You are in: eMedicine Specialties > Orthopedic Surgery > FOOT AND ANKLE BunionArticle Last Updated: Mar 30, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: Richard T Laughlin, MD, Associate Professor and Residency Program Director, Department of Orthopedics and Sports Medicine, Wright State University Boonshoft School of Medicine; Co-director, Foot and Ankle Care Center, Consulting Staff, Miami Valley Hospital Richard T Laughlin is a member of the following medical societies: Alpha Omega Alpha, American Academy of Orthopaedic Surgeons, American College of Surgeons, American Medical Association, American Orthopaedic Association, American Orthopaedic Foot and Ankle Society, Mid-America Orthopaedic Association, and Orthopaedic Trauma Association Coauthor(s): Emmanuel K Konstantakos, MD, Research Fellow, Department of Orthopedic Surgery, Miami Valley Hospital, Wright State University; Kyle Randall, Wright State University Boonshoft School of Medicine Editors: James K DeOrio, MD, Director of Foot and Ankle Fellowship Program, Assistant Professor of Orthopedic Surgery, Orthopedic Surgery, St. Luke's Hospital, Jacksonville, Florida; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Shepard R Hurwitz, MD, Executive Director Designate, American Board of Orthopaedic Surgery; Dinesh Patel, MD, FACS, Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital; Jason H Calhoun, MD, FAAOS, Chairman, J Vernon Luck Distinguished Professor, Department of Orthopedic Surgery, University of Missouri Author and Editor Disclosure Synonyms and related keywords: hallux valgus deformity, HV deformity, metatarsus primus varus, foot deformity INTRODUCTIONSection 2 of 12
  Hallux valgus (HV), with its accompanying bunion, is a common deformity of the forefoot. Understanding and characterizing each component of the deformity is the key to treating it successfully. Many treatments have been proposed; the best choices are those that directly address the location of the deformity. ProblemIn order for the most effective surgical procedure to be chosen, the deformity must be carefully characterized (see Relevant Anatomy). FrequencyIn the United States, the number of forefoot operations for the 3 most common forefoot ailments (HV, hammertoe, neuroma) is markedly higher in females than in males. This discrepancy is attributed to differences in footwear (Coughlin and Thompson, 1995; Frey et al, 1993). EtiologyA connection has been found between shoes that are too narrow and forefoot complaints in women (Coughlin and Thompson; Frey et al). PathophysiologySee Relevant Anatomy. ClinicalPatient demands and expectations, as well as footwear, should be assessed prior to treating the patient with a bunion deformity. Obviously, a directed history should be taken and physical examination should be performed to address vascular status, possible neuropathies, and medical comorbidities. Activity level must be assessed, as the athletic patient with high physical demands may place more emphasis on mobility of the joint than on deformity correction. Finally, footwear must be addressed. A good radiographic result does not necessarily translate into unrestricted footwear use; Mann and Coughlin (1993) reported that only 59% of his patients had unrestricted footwear use after bunion correction. INDICATIONSSection 3 of 12
If footwear modifications (eg, shoes with a rounded and enlarged toe box; see Treatment, 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 Treatment, Surgical therapy. RELEVANT ANATOMYSection 4 of 12
Deformities encountered in HV surgery center around the first metatarsophalangeal joint (MTPJ); however, when assessing this deformity, one must analyze the interphalangeal joint (IPJ), 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 (Coughlin, 1997; Mann and Coughlin, 1993). The first MTPJ receives the most attention in HV surgery. It is a complex joint consisting of the proximal phalanx (PP), the first metatarsal (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 (Coughlin, 1997; Mann and Coughlin, 1993). 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 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 (Coughlin and Thompson; Hattrup and Johnson, 1985). 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. 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 (Richardson et al, 1993) (see Image 1). 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. 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 Image 2). Deformity at this level contributes to an increased valgus deformity of the first toe; however, the deformity is expressed at the IPJ rather than the MTPJ. 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. MTPJ congruence is another factor that is considered when 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 Image 3). When the lines are parallel, a congruent joint exists. When they are not parallel, an incongruous or subluxed joint exists. This relationship is important to consider when choosing the surgical procedure; intra-articular procedures (eg, distal soft-tissue realignment) should not be used with a congruent joint that has an increased DMAA, 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. The 2 angles most commonly used to describe the HV deformity are the hallux valgus angle (HVA) and the angle formed by the first and second metatarsals (1-2 intermetatarsal angle [IMA]) (see Image 5). 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°. 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 and colleagues (2005) were able to demonstrate that while the first intermetatarsal (IM) 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 IM ligament is divided. Itisimportant to recognize that both the first IM ligament and the plantar aponeurosis stabilize the first MT head. 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 MTPJ. 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 relationship should be chosen. 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 MTPJ plays a role in the HV deformity. The first MT head has no direct muscle attachments, so its position is influenced greatly by the alignment of the PP. Essentially, 4 groups of muscles and tendons cross the first MTPJ 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 extensor hallucis longus (EHL) and 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 flexor hallucis longus (FHL) runs centrally between the sesamoids and inserts on the distal phalanx. The FHB has 2 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 relationship exists on the lateral side of the joint, with the adductor hallucis tendon inserting onto the lateral sesamoid and plantar lateral joint capsule. The abductor hallucis has 2 muscle bellies, which are 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 4 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. CONTRAINDICATIONSSection 5 of 12
Contraindications to surgery include vascular insufficiency and active infection of the foot. WORKUPSection 6 of 12
Lab Studies
Imaging Studies
TREATMENTSection 7 of 12
Medical therapyNonoperative treatment should be the initial option discussed. The first aspect of HV treatment is for patients to 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 (Coughlin and Thompson; Frey et al). When compared to other women in the general population in the same age group, according to Thordarson and colleagues (2005), 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 and Morris (2005) 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 smallertotal area than those worn by men. This was associated with corns on the toes, HV deformity, and foot pain. Shoe modifications, such as 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), an 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 (Sammarco and Nichols, 2005). Some nonprescription devices also can provide symptomatic relief, although none have been demonstrated to achieve lasting correction. Surgical therapyA multitude of procedures are available to correct the deformity, although the results of surgery can be quite variable if the deformity is not addressed directly. The table below divides HV deformities into mild, moderate, and severe. These categories are used extensively in order to simplify choosing the best procedure, although they are probably best used to choose a category of procedure rather than a specific procedure. Categories of Hallux Valgus Deformity
Surgical options fall into several broad categories, as follows: distal soft-tissue reconstruction (DSTR), PP and first MT (distal and proximal) osteotomies, arthrodesis (MTPJ and first tarsometatarsal [TMT]), and resection. Distal soft-tissue reconstructionA mild HV deformity can be corrected with a DSTR (McBride, 1967). This consists of medial eminence excision and medial capsulorraphy. 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 MTPJ, or the capsule may be sutured to the medial capsule of the second MTPJ. 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 DMAA and 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:
Akin osteotomyOsteotomy 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 (Akin, 1925; Brahms, 1981; Goldberg et al, 1987; Plattner and Van Manen, 1990). 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 alignment created by an elevated DMAA (Mitchell and Baxter, 1991; Barouk et al, 2005) (see Image 7). The incision is made just proximal to the medial eminence and is extended distally to the IPJ. The dissection is taken down to the joint capsule. Once exposed, a vertical capsulotomy is made, with not 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 (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:
First-metatarsal osteotomyThe next category of procedure for HV correction is the first-MT osteotomy. This can be divided into distal and proximal osteotomies. Distal osteotomies are mainly for individuals with mild deformities (eg, HVA <30°, 1-2 IMA <13°) (Austin and Leventen, 1981; Johnson et al, 1991; Johnson et al, 1979). 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 HV angle, first IM angle, DMMA, and sesamoid position were observed, using the percutaneous method. A shorter operating time and reduced risks of complications were noted as well (Magnan et al, 2005; Sanna and Ruiu, 2005). Mitchell's 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 (Robinson and Limbers, 2005). A Japanese study found that this procedure can produce MTP malalignment, metatarsalgia, and plantar callosity after surgery. According to the report, combining a modified Mitchell's 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 (Yamamoto et al, 2005). Chevron distal metatarsal osteotomy One of the more commonly used distal osteotomies is the chevron osteotomy (see Image 9). 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 metatarsal 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, as this may lead to damage of the lateral soft tissues. 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 avoidviolatingtheMThead–sesamoidarticulation. 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 (2001) have shown 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. Kuhn and colleagues (2005) have shown that blood flow to the head of the MT decreases by71%overbaselinerecordings,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 avascular necrosis (AVN) is one of the possible complications of this surgery. However, clinically significant AVN requiring 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:
Proximal metatarsal osteotomy Proximal MT osteotomies are used for larger deformities, generally those with an IMA of greater than 15°. 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 (Coughlin, 1997). The wedge osteotomies, which can change the length of the first MT, have not been widely advocated. Additional osteotomies include the Scarf, Ludloff, and Mao types. Presently, the proximal chevron and crescentic osteotomies are widely used, and with proper technique, they can achieve excellent correction (Mann et al, 1992; Sammarco et al, 1993; Thordarson and Leventen, 1992; Wanivenhaus and Feldner-Busztin, 1988). The proximal chevron osteotomy is described by Sammarco and colleagues (1993) (see Image 11). 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 (TMTJ). 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 using a microsagittal saw. Care must be taken not to extend the cuts past the apex of the osteotomy, as this 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 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 using a proximal crescentic osteotomy (Mann et al, 1992; Thordarson and Leventen). 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. The osteotomy is performed through a dorsal incision. Care must be taken to protect the EHL and to avoid injury to the terminal portion of the medial branch of the superficial peroneal nerve, which passes over the first TMTJ. The osteotomy is performed 1-1.5 cm distal to the first TMTJ. 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 TMTJ 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 (Beischer et al, 2005). The osteotomy is fixed using a cortical lag screw going dorsal, distal to plantar proximal. TwoK-wiresmaybeaddedto 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 and colleagues (2005) have shown that when screw purchase is poor with the second screw, the use of 2 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 having bilateral hallux valgus correction (Unver et al, 2004). 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:
Arthrodesis and resectionFirst-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°) (Klaue et al, 1994; Maguire, 1973; Mauldin et al, 1990; Myerson, 1990; Sangeorzan and Hansen, 1989). The incidence of hypermobile first ray has been debated. Mann and Coughlin have reported that a hypermobile first ray is present in fewer than 5% of patients with HV. 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 and colleagues (2003) 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 TMTJs. 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, 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. In persons in whom 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 3 screws: the first goes dorsal distal to plantar proximal; the second goes dorsal proximal to plantar distal, crossing the TMTJ; and the third goes transversely medial to lateral across the base of MTs 1 and 2. Care must be taken to maintain compression across the TMTJ. 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), according to Kopp and colleagues (2005), good clinical results were achieved, with significant improvements in pain, activity, limitations, and footwear requirements. Radiographically, the investigators also reported significant improvements in the IM and HV angles, with an average correction of 8-10° and 10-15°, respectively. First-TMT fusion can be summarized as follows:
The final procedures to consider in bunion correction are joint-sacrificing surgeries. These are arthrodesis of the first MTPJ and resection arthroplasty. Metatarsophalangeal joint arthrodesis Arthrodesis of the first MTPJ 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 (Coughlin and Abdo, 1994; Coughlin and Mann, 1987; Coughlin, 1990; Mann and Katcherian, 1989; Mann and Oates, 1980; Turan and Lindgren, 1987). Results of first-MTPJ arthrodesis as a treatment for severe hallux valgus 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 (Coughlin et al, 2005). Also, the IMA will correct without the addition of a basal osteotomy in patients undergoing MTPJ arthrodesis (Cronin et al, 2006). 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 advantage of this latter technique is that less shortening is achieved and 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 neutral rotation. The best landmarks are clinical, though, because the first toe should be positioned adjacent to the second toe and 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 IPJ. 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. The head of the 2.7-mm screws is very shallow, so hardware prominence has not been problematic. When no previous scars are present, the joint is approached through a dorsal incision, although 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 using a rongeur or oscillating saw. The articular cartilage is removed using 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,whicharebestforachieving 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 plantar flexion 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 2-3 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. MTPJ arthrodesis can be summarized as follows:
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 (Richardson, 1990; Vallier et al, 1991; Wrighton, 1972). The procedure, which can accomplish mild correction, decompresses the MTPJ and allows quick healing. However, it does result in shortening of the toe and loss of push-off power; in cases when excessive resection is performed, it may produce a cock-up deformity resulting from loss of the plantar attachment of the FHB. It 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 cock-up deformity; thus, not 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 cock-up deformity. Medial capsular repair corrects the vagus deformity. The joint is then pinned with 2 crossed, 0.062-inch 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:
Preoperative detailsIt is worth repeating that it is critical to obtain high-quality standing radiographs in the AP and lateral direction prior to surgery. Follow-upFor excellent patient education resources, visit eMedicine's Foot, Ankle, Knee, and Hip Center. Also, see eMedicine's patient education article Chronic Pain. COMPLICATIONSSection 8 of 12
Recurrence is the most common complication following bunionectomy, particularly in cases in which the deformity and soft tissues at the first MTPJ are undercorrected. For additional complications related to specific surgical procedures, see Treatment, Surgical therapy. OUTCOME AND PROGNOSISSection 9 of 12
In a 2-year follow-up study evaluating the effect of 3 different types of HV surgeries, Thordarson and colleagues (2005) reported that patients who had HV surgery had significant improvements in 4 of their short form (SF)–36 scores, in 4 out of 5 American Academy of Orthopaedic Surgeons (AAOS) lower-extremity scores, and in 4 out of 5 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. FUTURE AND CONTROVERSIESSection 10 of 12
The HV deformity is complex, as it often involves multiple levels of the first ray. Successful treatment requires careful definition of the deformity. Probably the most common reason for recurrence and less-than-optimal results is failure to carefully define the deformity. If the deformity is not carefully defined, the surgical procedure chosen may not address all components of the deformity. Recurrence or less-than-optimal 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. MULTIMEDIASection 11 of 12
REFERENCESSection 12 of 12
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
