Review Question - QID 218834

Excessive lateral guidewire positioning during insertion of a trochanteric intramedullary nail can cause a varus deformity postoperatively.

Intertrochanteric hip fractures are extracapsular hip fractures of the proximal femur that are most commonly seen in the elderly population with osteoporotic bone. Stability is based on the fracture pattern seen on radiographs and may help guide treatment. Fractures with subtrochanteric extension are deemed unstable and typically require cephalomedullary nailing. Different nail designs exist that utilize different starting points. These include the piriformis start, trochanteric start and lateral entry nails. The most popular starting point is the tip of the greater trochanter but appropriate guidewire positioning must be scrutinized and confirmed on fluoroscopy before proceeding to entry reaming and nail passage. The most common mistake is excessively lateral placement of the initial guidewire which can cause lateral cortical gapping and varus malreduction of the fracture site.

Nicolaou et al. reviewed the choice of hip nail starting points and proximal screw configurations. They note that the fracture pattern, patient characteristics (body habitus, bone quality, overall health), and implant choice contribute significantly to start point decision. They go on to discuss technical pearls regarding start point placement and discuss additional configurations for proximal screw configuration.

Ostrum et al. reviewed the effect of eccentric starting points when using a trochanteric entry point for an intramedullary femoral nail. They used multiple trochanteric-entry nails in 21 different cadavers and used start points at the tip of the greater trochanter and both 3 mm lateral and medial. They noted that starting points at the tip of the greater trochanter achieved neutral alignment in all cases, whereas lateral starting points led to varus malreduction in all cases.

Figure A is an example of a trochanteric starting point that is positioned too far lateral. Illustration A demonstrates a trochanteric starting point that is appropriately positioned.

Incorrect Answers:
Answers 1, 3-5: Varus is the most likely deformity seen with a trochanteric start point that is too lateral.