Anatomic considerations for retrograde fibular medullary screw insertion: a cadaveric study

Area of Science:

• Orthopedic Surgery
• Anatomy
• Biomechanics

Background:

• Retrograde fibular medullary screws offer a treatment option for specific ankle fractures.
• Understanding the proximity of this fixation method to surrounding anatomy is crucial for surgical safety.

Purpose of the Study:

• To investigate the anatomical considerations of retrograde medullary screw insertion from a lateral starting point in the distal fibula.
• To assess the proximity of the screw and its insertion trajectory to nearby neurovascular and ligamentous structures.

Main Methods:

• Ten fresh-frozen cadaveric lower extremities were dissected.
• A Kirschner wire and drill bit were inserted from a lateral starting point in the distal fibula.
• Measurements were taken from the drill bit and a subsequent 4.5-mm screw to adjacent tendons, nerves, and ligaments.

Main Results:

• The mean distance from the drill bit to the sural nerve was 4.13 mm and to the peroneus longus tendon was 4.56 mm.
• The mean distance from the 4.5-mm screw head to the anterior talofibular ligament (ATFL) was 4.16 mm and to the calcaneofibular ligament (CFL) was 5.14 mm.
• Anatomic structures were found to be in close proximity but not immediately adjacent to the screw trajectory.

Conclusions:

• Retrograde medullary fibular screw fixation via a lateral starting point is anatomically feasible and potentially safe.
• Careful consideration of lateral ankle anatomy is necessary during the retrograde fibular screw insertion procedure.