SURGICAL MANAGEMENT

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.

 

 

 

FIG 1 • Line diagram showing the closing wedge osteotomy.

 

 

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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).

 

 

 

 

TECH FIG 1 • A. The adductor hallucis tendon is released off the proximal phalanx and fibula sesamoid. The suspensory ligaments of the fibula sesamoid are released. B. Medial capsulotomy and exostectomy.

 

 

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.

• Osteotomy

   

  Extend the first web space incision in an S shape to the first MC joint (TECH FIG 2A).

   

  Approach the dorsal metatarsal shaft through the interval between the extensor hallucis brevis and extensor hallucis longus.

   

  Retraction with two small pointed retractors facilitates exposure of the metatarsal base.

   

  The proposed wedge for resection has its apex on the medial cortex about 3 mm from the MC joint. The proposed long oblique osteotomy should leave a large residual proximal fragment for maximal contact area and solid fixation.

   

   

   

  TECH FIG 2 • A. The web space incision is extended proximally in a lazy S shape toward the base of the first metatarsal. The extensor hallucis brevis is identified and protected. B. The first tarsometatarsal joint

  is localized to define the limit of the cut. (continued)

   

   

  The first cut, the proximal of the two, is perpendicular to the weight-bearing axis of the foot. This is demonstrated during surgery by the simulated weight-bearing test. To maintain control of the osteotomy, the medial cortex is scored but not penetrated with the saw blade (TECH FIG 2B).

   

  After making the second distal cut, excise a lateral wedge-shaped wafer of bone; this leaves a defect, which is compressed with a towel clip. This “greensticks” the intact but weakened medial cortex and the IMA is reduced (TECH FIG 2C-E).

   

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  TECH FIG 2 • (continued) C-E. The two osteotomies leave a wedge-shaped segment of bone, which is removed.

• Reduction, Fixation, and Closure

 

Insert two 2.7-mm cortical screws (Synthes, Paoli, PA) from the lateral to medial cortex in a lag screw fashion (TECH FIG 3A,B).

 

The small size of the proximal fragment does not allow both screws to be parallel to the osteotomy, but this is not vital, as compression has already been obtained with the reduction forceps.

 

 

 

TECH FIG 3 • A. Compression with the clamp greensticks the medial cortex. B,C. Two screws are inserted in a lag screw fashion. D. The capsule is repaired. The skin is closed.

 

 

Confirm the reduction in the IMA, screws, and relocation of the sesamoids with image intensification.

 

Imbricate the medial capsule with a strong absorbable suture while holding the hallux in a neutral or slightly abducted position (TECH FIG 3C).

 

Close the wounds in layers with interrupted nylon sutures to the skin and apply a forefoot bandage to maintain the correction (TECH FIG 3D).

 

 

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PEARLS AND PITFALLS
		Keep the	The apex of the deformity is the MC joint. To maximize the power of the

 

	center of osteotomy, the center of correction should be as close to the joint as possible, correction leaving a safe bridge of medial cortex. proximal.     Beware the ▪ If the osteotomy is too short, it will exit the lateral cortex too proximally, leaving a short small proximal fragment. This compromises the contact area and stability of the osteotomy! osteotomy, precludes adequate fixation, and decreases the corrective power of the osteotomy.     Maintain ▪ By only scoring the medial cortex, complete control of the osteotomy segments is continuous maintained at all times. control of the osteotomy.     Avoid early ▪ The excessive sagittal loading can lead to a dorsiflexion malunion. full weight bearing.

 

 

POSTOPERATIVE CARE

 

If safe, patients are discharged home on the day of surgery with strict advice to elevate the foot whenever resting for the first 2 weeks.

 

In most cases, patients are allowed to bear weight on their heel and lateral forefoot in a hard-soled postoperative shoe.

 

In noncompliant patients or those with poor bone quality and fixation, we do not hesitate to use cast immobilization from the outset.

 

The wound is inspected and sutures are removed at 2 weeks, at which time, the hallux is restrapped and patients are taught simple passive and active toe flexion-extension exercises.

 

At 6 weeks postoperatively, the osteotomy is assessed with radiographs (FIG 2).

 

 

If there is some consolidation at the line of the osteotomy, the patient is instructed to wear a wide shoe or sneaker and to progress weight bearing as tolerated.

 

 

 

FIG 2 • A-D. Preoperative and postoperative radiographs.

 

 

Strapping of the hallux is discontinued at this time.

 

If there is evidence of a delayed union, the patient is kept non-weight bearing in a hard-soled postoperative shoe.

 

 

OUTCOMES

A review of our first 40 cases with an average age at surgery of 51 years identified one case of transfer metatarsalgia in a patient who had not had it before surgery, one malunion due to loss of fixation, one delayed union requiring prolonged immobilization, and one asymptomatic nonunion. Shortening of the first metatarsal was minimal with this technique, with an average of 0.98 mm (-1 to 3 mm).

In the subset of 11 patients with a severe deformity and an IMA exceeding 18 degrees (range 18 to 22 degrees), the average postoperative IMA was 7.8 degrees, with an average 1.8 mm of shortening.

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Some studies have reported more shortening (average of 5 mm) with similar osteotomies, but this may be due to two factors:

A transverse rather than long oblique closing wedge osteotomy

Dorsiflexion malunion, which may make the metatarsal appear shorter on radiographic evaluation

The stability of this osteotomy is not compromised even when correcting hallux valgus with a large intermetatarsal deformity. This is in contrast to the Scarf, Ludloff, and proximal crescentic osteotomies in

which bone contact area is substantially reduced.

 

 

COMPLICATIONS

Complications include those of any hallux valgus surgery: iatrogenic fracture, injury to the dorsal medial cutaneous nerve, superficial infection, loss of fixation, and delayed union.

The risk of iatrogenic fracture can be minimized by using appropriate-diameter screws, leaving a bridge of at least 3 mm between screws, and both drilling and tapping the near cortex (even when using a self-tapping screw).

 

 

SUGGESTED READINGS

1. Mann RA, Rudicel S, Graves SC. Repair of hallux valgus with a distal soft-tissue procedure and proximal metatarsal osteotomy: a long-term follow-up. J Bone Joint Surg Am 1992;74A:124-129.

    

    

2. Ruch JA, Banks AS. Proximal osteotomies of the first metatarsal in the correction of hallux abducto valgus. In: McGlamry ED, Banes AS, Downey MS, eds. Comprehensive Textbook of Foot Surgery. Baltimore: Williams & Wilkins, 1987:195-211.

    

    

3. Trnka HJ, Muhlbauer M, Zembsch A, et al. Basal closing wedge osteotomy for correction of hallux valgus and metatarsus primus varus: 10- to 22-year follow-up. Foot Ankle Int 1999;20:171-177.

    

    

4. Trnka HJ, Parks BG, Ivanic G, et al. Six first metatarsal shaft osteotomies: mechanical and immobilization comparisons. Clin Orthop Relat Res