Hallux Varus
Chris Evensen, OMS-III
Touro University – Nevada
Hallux Varus
What is Hallux Varus
Hallux varus is a condition in which the big toe begins to medially deviate from the midline of the foot. The condition has various degrees of severity and causes. Hallux varus most commonly develops after a previous bunion surgery, but it can also be due to trauma, removal of sesamoid bones, arthritis, or congenital deformity.
What is the anatomy of the big toe?
The big toe involves three bones and two joints. The biggest bone is the metatarsal bone which connects to the proximal phalanx. These two bones make up the metatarsophalangeal (MTP) joint, or first joint of the big toe. The proximal phalanx also connects to the distal phalanx to create the interphalangeal (IP) joint, or second joint of the big toe. The MTP and IP joints allow for the flexion and extension (down and up) movements of the toe similar to that of a finger or thumb. MTP and IP joints are held together and supported by medial (inside) and lateral (outside) collateral ligaments. However, the MTP joint of the great toe differs form the MTP joints of the lesser toes because it has sesamoid bones, encased in the flexor hallucis brevis tendons, which form a small joint on the plantar (bottom) surface of the MTP joint.
Figure 1: Metatarsal and phalanx bones of the great toe and foot.
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Figure 2: Sole of foot showing ligaments of the great toe and foot and sesamoid bone.
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The muscles and tendons involved in movement of the big toe surround the MTP joint in four main regions. The long and short extensor muscles are found on the dorsal (top) portion of the joint, long and short flexor muscles are on the plantar (sole) portion, abductor muscles on the medial side and adductor muscles on the lateral side. Along with ligaments these muscles cooperate to allow movement, stability and alignment of the toe.
What causes hallux varus?
Hallux varus is most commonly caused by rupture of the lateral collateral ligament at the MTP joint following a surgical procedure or trauma. However, it can also occur congenitally, although rarely. Soft tissue factors that can contribute to a hallux varus deformity are excessive pull of the abductor hallucis muscle against a weak lateral ligament, medial displacement of the tibial sesamoid bone, overplication of the medial capsule structures, and overcorrection with a postoperative dressing that holds the MTP joint in a varus position. A metatarsal osteotomy can also contribute to hallux vaurs if the metatarsal head is aligned too far laterally or if too much of the metatarsal head is removed causing MTP joint instability.
Figure 3: Hallux varus
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Figure 4: X-ray showing hallux varus
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What are the symptoms of hallux varus?
Of course the most common finding for hallux varus is the cosmetic concern due to the medial deviation of the big toe. However, other more subtle symptoms may be difficulty fitting shoes, pain wearing shoes, IP joint bursitis, MTP joint extension, compensatory hindfoot supination, and continual medial ingrown toenails.
What can be done to fix a hallux varus deformity?
The treatment of hallux varus often depends on the severity and cause of the condition. If the deformity is mild, not painful and the toe is still moveable then no treatment may be necessary. However, if the deformity is severe or the toe is arthritic (stiff and rigid) then surgical correction is usually needed. Nonsurgical treatment usually consists of adapting shoe wear to a shoe with a wide forefoot or toe box and using a toe sling or splint to try and prevent the deforming forces.
Various surgical options can be used to fix hallux varus and thus careful examination must be done to determine which procedure is most appropriate. Tendon transfer is the most common choice for surgical repair. Tendons are transferred around the toe to balance the tension forces and straighten the toe while still allowing toe movement. Other options range from a simple release of the medial MTP joint capsule to MTP joint fusion and loss of MTP joint motion. A newer technique involves use of a TightRope device to correct the varus deformity. Your doctor can discuss the options and the pros and cons of each in the treatment of a hallux varus deformity.
What are the complications and what can I expect my recovery to be like after surgery?
As with any surgery there is always a risk of complications with anesthesia, infection, or nerve and blood vessel damage. In non fusion corrective surgery such as a tendon transfer, the main complication is overcorrection or undercorrection of the MTP joint, but this is usually well tolerated. Nonunion or malunion problems are complications that can occur following MTP joint fusion surgery.
Recovery is dependant on the surgical procedure used to fix the deformity. For tendon transfer surgery the patient is in a postoperative walking shoe or CAM walker boot for 10 weeks to ensure proper healing and maturation of the tendon transfer. MTP joint fusion requires the patient to be in a CAM boot for 8-12 weeks following surgery. The TightRope procedure may be advantageous due to a decrease time (6-8 weeks) in a postoperative sandal or CAM boot.
References
1. Coughlin MJ, Mann RA, Saltzman CL. Hallux Varus. Surgery of the Foot and Ankle, 8th Edition. 2007 Elsevier : Philadelphia. Chapter 6: pp 345 - 352
2. Davies and Parker, 1995. Davies MS, Parker BC: Idiopathic hallux varus. Foot Ankle 1995; 16:210.
3. Donley, 1997. Donley BG: Acquired hallux varus. Foot Ankle 1997; 18:586.
4. Drake RL, Vogl W, Mitchell AWM. Gray’s Anatomy for Students. 2005 Elsevier : Philadelphia.
(Gray’s Anatomy for Students – www.studentconsult.com)
5. Edelman, 1991. Edelman RD: Iatrogenically induced hallux varus. Clin Podiatr Med Surg 1991; 8:367.
6. Granberry and Hickey, 1994. Granberry WM, Hickey CH: Idiopathic adult hallux varus. Foot Ankle 1994; 15:197.
7. Johnson KA, Spiegl PV: Extensor hallucis longus transfer for hallux varus deformity. J Bone Joint Surg Am 66:681-686, 1984
8. Miller JW: Acquired hallux varus: A preventable and correctable disorder. J Bone Joint Surg Am 57:183-188, 1975.
9. Mills and Menelaus, 1989. Mills JA, Menelaus MB: Hallux varus. J Bone Joint Surg 1989; 71B:437.
10. Trnka HJ, Zettl R, Hungerford M, et al: Acquired hallux varus and clinical tolerability. Foot Ankle Int 18:593-597, 1997.