Muscular Pronation in First Metatarsal After Hallux Valgus Osteotomies: A Biomechanical Simulation Study

Area of Science:

• Orthopedic Surgery
• Biomechanics
• Foot and Ankle Research

Background:

• Metatarsal pronation is a key factor in hallux valgus recurrence post-osteotomy.
• The degree of pronation correction varies unpredictably after distal metatarsal I osteotomies.

Purpose of the Study:

• To investigate how the angle of metatarsal I osteotomy influences muscular torque on the first metatarsal.
• To determine if variations in the transverse cut angle affect pronating torque.

Main Methods:

• Simulated distal metatarsal I corrective osteotomy on three 3D foot models.
• Varied the transverse cut angle (-10°, 0°, 10°) during simulated osteotomy.
• Calculated pronating/supinating torque and muscle components for eight muscles acting on the first metatarsal.

Main Results:

• No significant difference in pronating/supinating torque was observed between different osteotomy angles.
• Lateral shifting of the metatarsal I head in ReveL osteotomy consistently increased supinating torque.
• A trend towards reduced muscular pronating torque was noted for all ReveL osteotomies compared to the native state.

Conclusions:

• The angle of the transverse cut in distal metatarsal I osteotomy does not significantly alter muscular torque.
• ReveL osteotomy's lateral shift component appears to enhance supination, potentially mitigating pronation.
• Further research may elucidate the clinical implications of this induced supination on hallux valgus recurrence.