Landmarking an Extra-Capsular Position for Minimally Invasive Transverse First Metatarsal Osteotomy for Hallux Valgus...

Area of Science:

• Orthopedic Surgery
• Foot and Ankle Reconstruction
• Surgical Anatomy

Background:

• Minimally invasive hallux valgus reconstruction techniques are evolving.
• The fourth-generation technique utilizes a transverse metatarsal osteotomy.
• Precise osteotomy placement is crucial for optimal outcomes and avoiding complications.

Purpose of the Study:

• To identify a distal, extra-capsular osteotomy location for fourth-generation hallux valgus reconstruction.
• To assess the impact of this osteotomy on the blood supply to the capital fragment of the first metatarsal.

Main Methods:

• Cadaveric specimens were used to map the first metatarsophalangeal (MTP) joint capsule using radiopaque contrast.
• Radiographic measurements determined distances from the metatarsal head and sesamoids to the capsule.
• Minimally invasive transverse osteotomies were performed under fluoroscopic guidance, followed by anatomical dissection to evaluate vascular integrity.

Main Results:

• The mean distance from the articular surface to the capsule's proximal edge was 27.3 mm.
• An osteotomy at 29.5 mm from the articular surface was extra-articular in 80% of specimens.
• All dissections confirmed extra-capsular placement and preserved vascular supply to the capital fragment.

Conclusions:

• The first MTP joint capsule's insertion varies, necessitating reproducible intraoperative guidance.
• A transverse osteotomy at 29.5 mm provides a reliable extra-capsular position in most cases.
• This technique preserves the vascular supply to the capital fragment during minimally invasive hallux valgus reconstruction.