Femur TENS procedure: 10 steps

1. Confirm indication and plan
   • Obtain AP and lateral radiographs of the entire femur.
   • Best suited to a skeletally immature child with a length-stable, transverse or short-oblique diaphyseal fracture.
   • Measure the canal and select two equal-diameter nails, usually each approximately 40% of the narrowest canal diameter.
2. Anaesthesia, antibiotics, and positioning
   • Give general anaesthesia and perioperative antibiotic prophylaxis.
   • Position supine on a radiolucent table, with the complete femur visible on image intensifier in AP and lateral planes.
3. Closed reduction
   • Apply gentle traction and correct length, angulation, translation, and rotation under fluoroscopy.
   • Open reduction is reserved for an irreducible fracture or interposed soft tissue.
4. Mark distal entry sites
   • For the usual retrograde technique, make medial and lateral entry points in the distal femoral metaphysis.
   • They should be about 2-3 cm proximal to the distal femoral physis and must not injure the physis.
5. Make skin incisions and create cortical openings
   • Make small medial and lateral incisions.
   • Protect soft tissues, especially medially.
   • Use an awl or drill to make an oblique cortical entry hole directed into the medullary canal.
6. Prepare the two nails
   • Pre-bend both nails into smooth, similar curves.
   • The apex of each curve should be planned near the fracture level so opposing nails create balanced three-point fixation.
7. Insert the first nail
   • Insert the first nail through one distal entry point and advance it up the canal to just below the fracture.
   • Keep fluoroscopic control and avoid cortical perforation.
8. Insert the second nail and cross the fracture
   • Insert the second nail from the opposite side to the fracture level.
   • Reduce the fracture and advance each nail across it under fluoroscopy.
   • Confirm restoration of length, coronal and sagittal alignment, and rotation.
9. Advance and seat nail tips
   • Advance the medial and lateral nails to divergent proximal positions, avoiding the proximal femoral physis.
   • Cut the distal ends short enough to reduce irritation but leave enough length for later removal.
   • Bend and recess the nail ends appropriately.
10. Final imaging, closure, and postoperative care

• Obtain AP and lateral fluoroscopic views of the entire femur to verify reduction, nail position, and absence of physeal penetration.
• Irrigate and close the small wounds.
• Provide analgesia and an individualized plan for weight bearing, physiotherapy, and follow-up radiographs. Nail removal is commonly considered after union, depending on local practice and symptoms.

Key technical points

• Use two equal-sized, symmetrically prebent nails for balanced fixation.
• The nails should be inserted from opposite sides and their tips should diverge proximally.
• Avoid both distal and proximal physes.
• Confirm rotation clinically and fluoroscopically before finishing.
• Nail-end prominence can cause painful skin irritation and is a common minor complication.

Important limitations