14 – Pins, Wires, Interlocking Nails Flashcards
What are the indications for surgical fracture repair? (internal fixation)
- Open fractures
- Fractures of humerus, femur and some fractures of pelvis, scapula, vertebral column, skull
- Articular fractures (otherwise have an edge that rubs)
- Many oblique or comminute fractures
- Avulsion fractures
What are the forces neutralized by intramedullary (IM) pins?
- *bending, but that’s it
o Why IM pinning is often combined with some other form of fixation
What determines if an IM pin will be enough?
- Nature of fracture
o If jagged, and align it perfectly=some torsion control
o If straight across=not as great at controlling torsion - Ex. fracture of growth plate of distal femur=many bumps
What direction is this fracutre?
-caudal medial
What are the two ways you can put a pin in?
- Normograde pin placement
- Retrograde Pin placement
Normograde pin placement
- Put fracture together, then run pin from one end of bone to the other end
*need to have fracture reduced already
Ex. tibia or ulna (tough with femur)
Retrograde pin placement
- Start at fracture site, open it
- Run pin up and then reduce fracture and run pin into the distal portion
- Ex. femur: need to think of sciatic nerve of avoid it (don’t want to have limb abducted, want to have it ADDUCTED and EXTENDED)
What is the diameter % of this rod?
-60% (on the lower end)
What are some IM pining rules?
- Use a pin with a diameter 60-80% of the medullary canal at its narrowest point
o Unless combining with external skeletal fixation (ESF) or plating=then can be 30-50% - Spear the pin into the cortex at the other end of the bone (from where you entered, but do NOT penetrate this cortex: don’t go all the way through)
- Avoid threaded IM pins: they do NOT prevent migration and they break
- Anatomic fracture repair is required
- *need a nonarticular projection at one end of bone to allow introduction or exit of your IM pin
What can pin migration or bad placement of pin do?
- Damage adjacent joints or soft tissues
- Ex. if pining femur and ‘hit’ the sciatic nerve
What are some bones that are good to pin?
- Humeral, femoral, tibial, olecranon, calcaneal fractures
- *NOT good for radial fractures
What kind of fracture is this and direction?
-short oblique
-lateral displacement
What are cross pins?
- Do NOT go up the medullary canal
- Engage a cortex on either side of the fracture
- Short and do NOT control bending well
o Good for distal fractures NOT proximal fractures
What is cross pin use limited to?
- Metaphyseal and physeal fractures, where the adjacent joint will bend instead of repair
What is pin and tension band fixation used for?
- Repair of fractures acted upon by a tensile force
- *when have upper pull by patella tendon=have a counter force
- *getting compression at the fracture site=cool technique
What is cerclage wiring?
- Circumferential wiring
- Used to augment other repairs
o NEVER used by itself - Helps control torsion and compression that causes shearing
- Minimal bending control
What are the principles of cerclage?
- Fracture MUST have a LONG oblique component to it
- Wires must be perpendicular to the bone and they must be TIGHT
- Must reconstruct the cylinder of the bone=NO gaps and NO mushing
What are interlocking nails used for?
- Hold pin in place with screws/bolts that go through the bone’s cortices as well as through the holes in the pin
- *anatomic reconstruction of fracture is NOT necessary with interlocking nail repair
- *compression, torsion, bending forces are accounted for (ALL)
What are the limitations of interlocking nails?
- Can be placed on: femur, humerus and tibia
- *used for fractures of diaphyseal fractures rather than fractures near bone
