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).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.

The technique described in this chapter—known as SERI for “simple, effective, rapid, inexpensive”—can be applied to congruent and incongruent hallux valgus deformity.

 

 

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 hallucis brevis 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.

 

 

 

FIG 1 • Hallux valgus deformity in a 50-year-old female patient.

 

 

When functioning properly, the first MTP joint optimizes push-off of the hallux during gait.4

 

Although 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.

 

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.15,16

 

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.1,2,3,10,18,19

 

Controversy remains over the greatest primary cause leading to hallux valgus: valgus deviation of the hallux or metatarsus primus varus.5,8,9,10,11

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).

 

 

 

 

FIG 2 • Inflamed bursitis in a 63-year-old female patient.

 

 

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FIG 3 • A,B. Dorsoplantar and lateral view of a case of hallux valgus associated with a lesser toes deformity in a 58-year-old female patient. C. Plantar view of a case of hallux valgus associated with metatarsalgia and plantar callosity in a 55-year-old female patient.

 

 

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.

 

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 claw toes, 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 anteroposterior (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,17,20,21 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

 

In our experience, the SERI technique is effective in correcting mild to moderate hallux valgus, with HVA and IMA not exceeding 40 degrees and 20 degrees, respectively.6,7

 

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.

 

 

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In our experience, the SERI technique can be performed as simultaneous bilateral procedures or combined with concomitant correction of associated foot deformities.7

Preparation and Positioning

 

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 hydrochloride 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.

 

TECHNIQUES

• Exposure

   

  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.

   

   

   

  TECH FIG 1 • A. Surgical field showing the 1-cm medial incision. B. Retracting the soft tissues.

   

   

  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.

• Osteotomy

   

  Perform a complete osteotomy using a standard pneumatic saw with a 9.5- × 25- × 0.4-mm blade (Hall Surgical, ConMed Linvatec Corp., Largo, FL) (TECH FIG 2).

   

  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.

   

   

   

  TECH FIG 2 • The osteotomy is performed with a pneumatic saw.

   

   

  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.

   

• Correction of the Deformity

  41

   

  With a small osteotome, mobilize the head.

   

  Using a standard wire driver, insert a single-tipped 2.0-mm 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 3A).

   

  The Kirschner wire exits at the medial tip of the toe close to the toenail. Regrasp it with the wire driver (TECH FIG 3B) and retract it so that its proximal tip rests at the level of the osteotomy (TECH FIG 3C).

   

   

   

  TECH FIG 3 • A. Inserting the 2-mm Kirschner wire. B,C. The Kirschner wire is retaken by the drill and retracted at the osteotomy line. D. The grooved lever is used to pry the osteotomy. E,F. Metatarsal head dislocation.

   

  Using a small grooved lever to pry the osteotomy (TECH FIG 3D), obtain the correction by moving the metatarsal head depending on the pathoanatomy of the deformity (TECH FIG 3E,F).

   

   

  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.

   

• Fixation

  42

   

  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 4).

   

   

   

  TECH FIG 4 • The Kirschner wire is inserted in the diaphyseal channel.

• Closure

   

  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 5).

   

  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.

   

  TECH FIG 5 • Proximal stump regularization.

   

   

   

  PEARLS AND PITFALLS

  Stability of the ▪ A 15-degree inclination in the osteotomy from dorsal to plantar and distal to proximal affords stability to osteotomy the osteotomy to limit dorsal displacement of the metatarsal head with weight bearing.     Modification of ▪ If shortening of the metatarsal or decompression of the MTP joint is necessary, the osteotomy should be first metatarsal inclined in a distal-proximal direction up to 25 degrees. More rarely, if lengthening of the metatarsal is length necessary, the osteotomy should be inclined in a proximal-distal direction up to 15 degrees (FIG 5).       FIG 5 • Possibilities of metatarsal lengthening or shortening by using different SERI osteotomy inclinations.

   

   

   

   

  Correction of the deformity according to insertion of the Kirschner wire

• An adjustment of the final intraoperative correction of the first metatarsal head in the mediolateral dislocation plane of the metatarsal head is dictated by the position of the Kirschner wire in the metatarsal diaphysis. Greater correction warrants a more lateral placement of the wire within the metatarsal shaft. Greater plantar displacement of the metatarsal head necessitates placing the Kirschner wire more dorsally into the soft tissue immediately adjacent the metatarsal head (FIG 6).

   

   

   

  FIG 6 • Possibility of plantar or dorsal dislocation of the metatarsal head.

   

   

   

  Correction of the DMAA

  • To correct the DMAA, the Kirschner wire must be introduced obliquely into the medial soft tissues in a mediolateral direction (FIG 7). Then manual adduction of the hallux must be performed to rotate the metatarsal head, correcting the DMAA.

  • In our experience, an osteotomy performed proximal to the recommended position increases the risk of first metatarsal malunion and nonunion.

  • If the Kirschner wire is inserted into the phalanx rather than immediately adjacent to the phalanx, it has been our experience that the DMAA cannot be properly corrected.

     

     

     

    	Shortening of ▪ Excessive shortening of the first metatarsal may lead to overload of the lesser toes. the first metatarsal and complications   Contraindication ▪ Like most other corrective procedures for hallux valgus, the SERI technique is not indicated for hallux in hallux rigidus valgus associated with moderate to severe hallux rigidus.

     

    POSTOPERATIVE CARE

    43

    FIG 7

     

     

     

    • Correction of DMMA.

 

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.

 

 

44

 

 

 

 

FIG 8 • A-C. Step-by-step application of the gauze compression dressing.

 

 

 

FIG 9 • A. Dorsoplantar radiographs showing a hallux valgus deformity in a 50-year-old female patient. B. Postoperative radiograph. C.

Radiographs at 3 years of follow-up.

 

 

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.6,7

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. Radiographic evaluation shows 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.6,7

There was a 2.1% rate of skin irritation or erythema about the Kirschner wire at the tip of the great toe.6,7

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.6,7

There was a 0.5% rate of deep vein thrombosis.6,7

 

 

REFERENCES

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2. Coughlin MJ. Roger A. Mann Award. Juvenile hallux valgus: etiology and treatment. Foot Ankle Int 1995;16:682-697.

    

    

3. Coughlin MJ, Jones CP. Hallux valgus: demographics, etiology, and radiographic assessment. Foot Ankle Int 2007;28:759-777.

    

    

4. Dragonetti L. Inquadramento eziopatogenetico e clinico dell'alluce abdotto-valgo. In: Malerba F, Dragonetti L, Giannini S, eds. Progressi in Medicina e Chirurgia del Piede: L'alluce Valgo, ed 6. Bologna, Italy: Aulo Gaggi, 1997.

    

    

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6. Giannini S, Cavallo M, Faldini C, et al. The SERI distal metatarsal osteotomy and Scarf osteotomy provide similar correction of hallux valgus. Clin Orthop Relat Res 2013;471:2305-2311.

    

    

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20. Suzuki J, Tanaka Y, Takaoka T, et al. Axial radiographic evaluation in hallux valgus: evaluation of the transverse arch in the forefoot. J Orthop Sci 2004;9:446-451.

     

     

21. Tanaka Y, Takakura Y, Kumai T, et al. Radiographic analysis of hallux valgus: a two-dimensional coordinate system. J Bone Joint Surg Am 1995;77(2):205-213.