Introduction
Fossilized evidence of modern man in Africa from 3 million years ago reveals footprints that show hallux varus. Other imprints uncovered in northern Japan are dated to 2300 BC and also show varus alignment. The later impact of shoe wear had a definite influence on alignment of the hallux.
Clinical photo of idiopathic hallux varus of the left foot.
Lateral radiograph of the foot. This image depicts iatrogenic hallux varus following proximal osteotomy and distal soft-tissue realignment.
Flexible hallux varus is seen in newborns and is a reflection of intrauterine positioning. On the other hand, the normal 0-20º that is seen in hallux valgus occurs after walking has begun in the child and after shoes have been introduced to the child's feet.
Problem
The term hallux varus refers to medial deviation of the great toe. Hallux varus has variable degrees of severity, symptomatology, and etiology. Causes range from the most common iatrogenic postoperative variety to idiopathic, rheumatic, and posttraumatic (tear of the hallux lateral collateral ligament) forms. Flexible hallux varus is a common finding in newborn children and usually corrects to valgus in early childhood when walking begins.1,2
Frequency
The incidence of iatrogenic postoperative hallux varus ranges from 0% for distal osteotomies without a lateral release to 15% for proximal osteotomies (specifically, the Lapidus procedure) with distal soft-tissue release. Most reports are of crescentic osteotomies, which have an overall varus rate of 10%. The incidence of idiopathic, congenital/infantile, traumatic, and otherwise acquired hallux varus, however, is unknown.
Etiology
Congenital
Congenital hallux varus is separated into primary and secondary pathologic deformities. Primary hallux varus is a rare condition that is usually related to an overactive abductor hallucis muscle. Secondary hallux varus is related to other congenital abnormalities, such as metatarsus adductus, great toe polydactyly, longitudinal epiphyseal bracket syndrome, and delta phalanx.
Primary dynamic infantile and acquired adult
Primary dynamic infantile hallux varus is caused by medial insertion of the abductor tendon. Acquired adult hallux varus is described in inflammatory arthropathies, including rheumatoid and psoriatic arthritis. The mechanism of such arthropathies combines destruction of the articular surfaces by pannus, intrinsic muscular contracture, and distention of the joint capsule with subsequent laxity of the collateral ligaments.
Traumatic
Few reports exist of traumatic hallux varus following sports injuries. Of these cases, hallux varus occurred secondary to rupture of the lateral collateral ligament and conjoined tendon.
Spontaneous idiopathic
Spontaneous idiopathic hallux varus may be noted incidentally and is usually supple (see Images 3-5).3 An etiologic factor is not always demonstrable.
Anteroposterior radiograph of the foot. This image depicts idiopathic hallux varus.
Lateral radiograph of the foot. This image shows idiopathic hallux varus.
The initial deforming force is likely overpull of the abductor tendon, which is related to medial insertion into the proximal phalanx; this may be influenced by an inflammatory process or by minor trauma. The imbalance leads to varus deformity and subsequent contracture of the medial capsule, decrease of the intermetatarsal (IM) angle, and medial subluxation of the flexor and extensor mechanisms. Shoe wear tends to correct the varus deformity rather than exacerbate it, as it does for hallux valgus. Therefore, spontaneous idiopathic hallux varus may be more common than is reported.
Classic deformity
The classic deformity of hallux varus occurs most frequently following a surgical procedure, typically a distal soft-tissue or McBride4 type of bunionectomy, but it can also be produced following Silver, Chevron, Mitchell, Keller, and Lapidus5 procedures (see Image 1, Image 2).6
Anteroposterior radiograph of the foot. This image shows iatrogenic hallux varus following proximal osteotomy and distal soft-tissue realignment.
Lateral radiograph of the foot. This image depicts iatrogenic hallux varus following proximal osteotomy and distal soft-tissue realignment.
Classically, the deformity is characterized by hyperextension of the metatarsophalangeal (MTP) joint, flexion of the interphalangeal (IP) joint, medial deviation of the hallux, and supination of the entire ray. This posture results from muscle imbalance that is brought about by the medial subluxation of the tibial sesamoid. Release or transfer of the adductor hallucis alone is not sufficient to produce dynamic hallux varus; however, when coupled with excision of the fibular sesamoid or transection of the lateral head of the flexor brevis tendon, hallux varus likely results. Other predisposing factors for hallux varus are a small IM angle and a round metatarsal head.
Flexion of the MTP joint is brought about by the flexor hallucis brevis muscle through its pull on the sesamoid sling. If the fibular sesamoid is excised, the metatarsal may buttonhole through the defect and result in hyperextension and medial deviation of the MTP joint. Medial deviation is exacerbated when the adductor tendon is detached and nothing opposes the pull of the abductor hallucis muscle.
Potential contributing factors include overplication of the medial capsular structures, medial displacement of the tibial sesamoid, overpull of the abductor hallucis muscle against an incompetent lateral ligamentous complex, excessive resection of the medial eminence, and overcorrection with a postoperative dressing that holds the MTP joint in a varus position. Another cause of hallux varus is overcorrection of a proximal first metatarsal osteotomy, leading to a negative IM angle.
Presentation
The usual symptoms encountered with hallux varus include deformity, pain, decreased range of motion (ROM), instability, clawing of the great toe, weakness with push-off, and problems with shoe wear. Clinical examination is important to assess the stiffness of the MTP and IP joints. Carefully analyze the degree of extension of the first MTP joint, and determine whether weight bearing and the dynamics of ambulation accentuate the deformity. Examine the plantar surface for any callosity under the metatarsal head. Evaluate and note the ROM of the MTP and IP joints and whether there is any pain or crepitation.
Cosmetic alignment of the hallux may not require radiographic congruence of the MTP joint. Based on the literature, some degree of varus is acceptable to patients, appears to be stable, and does not require reconstruction. According to some sources, there is little clinical significance to hallux varus of 8 º or less.7 Additionally, hallux varus is better tolerated by the patient if the condition does not include a cockup deformity. However, over time, a varus deformity becomes fixed, making it difficult to wear shoes. Contracture of the IP joint, coupled with fixed extension of the MTP joint, can produce a painful dorsomedial callosity.
Indications
The patient who has hallux varus and is symptomatic despite conservative measures for the condition, such as shoe modification, is a surgical candidate. The treatment options are either soft-tissue or bony reconstruction, including arthrodesis.
Relevant Anatomy
Cadaveric biomechanical studies have revealed that the anatomic restraints to hallux varus, in descending order, are the lateral capsule, the adductor hallucis, and the lateral flexor brevis tendon.
Contraindications
Relevant contraindications to tendon transfer reconstruction for hallux varus include, but are not limited to, degenerative arthrosis, inflammatory arthritides, infection, peripheral neuropathy, and vascular compromise, in addition to excessive resection of the medial eminence and fixed deformity of the MTP joint.
More on Hallux Varus |
 Overview: Hallux Varus |
| Workup: Hallux Varus |
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References
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Miller JW. Acquired hallux varus: a preventable and correctable disorder. J Bone Joint Surg Am. Mar 1975;57(2):183-8. [Medline]. [Full Text].
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Orzechowski W, Dragan S, Romaszkiewicz P, Krawczyk A, Kulej M, Morasiewicz L. Evaluation of follow-up results of McBride operative treatment for hallux valgus deformity. Ortop Traumatol Rehabil. May-Jun 2008;10(3):261-73. [Medline].
Popelka S, Vavrík P, Hromádka R, Sosna A. [Our results of the Lapidus procedure in patients with hallux valgus deformity]. Acta Chir Orthop Traumatol Cech. Aug 2008;75(4):271-6. [Medline].
Lagaay PM, Hamilton GA, Ford LA, Williams ME, Rush SM, Schuberth JM. Rates of revision surgery using Chevron-Austin osteotomy, Lapidus arthrodesis, and closing base wedge osteotomy for correction of hallux valgus deformity. J Foot Ankle Surg. Jul-Aug 2008;47(4):267-72. [Medline].
Mann RA, Coughlin MJ, eds. Adult hallux valgus. Surgery of the Foot and Ankle. 6th ed. St. Louis, Mo: Mosby, Inc; 1993:284-92.
Leemrijse T, Hoang B, Maldague P, Docquier PL, Devos Bevernage B. A new surgical procedure for iatrogenic hallux varus: reverse transfer of the abductor hallucis tendon: a report of 7 cases. Acta Orthop Belg. Apr 2008;74(2):227-34. [Medline].
Hawkins FB. Acquired hallux varus: cause, prevention and correction. Clin Orthop Relat Res. May 1971;76:169-76. [Medline].
Johnson KA, Spiegl PV. Extensor hallucis longus transfer for hallux varus deformity. J Bone Joint Surg Am. Jun 1984;66(5):681-6. [Medline]. [Full Text].
Skalley TC, Myerson MS. The operative treatment of acquired hallux varus. Clin Orthop Relat Res. Sep 1994;(306):183-91. [Medline].
Myerson MS, Komenda GA. Results of hallux varus correction using an extensor hallucis brevis tenodesis. Foot Ankle Int. Jan 1996;17(1):21-7. [Medline].
Juliano PJ, Myerson MS, Cunningham BW. Biomechanical assessment of a new tenodesis for correction of hallux varus. Foot Ankle Int. Jan 1996;17(1):17-20. [Medline].
Tourné Y, Saragaglia D, Picard F, et al. Iatrogenic hallux varus surgical procedure: a study of 14 cases. Foot Ankle Int. Aug 1995;16(8):457-63. [Medline].
Tanaka Y, Takakura Y, Kumai T, Sugimoto K, Taniguchi A, Hattori K. Proximal spherical metatarsal osteotomy for the foot with severe hallux valgus. Foot Ankle Int. Oct 2008;29(10):1025-30. [Medline].
Chow FY, Lui TH, Kwok KW, Chow YY. Plate fixation for crescentic metatarsal osteotomy in the treatment of hallux valgus: an eight-year followup study. Foot Ankle Int. Jan 2008;29(1):29-33. [Medline].
Sanders M. Complications of hallux valgus surgery. Complications of Foot and Ankle Surgery. 1998:1-18.
Vanore JV, Christensen JC, Kravitz SR, et al. Diagnosis and treatment of first metatarsophalangeal joint disorders. Section 3: hallux varus. J Foot Ankle Surg. May-Jun 2003;42(3):137-42. [Medline].
Further Reading
Chevron Osteotomy Versus SCARF Osteotomy in the Treatment of Hallux Valgus
Diagnosis and treatment of first metatarsophalangeal joint disorders. American College of Foot and Ankle Surgeons - Medical Specialty Society. 2003 May-Jun. 43 pages. NGC:003064
Hallux abductovalgus. Academy of Ambulatory Foot and Ankle Surgery - Medical Specialty Society. 2000 (revised 2003 Sep). 10 pages. NGC:003240
Hallux limitus and hallux rigidus. Academy of Ambulatory Foot and Ankle Surgery - Medical Specialty Society. 2000 (revised 2003 Sep). 7 pages. NGC:003244
Keywords
hallux varus, medial deviation of the great toe, flexible hallux varus, hallux valgus, congenital hallux varus, primary dynamic infantile hallux varus, traumatic hallux varus, idiopathic hallux varus, first metatarsophalangeal joint arthrodesis, MTP arthrodesis, intermetatarsal angle, IM angle
