Brachymetatarsia is a relatively uncommon disorder of the foot, but one that is interesting in its discussion. “Brachy” means short and “metatarsia” refers to the metatarsal bones (the long bones in the middle of the foot). A short metatarsal is one that is 5mm or more shorter than the length that it “should” be when compared to the adjacent metatarsals.
Patients develop this disorder due to premature closure of the growth plate in the affected metatarsal while the surrounding metatarsals continue to grow at a normal rate. The premature growth arrest can be congenital (something that we’re born with) or acquired throughout childhood. Congenital disorders that tend to lend themselves to brachymetatarsia include Down’s Syndrome, Turner’s Syndrome or bone enlargement. The most commonly acquired causes of ‘brachymet’ include trauma to the growth plate or infection both of which also arrest growth in the bone.
Most commonly, the 4th metatarsal is affected, and patients usually know something isn’t right, not by the symptoms they experience, but simply by the appearance of their foot. Their primary complaint upon presentation to a Podiatrist is that their toe “looks funny!” They may relay symptoms of calluses with associated pain beneath the adjacent metatarsals, a dorsal corn on the affected toe that rubs with shoe-wear, or contractures of both the affected digit and the surrounding digits. However, the conversation always leads back to the look of the toe. That is, their primary concern is cosmesis!
After x-ray evaluation, your Podiatrist will determine how short the metatarsal is in relation to the adjacent metatarsals, and although the number in millimeters doesn’t mean much to you as the patient, it means a lot in terms of how your Podiatrist can correct for this abnormality, should you opt for surgical correction.
Conservative options for Brachymetatarsia only treat the associated symptoms and will not treat the look of the digit. Options for treating the associated symptoms include padding, orthotics and trimming of corns and calluses associated with the deformity. However, since the primary patient complaint is the appearance of the digit, it is common that the patient selects surgical intervention.
In terms of surgical intervention, there are two choices: one-stage lengthening of the metatarsal vs. gradual lengthening of the metatarsal. One-stage lengthening involves a surgical break of the bone with insertion of bone bank bone into the defect. This will achieve lengthening of the metatarsal in one stage, but does have complications that involve compromise of the nerves and blood vessels surrounding the digit. Gradual lengthening of the metatarsal also involves a surgical break of the metatarsal bone, but rather than filling the defect, a distraction device is applied to the foot. Over a period of several weeks the distraction device is turned so as to lengthen the area of defect, allowing the body to make its own bone. The healing process in gradual lengthening does take longer but limits the risk to the surrounding nerves and vessels.
Your Podiatrist will recommend the surgical procedure that will work best for your case, with regards to the amount of lengthening required and your postoperative weight-bearing limitations. Keep in mind, however, that with any surgical procedure, although you will lengthen the toe and improve the overall alignment of the foot, you will have a scar on the top of the foot. Careful consideration, before opting for surgical correction for your Brachymetatarsia, is necessary and it is a decision that should not be taken lightly.