What is brachymetatarsia?
Brachymetarsia is a condition in which one of the bones in the front of the foot (metatarsal) is significantly smaller than the others. This usually affects both feet and although it can affect any of the five metatarsals, it most commonly affects the fourth metatarsal.
Causes of brachymetatarsia
The condition may be congenital or may be due to acquired deformity following trauma, infection, tumour, radiation or previous surgery. The disease is also associated with several genetic syndromes such as trisomy 21 and Turner syndrome. Brachymetastarsia has a much higher prevalence in women than men, at a ratio of 25:1. It typically occurs in early childhood during bone development and the diagnosis is easily confirmed by X-ray.
What are the symptoms of brachymetastarsia?
The condition occurs when the affected metatarsus fails to fully develop or there is premature closure of the epiphyseal plate. The other metatarsals continue to grow around it, and the affected toe appears shorter than the other one in comparison.
On examination of the toe, it may appear that the involved toe, often the fourth toe, is shorter than the adjacent toes. Sometimes it may even appear as if the fourth toe is raised with the neighboring toes sometimes touching underneath.
Patients with brachymetarsia often report pain and difficulty using shoes. Often the pain and deformity can interfere with walking and other activities, and have a negative psychological impact due to the appearance of the foot. Often these problems are progressive as the foot grows and develops.
How is brachymetastarsia treated?
There are both conservative and surgical options to treat the condition. Conservative methods consist of wearing comfortable, wide and high shoes and avoiding activities that aggravate the problem and exacerbate the symptoms.
There are two surgical methods that can be used to correct the deformity and restore the length of the metatarsal. The first option, involves the use of grafts. This is a one-stage technique where the metatarsal is cut and brought to the correct length. A structural bone graft is then inserted into the gap between the two pieces of the metatarsal and held in place with a plate and screws. After surgery, immobilisation is recommended for 8 weeks or until the bone graft is sufficiently integrated/healed. This technique can be used when the involved metatarsal needs lengthening up to 15 mm.
The second surgical method is the application of external osseous fusion. In this method, the metatarsal is cut and then “stretched” in length using a technique called extensional osteogenesis. A small incision is made in the involved metatarsal and then a mini external osteosynthesis is applied. After surgery in about 7 days, the patient begins to gradually turn a nut on the device (daily), painlessly, to slowly lengthen the metatarsal. Lengthening is done about 1 mm per day until the desired length is achieved. This usually takes about 4 – 6 weeks based on the required length. At that time, the mini external osteosynthesis is left in place while the newly created bone heals. The final step is the removal of the external osteosynthesis.
If you are suffering from brachymetastarsia, contact Dr. Antonis Petta. The Orthopaedic Surgeon has extensive experience and is specialized in foot conditions and foot surgery. After diagnosis, you will discuss a personalized treatment plan for your problem.