Proximal Chevron Osteotomy with Plate Fixation

Correction of major bunion deformities through the proximal portion of the first metatarsal is widely recognized as the established method of reducing the angle between the first and second metatarsal.^3–6

More than 138 techniques have been described for bunion correction, with widely varied methods of fixation of these osteotomies including pins or screws.

Pins provide little inherent stability and have been associated with postoperative infections.

Getting excellent fixation of screws can be a problem in cases in which there is poor bone quality.

Plates, although widely used in all other osteotomies, have not been routinely employed in bunion surgery because of the fear of prominence and irritation of the patient’s foot.

Recently, the use of locking plates and locking screws has been increasing in the orthopaedic world. The locking plates provide a fixed-angle device, which allows for a potentially stronger method of fixation.⁴

The advantages of plate fixation for the patient include no external pins, potentially no second procedure to remove hardware, less pain because the osteotomy is stable, and early full or at least partial weight bearing.

Advantages for the surgeon are that it is possible to do any osteotomy for the first metatarsal and that excellent and secure fixation is obtained.

Although many different configurations of the osteotomy can be used, the proximal chevron osteotomy permits a greater degree of correction compared with distal osteotomies. It does this through both an angular and translational displacement of the distal portion of the first metatarsal.²

SURGICAL MANAGEMENT

Approach

The procedure is performed through a single midmedial longitudinal approach to the first metatarsal with the use of an Esmarch tourniquet (FIG 1) or pneumatic calf tourniquet.

TECHNIQUES

Exposure

The skin and subcutaneous tissues are incised sharply to expose the first metatarsophalangeal joint capsule. Care is taken to protect the medial dorsal and plantar cutaneous nerves.

A vertical capsular resection is performed to remove about 3 to 5 mm of capsule just proximal to the base of the proximal phalanx (TECH FIG 1).

A longitudinal incision may also be made in the capsule, excising the midportion.

A dorsomedial incision is made in the capsule parallel to the first metatarsal, creating a plantarly based capsular flap with exposure of the medial eminence.

Release of Lateral Joint Structures

The lateral soft tissues are released from within the metatarsophalangeal joint after distraction of the sesamoids from the first metatarsal with a lamina spreader.

First, use a blunt Freer elevator to develop some room and then cut the capsular tissue with a sharp no. 15 blade (TECH FIG 2).

• The medial approach to the release avoids making a separate 1 to 2 incision, and the medial incision is just as effective.^1,6 It is no longer necessary to make a separate 1 to 2 incision to release the lateral capsule. And it has been shown that release of the adductor does not significantly improve the ability to correct hallus valgus.²

Complete release can be confirmed when the great toe can be brought into about 15 degrees of varus through the metatarsophalangeal joint.