Closing Wedge Proximal Osteotomy

The primary indication for a proximal closing wedge osteotomy is a symptomatic hallux valgus deformity with a first intermetatarsal angle (IMA) of 14 degrees or greater.

The first metatarsocuneiform (MC) joint should be stable. We evaluate stability of this joint both by physical examination and radiographs. On physical examination, the cuneiform is stabilized in one hand while the first metatarsal is translated superiorly and inferiorly with the other hand. On weight-bearing radiographs, the MC joint is inspected for incongruency on the anteroposterior (AP) view and plantar widening on the lateral view. We favor a Lapidus-type procedure for hallux valgus associated with first MC joint instability.

Relative contraindications to this osteotomy include mild osteoarthritic changes in the first metatarsophalangeal (MTP) joint and the presence of an inflammatory arthropathy. In the presence of mild osteoarthritic changes, an active individual who understands the possible future need for a fusion may remain a candidate for a corrective osteotomy. Similarly, given the improved medical management of inflammatory arthropathy, an informed patient with well-managed rheumatoid arthritis may also be a candidate for reconstructive hallux valgus surgery rather than fusion.

Absolute contraindications to this osteotomy are advanced osteoarthritis of the first MTP joint or the skeletally immature patient, in whom the very proximal nature of this osteotomy can jeopardize the growth plate.

Preoperative Planning

AP and lateral weight-bearing radiographs of the foot are evaluated for metatarsal length, IMA, and hallux valgus angle. Congruency of the joint, the size of the bony medial eminence, and the position of the sesamoids are noted. We routinely mark the proposed osteotomy on the radiograph (FIG 1).

Positioning

We perform this procedure on an outpatient basis. Prophylactic antibiotics are administered. A thigh tourniquet is applied. The patient is positioned supine with a small sandbag placed under the ipsilateral buttock to ensure the foot points up, allowing for easier osteotomy orientation.

Approach

We perform the proximal closing wedge osteotomy with a distal soft tissue procedure through two incisions.

The first is a dorsal first web space incision extended proximally in a lazy S curve to the dorsal first MC joint. This incision allows access for lateral release and proximal osteotomy.

The second medial midaxial incision over the first MTP joint is the traditional approach for medial capsulotomy, medial eminence resection, and medial capsular plication.

TECHNIQUES

Soft Tissue Release and Bunionectomy

Perform a standard lateral release of the first MTP joint through a dorsal incision centered over the first web space.

After incising the skin, continue deep dissection bluntly.

Using sharp dissection, release the tendinous insertion of the adductor hallucis muscle onto the fibular sesamoid and proximal phalanx; we have not found it necessary to reattach this structure proximally (TECH FIG 1A).

Release the suspensory metatarsal–sesamoid ligaments and make multiple sharp perforations in the lateral capsule at the joint line. Apply a varus force to the hallux, completing the capsular release.

Approach the medial eminence through a midline longitudinal incision extending from just proximal to the medial eminence to the base of the proximal phalanx. Identify the dorsal medial cutaneous nerve and incise the medial capsule sharply in a longitudinal direction (TECH FIG 1B). Expose the medial eminence and resect it 1 mm medial to the sagittal sulcus. Overresection can lead to a postoperative varus deformity.