Most of us in the podiatric field know a lot about bunions. You mastered them as a first-year resident and have never looked back. They are the bread and butter of podiatry.
What we often forget is the problematic complication that often follows bunion surgery — hallux varus. Hallux varus can be a complication of bunion surgery but can also be a congenital anomaly.
One can appreciate acquired hallux varus after the reduction of a bunion deformity. Intraoperatively, one can correct the deformity by adjusting the osteotomy, capsulotomy or capsulorrhaphy. Acquired hallux varus occurrence varies but most of the literature shows it around 1 to 2 percent.1,2
The common causes of hallux varus associated with a bunionectomy are excessive recession (staking) of the metatarsal head, over-aggressive medial capsulorrhaphy or lateral capsulotomy. Additionally, the cause can be an aggressive plantar lateral release, an adductor tendon transfer, a fibular sesamoidectomy or anything that can lead to a negative intermetatarsal angle such as moving a capital fragment too much. Always consider metatarsus adductus as a cause of hallux varus.
Physicians usually identify and treat congenital hallux varus soon after birth. The Podiatry Institute classifies hallux varus into three causal categories: 1) caused by a tight band of tissue that is a precursor to the abductor hallucis; 2) caused by metatarsus adductus; or 3) caused by skeletal abnormalities.3 If left untreated, the deformity can persist into adulthood.
For treatment, Banks and colleagues and the Podiatry Institute have suggested a stepwise approach.3-5 Similar to many aspects of surgery, start small and build upon the incision line. Determine if the deformity is flexible or structural. If it is flexible, begin with a soft tissue release. Attempt to release the medial capsule and soft tissue structures without sacrificing the extensor digitorum longus, which one can utilize later in an extensor hallucis brevis transfer.
Although surgeons do not often perform these procedures, a syndactylization of the first and second toes, or skinplasty of the first webspace can also help in flexible hallux varus.
If the deformity is structural, attempt to correct the deformity by performing a reverse Austin, reverse Akin or another indicated osteotomy. A tendon transfer is indicated for a flexible deformity but could also help reinforce an osteotomy to reverse the hallux varus. The Mini TightRope system (Arthrex) can help pull the proximal phalanx back over the metatarsal. However, not much history is this technique.
The extensor hallucis brevis transfer is indicated in a flexible deformity with no arthritic component and following failed soft tissue releases. An extensor hallucis longus release or lengthening can help reduce medial pull on the digit. When all else fails I will do a fusion at the first metatarsophalangeal joint. Reserve the tibial sesamoidectomy and joint destructive procedures like the Keller arthroplasty or implant arthroplasty for when all other modalities have failed.
Complications of hallux varus include overcorrection that can lead to hallux valgus, stiffness, avascular necrosis of the metatarsal head, a shortened medial column, progressive degeneration, transfer metatarsalgia, wound dehiscence and infection.
Plovanich and coworkers found that most surgeries attempting to correct iatrogenic hallux varus are 60 to 80 percent effective.6 These results with the aforementioned stepwise approach can help your success rate for patients with hallux varus.
For more information, contact Jeff Bowman, DPM, at www.houstonfootspecialists.com  .
1. Janis LR, Donick IL. The etiology of hallux varus: a review. J Am Podiatr Med Assoc. 1975; 65(3):233-237.
2. Feinstein MH, Brown HN. Hallux adductus as a surgical complication. J Foot Surg. 1986; 19:207-211.
3. Dinapoli R, Jimenez AL. Hallux varus. In: McGlamry ED, McGlamry R (eds.) Reconstructive Surgery of the Foot and Leg: Update ’88. The Podiatry Institute, Tucker, GA, 1988, pp. 129-35.
4. Banks AS, Ruch JA, Kalish SR. Surgical repair of hallux varus. J Am
Podiatr Med Assoc. 1988; 78(7):339-47.
5. Taylor GC, Jimenez AL. Hallux varus. In: McGlamry ED, McGlamry R (eds.) Reconstructive Surgery of the Foot and Leg: Update ’92, The Podiatry Institute, Tucker, GA, 1992. pp. 367-77.
6. Plovanich EJ, et al. Failure after soft-tissue release with tendon transfer for flexible iatrogenic hallux varus: a systematic review. J Foot Ankle Surg. 2012; 51(2):195-7