Limb Lengthening Library
Internal Nail vs External Fixator
Where the Devices Go
Refer to the labeled bone anatomy on the left as you read the descriptions on the right
OpenStax Anatomy & Physiology
(CC BY 4.0)
🔵 Internal Nail → Medullary Cavity
Find "Medullary cavity" in the image. An internal nail is inserted into this canal and remains beneath the skin. Incisions and locking screws are still required, and the implant has its own infection and mechanical risks.
🟠 External Fixator → Through Cortical Bone
Find "Cortical bone" — the dense outer wall. External fixator pins drill through this layer, passing through the "Periosteum" and surrounding soft tissue. Each pin site is a potential infection entry point.
📍 Osteotomy → Planned Bone Segment
The osteotomy level is selected for the anatomy, correction plan, fixation method, and local biology. Preserving the periosteum and surrounding blood supply supports regenerate formation.
🩸 Blood Supply — Must Protect
The nutrient artery and periosteal circulation both contribute to bone health. Surgical technique aims to limit unnecessary disruption while achieving the planned correction.
Potential benefits
No external frame during distraction
No transcutaneous pin sites
Device remains beneath the skin
Daily adjustments may use an external controller
Planning considerations
Requires compatible anatomy and canal dimensions
Loading limits depend on the exact implant and plan
Implant, insertion, and removal can add costs and procedures
Correction options depend on the nail and operative strategy
Potential benefits
Can be used when an internal canal is unsuitable
Some frame systems permit multiplanar adjustment
Hardware can be modified during treatment
Loading options depend on the frame construction and plan
Planning considerations
Pins or wires cross skin and soft tissue
Requires frame and pin-site care
Visible external hardware affects daily activities
Pin-tract and deeper infection risks require monitoring
Questions for Method Comparison
No external frame
Skin interface
Pins or wires cross skin
Canal must fit implant
Anatomy
May suit a narrow canal
Nail- and plan-specific
Correction options
Frame-dependent, often multiplanar
Controller and incision care
Daily care
Frame adjustment and pin-site care
Implant-specific limits
Loading
Construction-specific limits
Compare total care episode
Cost
Compare total care episode
Method choice is case-specific. Published cohorts differ in indication, anatomy, device generation, follow-up, and how adverse events are counted. A rate from one study should not be treated as a forecast for another patient.
Bone anatomy: OpenStax (CC BY 4.0). Comparison framework informed by peer-reviewed limb reconstruction literature; current device labeling governs device-specific use.
Educational reference only. Not medical advice. Device status, treatment parameters, and emergency instructions must be confirmed with current official sources and the treating team.