Elastic stable intramedullary nailing (ESIN) for displaced diaphyseal radius and ulna fractures | intermediate
Surgical Imaging
The trap: Placing the radial entry point too distal (within 1 cm of the physis) or using a dorsal starting point that crosses the growth plate — risks iatrogenic physeal injury and premature closure with radial shortening and wrist deformity.
The fix: Identify the physis on fluoroscopy; place the entry point 1.5-2 cm proximal in the metaphyseal flare on the radial border. Use a 15-degree oblique trajectory that stays within the metaphysis. Confirm the guidewire position in both planes before reaming or nail insertion.
Location: The superficial branch of the radial nerve emerges from beneath the brachioradialis 8-10 cm proximal to the radial styloid and lies immediately subcutaneous and radial to the planned entry point.
Risk: A percutaneous or minimally invasive approach without direct visualisation can transect or stretch the nerve, causing permanent dorsal radial hand numbness. In children the nerve is proportionally larger relative to the incision.
Protection: Use a 2 cm longitudinal incision, identify the nerve under direct vision or with blunt spreading dissection, and protect it with a vessel loop or retractor throughout nail insertion and removal.
Location: The PIN exits the supinator 1 cm distal to the radial head and lies on the radial neck in the interval between the radial and ulnar bones — directly in the path of a proximal radial nail that is too long or poorly contoured.
Risk: An overly long radial nail that protrudes into the radial head or an aggressive proximal reduction manoeuvre can compress or lacerate the PIN, causing finger and thumb extension weakness.
Prevention: Choose nail length so the tip stops 1 cm short of the radial head; avoid over-insertion and confirm final nail position fluoroscopically in the lateral view.
The mechanism: Straight nails or nails inserted without pre-contouring restore length but eliminate the normal 15-20 degree radial bow; the radius heals straight and rotation is permanently lost.
Clinical consequence: Patients lose 20-40 degrees of combined pronation-supination; the deficit is not correctable by later osteotomy once the fracture has united in malposition.
Prevention: Pre-contour both nails with a gentle 15-20 degree bow matching the normal radius; insert the radial nail with the bow oriented radially; verify the bow on the immediate post-operative AP radiograph and accept no less than 12-15 degrees.
Why higher risk: Children have smaller compartment volumes, more swelling from the fracture haematoma, and may not verbalise early symptoms; both-bone fractures and floating-elbow patterns carry the highest risk.
Warning signs: Increasing analgesia requirement, agitation, disproportionate pain on passive stretch, tense forearm compartments. Do not wait for the classic 5 P signs — they appear late.
Action: Measure compartment pressures if clinical doubt exists (threshold greater than 30 mmHg or delta pressure less than 30 mmHg); proceed to fasciotomy without delay. Prophylactic fasciotomy is considered in high-risk patterns with prolonged surgery or severe swelling.
Incidence: Up to 10 percent within 6 months of elective nail removal; the risk is highest in the first 4-6 weeks after hardware removal when the stress-riser effect of the empty canal is maximal.
Prevention: Delay elective removal until at least 6-12 months after radiographic union and clinical consolidation. Protect the forearm in a well-moulded above-elbow cast for 4-6 weeks after removal; restrict contact sports for 3 months.
Management: If refracture occurs, treat with cast immobilisation if acceptable alignment can be maintained; otherwise repeat flexible nailing or convert to plate fixation.
F.O.R.E.A.R.MFOREARM — Flexible Nailing Principles
N.A.I.LNAIL — Step-by-Step Insertion Sequence
Surgical Indications
Absolute Indications
- Irreducible displaced both-bone diaphyseal forearm fracture after attempted closed reduction
- Unstable fracture pattern with greater than 50 percent translation or greater than 15 degrees angulation after reduction
- Open both-bone forearm fracture (Gustilo I-II) requiring debridement and stabilisation
- Floating elbow injury (ipsilateral supracondylar humerus and forearm fracture) with unstable forearm segment
- Neurovascular compromise requiring exploration and fracture stabilisation
Relative Indications
- Older child (greater than 10-12 years) approaching skeletal maturity where remodelling potential is limited
- Failed closed reduction with unacceptable alignment on post-reduction radiographs
- Polytrauma patient requiring reliable fixation for early mobilisation and nursing care
- Recurrent fracture or refracture of a previously healed forearm fracture
Acceptable for Cast Treatment (Younger Children)
- Children younger than 8-10 years with acceptable closed reduction (less than 15 degrees angulation, less than 50 percent translation, maintained radial bow)
- Greenstick or plastic deformation patterns with good remodelling potential
- Isolated radius or ulna fracture with acceptable alignment
Contraindications
Absolute:
- Active infection at planned entry sites
- Severe open fracture with segmental bone loss requiring external fixation or other reconstruction
- Patient too small for available implant diameters (nail must be at least 40 percent of canal diameter)
Relative:
- Skeletally mature adolescent — consider plate fixation instead
- Severe comminution or segmental fracture where length stability cannot be achieved with nails alone
Evidence for Flexible Intramedullary Nailing
Why ESIN Over Cast or Plate Fixation
- Maintains length, alignment and rotation while allowing early motion
- Lower refracture rate than cast treatment in older children
- Avoids extensive surgical exposure and periosteal stripping required for plate fixation
- Implant removal is simpler than plate removal and can be performed as a day-case procedure
Key Evidence
- Meta-analyses and prospective series show greater than 90 percent excellent or good functional outcomes (Price criteria) when radial bow and rotation are restored
- Complication rates are acceptable (nerve injury less than 2 percent, compartment syndrome 1-3 percent, refracture 5-10 percent) when technique is meticulous
- Loss of radial bow greater than 10 degrees is the strongest predictor of poor rotation outcome
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
“A 9-year-old boy sustains a displaced both-bone forearm fracture after a fall from a climbing frame. Closed reduction under general anaesthesia achieves 40 percent translation and 20 degrees angulation. What is your management?”
“You are about to remove flexible nails from a 10-year-old girl 14 months after both-bone forearm nailing. The fracture is solidly united. What specific risks do you discuss with the family and how do you mitigate them?”
“A 7-year-old child with a both-bone forearm fracture develops increasing forearm pain and swelling 18 hours after flexible nailing. The child is agitated and requires escalating analgesia. What is your assessment and management?”