Bunion 

Updated: Jun 05, 2018
Author: Richard T Laughlin, MD; Chief Editor: Vinod K Panchbhavi, MD, FACS 

Overview

Background

Hallux valgus (HV), with its accompanying bunion, is a common deformity of the forefoot involving the first ray, with first-phalanx abduction and pronation, as well as first-metatarsal (MT) adduction, pronation, and elevation, along with capsular and ligamentous derangement.[1, 2]

Understanding and characterizing each component of the deformity are the keys to treating it successfully. Many treatments have been proposed; the best choices are those that directly address the location of the deformity.

For patient education resources, see the Foot, Ankle, Knee, and Hip Center, as well as Chronic Pain.

Anatomy

Deformities encountered in HV surgery involve the first metatarsophalangeal (MTP) joint. However, when assessing this deformity, one must also analyze the interphalangeal (IP) joint, the first metatarsocuneiform (MTC) joint, the hindfoot, and the ankle. The deformity may involve all of these levels, which can affect the success of a chosen operation.[3, 4]

Early in the disease, the medial supporting structures of the first MTP joint (ie, the medial collateral ligaments and medial sesamoid) are typically the first structures to fail. Several other parts of the anatomy begin to fail as well. Once the medial supporting structures fail, the MT head can move medially, off the sesamoid apparatus, and the proximal phalanx falls into a valgus position. The proximal phalanx remains attached by the deep transverse ligament and the adductor hallucis tendon.

Once the MT head has moved laterally over the sesamoid complex, the medial sesamoid can erode the crista and plantar-facing cartilage. The bursa over the medial aspect of the joint can thicken secondary to the increased pressure, worsening the condition. The extensor hallucis longus (EHL) and flexor hallucis longus (FHL) tendons are now in position to worsen the HV as they “bowstring” across the joint. The abductor hallucis attachments on the medial and plantar surface change position as the hallux pronates, and the force of the abductor hallucis then contributes to the pronation.[5]

First metatarsophalangeal joint

The first MTP joint receives the most attention in HV surgery.[6] It is a complex joint consisting of the proximal phalanx (PP), the first MT head, and the medial and lateral sesamoids. The variations in bony anatomy and the soft tissues that cross this joint determine the stability of the joint and its tendency to deform into a valgus alignment.[3, 4]

The rounded head of the first MT articulates with the concave base of the PP. The shape of the MT head plays a large role in the tendency to produce a valgus deformity. A more rounded first MT head is unstable and, therefore, more subject to deformity when acted on by external forces, such as narrow-toed shoes.[7, 8] This is compounded when combined with other commonly associated deformities of the foot, such as pes planus, hindfoot valgus, and congenitally tight heel cord. Flatter MT heads are more stable and less likely to contribute to HV.

Distal metatarsal articular angle

The second characteristic that contributes to HV is the orientation of the articular surface of the MT head in relation to the long axis of the first MT (see the image below).[9]  The distal metatarsal articular angle (DMAA) describes the lateral slope of the articular surface in relation to the long axis of the first MT. Normally, the DMAA is less than 10°. Surgical decision-making must take into account an increased DMAA angle.

Distal metatarsal articular angle (DMAA; normal, < Distal metatarsal articular angle (DMAA; normal, <10°, average in normal feet, 7°).

Proximal phalanx articular angle

The orientation of the great toe is also determined by the proximal phalanx articular angle (PPAA). This is the angle formed by the intersection of a line along the long axis of the PP and a line along the proximal joint surface of the PP (see the image below). Deformity at this level contributes to an increased valgus deformity of the first toe; however, the deformity is expressed at the IP joint rather than the MTP joint.

Proximal phalanx articular angle (PPAA; normal, <1 Proximal phalanx articular angle (PPAA; normal, <10°). This deformity is within proximal phalanx.

The importance of the DMAA and PPAA cannot be overstated, because these angles reflect the lateral inclination of the joint. Correction of these angles must be a goal of any surgery chosen to address the bunion deformity.

Metatarsophalangeal joint congruence

MTP joint congruence is another factor that is considered in choosing a procedure for bunion correction. The congruence of the joint is determined by combining the PPAA and the DMAA. The lines drawn parallel to the joint surface of both the PP and the first MT head should be parallel (see the image below).

Metatarsophalangeal joint congruence. Metatarsophalangeal joint congruence.

When the lines are parallel, a congruent joint exists; when they are not, an incongruous or subluxed joint exists. This relation is important to consider in choosing the surgical procedure. Intra-articular procedures (eg, distal soft-tissue realignment [DSTR]) should not be used with a congruent joint that has an increased DMAA, an increased PPAA, or both.

Congruent joints with an increased DMAA must be addressed with extra-articular procedures (ie, osteotomies) in order to prevent converting a congruent joint to an incongruent one. An incongruent joint, because of the unusual stresses on it, would be more prone to develop osteoarthritic changes.

Hallux valgus and intermetatarsal angles

The two angles most commonly used to describe the HV deformity are the HV angle (HVA) and the angle formed by the first and second MTs (1-2 intermetatarsal angle [IMA]) (see the image below).

Intermetatarsal angle (IMA; normal, <9°). Intermetatarsal angle (IMA; normal, <9°).
Hallux valgus angle (normal, <15°). Hallux valgus angle (normal, <15°).

The HVA is formed by the intersection of the lines along the long axis of the PP and the first MT. This angle is measured easily. The normal angle should be less than 15°. The next important measurement is the angle formed by the intersecting long axis lines along the first and second MTs. Normally, this angle should be less than 9°.

Metatarsocuneiform joint

The final joint that must be assessed carefully is the MTC joint. The shape and orientation of this joint vary and affect the medial inclination for the first MT. Reliable radiographic measurements of this joint are difficult to obtain, because these measurements can vary depending on the plane of the radiographic beam.

Excessive obliquity is associated with hypermobility instability of the first MTC joint. Hypermobility of the first MT as it moves through its oblique axis from dorsomedial to plantar lateral is believed to contribute to the deformity and is accentuated by the obliquity of the joint.

Excessive medial obliquity is associated with instability. In an in-vitro biomechanical study, Khaw et al[10] were able to demonstrate that whereas the first intermetatarsal ligament is important in stabilizing the first MT in all directions, the plantar aponeurosis is a secondary stabilizer that resists medial and dorsal rotation of the first MT after the first intermetatarsal ligament is divided. It is important to recognize that both the first intermetatarsal ligament and the plantar aponeurosis stabilize the first MT head.

Sesamoids

The final bony anatomic considerations involve the sesamoids. The sesamoids are located in the flexor hallucis brevis (FHB) tendon and lie under the first MT head. They have an important function for weightbearing and improve the biomechanical axis of the FHB action.

The plantar aspect of the first MT head has a longitudinal intersesamoid ridge in its center, termed the crista. The sesamoids lie on either side of this ridge as they articulate with the plantar surface of the first MT head. Normally, they should be centered under the first MT head on the standing anteroposterior (AP) radiograph of the foot. As the great toe develops a valgus deformity, the first MT head deviates medially, and rotation occurs at the MTP joint. The great toe pronates, the intrinsic musculature rotates laterally, and the first MT head displaces medially, subluxing off the sesamoids.

Normally, the sesamoids should be centered under the first MT head, and corrective procedures that restore this relation should be chosen.

Other considerations

Other considerations in assessing the deformity include associated pes planus deformity, pronation of the great toe, and Achilles tendon (AT) contraction. The AT has a dynamic effect on ambulation. A contracted AT compromises the ability to dorsiflex the foot. During gait, the result is external rotation, with increased demands placed on the medial structures of the forefoot. HV deformity is believed to be a result of this repetitive stress. A contracted AT can be idiopathic or can result from neuromuscular disease. Which of these it derives from should be noted during the physical examination because the presence of contracted AT, if not addressed, can contribute to recurrence of deformity.

In addition to the bony anatomy of the deformity, the soft-tissue envelope at the first MTP joint plays a role in the HV deformity. Because the first MT head has no direct muscle attachments, its position is influenced greatly by the alignment of the PP.

Essentially, four groups of muscles and tendons cross the first MTP joint and attach on the proximal aspect of the PP. The balance of these structures and the bony contour of the joint determine whether the PP stays aligned on the MT head. Dorsally, the EHL and the extensor hallucis brevis (EHB) insert centrally on the distal and proximal phalanges, respectively. They are kept in a central position by the hood ligaments, a fibrous band of tissue that is anchored to the collateral ligaments.

On the plantar surface, the FHL runs centrally between the sesamoids and inserts on the distal phalanx. The FHB has two tendon slips, which insert onto the medial and lateral sesamoids. The sesamoids then connect onto the PP through the plantar plate. Medially, the abductor hallucis tendon inserts onto the plantar medial PP and plantar medial joint capsule. The capsule becomes much thinner dorsally.

A similar relation exists on the lateral side of the joint, with the adductor hallucis tendon inserting onto the lateral sesamoid and plantar lateral joint capsule. The adductor hallucis has two muscle bellies, the transverse head and the oblique head. These come together in the conjoined tendon and insert on the lateral sesamoid. Comparatively, more muscle mass is present in the adductor hallucis when the muscle bellies are combined, creating a natural tendency to pull the PP into valgus.

These four groups of attachments create a delicate balance for keeping the PP centered on the first MT head. This balance is enhanced greatly when the first MT head is relatively flat. When the head is rounded, it is much easier for the PP to deviate. Once a deviation is created, the forces are quickly unbalanced.

The insertion of the adductor hallucis onto the lateral plantar base of the PP becomes the primary deforming force as the HV increases. Because its insertion is on the plantar half of the capsule and sesamoid, it tends to pronate the toe. As the rotation occurs, the abductor hallucis becomes more plantar and the only medial restraint left is the thin dorsal joint capsule, which readily becomes attenuated.

Once an angular deformity exists, the EHL and extensor digitorum brevis (EDB) are no longer centered on the PP and bowstring across the lateral side of the deformity, creating further imbalance. In considering the treatment of HV, one must address both the bony deformity and the soft-tissue balance, because both contribute to the pathologic condition.

Etiology

A connection has been found between shoes that are too narrow and forefoot complaints in women.[7, 11] Risks for HV include the following[12] :

  • Female sex
  • Heel-wearing women
  • Overweight men
  • Men with pes planus

Obesity was found to be protective in women.[12] In addition, a longer first metatarsal correlates with more severe HV in elderly persons.[13] Children who wear footwear of insufficient length have an increased rate of HV; the relative risk for an HV angle of greater than or equal to 4° is 1.1171 if indoor shoes are one shoe size too short.[14]

Inheritable factors that may play a role in HV include the following[15] :

  • Metatarsal formula
  • Arch height
  • Hypermobility

Additional evidence showed that 90% of 350 white patients with HV had at least one affected relative and that the most common associated inheritance pattern was autosomal dominant with incomplete penetrance.[16]

Epidemiology

In the United States, the number of forefoot operations for the three most common forefoot ailments (HV, hammertoe, and intermetatarsal perineural fibrosis) is markedly higher in females than in males. The prevalence of HV is markedly higher in females, with studies reporting a female-to-male ratio of 8-9:1 and even as high as 15:1.[17, 18] This discrepancy is attributed to differences in footwear.[7, 11]

With regard to age, the peak onset of HV is from age 30-60 years, though it is likely that the initial changes occur during adolescence or even earlier in the case of juvenile HV.[19, 20]

Prognosis

In a 2-year follow-up study evaluating the effect of three different types of HV surgeries, Thordarson et al[21] reported that patients who had HV surgery had significant improvements in four of their Short Form (SF)-36 scores, in four of five American Academy of Orthopaedic Surgeons (AAOS) lower-extremity scores, and in four of five American Orthopaedic Foot and Ankle Society (AOFAS) scores. The degree of deformity, amount of correction, and type of operation did not influence outcome.

When treatment addresses each component of the deformity, satisfactory results are possible. However, patients must have realistic expectations. Recurrent deformity, HV, and stiffness are the most common complications. Even with good corrections, some limitations still exist in 30% of patients.

 

Presentation

History and Physical Examination

Patient demands and expectations, as well as footwear, should be assessed before treatment of a patient with a bunion deformity.[22] A directed history should be taken and physical examination performed to address vascular status, possible neuropathies, and medical comorbidities. Patients should be examined standing because this position often increases the hallux valgus (HV) and associated deformities.

The forefoot and hindfoot should be assessed, as should tightness of the gastrocnemius-soleus complex. Note pronation of the great toe, and assess the first metatarsophalangeal (MTP) joint for range of motion. To assess first tarsometatarsal (TMT) instability, the examiner can immobilize the lesser metatarsals (MTs) with one hand while using the other hand to grasp the first MT and move it from a plantar-lateral to a dorsomedial direction. Movement of more than 9 mm indicates hypermobility. The examiner should also check for signs of general ligamentous laxity.[23, 24]

Activity level must be assessed; the athletic patient with high physical demands may place more emphasis on mobility of the joint than on correction of the deformity.[25]

Finally, footwear must be addressed. A good radiographic result does not necessarily translate to unrestricted footwear use; Mann and Coughlin[4] reported that only 59% of their patients had unrestricted footwear use after bunion correction.

 

Workup

Laboratory Studies

In general, specific laboratory studies are unnecessary. However, it behooves the surgeon to be aware of subtleties. For example, if small, punched-out lesions are noted around the articular surfaces, a uric acid level may help rule out gout. If symmetric narrowing is appreciated in the metatarsophalangeal (MTP) joints, a rheumatoid factor level may be helpful in ruling out rheumatoid arthritis.

Finally, if there is any appearance, either clinically or radiographically, of infection, laboratory work, including complete blood count (CBC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP), can be ordered to rule out infection.[26] Arthrocentesis is most valuable in helping to evaluate for infection.[26]

Imaging Studies

A standing foot radiograph in the anteroposterior (AP) and lateral planes is mandatory in determining the type of surgery needed for bunion correction.[27] In additional, an oblique nonstanding film can be obtained to gain a different perspective of the metatarsal (MT) head and hindfoot. A sesamoid view, though seldom necessary, also should be obtained if a special problem with the sesamoids (eg, fracture or avascular necrosis) appears to be present. This information is then combined with the clinical picture to help determine the optimal surgical approach. (See the images below.)

Severe bunion deformity. Severe bunion deformity.
50-year-old woman with bilateral severe hallux val 50-year-old woman with bilateral severe hallux valgus deformity.

Although it is generally accepted that treatment decisions for hallux valgus (HV) are based on plain weightbearing radiographs, a study by Burg et al suggested that treatment strategies can also be confidently determined on the basis of nonweightbearing radiographs.[28] In this study, 21 expert and ankle surgeons evaluated 10 random clinic patients with HV by measuring the HV angle (HVA), the intermetatarsal angle (IMA), and the distal metatarsal articular angle (DMAA); they then used that information to make an intervention recommendation.

No statistically significant difference was detected in the angles measured.[28] In terms of surgical procedures chosen, the distal osteotomy was chosen 10.8 times in the weightbearing group and 11.2 times in the nonweightbearing group. No differences were observed in the preferred surgical treatments chosen by the surgeons. A relative weakness of the study was the lack of clinical evaluation of the patient's foot before the choice of an intervention.

 

Treatment

Approach Considerations

The hallux valgus (HV) deformity is complex, often involving multiple levels of the first ray. Nonoperative treatment should be the initial option discussed. If footwear modifications (eg, shoes with a rounded and enlarged toe box; see Medical Therapy) fail to relieve the pain that comes with the deformity, surgical correction may be offered to the patient. For indications for specific surgical procedures used to address HV and bunion deformity, see Surgical Options. Contraindications for surgery include vascular insufficiency.

Successful treatment requires careful definition of the deformity, with appropriate consideration of its three-dimensional (3D) nature.[29, 30] Failure to accomplish such definition is probably the most common reason for recurrence and suboptimal results. If the deformity is not carefully defined, the surgical procedure chosen may not address all of its components. Recurrence or suboptimal results also occur when the procedure is used at the upper limits of its indications. When each component of the deformity is addressed, satisfactory results can be achieved.

It is worth repeating that it is critical to obtain high-quality standing radiographs in the anteroposterior (AP) and lateral directions prior to surgery.

Medical Therapy

The first aspect of HV treatment is to have patients wear properly fitting shoes. The forefoot should be no more than 0.5 cm wider than the toe box of the shoe. Women who wear shoes narrower than this have a higher incidence of forefoot complaints.[7, 11] When compared to other women in the general population in the same age group, according to Thordarson et al,[31] women about to undergo bunion surgery reported significant increased body pain, decreased foot and ankle function, and decreased shoe comfort.

Foot problems are also very common in the elderly population. Using a questionnaire and clinical assessment, Menz et al[32] evaluated 176 patients aged 62 to 96 years with foot pain and deformity. They found that most of the patients wore shoes narrower than their feet and that women, in proportion to their feet, wore shoes that were shorter, were narrower, and had a smaller total area than those worn by men. This was associated with corns on the toes, HV deformity, and foot pain.

Orthoses have been shown to be more effective at reducing pain at 6 months of treatment, but at 12 months, no difference is noted in comparison with the control of no treatment. They also are not effective at increasing the ability to work at 1 year. Chevron osteotomy is superior to orthotic treatment.[33]

Shoe modifications (eg, bubble stretching) can ease the pressure over a bony prominence. Orthotic inserts seem to be of limited help in treatment of HV, but custom orthotics can be of great assistance if the symptoms are caused mainly by a transfer lesion. A good orthotic prescription should include medial posting to control pronation (which increases valgus forces on the hallux), a metatarsal (MT) pad for transfer lesions, extra shoe depth with an oblique toe box, and possibly a bunion flare, which goes behind the bunion deformity to alleviate pressure from the shoe.[34]

A study by Reina et al was aimed at determining whether custom-made orthotics prevented or slowed the progression of HV in women with mild-to-moderate deformity. At 1-year follow up, no significant differences in the HV angle (HVA) and intermetatarsal angle (IMA) were noted. This study helps confirm that custom-made orthotics have no effect during a 12-month period.[35] Some nonprescription devices can provide symptomatic relief, though none has been demonstrated to achieve lasting correction.

Surgical Options

A multitude of procedures are available to correct the deformity, though the results of surgery can be quite variable if the deformity is not addressed directly.[36] HV deformities may be categorized as mild, moderate, or severe (see Table 1 below). These categories are used extensively in order to simplify choosing the best procedure, though they are probably best used to choose a category of procedure rather than a specific procedure.

Table 1. Categories of Hallux Valgus Deformity (Open Table in a new window)

Angle

Mild Subluxation

Moderate Subluxation

Severe Subluxation

Hallux valgus angle

<20°

20°-40°

>40°

1-2 Intermetatarsal angle

<11°

<15°

>15°

Sesamoid

<50°

50º-75º

>75º

Surgical options fall into several broad categories, as follows:

  • Distal soft-tissue reconstruction (DSTR)
  • Proximal-phalanx (PP) and first-MT (distal and proximal) osteotomies
  • Arthrodesis (metatarsophalangeal [MTP] joint and first tarsometatarsal [TMT])
  • Resection

Elliot et al conducted a prospective study investigating the use of intraoperative fluoroscopy by analyzing 28 cases of HV surgery during which fluoroscopic images were taken.[37] No unforeseen intraoperative events were discovered, and no surgical modifications were made as a result of the fluoroscopic images. Although intraoperative fluoroscopy is a reliable technique, it is not recommended that it be used routinely in HV surgery.

Distal Soft-Tissue Reconstruction

A mild HV deformity can be corrected with a DSTR.[38] This consists of medial eminence excision and medial capsulorrhaphy. On the lateral side, the deforming structures must be released to balance the toe, a procedure that typically is performed through a dorsal longitudinal incision in the first webspace.

The conjoined tendon is released from the lateral sesamoid. The transverse MT ligament is released from its attachment on the lateral sesamoid as well. The lateral joint capsule is divided parallel to the joint surface. The proximal portion of the released adductor tendon may be sutured to the proximal joint capsule of the MTP joint, or the capsule may be sutured to the medial capsule of the second MTP joint.

This soft-tissue procedure is considered an intra-articular realignment. It must be performed only in persons with a round MT head and a relatively normal distal MT articular angle (DMAA) and PP articular angle (PPAA). This procedure realigns the toe, provided that the bony anatomy accepts this realignment. In reality, the DSTR is seldom used alone, usually being combined with a bony procedure.

DSTR can be summarized as follows:

  • Indications - Mild to moderate bunion deformity; HVA less than 35°; IMA less than 15°; nonelevated DMAA; noncongruent joint
  • Expected corrections - HVA 14°; IMA 5°
  • Complications - Hallux varus (usually asymptomatic if less than 10°; the incidence is significantly lowered by not excising the lateral sesamoid); recurrence of deformity (occurs when the procedure is extended to larger deformities or when the bony alignment is not favorable (eg, elevated DMAA)
  • Results - After correction of HV deformities with a DSTR and a proximal crescentic osteotomy, first-ray mobility in cadaver specimens was significantly reduced (with several studies having demonstrated that patients with HV deformities have increased first-ray sagittal mobility) [39]

A study by Schneider evaluated the efficacy of individual steps of the lateral release and assessed which surgical steps are essential to HV deformity correction, which steps are not effective, and which steps may pose risk.[40] Transecting the lateral metatarsosesamoid ligament appeared to be the key step to a successful lateral release. The release of the deep transverse MT ligament and the adductor hallucis did not help correct HV. The author suggested that the lateral short sesamophalangeal ligament and the plantar attachment of the articular capsule should be preserved to minimize possible joint instability.[40]

Akin Osteotomy

Osteotomy of the PP, the first MT, or both is used extensively to correct alignment of the first ray. The PP osteotomy (Akin procedure) is a medially based closing-wedge osteotomy of the PP.[41, 42, 43, 44] It is combined with medial eminence excision and medial capsulorrhaphy. This procedure is best for deformity in the PP, manifesting as HV interphalangeus in which the PPAA is abnormal. The Akin osteotomy may also be combined with a first MT osteotomy to compensate for alignment created by an elevated DMAA (see the image below).[45, 46]

Akin proximal phalanx closing-wedge osteotomy to c Akin proximal phalanx closing-wedge osteotomy to correct high proximal phalangeal articular angle (PPAA).

The incision is made just proximal to the medial eminence and is extended distally to the interphalangeal (IP) joint. The dissection is taken down to the joint capsule. Once this is exposed, a vertical capsulotomy is made, with no more than 2-4 mm of capsule removed. The medial eminence is then excised in line with the shaft of the first MT and just medial to the sagittal sulcus.

Next, the osteotomy of the PP is completed, and 3-4 mm of bone is removed. Care must be taken at the proximal cut to ensure that the articular surface is not violated. The medial capsule is then repaired first in order to observe the amount of correction that must be completed with the osteotomy. The osteotomy is subsequently fixed with Kirschner wires (K-wires) or suture. Care must be taken to check for correct rotation as the osteotomy is fixed.

Akin osteotomy can be summarized as follows:

  • Indications - HV interphalangeus; also can be combined with other procedures to compensate for an increased DMAA in a congruent joint
  • Expected corrections - May correct 10-15° of deformity in PP; HVA tends to recur, according to long-term follow-up results; has no effect on 1-2 IMA
  • Complications - Recurrence of deformity; poor cosmetic appearance
  • Results - Used alone, the Akin osteotomy should be reserved for deformity in the proximal phalanx; Basile et al [47] compared the distal first-MT chevron-Akin osteotomy with the DSTR-Akin osteotomy for correction of mild HV and noted a statistically significant outcome in which the distal first-MT chevron-modified Akin double osteotomy resulted in a greater correction of 1-2 IMA, HVA, and tibial sesamoid position than that accomplished with the DSTR-modified Akin osteotomy

First-Metatarsal Osteotomy

The next category of procedure for HV correction is the first-MT osteotomy, which can be divided into distal and proximal osteotomies.[48] Distal osteotomies are mainly for individuals with mild deformities (eg, HVA <30°, 1-2 IMA <13°).<ref>49</ref>[50, 51] Some authors have advocated the use of these in deformities as large as 15° in the 1-2 IMA.

Distal MT osteotomies performed through a percutaneous approach have been used in Europe but have not been widely accepted in the United States. Statistically significant improvements in the postoperative mean HVA, first IMA, DMAA, and sesamoid position were observed with the percutaneous method. A shorter operating time and reduced risks of complications were noted as well.[52, 53]  A study by Magnan et al found 

Mitchell osteotomy is another means of distal correction; it involves a double cut through the MT neck, leaving a step in the lateral cortex to hitch onto the MT head. The capital fragment is displaced laterally and plantarward and then is held in place with a stitch through drill holes.[54, 55] A Japanese study found that this procedure can produce MTP malalignment, metatarsalgia, and plantar callosity after surgery[56] ; combining a modified Mitchell osteotomy with an oblique MT osteotomy of the lesser MT bones significantly improved callosity and metatarsalgia and the use of commercially available shoes at 5-year follow-up.

Chevron distal metatarsal osteotomy

One of the more commonly used distal osteotomies is the chevron osteotomy (see the image below).[57, 58]

Distal chevron metatarsal osteotomy fixed with Kir Distal chevron metatarsal osteotomy fixed with Kirschner wire.

This procedure is performed through a medial incision. An L-shaped capsulotomy is carried out to expose the medial eminence. The exostosis is removed with a saw, using a cut parallel to the medial border of the foot. Making the exostectomy cut parallel to the medial border increases the surface area of contact for the chevron osteotomy. On the other hand, making the cut parallel to the medial MT shaft obviates the danger of removing too much medial eminence. If too much medial eminence is removed, it can result in loss of support for the PP, with a resultant varus deformity.

Once the medial eminence is resected, an ink marker is used to outline the chevron, the apex of which is placed in the center of the MT head. The osteotomy is V-shaped; the angle of the chevron may vary. Making one limb longer than the other is advantageous because this simplifies fixation. The author makes the plantar limb longer. Care is taken not to overpenetrate the lateral cortex; doing so may lead to damage of the lateral soft tissues.

The chevron osteotomy angle was investigated at 60° versus 90° with longer plantar limb, by cohort and finite element analysis (FEA). The FEA demonstrated that there were more compressive forces and less shear stresses at the osteotomy site with a 90° cut, which is more conducive to bone formation, with at least similar results between the cohorts.[59]

Once the osteotomy is complete, the MT head is translated laterally; a skin hook or towel clamps are placed on the proximal fragment, and then the capital fragment is translated laterally. Sometimes, an osteotome must be inserted along the osteotomy cuts to free the soft tissues enough to allow the lateral translation. Also, when a long plantar limb is used, the soft issue is more likely to impede lateral translation; thus, gently mobilizing the capital fragment with an osteotome is advantageous.

Excessive manipulation should be avoided. It also is important to not let the saw cut extend across the apex, because this can create a stress riser in the capital fragment when fracture may occur during manipulation of the MT head. The MT head should be translated 3-5 mm laterally but no more than one third the width of the MT shaft. It is then fixed with a single K-wire (0.62), which is inserted from dorsal-proximal to plantar-distal. Care must be taken to avoid violating the MT head–sesamoid articulation.[60]

The pin is left in place for 3-5 weeks and removed in the office. The osteotomy is inherently stable and is through metaphyseal bone, which heals quickly. Screws and more complex fixation methods are not necessary. Because of the mild risk of sterile abscess, the author chooses to avoid bioabsorbable implants. However, DeOrio and Ware[61] showed that a single poly-p-dioxanone pin attached to a K-wire can be used routinely for fixation, obviating the need for external pin placement.

After the osteotomy is fixed, the excess medial cortex of the proximal fragment is resected in line with the MT head. All edges are smoothed with a rasp or rongeur. The capsule can be shortened to gain further correction by resecting the redundant segment from the proximal aspect of the limb of the capsulotomy made parallel to the joint.

One concern with distal osteotomies is the risk of avascular necrosis (AVN). Kuhn et al[62] showed that blood flow to the head of the MT decreases by 71% over baseline recordings, with the largest drop coming after capsulotomy (45%). The total blood flow goes up to 58% after lateral release and adductor tenotomy, then to a 71% decrease from baseline when the osteotomy is added. This explains why AVN is one of the possible complications of this surgery. However, clinically significant AVN necessitating treatment is actually quite rare.

Standard compression bunion dressings are used for 7-8 weeks and changed every 1-2 weeks. The pin is removed after 4 weeks. The patient should expect to return to full-time footwear in 10-12 weeks. This may vary depending on any additional procedures performed on the foot (eg, hammertoe correction, bunionette correction).

Chevron distal MT osteotomy can be summarized as follows:

  • Indications - HVA less than 30°; 1-2 IMA less than 13°; DMAA less than 15°
  • Expected corrections - HVA 12-13°; 1-2 IMA 4-5
  • Complications - Undercorrection when indications are extended to large deformities [8, 63] ; AVN in 12-20% (theoretically, there is an increased risk when adductor release is performed, but this has not been observed in clinical series)
  • Results - In a comparison study after 2 and 5 years of follow-up, the chevron osteotomy was found to be a reliable procedure for the correction of mild and moderate hallux valgus deformity, and outcome did not differ on the basis of age [64, 65] ; subsequently, a systematic review involving 1028 participants in the chevron osteotomy group confirmed a mean reduction in pre-to-post 1-2 IMA of 5.33° [66]

Proximal metatarsal osteotomy

Proximal MT osteotomies are used for larger deformities, generally those with an IMA of greater than 15°.[67, 68] These osteotomies usually are combined with a DSTR, which is necessary to correct MTP subluxation with an HVA of greater than 35°.

Many types of osteotomy have been described, including medial opening-wedge, lateral closing-wedge, proximal chevron, and crescentic osteotomies.[3] The wedge osteotomies, which can change the length of the first MT, have not been widely advocated. Additional osteotomies include the scarf,[69, 70, 71] Ludloff,[72] and Mao[73, 74] types. Presently, the proximal chevron and crescentic osteotomies are widely used, and with proper technique, they can achieve excellent correction.[75, 76, 77, 78]

As compared with chevron osteotomies, the Ludloff osteotomy has been reported to yield better correction of the IMA but results in greater shortening of the first ray.[79]

The proximal chevron osteotomy is described by Sammarco et al (see the image below).[76] This is combined with a DSTR. After the distal releases have been performed, the medial incision is extended proximally to the level of the first TMT joint.

Proximal chevron osteotomy fixed with 2 screws. No Proximal chevron osteotomy fixed with 2 screws. Note Akin proximal phalanx osteotomy fixed with Kirschner wires (K-wires) and hammertoe correction held with K-wire.

The periosteum is elevated just enough to expose the medial cortex of the first MT. The osteotomy is designed with the apex pointing proximally with a long plantar limb. The angle of the osteotomy is approximately 70-80°. The osteotomy is performed with a microsagittal saw. Care must be taken not to extend the cuts past the apex of the osteotomy; doing so may create a stress riser and increase the risk of fracture.

After the osteotomy is completed, the distal fragment is rotated laterally with the osteotome; the upper limb behaves like an opening-wedge osteotomy, and the lower limb acts as a shelf to prevent elevation or depression of the distal fragment. Once the desired correction is achieved, the osteotomy can easily be fixed by using a pair of 2.7-mm cortical lag screws placed dorsal to plantar. The resected medial eminence is morselized and packed into the opening-wedge portion of the osteotomy. Two screws provide very stable fixation, and the technique of using an osteotomy with a plantar shelf has been demonstrated to be biomechanically sound.

Similar correction can be obtained by using a proximal crescentic osteotomy.[75, 77] This procedure is analogous to the focal dome osteotomy used in the correction of lower-extremity deformity. The main advantage of the proximal crescentic osteotomy is that it results in minimal shortening. Although proximal chevron osteotomy and proximal crescentic osteotomy were similar at reducing the HVA, the chevron osteotomy was better at reducing healing time and was associated with a lower incidence of dorsiflexion malunion.[80]

The proximal crescentic osteotomy is performed through a dorsal incision. Care must be taken to protect the extensor hallucis longus (EHL) and to avoid injury to the terminal portion of the medial branch of the superficial peroneal nerve, which passes over the first TMT joint. The osteotomy is performed 1-1.5 cm distal to the first TMT joint. The crescentic cut is made perpendicular to the plantar surface of the foot or at a 120° angle to the long axis of the first MT. Some literature supports either a concave distal or concave proximal cut orientation. Either way, care must be taken to avoid overcorrection.

Three-dimensional computer analysis has shown that the osteotomy started distal to the TMT joint and angled at 22° toward the proximal sesamoid articulation allows for a longer osteotomy and, therefore, less shortening and MT-head elevation. Adding a 10° plantarward coronal tilt also can help limit MT-head elevation.[81] The osteotomy is fixed with a cortical lag screw going dorsal, distal to plantar proximal.

Two K-wires may be added to provide a significantly more stable fixation, providing a viable option to the limited methods of additional fixation. Achieving rigid stabilization is an important means of avoiding loss of fixation and elevation of the first MT. Jung et al[82]  showed that when screw purchase is poor with the second screw, the use of two K-wires can provide fixation without a significant loss of strength. Rigid fixation may be difficult to obtain, especially in osteoporotic bone.

The postoperative course is much the same as that of the distal MT osteotomy. Depending on the fixation, a postoperative shoe, fracture walker, or cast may be used. An immobilization orthosis is an option that makes walking possible on postoperative day 1 by supporting the first MT and shifting weight to the other MT shafts. This orthosis could be an effective solution for patients who, for whatever reason, need to walk right away or for patients undergoing bilateral HV correction.[83]

Weightbearing is protected for the first 4 weeks. Generally, most patients do not bear weight much in the first 3-4 weeks, because of pain. Once wound healing is ensured, weightbearing progresses. Patients with more proximal procedures have a slightly longer recovery period.

Proximal first-MT osteotomy with DSTR can be summarized as follows:

  • Indications - HVA greater than 30°; 1-2 IMA greater than 14°
  • Expected outcome - HVA 23-24° (HV correction is directly proportional to the severity of the preoperative deformity); 1-2 IMA greater than 8-11° (crescentic), 3-6° (closing wedge), 7° (opening wedge)
  • Complications - Shortening of first ray (closing wedge); elevation of first ray, causing transfer lesion to the second MT head (however, crescentic osteotomies have variable pressure patterns under the second MT head, which were thought to result from the overall geometric design of the crescenteric osteotomy, which is well suited for rotation in the horizontal plane but inherently unstable in the sagittal plane [84] ); undercorrection; overcorrection; stiffness of first MTP joint; delayed union or malunion
  • Results - Jones et al [85] showed that total range of motion (ROM) and dorsiflexion were significantly decreased postoperatively when compared to their preoperative ROM, and the magnitude of correction showed no correlation with the change; this immediate decrease in motion underscores the importance of joint mobilization early in recovery to prevent long-term loss of mobility

A 1- and 3-year follow-up study showed that patients with first-MT pain and metatarsalgia at 1 year postoperatively were also more likely to experience pain and metatarsalgia at 3 years. The same study showed that in 87% of patients, radiologic changes were minimal or nonexistent between 1 and 3 years, providing evidence that a patient's 1-year follow-up clinical status is predictive of long-term outcome.[86]

In the same systematic review cited above, the scarf osteotomy group consisting of 300 participants was associated with a mean reduction in pre-to-post 1-2 IMA of 6.21°.[66]

Arthrodesis and Resection

First-tarsometatarsal fusion

The first-TMT arthrodesis can be used to correct moderate-to-severe HV. Its main use is in the patient with a hypermobile first ray and a moderate-to-severe deformity (1-2 IMA >15°, HVA >30°).[87, 63, 88, 89, 90] The incidence of hypermobile first ray has been debated. Mann and Coughlin reported that a hypermobile first ray is present in fewer than 5% of patients with HV.[4]

TMT arthrodesis can also be used as a salvage operation after a failed bunion repair, when there is still an increased 1-2 IMA. In a prospective observational cohort study of patients who presented with a recurrent HV deformity after undergoing surgery between May 1996 and August 1999, Coetzee et al[91] showed that first-TMT arthrodesis is a dependable and successful option for revision after failure of surgical treatment of HV. Contraindications are juvenile HV with an open epiphysis, short first ray, and MTP degenerative arthritis.

The procedure is performed through a dorsal incision extending from the first webspace proximally to the TMT joints. The EHL is retracted laterally. The subchondral bone is exposed, using a small osteotome to scrape off the cartilage.

In people who truly have a hypermobile first ray,[92] resection of wedges of bone may not be necessary. Often, the 1-2 IMA can be reduced and the joint pinned with wires for provisional reduction. A radiograph is obtained. If the positioning of the first ray is acceptable, it can be fixed after the preparation of the subchondral surface by feathering using an osteotome or with multiple drill holes. The margins of the fusion are bone grafted with local bone obtained from the bunion resection, distal tibia, or calcaneus.

If the first TMT cannot be reduced, joint resection is performed with a microsagittal saw, removing biplanar wedge based laterally and plantarward. This resection must be performed carefully to avoid excessive shortening.

Fixation is performed with 3.5-mm cortical screws placed in lag fashion. Cannulated screws may be used in persons in whom wire fixation is performed first to ensure acceptable positioning. The screw configuration consists of three screws, with the first going dorsal distal to plantar proximal, the second going dorsal proximal to plantar distal and crossing the TMT joint, and the third going transversely medial to lateral across the base of MTs 1 and 2. Care must be taken to maintain compression across the TMT joint.

This procedure is always combined with DSTR. The postoperative course typically involves a longer recovery period than procedures that are more distal. Patients are placed in a standard soft bunion dressing, with a plaster splint to immobilize the ankle. At the first dressing change, this is converted to a short leg cast with a soft spica dressing to hold the great toe in place.

Patients are kept nonweightbearing for the first month and are then allowed to engage in touchdown weightbearing for balance in the second month. The bunion dressing is continued until the 2-month postoperative check. At that point, if radiographs demonstrate fusion, the patient can progress slowly to wearing a firm-soled shoe. Typically, it can take another 6 weeks before patients are comfortably wearing a shoe full-time.

When this procedure was used in conjunction with a bunionectomy and distal soft-tissue realignment (Lapidus procedure; see the image below),[93, 94] according to Kopp et al,[95] good clinical results were achieved, with significant improvements in pain, activity, limitations, and footwear requirements. Radiographically, the investigators also reported significant improvements in the IMA and HVA, with average corrections of 8-10° and 10-15°, respectively.

Postoperative films after Lapidus procedures in 50 Postoperative films after Lapidus procedures in 50-year-old woman with bilateral severe hallux valgus deformity.

First-TMT fusion can be summarized as follows:

  • Indications - HVA greater than 30°; 1-2 IMA greater than 15°; MTP subluxation and hypermobile first ray
  • Expected corrections - HVA 18°; 1-2 IMV 6-8°
  • Complications - Nonunion (10-12%); pain (42%); dorsiflexion plantarflexion malunion; overcorrection; undercorrection; painful hardware
  • Results - In a clinical follow-up study using radiologic and pedobarographic examinations in 56 patients with arthrodesis of the first TMT joint, bony consolidation occurred at 9 weeks postoperatively; average first IM angle improved from 20.4° to 11.2°, and the American Orthopaedic Foot and Ankle Society (AOFAS) score significantly improved, from 51 to 92 points at 8.2 months postoperatively [96]

The final procedures to consider in bunion correction are joint-sacrificing surgeries. These are arthrodesis of the first MTP joint and resection arthroplasty.

Metatarsophalangeal arthrodesis

Arthrodesis of the first MTP joint is used for salvage after failed bunion surgery, for bunions associated with osteoarthritis or rheumatoid arthritis, and for severe HV (HVA >40°, IMA >16°). With modern internal fixation methods, high rates of fusion can be achieved.[97, 98, 99, 100, 101, 102]

Results of first-MTP arthrodesis as a treatment for severe HV deformities resulted in a high percentage (>85%) of successful results at an average follow-up of over 8 years, with a significant reduction in postoperative pain.[103] Also, the IMA will correct without the addition of a basal osteotomy in patients undergoing MTP arthrodesis.[104] Rarely, however, when the IMA associated with the HV deformity is in the severe range, a combination of a more proximal procedure with a first-MTP arthrodesis (Mau osteotomy or modified Lapidus) may be necessary and is safe and clinically successful.[105]

Many methods for preparing the joint have been described. Resection may be performed with flat surfaces or with reamers that shape the PP and MT head in mirror images. The advantages of this latter technique are that less shortening is achieved and that the position of the toe can be adjusted when hemispheric reamers are chosen.

The most critical aspect of the arthrodesis is the position of the first toe. Generally, it should be fused in 10-15° of valgus and 30° of dorsiflexion in relation to the first MT and in neutral rotation. The best landmarks are clinical, though, because the first toe should be positioned adjacent to the second toe and should have enough dorsiflexion for the surgeon to be able to place the tip of his or her finger under the distal phalanx of the toe being fused, when this foot is placed in a plantigrade position on a hard, flat surface.

Too much dorsiflexion leads to pain at the tip of the toe when the patient wears shoes; too little dorsiflexion can lead to premature arthrosis or instability of the first IP joint. Too much valgus can cause impingement on the second toe; one must anticipate the gradual decrease in the IMA that will occur after an MTP fusion, so that late impingement does not occur.

The technique currently used by the author for fusion is hemispheric reaming and compression screw fixation. Currently, the author uses a 2.7-mm lag screw with a one-quarter tubular plate. This provides very stable fixation, allowing early weightbearing. Because the head of the 2.7-mm screws is very shallow, hardware prominence has not been problematic. When no previous scars are present, the joint is approached through a dorsal incision, though the arthrodesis can also be accomplished through a previous medial incision if it is performed for recurrent HV. Full-thickness flaps are raised sharply off the MT head.

The collateral ligaments are elevated and released, if necessary, to achieve correction. The medial eminence is removed with a rongeur or oscillating saw. The articular cartilage is removed with an osteotome to expose the subchondral bone.

At this point, the cannulated hemispheric reamer is used to ream the surfaces, removing the subchondral bone to expose cancellous surfaces, which are best for achieving fusion. Care must be taken not to remove too much bone. Additionally, when a dorsal approach is used, a tendency may exist to remove too much bone dorsally, leading to excessive dorsiflexion. This can be avoided by increased exposure and plantarflexion of the PP during the reaming.

Once the joint is prepared, the surfaces are opposed in the desired position and pinned with a K-wire. The author uses an intraoperative fluoroscan to check position of the fusion and hardware. A low-profile plate is best chosen, with 2.7-mm screws. In this case, only one screw crosses the joint, using a lag technique. The plate is applied dorsally, with two or three screws proximal and distal.

Postoperatively, bulky gauze compression dressing and a surgical shoe are used. When fixation is tenuous, a cast or fracture walker may be used for additional immobilization. Patients are allowed to bear weight once wound healing is ensured, usually after 2-3 weeks. After 6 weeks, if fusion is evident on radiographs, patients are allowed to start bearing weight in a firm-soled shoe. Most patients have returned to full-time footwear use by 8-10 weeks postoperatively.

MTP joint arthrodesis can be summarized as follows:

  • Indications - HV with arthrosis and/or rheumatoid arthritis; neuromuscular conditions (spasticity); recurrent valgus (HVA >40°); fixed hallux valgus deformity; severe HV with severe IMA (when IMA will not be fixed with MTP joint arthrodesis alone)
  • Complications - Nonunion (generally <10% with internal fixation techniques); malunion (too little valgus, increased IP joint arthrosis); excessive plantarflexion (pressure at the tip of the toe and increased IP joint arthrosis); excessive dorsiflexion (intractable plantar keratosis in the first MT head, pain at the tip of the toe or nail, dorsally); painful hardware; infection
  • Results - Coughlin et al [103] evaluated the results of first-MTP arthrodesis as treatment for severe and moderate HV deformities, using data derived over a 22-year period in a single surgeon's practice; arthrodesis of the first MTP joint for idiopathic HV resulted in a high percentage of successful results, at an average follow-up of over 8 years; in addition to a significant reduction in postoperative pain, postoperative AOFAS scores averaged 84 (range, 72-90), and there was complete resolution of lateral metatarsalgia at final follow-up

Rippstein et al evaluated the results when an MTP arthrodesis was combined with a more proximal procedure to fix the associated severe IMA. Mean HVA decreased from 49.9º (range, 40.1º-66.7º) preoperatively to 9.7º (range, 4.2º-17.7º). Mean IMAs decreased from 18.8º (range, 15.1º-21.4º) to 4.6º (range, 0.7º-8º). Of the total 18 patients, 15 were very satisfied and three were satisfied.[105]

When compared with the Hohmann osteotomy in patients with first-ray hypermobility, the Lapidus procedure (arthrodesis) was equally effective at reducing pain at 2 years and equal at correcting the HVA (N=101; 50 Homan, 51 Lapidus).[106]

Excisional arthroplasty (Keller)

Resection arthroplasty is rarely used for correction of HV. It should be employed for moderate deformity with coincident arthrosis, in patients who are elderly and have low demands.[107, 108, 109, 110] The procedure, which can accomplish mild correction, decompresses the MTP joint and allows quick healing. However, it does result in shortening of the toe and loss of pushoff power; in cases when excessive resection is performed, it may produce a cockup deformity resulting from loss of the plantar attachment of the flexor hallucis brevis (FHB).

Compared with a distal osteotomy, a Keller arthroplasty is less effective at improving the IMA and range of motion at 3-year follow-up.[111] However, the Keller arthroplasty is better than arthrodesis at retaining mobility at 2 years, though there was no demonstratable difference in pain or dissatisfaction.[112] The Keller arthroplasty should be used mainly as a salvage procedure in patients with low physical demands.

The procedure can be performed through either a dorsal or medial incision. A medial incision is preferred because it allows medial capsular plication to accomplish correction of alignment.

The capsule is elevated from distal to proximal, leaving the proximal attachment. It is tagged with a resorbable suture. The medial eminence is excised. The base of the PP is exposed. Care must be taken to preserve the plantar capsule. The cut is made at the metaphyseal flare. Excessive resection leads to shortening and increases the chances of a cockup deformity; thus, no more than the proximal 25% of the phalanx should be excised.

After excision, the capsule is repaired to the remaining phalanx through drill holes. Repairing the plantar capsule is essential because it minimizes the risk of postoperative cockup deformity. Medial capsular repair corrects the valgus deformity. The joint is then pinned with two crossed 0.062-in. K-wires, which are removed 3-5 weeks postoperatively.

A standard soft gauze postoperative bunion dressing is used, and the patient is allowed limited weightbearing in a postoperative shoe. Walking should be restricted to avoid the complication of pin breakage.

Excisional arthroplasty (Keller) can be summarized as follows:

  • Indication - Moderate HV in a low-demand patient with osteoarthrosis of the MTP joint
  • Expected corrections - HVA correction up to 50%, with best results achieved when the HVA is less than 30°; IMA correction minimal
  • Complications - Metatarsalgia resulting from the loss of weightbearing function of the great toe (results tend to deteriorate with time); cockup deformity; shortening; flail toe; diminished pushoff strength
  • Results - In a long-term retrospective analysis of an uncontrolled series of basal metatarsal closing-wedge osteotomies and Keller excision arthroplasties performed in patients aged 14-40 years, statistical analysis revealed significantly better clinical and radiologic outcomes after osteotomy; in fact, it was recommended that Keller arthroplasty be abandoned for the treatment of HV in young and active patients [113]

Less Invasive Techniques

Various less invasive techniques have been developed in attempts to decrease soft-tissue injury (primarily), decrease healing time and morbidity, and improve cosmesis. These techniques may be divided into the following three categories:

  • Percutaneous
  • Minimally invasive
  • Arthroscopic

To date, the majority of articles published on minimally invasive, percutaneous, and arthroscopic techniques have yielded low-quality level IV evidence.[114] Relatively few prospective comparative trials have been performed.

Percutaneous forefoot surgery

Percutaneous forefoot surgery (PFS) is typically performed with a 1- to 3-mm incision using a miniblade and power rotary burr by way of tactile sensation and intraoperative image intensification.[115]

A 2-year prospective study was performed on the percutaneous Reverdin-Isham osteotomy and included 104 cases.[1] For the procedure, a 3- to 5-mm plantar-medial incision is created over the MT head. Capsule detachment and resection of the medial and dorsal protrusions of the MTP head are performed with a low-speed conical burr under fluoroscopic guidance. This is followed by the actual Reverdin-Isham osteotomy created by a straight burr with the same medial approach, conserving the lateral cortex.

A lateral capsule and ligamentous release is then performed via a second 3-mm incision medial to the EHL using a Beaver blade.[1] In addition to this, a varisation osteotomy of the first phalanx is performed via a dorsal approach medial to the EHL with a straight burr, again preserving the lateral cortex.

Complete weightbearing was resumed immediately in a rigid postoperative shoe.[1] Several complications included four first-MT and five first-PP lateral cortex fractures, six DMAA hypercorrections of less than 0°, two subjects with painful severe joint rigidity, two with complex regional pain syndrome, three with recurrence of deformity, and two with transfer metatarsalgia after 18 months. The results of functional outcomes via AOFAS were comparable to other studies of percutaneous or standard open HV procedures such as chevron osteotomy or scarf osteotomy.

An additional article mentions that to decrease complications and maintain corrections performed during surgery, specifically designed dressings are used. Dressing management requires specific training, and close monitoring is required to make sure the correction is maintained while the patient resumes ambulation.[116]

This procedure does seem to fall short on reliably reducing the DMAA.[1, 117] Bauer et al therefore concluded that this procedure should be restricted to medium-to-moderate HV correction without significant metatarsus varus (IMA ≤15°).[1] It also is a difficult procedure to perform with a long learning curve. A few studies have shown higher complication rates with the percutaneous distal metatarsal osteotomy for HV, including a high rate of recurrence of HV and dorsal malunion.[118]

A technique of distal percutaneous MT osteotomy was described by Magnan et al.[52] A 2-mm-diameter K-wire is inserted extraperiosteally from the medial corner of the nail of the great toe along the medial side of the hallux. A 3- to 5-mm incision is made down to bone at the metatarsal neck, and the periosteum around the osteotomy site is detached.

The osteotomy is made through the subcapital region of the first MT under fluoroscopy in the sagittal plane, perpendicular to the long axis of the shaft of the first MT, but with slight mediolateral obliquity in the frontal plane. The K-wire is then driven down the central axis of the MT through the osteotomy. Patients are allowed to bear weight in a firm-soled postoperative shoe on postoperative day 1. This procedure is for mild-to-moderate HV with a first IMA of 10-20°.[52]

A subsequent study by Magnan et al found percutaneous distal first-MT osteotomy to be a reliable and safe option for recurrent HV.[119]

Percutaneous double and triple osteotomies have been performed for severe hallux valgus.[120]

Minimally invasive techniques

Minimally invasive surgery is performed via a 1- to 2-cm incision with a traditional blade and power saw under direct visualization, possibly with fluoroscopic guidance.[115] The SERI (simple, effective, rapid, inexpensive) technique is similar to the percutaneous method described above, except that it is performed through a slightly larger incision under direct visualization and the osteotomy is made via an oscillating saw.

The SERI technique is indicated to correct mild-to-moderate reducible deformity when the HVA is 40° or less and the IMA is 20º or less, with only mild arthritis. Contraindications include age older than 75 years, severe arthritis or stiffness of the MTP joint, and severe instability of the cuneometatarsal joint and MTP joint.[121] Mixed studies exist regarding the results, and the procedure may require a significant learning curve in order to achieve acceptable results.[118, 121]

Another minimally invasive surgical technique is the Bösch osteotomy. This procedure is indicated for an HVA of 20-40°, an IMA up to 20°, and a DMAA up to 25°, with no radiographic evidence of degenerative MTP arthritis. It is performed via a medial approach through an incision approximately 2 cm long, and the osteotomy is customized to correct the patient’s individual deformities. The head is freed with an osteotome, and the osteotomy is fixed with two K-wires.

In a comparative retrospective study by Maffulli et al that included 72 subjects, the Bösch osteotomy (n = 36) was compared with the open scarf osteotomy (n = 36).[122]  Immediate heel walking was allowed for both groups. There was decreased operating room time for the minimally invasive Bösch procedure, shorter hospital stay, and equivalent AOFAS and FAOS scores at 2-year follow-up.

The Bösch osteotomy was also compared with the open Kramer technique.[123] The minimally invasive Bösch approach did allow earlier discharge; however, it had a trend toward a higher complication rate (which was not statistically significant, though the study may have been underpowered) and had lower patient satisfaction with a trend toward more shortening in comparison with the open Kramer procedure.

Another minimally invasive technique involves reconstruction of the medial collateral ligament in the correction of HV deformity with primary medial collateral ligamentous insufficiency.[124] There will be times when medial capsular plication is not strong enough to provide strong and lasting stability to the first MTP joint. Medial collateral reconstruction by means of extensor hallucis brevis (EHB) tendon graft can be performed in cases of medial collateral ligament rupture, metatarsus adductus with a disproportionate HVA, and recurrent HV deformity with a relatively normal IMA.

Arthroscopic techniques

Proposed advantages of arthroscopic procedures, in addition to the advantages of other lesser invasive techniques, include improved assessment of sesamoid reduction and minimization of overcorrection.[6]

An arthroscopic Lapidus procedure was described by Michels et al[125] in a limited study involving five patients followed for 1 year. The procedure included an arthroscopic Lapidus as well as a minimally invasive chevron osteotomy distally on patients with severe HV (>16°) and hypermobility of the first MTP joint.

In this procedure, a percutaneous release of the lateral joint capsule and adductor tendon is performed, followed by insertion of three portals: medial to the tibialis anterior, superior between the tibialis anterior and the EHL, and lateral between the EHL and the deep peroneal neurovascular bundle. The working space is created just around the joint capsule.[125]

The joint cartilage is removed with a Beaver blade, followed by limited abrasion of subchondral bone with a bone resector to prevent shortening.[125] Then, several holes are drilled into the subchondral bone. An intermetatarsal screw is inserted between the first and second MTs to correct the IMA. Fixation of the joint is achieved with two percutaneously placed screws.

Next, the minimally invasive chevron osteotomy is performed to correct the HVA.[125] In a study analyzing results from 59 cases of first-MTP arthroscopy, osteotomy sites from a distal chevron osteotomy were fixed with one 1.4-mm K wire and proximal chevron osteotomy sites were fixed with three 1.4-mm K wires.

In the five patients described by Michels et al, no complications were reported, and all five returned to preoperative activities within 4 months. One-year postoperative AOFAS scores improved by an average of 51 points, to a range of 87-90. Radiographic evaluation confirmed fusion in all patients by 4 months, with an average HVA improvement of 26° and IMA improvement of 11°. Functional results are similar to other reported outcomes with open Lapidus,[126, 95] and radiographic results were at least equivalent.[127, 126, 88]

In a subsequent study analyzing 59 MTP joint arthroscopy procedures, the AOFAS score improved from an average of 71 preoperatively to 95 points for those patients with HV.[128] Radiographic results showed a mean HVA improvement from 29.2° to 9.7° and a mean IMA improvement from 14.8° to 7.7°. Of the 36 patients with HV, all cases showed an improvement in medial sesamoid positioning postoperatively, no hallux varus, and no postoperative stiffness. The authors suggested that the minimal invasiveness of the arthroscopy may have contributed to the results. Additionally, all 36 were without any recurrences of the deformity at the latest follow-up.

An arthroscopic technique with the claimed benefit of affording an improved view of the articular surface allows more controlled resection of only the cartilage, and no subchondral bone, to limit shortening and promote bone healing, in addition to minimizing soft-tissue damage and offering a better cosmetic result. The authors noted that it is a more technically demanding procedure, requiring a skilled arthroscopist.[125]

Whereas several less invasive techniques are beginning to be performed more frequently, and early results have been published, larger comparative trials are needed to provide  proof that the additional proposed benefits can be achieved without increased failure and morbidity.

Postoperative Care

A liposomal form of the local anesthetic bupivacaine was approved by the US Food and Drug Administration (FDA) in October 2011. A single dose infiltrated into the surgical site produces postoperative analgesia for bunionectomy. The recommended dose for bunionectomy is 93 mg (7 mL) infiltrated into tissues surrounding the osteotomy and the remaining 13.3 mg (1 mL) into the subcutaneous tissue.

In two randomized, placebo-controlled studies, Apfelbaum et al found that the cyclooxygenase (COX)-2 inhibitor parecoxib, along with supplemental analgesia provided as needed, was effective for pain relief over 1-3 days in patients who underwent bunionectomy[129] ; however, this agent is not approved by the FDA for use in the United States.

In patients with arthroscopic correction of mild-to-moderate HV, active dorsiflexion exercises begin 2 days postoperatively and passive dorsiflexion and plantarflexion are started 7 days postoperatively. An HV strapping and postoperative shoe is worn for 8 weeks. The percutaneous K-wire used for the DCMO is removed 4 weeks after surgery, and the three K-wires used for PCMO are removed 8 weeks after surgery under local anesthesia.

Complications

Recurrence is the most common complication after bunionectomy, particularly in cases where the deformity and soft tissues at the first MTP joint are undercorrected. For additional complications related to specific surgical procedures, see Distal Soft-Tissue Reconstruction, Akin Osteotomy, First-Metatarsal Osteotomy, Arthrodesis and Resection, and Less Invasive Techniques.