Structures at Risk From an Intermetatarsal Screw for Lapidus Bunionectomy: A Cadaveric Study

Area of Science:

• Orthopedic Surgery
• Foot and Ankle Surgery
• Surgical Anatomy

Background:

• The Lapidus bunionectomy is a surgical procedure to correct hallux valgus.
• Recurrence of hallux valgus after surgery is a clinical concern.
• Transverse intermetatarsal screw fixation at the base of the first and second metatarsals can enhance surgical stability.

Purpose of the Study:

• To assess the anatomical risks associated with using a transverse intermetatarsal screw in the modified Lapidus procedure.
• To evaluate the proximity of the neurovascular bundle to the screw placement.
• To determine the potential for iatrogenic injury to the neurovascular structures.

Main Methods:

• Ten cadaveric foot specimens were utilized for the study.
• A guide wire and a 4.0-mm cannulated screw were inserted across the first and second metatarsals.
• The neurovascular bundle was dissected and inspected for direct trauma; distances were measured using a digital caliper.

Main Results:

• In 9 out of 10 specimens, the dorsalis pedis artery and deep peroneal nerve were not injured, with the neurovascular bundle located dorsally to the screw.
• The mean distance from the screw to the neurovascular bundle was 7.1 ± 3.3 mm.
• One specimen demonstrated the screw traversing through the neurovascular bundle.

Conclusions:

• While the intermetatarsal screw placement generally avoids the neurovascular bundle, there is an inherent anatomical risk.
• The study highlights the importance of careful screw placement to minimize potential neurovascular complications.
• Further clinical studies are warranted to correlate these anatomical findings with patient outcomes.