Sandro Giannini, Cesare Faldini, Francesca Vannini, Matteo Cadossi, and Deianira Luciani
DEFINITION
Hallux valgus is a deformity of the forefoot characterized by progressive lateral subluxation of the proximal phalanx of the first toe on the first metatarsal head. It is considered pathologic when the patient experiences symptoms associated with a valgus deviation (hallux valgus angle [HVA]) greater than 15 degrees (FIG 1).7,8
Hallux valgus is more common in adult women. It is often bilateral, and in many cases it is associated with other foot deformities, such as lesser toe or hindfoot or midfoot deformities that may exacerbate the pathology.14
Hallux valgus is often a progressive disease that compromises the physiologic function of the first metatarsophalangeal (MTP) joint and potentially the entire forefoot.
ANATOMY
The first metatarsal is the broadest and shortest of the five metatarsals, and the distal condyle of the first metatarsal head articulates with the proximal phalanx of the great toe. In addition, the plantar aspect of the first metatarsal head articulates with the sesamoids, which are contained in the flexor brevis hallucis tendon.
The relationship of the medial and lateral sesamoids is maintained by the intersesamoid ligament. In association with the ligaments of and muscle balance about the first MTP joint, the sesamoid complex contributes to stabilizing the first MTP joint.
When functioning properly, the first MTP joint optimizes push-off of the hallux during gait.4
While physiologically the first MTP joint has a wide motion arc in the sagittal plane, it exhibits very little flexibility in the coronal plane. Hallux valgus occurs with greater than physiologic coronal plane motion of the first MTP joint.
FIG 1 • Hallux valgus deformity in a female patient 50 years old.
The first metatarsal head receives its main dorsal blood supply from the first dorsal metatarsal artery, a major contributor to an extracapsular anastomosis at the first MTP joint. On the plantar aspect of the first metatarsal head, the blood supply is from a combination of capsular arteries, branches of the first plantar metatarsal artery, and the first dorsal metatarsal artery.15,17
PATHOGENESIS
The pathogenesis of hallux valgus is not fully understood.
In some patients, hallux valgus deformity may be due to congenital malalignment, neurologic conditions, systemic disease (such as rheumatoid arthritis), connective tissue disorders (with greater than physiologic ligamentous laxity), valgus deviation of the lesser toes, or trauma.3,4,12,13
Several factors that may compromise the normal biomechanics of the foot have been implicated in the development of hallux valgus, including hereditary factors, shape of the first MTP joint, shoe wear, pes planus, and metatarsus adductus.1–3,10,18,19
Controversy remains over the greatest primary cause leading to hallux valgus: valgus deviation of the hallux or metatarsus primus varus.5,7–11
PATIENT HISTORY AND PHYSICAL FINDINGS
With loss of the physiologic balance of the first MTP joint, dynamic muscle function leads to progression of hallux valgus deformity in the majority of cases.
Progressive hallux valgus may create other forefoot problems, including bursitis of the first MTP joint (FIG 2), callosities, and onychocryptosis (between the first and the second toe).
Advanced hallux valgus may diminish first MTP joint function to the point that it leads to lesser toe deformity (claw and hammer toes) and associated transfer metatarsalgia (FIG 3).
For ideal decision making in the management of hallux valgus, the following factors must be considered: pain, mobility and stability of the first MTP joint, and associated deformity.
The site of the pain should be evaluated. The pain is often localized at the prominent medial eminence. At times, an inflamed bursa, a site of tenderness, overlies the prominent medial eminence. In advanced hallux valgus the pain should be referred to the lateral metatarsal head.
FIG 2 • Inflamed bursitis in a female patient 63 years old.
FIG 3 • A,B. Dorsoplantar and lateral view of a case of hallux valgus associated with a lesser toes deformity in a female patient 58 years old. C. Plantar view of a case of hallux valgus associated with metatarsalgia and plantar callosity in a female patient 55 years old.
Hallux mobility at the first MTP joint should be evaluated. Range of motion of the first MTP joint should be checked both in its resting valgus position and its correct neutral position. Any limitation may be a sign of first MTP joint incongruency or arthritis and should be evaluated radiographically.
Stability of the first MTP joint should be assessed. Severe instability of the first MTP is a contraindication for use of the SERI technique.
Associated lesser toe deformities, such as clawtoes, result in metatarsal overload and callus formation, often creating symptoms that exceed those directly related to the hallux.
IMAGING AND OTHER DIAGNOSTIC STUDIES
A standard radiographic examination, including AP and lateral weight-bearing views of the forefoot, allows the assessment of arthritis and congruency of the joint; measurement of the HVA, intermetatarsal angle (IMA), and distal metatarsal articular angle (DMAA); and calculation of the metatarsal formula,16,20,21 especially the relation between the length of the first and the second metatarsal.
Preoperative planning is performed using the preoperative weight-bearing radiographs of the foot. In particular, we assess the radiographs to determine the desired obliquity of the bone cut and the amount of mediolateral and dorsoplantar shift of the metatarsal head required to reduce the metatarsal head over the sesamoid complex and correct an increased DMAA (FIG 4).
NONOPERATIVE MANAGEMENT
Comfortable shoes with a wide toe box and sole may reduce the pressure on the first metatarsal head’s medial prominence. In severe deformity, custom-made shoes or insoles with a metatarsal support may relieve symptoms attributable to transfer metatarsalgia and associated plantar callus formation.
Nonoperative treatment of hallux fails to correct the deformity; it only accommodates to it. Given that hallux valgus deformity tends to progressively worsen, probably due to muscle imbalance about the first MTP joint, symptoms may abate only with surgical correction when conservative treatment proves inadequate.
SURGICAL MANAGEMENT
Indications for SERI Technique
In our experience, the SERI (“simple, effective, rapid, inexpensive”) technique is effective in correcting mild to moderate hallux valgus, with HVA and IMA not exceeding 40 degrees and 20 degrees, respectively.
The SERI technique may be applied to congruent and incongruent hallux valgus deformity. The operation is indicated in case of hallux valgus presenting with any degree of DMAA and a mild degenerative arthritis of the first MTP joint.
Specific contraindications to the SERI technique are severe degenerative arthritis, stiffness, or severe instability of the first MTP joint.
FIG 4 • Preoperative planning for hallux valgus correction by the SERI osteotomy.
TECHNIQUES
Before surgery, the patient’s foot or feet (simultaneous bilateral procedures) are scrubbed using disinfectant soap solution.
Several anesthetic techniques can be used. We usually prefer a sciatic nerve block using ropivacaine hydrochlorate monohydrate 7.5 mg/mL.
The patient is placed in a supine position, with the lower extremity externally rotated with the foot’s lateral border contacting the operating table.
After the foot is exsanguinated, an Esmarch elastic bandage is used as an ankle tourniquet with adequate padding.
The SERI technique does not require a lateral soft tissue release, particularly with a flexible hallux valgus deformity, because the lateral soft tissues relax with lateral translation of the first metatarsal head. Even with slight stiffness of the first MTP joint we do not perform a lateral release, instead applying an intraoperative manual stretch to the adductor hallucis by forcing the hallux in a varus position.
Make a 1-cm medial longitudinal incision midaxially just proximal to the medial eminence through the skin and subcutaneous tissue, directly to the medial aspect of the first metatarsal (TECH FIG 1A). The capsule of the joint is spared.
Retract the soft tissues dorsally and plantarly using two 5-mm retractors (TECH FIG 1B).
If performed as described, the medial aspect of the first metatarsal neck will be adequately exposed.
Perform a complete osteotomy using a standard pneumatic saw with a 9.5 × 25 × 0.4-mm blade (Hall Surgical, Linvatec Corp., Largo, FL) (TECH FIG 1C). In the sagittal plane, the osteotomy is performed with 15 degrees of inclination from dorsal to plantar and distal to proximal. The inclination of the osteotomy in the mediolateral direction is perpendicular to the foot axis (ie, to the long axis of the second metatarsal bone) if the length of the first metatarsal bone must be maintained. If shortening of the metatarsal bone or decompression of the MTP joint is necessary, as in the case of mild arthritis, the osteotomy is inclined in a distal to proximal direction up to 25 degrees. More rarely, if a lengthening of the first metatarsal bone is necessary (ie, if the first metatarsal bone is shorter than the second or if laxity of the MTP joint is present), the osteotomy is inclined in a proximal to distal direction as much as 15 degrees.
With a small osteotome, mobilize the head.
Using a standard wire driver, insert a single-tipped 2.0mm Kirschner wire retrograde through the incision into the soft tissue immediately adjacent to the proximal and distal phalanges of the hallux, in the longitudinal axis of the great toe (TECH FIG 1D).
The Kirschner wire exits at the medial tip of the toe close to the toenail. Regrasp it with the wire driver (TECH FIG 1E) and retract it so that its proximal tip rests at the level of the osteotomy (TECH FIG 1F).
Using a small grooved lever to prize the osteotomy (TECH FIG 1G), obtain the correction by moving the metatarsal head depending on the pathoanatomy of the deformity (TECH FIG 1H,I).
If pronation of the first metatarsal bone is present, obtain the correction with a derotation of the hallux at the osteotomy up to the neutral position of the first metatarsal head.
After correcting the HVA, IMA, DMAA, and pronation, advance the Kirschner wire antegrade into the diaphysis of the first MTP joint so that its proximal tip reaches the metatarsal base (TECH FIG 1J).
Expose the medial prominence at the osteotomy site on the distal aspect of the metatarsal shaft by two retractors and remove it using a pneumatic saw or a rongeur (TECH FIG 1K).
The wound requires only a single 3-0 absorbable suture to reapproximate the skin.
Bend and cut the segment of the Kirschner wire that is protruding from the tip of the toe in routine fashion.
In our experience, the SERI technique may be performed as simultaneous bilateral procedures or combined with concomitant correction of associated foot deformities.
TECH FIG 1 • A. Surgical field showing the 1-cm medial incision. B. Retracting the soft tissues. (continued)
TECH FIG 1 • (continued) C. The osteotomy is performed with a pneumatic saw. D. Inserting the 2-mm Kirschner wire. E,F. The Kirschner wire is retaken by the drill and retracted at the osteotomy line. G.The grooved lever is used to prize the osteotomy. H,I. Metatarsal head dislocation. (continued)
TECH FIG 1 • (continued) J. The Kirschner wire is inserted in the diaphyseal channel. K. Proximal stump regularization.
POSTOPERATIVE CARE
After the completion of the surgery, a mildly compressive gauze dressing is applied to the wound and forefoot (FIG 8) and AP and oblique radiographs are obtained to confirm the placement of the osteotomy and the correction of any characteristics of the deformity.
Ambulation is allowed immediately using “talus” shoes. These shoes maintain the foot in the talus position of the ankle, allowing weight bearing on the hindfoot and discharging weight from the forefoot. Foot elevation is advised when the patient is at rest in the immediate postoperative period.
Kirschner wire fixation due to wire bending upon insertion produces a very stable and elastic stabilization, maintaining the same position obtained during surgery and favoring early healing of the osteotomy combined with early weight bearing.
After 1 month, the dressing, suture, and Kirschner wire are removed. Passive and active exercises with cycling and swimming are advised and comfortable normal shoes are worn, gradually returning to standard footwear.
As a rule, significant postoperative swelling does not last for more than 1 month.
OUTCOMES
With appropriate indications, the SERI technique of minimally invasive distal metatarsal osteotomy is simple, effective, rapid, and inexpensive, giving satisfactory results in more than 90% of cases.
This technique is easily repeated, without removal of the eminence and without open lateral release. It is minimally invasive but performed under direct line of vision and without radiations.
Normally, the osteotomies heal well, with callus evident after an average of 3 months.
The radiographic evaluation showed significant correction of the parameters over time (FIG 9).
No severe complications, such as avascular necrosis of the metatarsal head, nonunion of the osteotomy, or hallux varus, were observed.
All the metatarsal bones remodeled themselves over time, even in cases with significant offset at the osteotomy (few millimeters of bony contact). In our experience, the healing of the osteotomy and the remodeling capability of the metatarsal bone are not related to the offset at the osteotomy, but it is necessary to obtain a bony contact.
COMPLICATIONS
There was a 1.9% rate of delayed union of the osteotomy (over 4 months). In our experience, delayed union is not related to the amount of displacement or correction at the osteotomy.
There was a 2.1% rate of skin irritation or erythema about the Kirschner wire at the tip of the great toe.
FIG 8 • Step-by-step application of the gauze compression dressing.
FIG 9 • A. Dorsoplantar radiographs showing a hallux valgus deformity in a female patient 50 years old. B. Postoperative radiograph. C. Radiographs at 3 years of follow-up.
There was a 12% rate of transfer metatarsalgia with plantar callosities under the second and third metatarsal heads, resolving by the use of insoles with metatarsal support.
There was a 0.5% rate of deep vein thrombosis.
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