Review Question - QID 8873

The recommended starting point on the tibia for guide wire and intramedullary (IM) nail fixation is at the medial edge of the lateral tibial eminence.

Tibial shaft fractures are commonly treated with IM nail fixation to allow relative stability and immediate weight bearing. Particularly for proximal third shaft fractures, deforming forces on the tibia often result in an apex anterior (procurvatum), valgus malalignment after rod placement. The deforming forces on the proximal segment are extensor mechanism extending the proximal fragment (causing apex anterior) and insertion at pes anserine medially (causing valgus). An appropriate starting point, use of temporary plating, a semi-extended knee position, and/or blocking screws placed posteriorly and laterally may all be used to prevent this deformity.

McConnell et al. conducted an anatomic and radiographic cadaveric study on 20 knees to evaluate a "safe zone" for tibial nailing. They conclude that wire entry point at the medial aspect of the lateral tibial spine (on the anteroposterior view) and just at or anterior to the edge of the anterior articular surface (on the lateral view) is a safe site for nail entry minimizing risk of damage to intra-articular structures.

Hak reviews proximal third tibial shaft fractures and multiple techniques to achieve adequate reduction. He describes Poller blocking screws (posterior and lateral placement), retropatellar approach in semi-extended position, and appropriate starting point, even suggesting a slightly more lateral position (directly on the lateral tibial eminence) can be helpful in proximal third fractures.

Figures A and B show an AP and Lateral of a tibial shaft fracture in mild flexion and valgus deformity.

Illustration A is from the Hak reference demonstrating starting point for tibial IM Nail on AP and Lateral views.

Incorrect answers:
Answer 1, 2, 4, 5 - The correct entry site for IM nailing of mid-shaft tibia fractures is at the MEDIAL edge of the LATERAL tibial eminence.