by Cookie » Mon Jun 20, 2011 12:55 pm
Will FiveFingers Fix My Bunion
Medical Resource Vol. 6
A bunion deformity is actually a dislocation of the great toe joint or the 1st metatarsophalangeal joint which allows the head of the metatarsal to become exposed. The "bump" that you see and feel is the 1st metatarsal head becoming exposed medially (inside of foot) as the toe itself is moving laterally (toward the 2nd toe). As this occurs it is also very common to see the 2nd toe "pop out of place" at the 2nd metatarsophalangeal joint from the force of being overcrowded by the great toe. Though we know the deformity is hereditary, we definitely see an increase secondary to shoe gear as well as muscle weakness in the foot.(1,2)
During the deformation process, we start to see an irregularity of the joint surfaces commonly described as "bone on bone." The longer the joint functions in this manner, the more the cartilage becomes eroded, and thus more pain.
So what do we do to prevent this?
Well, many advocate the use of a custom orthotic to "slow down" the progression of the deforming forces. Experience, as well as common sense" has demonstrated that the more you place into a shoe when someone has a bunion deformity, the more pressure you place against the bunion. The philosophy is that by implementing an orthotic, you reduce pronatory forces in a pes planus deformity (flatfoot) to slow down the progression. The problem with this is two-fold for one, not everyone with a bunion deformity has a flatfoot. And two, implementing an orthotic has been shown to weaken the intrinsic foot musculature, which can in turn lead to a worsening of the deformity. (3)
If we examine the foot musculature, we see that on the inside part of the foot, or medially, there is a muscle referred to as the abductor hallucis muscle. Its function is to abduct or pull the great toe medially at the metatarsophalangeal joint. If it looses its strength or weakens, the great toe will have a tendency to drift laterally or toward the 2nd toe during normal locomotion.
When the abductor hallucis muscle is strengthened, it will develop what is known as postural tone or postural control. This refers to its ability to maintain slightly contracted while in a relaxed stated to hold the great toe in a normal anatomic position. This is very similar to the muscle in our back known as the erector spinae muscles, or even the gastrocnemius muscle of the leg.
So to answer the question. If the abductor hallucis muscle becomes stronger (as it can wearing FiveFingers more often) we will see a tendency of the great toe to move medially to become "straighter." It is important to remember that the longer the deformity is present, the more likely the damage to the cartilage of this joint which can produce more pain. The toe may become straighter, but the "bump" can still be somewhat present as the bone has hypertrophied or enlarged in response to stress. I commonly tell my patients there are 3 reasons to fix a bunion surgically - pain, pain, and pain.
Strengthen your foot and you will decrease the likelihood for surgery.
1. Mickle KJ, Munro BJ, Lord SR, Menz HB, Steele JR.
Clinical Biomechanics Award 2009: toe weakness and deformity increase the risk of falls in older people. Biomech (Bristol, Avon). 2009 Dec;24(10):787-91. Epub 2009 Sep 13.
2. Nguyen US, Hillstrom HJ, Li W, Dufour AB, Kiel DP, Procter-Gray E, Gagnon MM, Hannan MT. Factors associated with hallux valgus in a population-based study of older women and men: the MOBILIZE Boston Study.
3. Nigg BM. The role of impact forces and foot pronation: a new paradigm. Clin J Sport Med. 2001 Jan;11(1):2-9.
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