OUTLINE
• Patient brief history
• Approach to interlocking nail of tibia
• Length and working length
• Patient’s outcome
• References
Brief history
• 29 years old malay gentleman
• No known comorbids
• Alleged MVA, sustained closed comminuted fracture midshaft of left tibia
• Planned surgery: Interlocking nail
Approach to interlocking nail of tibia
• Patient is placed on supine position
• Left lower limb is clean and drapped
• Figure of 4 position is used
• Skin incision is extended about 3cm proximal to the tibial plateau at the anterior aspect of the left knee
• Patella tendon is incised longitudinally in line with the medullary cavity
IN THE FRONTAL PLANE: IN LINE WITH THE MEDULLARY CANAL (3 MM MEDIAL OF THE TIBIAL CREST)IN THE SAGITTAL PLANE: JUST DISTAL TO THE ANGLE BETWEEN TIBIAL PLATEAU AND ANTERIOR TIBIAL METAPHYSIS
ENTRY POINT
• Solid curved awl is used to create an entry point for nail
• Fracture is reduced and ball-tipped guide wire is inserted
• Medullary cavity is reamed starting from smaller size reamer. Medullary cavity should be reamed 1 size larger than the intended nail
• Tissue protector is used during reaming procedure• Daflon is inserted and straight guide wire is inserted to
replaced the ball-tipped guide wire• Length of the nail is measured using radiographic ruler• Nail of appropriate length and diameter is inserted • Guide wire is removed and proximal and distal locking
screws are inserted• Patella tendon is repaired , paratenon is sutured.
Subcutanous tissue and skin is closed
Length and working length
• Total nail length
• Length of nail-bone contact
– Larger the contact area, the higher the resistance to motion
• Working length
Total nail length
• Too long a nail protruding at the insertion site causes pain and limitation on motion
• Too short a nail compromises fixation
Length of nail bone contact
• Total surface area of contact between the nail and bone
• Larger the contact, higher the resistance to motion
• Reflects the nail carrying the major load of stress across the fracture site
• Bending stiffness of a nail is inversely proportional to square of its working length
• Torsional stiffness is inversely proportional to its working length
• Conclusion: shorter working length means stronger fixation
• 2 ways of modifying the working length:1. Medullary reaming2. Interlocking