Proximal Realignment: Treatment of Moderate to Severe Hallux Valgus Deformities

Gordon R. Goplen, M.D., FRCSC
Edmonton, AB

Introduction

A hallux valgus deformity can be the result of anatomical abnormalities at a variety of points along the first ray. Moderate to severe hallux valgus deformities are usually the result of an increased intermetatarsal (IM) angle and an incongruent metatarsophalangeal (MTP) joint. An abnormal distal metatarsal articular angle (DMAA) may also be present and should not be overlooked. Generally, the procedure or procedures selected to correct a hallux valgus deformity should address the specific anatomical abnormalities causing the deformity. The degree as well as the type of deformity is also important. One of the most powerful tools we have for the correction of a hallux valgus deformity is the proximal osteotomy. It should be considered for the correction of the more severe hallux valgus deformities, often in conjunction with other procedures.

History and Physical Examination

Patients with a moderate or severe hallux valgus deformity usually have medial eminence pain and/or transfer metatarsalgia underneath the second metatarsal head. The deformity will increase and any clawing of the adjacent digit should become more apparent when the patient is weight bearing. Pronation is associated with significant deformity at the level of the MTP joint. Range of motion should be painless unless there are coexisting degenerative changes. A thorough examination of the foot always includes an assessment of the neurovascular status.

Radiographic Findings

Standing films are required to assess a hallux valgus deformity accurately. A deformity becomes classified as moderate when the hallux valgus angle is in the range of 20 to 40 and the intermetatarsal (IT) angle is between 11 and 161. Specific attention should be paid to the intra-articular portion of the first ray. Incongruity, degenerative change or a DMAA exceeding 10-15 should be factored into the operative plan2.

Figure 1

Hallux valgus (increased IM angle, incongruent MTP joint, normal DMAA. overlapping claw toes).


Indications and Contraindications

The major indication for a proximal osteotomy is a moderate or severe hallux valgus deformity produced in part or in whole by an intermetatarsal angle exceeding 133. The arc of a circle corresponding to an angle of one degree increases in direct proportion to the radius of the circle. A proximal osteotomy will therefore produce more lateral movement distally than a distal osteotomy for a given number of degrees of correction. Contraindications include significant degenerative disease of the MTP joint and metatarsus adductus. This is because a hallux valgus correction will tighten up the MTP joint making an arthritic joint more symptomatic. Metatarsus adductus is a problem because it limits the lateral rotation of the metatarsal and therefore the amount of correction.

Methods

There are four types of proximal osteotomy including closing wedge, opening wedge, chevron and crescentic. All are commonly performed in conjunction with a distal soft tissue release. One of the advantages of a proximal osteotomy over a distal osteotomy is that a distal soft tissue release can be performed with minimal risk of avascular necrosis of the metatarsal head. The different osteotomies have their advantages and disadvantages. Unlike the opening and closing wedge osteotomies, the chevron and crescentic osteotomies do not change the metatarsal length. They are probably the most commonly performed proximal osteotomies. The chevron osteotomy is performed from the medial aspect of the bone and the crescentic from the dorsal aspect. The osteotomies are made one centimetre from the adjacent joint and therefore within the metadiaphysis. This maximizes stability and healing potential and minimizes the risk of avascular necrosis. All methods are well described in the orthopaedic literature.




Figure 2

Corrected hallux valgus (proximal chevron and distal closing wedge osteotomies with distal soft tissue release).


A distal soft tissue release basically involves the release of the transverse intermetatarsal ligament as well as the adductor muscles from the lateral aspect of the proximal phalanx and fibular sesamoid. This defunctions some of the deforming forces around the joint and in conjunction with the medial capsular imbrications, helps to reduce the sesamoid sling.

Lapidus Procedure

The Lapidus procedure is another method of proximal realignment. It corrects the increased IM angle through the metatarsocuneiform joint, which is fused by the procedure. Its main indication is hypermobility of the first ray. Hypermobility is thought to be a factor in approximately 5% of patients with an advanced hallux valgus deformity2. One test for hypermobility involves grasping the first ray and moving it in a dorsomedial to plantarlateral direction and looking for more than 25 degrees of motion2. The significance of hypermobility and therefore the necessity of the Lapidus procedure is currently being called into question.




Figure 3
Corrected hallux valgus (Lapidus procedure)

Results

A proximal osteotomy and distal soft tissue release corrects the IM angle on average eight degrees and the hallux valgus angle 30 degrees3. Complications to watch out for include delayed union, loss of correction and overcorrection. Respect for the soft tissues, stable fixation and intraoperative fluoroscopy can go a long way towards preventing these problems. All hallux valgus deformities are not the same and one procedure will not correct them all. Proximal realignment in the form of a proximal osteotomy is a powerful and helpful tool when used in the right situation.

References

  1. Coughlin, M. J.: Hallux Valgus. J. Bone and Joint Surg., 78-A(6): 932-966, 1996.
  2. Mann, R. A., Coughlin, M. J.: Adult Hallux Valgus. In Surgery of the Foot and Ankle, pp150-269. Edited by M. J. Coughlin and R. A. Mann. St. Louis, Mosby, 1999.
  3. Coughlin, M. J.:Proximal first metatarsal osteotomy. In The Foot and Ankle. Master Techniques in Orthopaedic Surgery, pp 71-98. Edited by H. B. Kitaoka. Philadelphia, Lippincott Williams and Wilkins, 2002.

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