Bone health and safeguarding: recurrent fractures, low-energy mechanism, inconsistent history or injury pattern should be explored carefully.

Examination

Inspection separates a comfortable buckle fracture from a deformed unstable fracture. Look for swelling, bruising, deformity, open wounds, skin compromise and finger posture. Palpate the distal radius and distal ulna separately. Do not forget snuffbox tenderness in adolescents or elbow tenderness after higher-energy injury.

Document median nerve function before and after reduction. In a younger child, this may be simplified to sensation, finger movement, thumb flexion/opposition and observation of hand use. Check radial pulse, capillary refill, finger warmth and pain with passive stretch if swelling is severe.

Avoid forceful wrist movement when the fracture is obvious. In a cast or splint, escalating pain, numbness, swollen fingers, colour change or inability to move fingers is not normal and requires urgent review.

• Look at both cortices before calling a buckle fracture.
• Assess dorsal or volar tilt, translation, shortening and associated ulna fracture.
• Do not miss distal ulna physeal injury.
• In adolescents, consider carpal injury if pain is not explained by distal radius findings.
• Repeat imaging depends on stability, age, reduction and local fracture protocol.

• Wrist sprain: uncommon diagnosis in a child with focal bony tenderness.
• Scaphoid fracture: snuffbox pain, more relevant in adolescents.
• Distal ulna physeal injury: ulnar-sided tenderness and growth risk.
• Galeazzi equivalent: distal radial fracture with distal radioulnar joint or ulnar physeal injury.
• Non-accidental injury: mechanism inconsistent with age or injury pattern.
• Pathological fracture: cyst, metabolic bone disease or recurrent low-energy fractures.

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The first management decision is whether the injury is truly stable. A true buckle fracture can be managed simply. A displaced complete or physeal fracture needs alignment assessment, reduction decision, cast quality and follow-up.

Early

• Median nerve symptoms.
• Cast tightness, swelling or pressure injury.
• Loss of reduction.
• Compartment syndrome, rare but serious.
• Missed associated elbow or carpal injury.

Late

• Malunion with residual deformity.
• Distal radial or ulnar physeal arrest.
• Wrist stiffness from over-immobilisation.
• Refracture after early return to sport.
• Cosmetic deformity or functional limitation if alignment unacceptable.

Paediatric distal radius injuries should be separated into stable buckle fractures, greenstick or complete metaphyseal fractures, and physeal injuries. These are different problems. A buckle fracture is a stability and comfort problem; a displaced physeal injury is a reduction, growth and follow-up problem.

The practical error is over-treating stable buckle fractures while under-recognising physeal injuries. True torus fractures should not need repeated X-rays, prolonged casting or fracture-clinic congestion when diagnosis is secure and the family has clear return advice. Conversely, a displaced physeal injury needs reduction quality, neurovascular status, cast mould, re-displacement risk and later growth assessment considered.

Return to sport depends on pain-free wrist motion, tenderness resolution and injury pattern. A buckle fracture returns earlier than a displaced physeal fracture or complete metaphyseal fracture.

• Look at cortex, not only the report wording.
• A removable splint works because true buckle fractures are stable.
• If a fracture needs reduction, it is no longer in the same mental category as a buckle injury.
• Cast quality matters: moulding supports reduction, tightness harms fingers.
• Median nerve documentation is not optional in displaced wrist fractures.
• Younger children remodel, but adolescents do not forgive poor reduction as reliably.
• Distal ulna physeal injury is easier to forget than distal radius injury.
• Pain out of proportion in a cast is a safety event.
• Return-to-sport advice prevents refracture.
• Families appreciate simple language: stable bend versus displaced break.

Common pitfalls

• Calling a complete fracture a buckle fracture.
• Ignoring distal ulna physis.
• No neurovascular check after reduction.
• Overly tight circumferential cast in swelling.
• Repeated forceful physeal reduction.
• No safety advice for cast pain or numbness.