01OverviewDefinition, clinical context and the essential points that orientate the chapter.
Describe fracture level, pattern, comminution, displacement, open status and pathological features. Radial palsy may be present at injury, appear after manipulation or develop after surgery; timing changes concern. Document nerve functions before analgesia and every intervention so the distinction is credible. Motor testing is more informative than asking only about numbness: assess wrist, finger and thumb extension and note whether wrist extension deviates radially.
Most closed fractures can unite with functional bracing, but treatment must preserve shoulder and elbow motion and monitor alignment. Primary closed radial palsy often represents neurapraxia and recovers with observation. New or worsening deficit, open injury or vascular damage requires immediate specialist review. Persistent absent recovery prompts electrodiagnostic and imaging decisions at defined intervals. Pathological fracture requires tumour-aware planning before an unconsidered nail or plate contaminates tissue planes.
Initial splintage controls pain and gross deformity while swelling settles. Functional bracing then applies circumferential support while leaving shoulder and elbow free, using gravity and muscle activity to align the shaft. Review skin, brace fit and radiographs early because obesity, large breasts, very proximal or distal fracture, comminution and inability to follow adjustments can reduce control. Acceptable angulation is a clinical and specialist judgement; rotational deformity and persistent distraction are poorly tolerated and cannot be assessed from one projection alone.
Map radial recovery sequentially. Brachioradialis and wrist extensors may recover before finger and thumb extension, while Tinel progression can support regeneration. Provide a cock-up wrist splint and maintain full passive finger and thumb range to prevent contracture and preserve grasp. If no clinical recovery appears at the expected interval, the specialist team may use ultrasound, MRI neurography or electrodiagnostic studies to locate continuity and plan exploration, graft or tendon transfer. Testing too early can be non-diagnostic and should follow the nerve pathway.
Operative fixation is selected for open fracture, arterial repair, polytrauma mobilisation, segmental or bilateral injury, pathological bone, failure of acceptable closed alignment or established nonunion. Plate fixation permits direct control of rotation and nerve inspection where indicated; intramedullary nailing offers another load-sharing option but can affect shoulder function. Exploration is especially considered when the nerve is exposed by the wound, lacerated, associated with vascular injury, or becomes newly deficient after intervention. The operative note should state nerve appearance and relationship to implants.
Recovery surveillance extends beyond union. Compare shoulder elevation, elbow extension, forearm rotation and hand opening; a united shaft with stiff neighbouring joints remains a poor outcome. Persistent pain or movement raises nonunion concern and requires mechanical, infection and metabolic assessment. After fragility or atypical fracture, investigate bone health, medicine exposure and the opposite femur or humerus when symptoms suggest a systemic process. In pregnancy or renal disease, adjust analgesia, imaging and thromboprophylaxis while maintaining the same limb-safety priorities.
Nonunion assessment separates mechanics from biology. Review original pattern, gap, implant stability, smoking, infection risk, nutrition, diabetes and medication exposure. Obtain orthogonal radiographs and, when needed, CT to define bridging. Infection work-up uses symptoms, wound history and appropriate blood and deep tissue sampling rather than superficial swabs alone. Revision may require compression, bone graft and different fixation, but treating infection and host factors is equally important. The patient needs realistic advice about work restriction and the staged nature of revision rather than endless brace continuation.
Radial palsy safety-netting is practical. Return urgently for new loss of wrist or finger extension, spreading numbness, severe brace pain or hand colour change. During observation, inspect the splint and skin and maintain supple MCP, PIP, DIP and thumb joints. Recovery is charted by muscle grade and distribution, not merely whether tingling is present. If tendon transfer becomes necessary after failed nerve recovery, preserved passive motion and strong donor muscles determine function, which is why early therapy remains valuable even before the final nerve outcome is known.
Key points
- Inspect the whole arm for wounds, deformity and skin pressure and examine shoulder and elbow because associated joint injury changes care.
- Before and after splintage, test wrist extension, finger MCP extension, thumb extension, dorsal first-web sensation, median and ulnar functions, pulses and refill.
- Obtain AP and lateral radiographs of the full humerus including shoulder and elbow; pathological features may require staging before definitive fixation.
- A closed primary radial palsy is commonly observed with fracture treatment and serial recovery assessment rather than explored automatically.
- Open fracture, vascular injury, penetrating laceration, irreducible entrapment or a new post-manipulation palsy lowers the threshold for urgent exploration.
- Many closed suitable fractures use initial splintage followed by a functional brace, with early shoulder and elbow movement and alignment review.
- Operative fixation is considered for open, vascular, pathological, polytrauma, segmental, failed closed or functionally unacceptable patterns.
- Provide a wrist-extension splint and hand therapy for radial palsy to preserve grasp, joint position and passive range during nerve recovery.
02AetiologyUnderlying causes, associations and risk factors, with why each one matters.
Direct bending trauma
A direct blow or collision bends the humeral shaft, producing transverse or comminuted fracture with variable soft-tissue and radial-nerve injury.
Torsional fall
A fall onto the arm applies rotation, commonly creating a spiral pattern through the middle or distal third.
Pathological fracture
Minimal force with preceding pain or abnormal bone can indicate metastasis, myeloma or another lesion requiring planned biopsy and fixation strategy.
03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.
- 1Radial-nerve proximity
The nerve travels in the spiral groove and crosses the lateral intermuscular septum, making it vulnerable in middle and distal shaft injury.
- 2Motor interruption
Radial dysfunction weakens wrist, finger and thumb extension, producing wrist drop and impaired hand opening despite preserved finger flexion.
- 3Sensory change
The autonomous sensory territory is the dorsal first web space, although overlap means motor testing is essential for reliable documentation.
- 4Fracture healing
Relative stability in a functional brace permits callus while gravity and muscle tone restore alignment; distraction, infection and smoking impair union.
04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.
Arm pain, swelling, shortening, angulation and crepitus follow direct or torsional trauma.
Wrist, finger and thumb extension weakness with dorsal first-web sensory change produces wrist drop.
Radial weakness present before treatment in a closed fracture often reflects stretch or contusion and may recover.
A new deficit after manipulation, brace fitting or fixation raises concern for compression, entrapment or iatrogenic injury.
Pulse loss, coolness, delayed refill or expanding swelling requires immediate limb-saving coordination.
05InvestigationsWhat to request, why it matters and how to interpret it.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
Full-length AP and lateral humeral radiographsFirst step - Why
- Define fracture and include both shoulder and elbow joints.
- Interpretation and limitations
- Assess length, angulation, rotation, comminution and abnormal bone; correlate alignment with function.
- 02
Serial named nerve examination - Why
- Establish injury timing and monitor radial, median and ulnar motor and sensory function.
- Interpretation and limitations
- Write individual movements and territories rather than a global normal label.
- 03
CT angiography when arterial injury is suspected - Why
- Locate vessel damage in a stable enough patient after urgent realignment.
- Interpretation and limitations
- Hard signs and persistent ischaemia can require direct operative treatment without imaging delay.
- 04
Electrodiagnostic testing for delayed recovery - Why
- Assess reinnervation and lesion severity when clinical recovery does not appear as expected.
- Interpretation and limitations
- Timing is specialist directed because very early testing may not define axonal loss fully.
06Differential diagnosisRealistic alternatives and the features that help distinguish them.
Posterior interosseous palsy
Finger and thumb extension are weak but wrist extension may remain through extensor carpi radialis longus, and cutaneous sensation is spared.
Brachial-plexus injury
Weakness and sensory loss across radial, median and ulnar territories suggests broader traction injury rather than isolated spiral-groove dysfunction.
Cervical radiculopathy
Neck pain, reflex change and a myotomal pattern can mimic radial weakness but does not explain the acute shaft deformity.
Compartment or vascular injury
Escalating pain, swelling, coolness, delayed refill or deteriorating function may reflect acute ischaemia rather than an isolated radial neurapraxia.
07ManagementImmediate care, first-line treatment, alternatives and escalation.
01First assessmentAlign and map nerve functionFirst stepA humeral-shaft fracture is suspected after trauma.+
- 1Use ABCDE for high energy, expose wounds and inspect shoulder, arm and elbow.
- 2Give analgesia and document pulses and radial, median and ulnar motor and sensory findings.
- 3Obtain full-length films, align and splint and repeat the identical examination.
02Closed suitable fractureBrace and preserve adjacent motionThe fracture is closed and acceptably aligned without vascular or tissue threat.+
- 1Transition from initial splint to functional brace according to swelling and fracture review.
- 2Encourage hand, wrist, elbow and shoulder movement within the stability plan and support radial palsy with a wrist splint.
- 3EscalationReview alignment, skin, union and nerve recovery at defined intervals and escalate loss of position or nonunion.
03Urgent operative patternFix bone and address nerve or vesselOpen injury, vascular compromise, new palsy, pathological bone or unstable pattern is present.+
- 1Start open-fracture or vascular protocols immediately and avoid serial referral delay.
- 2Plan fixation with direct nerve inspection when indication and mechanism support exploration.
- 3Document operative nerve continuity, postoperative function and a specific recovery or reconstruction follow-up plan.
Key medicines and prescribing safety2 treatments · regimens, roles and cautions+
Paracetamol for adult arm-fracture pain
For an adult, prescribe 500 mg to 1 g orally as required, with a minimum 4-hour interval and a maximum of four administrations in one day.Reduce the limit in low body weight or hepatic risk and count all combination products.
Intravenous prophylaxis for an open humerus
Give the locally approved intravenous open-fracture agent and dose as soon as possible and within 1 hour, adjusted for allergy, renal function and contamination.Do not delay for imaging or cultures, and do not use continued antibiotics to compensate for inadequate excision.
08ComplicationsImportant consequences, why they occur and why they matter clinically.
Radial-nerve palsy
Neurapraxia commonly recovers, while laceration, entrapment or failure of reinnervation can leave persistent wrist and finger extension loss.
Nonunion
Transverse pattern, distraction, smoking, infection or instability can produce persistent pain and movement requiring revision strategy.
Malunion
Some angulation is functionally tolerated, but substantial rotational error or shortening impairs shoulder and elbow mechanics and visible arm alignment.
Shoulder and elbow stiffness
Pain and prolonged immobilisation restrict both neighbouring joints, making early hand, wrist and joint rehabilitation important.
09Monitoring and follow-upTreatment response, safety checks and longer-term review.
- Repeat wrist, finger and thumb extension and dorsal first-web sensation after every intervention.
- Check brace skin pressure, swelling and distal perfusion as oedema changes.
- Measure shoulder and elbow motion and provide hand therapy during nerve recovery.
- Use serial radiographs and tenderness to assess alignment and union.
- Escalate new palsy, absent recovery, persistent fracture movement or infection signs through the named specialist pathway.
10Special situationsVariants, exceptions and circumstances that change the usual approach.
Timing classifies the palsy
A deficit present before treatment has a different risk profile from weakness first detected after reduction or surgery.
First web space is autonomous
This dorsal sensory area is useful, but preserved sensation never substitutes for wrist and finger motor testing.
Brace works dynamically
Functional support allows gravity and muscle activity to align the shaft while avoiding complete shoulder and elbow immobilisation.
Wrist support preserves hand use
Holding the wrist extended lets finger flexors generate grasp while denervated extensors recover.
11Common pitfallsFrequent interpretation and management errors.
- 01
Recording only hand sensation and missing radial motor weakness before manipulation.
- 02
Exploring every closed primary palsy automatically without considering its high spontaneous recovery rate.
- 03
Reassuring a new post-reduction palsy as routine without urgent reassessment.
- 04
Taking a cropped shaft film that excludes the shoulder or elbow.
- 05
Immobilising the whole upper limb until union and creating avoidable joint stiffness.