It has been reported that as many as 15% of diabetics will develop a foot ulcer in their life and about 85% of lower leg amputations in diabetics arise from foot ulcers. Diabetes, and foot ulcers, are a very large component of medical complications not just in the United States but around the world.
The foot has 5 metatarsals which are the long bones connecting to the toes. The connection, or joint, is called the metatarsal-phalangeal joint. The end of the metatarsals forming the joint are called the metatarsal heads. When there is a problem with a head as it hits the ground as we walk one can get pain under the foot in the area of the head. The problem could be because the head is enlarged, or it can be pressing downward too much, or the metatarsal itself is a bit too long. The excessive pressure under the head can also cause an ulcer under the foot. If a diabetic has loss of feeling in that area, the ulcer can form without pain.
When presenting to your doctor with an ulcer, she will examine the foot by touching the area in different ways, feeling the heads, taking x-rays, usually different views, and taking a history about the problem which can include when and how often the pain is felt and other factors concerning this specific complaint. Sometimes, just changing the style of the shoe, or adding some padding, will relieve the pressure and stop the pain and ulcer formation. This would a form of conservative or non-surgical treatment. But many times this is not successful especially if the problem is due to a problematic metatarsal head.
So if the metatarsal head is the cause of the ulcer, why not just operate and “fix” or remove the head so that it longer puts excessive pressure in that area?
This very question was addressed by a group of doctors from Iran. They published an articled entitled “Comparison of Metatarsal Head Resection Verus Conservative Care in Treatment of Neuropathic Diabetic Foot Ulcers” in The Journal of Foot & Ankle Surgery (May/June 2017, Vol 56, No. 3). The surgery we are talking about is one where the metatarsal head is completely removed – called a resection. Metatarsal head resection has been traditionally used to treat problematic metatarsal heads on patients with rheumatoid arthritis and various forms of traumatic injuries to this area of the foot. Metatarsal head resection is “…also now considered one of the major therapeutic interventions for deformities caused by metatabolic disorders such as diabetes mellitus.”
These authors describe the cause of the metatarsal head problem like this: “The plantar (bottom) aspect of the metatarsal head is a common location for ulcer formation in diabetic patients because of biomechanical overloading forces, which lead to the necessity for surgical off-loading and healing of this area.”
Another form of bone surgery to treat these ulcers – not a subject of this article – is shift the head into a new position, a position where the head is not making excessive force in that area, excessive in relation to the force exerted by the other metatarsals. This surgery is a form of osteotomy – the bone is cut at or near the metatarsal head and the head is put into a slightly different position then held in place usually with a wire or internal fixation until the bone heals.
The authors’ study in this article was one designed to compare which is better: treating the ulcer conservatively (without bone surgery) or treating the ulcer with bone surgery to remove the metatarsal head. The object of either treatment is healing of the ulcer.
Their results are surprising: “Assessment of the wound healing showed that wound healing occurred more efficiently in the operative group than in the medical group.” In other words, they reported better outcomes for those having metatarsal head resection surgery over those whose ulcers were treated conservatively or “medically.” Their conclusions are these:
“We found more ulcer recurrence after medical therapy and also more infections. A comparison of complications showed that MHR (metatarsal head resection) is a better choice of treatment because it results in few patient morbidities and complications. Additionally, the mean duration of wound healing in the medical treatment group was 10.3 times longer (in days) than in the operative treatment group. Also, healing occurred significantly more quickly after MHR. We have clearly demonstrated that both early and late complications were significantly lower in those patients who underwent surgery than in the medical group. Thus, overall, the operative approach will be superior to a medical regimen in early and long-term outcomes in patients with DM (diabetes mellitus) and neuropathic diabetic foot ulcers located at the plantar aspect of the metatarsal heads.”
However, not all diabetic patients with foot ulcers are good candidates for surgery. And one study alone does not necessary determine the standard of care for the treatment of diabetic ulcers. However, if your podiatrist or doctor suggests surgery as a way to treat a diabetic ulcer on the bottom of your foot, in the area of the metatarsal heads, you should know that such treatment is acceptable in some patients in some circumstances. As with any type of surgery, you should ask questions, understand what the surgery is designed to do, ask about alternatives, and obtain a second opinion from someone else if you feel that you are not getting all of the information you think you need to make a decision to have surgery.