Brachymetatarsia is a condition in which one of the five long bones of the foot (the metatarsals) is abnormally short. This condition usually occurs in both feet (i.e., bilaterally) and in the fourth toe. In most cases, brachymetatarsia results when the metatarsal growth plate closes too early which can be caused by a genetic factor or by trauma. While walking, weight normally is transferred from the fifth toe to the fourth, then to the third, and so on until it reaches the first toe (hallux). This occurs because the toes are gradually longer and as weight is transferred to the forefoot, the next longest toe assumes the weight. Brachymetatarsia disrupts this process. If the fourth toe is shorter than the fifth toe, it never assumes the body weight and cannot transfer it to the third toe correctly. As a result, the fifth and third toes receive extra weight and pain develops in those areas. An abnormally short toe also tends to drift upward, which often causes problems with footwear.
Conservative treatment involves wearing shoes with extra depth, padding, and orthotics. In some cases, surgery is performed to lengthen the short toe. In this procedure, the short metatarsal is usually cut and a piece of bone is grafted between the two ends. When the graft heals, the metatarsal and toe are the correct size. Following surgery, all weight must be kept off the surgically repaired foot for 3 months, after which the patient wears a snug-fitting lace-up shoe for about 6 weeks.