Dr Mark Hamilton walks us through the use of dermal fillers in feet to address stiletto metatarsalgia
It’s all too common that women will compliment the lovely shoes each other are wearing on a night out, but by the end of the night significant number are walking around, holding those heels in their hand. Despite this, most women continue to wear heels nowadays and the reality is it’s a real fashion accessory. So what is it about high heels that’s making everyone want to wear them?
Why do we wear heels?
The truth is heels are always in fashion. They give the wearer a little bit of extra height; they seem to create good posture for the wearer; the bust and bum seem to be enhanced; legs look better, and some even argue that they have a better sex life.
Research undertaken by Italian urologist Dr Maria Cerruto and published in the Archives of Italian Urology and Andrology Journal presented a study of 66 women under 50, which measured electrical activity in the pelvic muscles. Her research suggested that muscles are at optimum position for strength and contraction when wearing heels.
I agree with Christian Louboutin when he says that he is certain that heels have never been as high as they are now. Louboutin is also a man who recognises that everybody has different pain thresholds—for some, a one inch heel will be the pain threshold that they can deal with, but often the threshold of pain becomes a threshold of pleasure, and of course, the fetish shoe—the eight inch stiletto heel – is coming into mainstream fashion.
High heels are now an integral part of a woman’s outfit, and despite the balls of the feet taking abuse like never before, women are refusing to give them up. Stiletto metatarsalgia is the pain secondary to the wearing of high heels. There are some other common causes of foot pain—plantar fasciitis is probably the most popular one; arthritis; corns and calluses; gout; neuromas are all common causes of foot pain.
Metatarsalgia is pain caused in the ball of the foot and is well localised. When wearing high heels, the whole weight of the body is transmitted through the metatarsal joint, and in a high-heeled shoe, there is constant pressure applied. Cushioning under the metatarsal is inadequate, so when that distal metatarsal joint is flexed into that high ankle position, the fat pad is displaced posteriorly and the cushioning becomes inadequate.
Solutions to metatarsalgia
Changing footwear would the sensible option, but we’ve already realised that women are reluctant to do that. The irony is that turning to flat shoes can however be a trigger for plantar fasciitis and interestingly sufferers of plantar fasciitis find that going into a heeled shoe can actually sometimes bring some relief. Many women use gel cushioning inserts, but the problem with that is that these shoe inserts change the fit of the shoe and can cause pressure and friction elsewhere on the feet.
With the evolution of dermal fillers it’s possible to use these as a way of cushioning the ball of the foot. Once inserted, the filler is constantly there and attempts to recreate the cushioning effect of this fat pad that has been displaced posteriorly. The technique for delivery is very simple, there’s minimal downtime and it’s relatively safe.
This use of dermal fillers is not yet something that’s well studied and very little research has been carried out into it. There is one case reporting on the use of collagen injections in the treatment of metatarsalgia3 and about failed relief of metatarsalgia from a collagen dermal filler. Evolence discussed the use of collagen within the feet for cushioning—something I advised against, because my experience was that it was really the HA fillers that were providing the real cushioning and I wasn’t sure that Evolence was ever going to create any sort of cushioning effect.
Underneath the distal metatarsal head, are little sesamoid bones, which must be paid attention to during a treatment. With the metatarsal head in a flexed position, the sesamoid bones are taking a lot of the weight, so you must be careful when you’re injecting that you’re not interfering with them. If interfered with and moved to the side, the weight that’s transmitted through that metatarsal head can become quite uncomfortable.
There are some unique aspects to the skin of the sole of the foot. It is the thickest part of the body; it lacks hair and pigmentation and the sweat pores themselves lack sebaceous glands. It is an incredibly sensitive area, but it’s the fibro-fatty chamber surrounded by thick connective tissue that we’re looking to enhance and to treat.
In terms of landmarking, it’s important to know of the location of the deeper intrinsic and extrinsic muscles in the foot, but you really should not be in this area with the needle. Working this deep is danger territory—activity should be restricted to the subdermal area and not anywhere near the deep intrinsic anatomy of the foot.
When a patient comes to talk about this metatarsalgia I begin by taking a full history, in order to determine whether it really is metatarsalgia and eliminate all other causes of foot pain. I’ll take a quick foot assessment and palpate the foot, while looking for obvious callouses and thickening of the skin, which usually highlights the area that is taking all the weight. Also I often I take an impression of the foot on some impression foam.
Once the patient’s foot is cleaned and prepped, I usually apply topical anaesthetic for about 20 minutes beforehand. I then infiltrate using 2% lidocaine with adrenaline—because adrenaline is very useful at causing basal constriction and it reduces bruising. The sole of the foot is not particularly vascular; it’s particularly just the subdermal region and this fibro-fatty compartment that we want to treat, but using the 2% lidocaine with adrenaline is great as a way of reducing the risk of bruising and allowing you to treat the patient in a degree of comfort.
I mark the sole of the foot by palpating the area, flexing the toe and feeling the metatarsal head—it’s a very straightforward technique. Its possible to feel areas of thickening of the skin and where the fat pad is, which is where want to inject into. I use a 27 gauge needle and my preference is to use a soft hyaluronic acid like Belotero Basic in most of my patients. In the past, I used Sub Q with the understanding that thicker fillers would give a better cushioning effect, but the reality was that these thicker filler patients took much longer to get comfortable. We want to give patients immediate comfort so they can get into their heels straight away with minimum downtime.
Post treatment, after I’ve injected the filler, I use about two mils of Belotero on each metatarsal head and a small amount of careful moulding. If you use something straightforward, like Belotero Basic or Juvederm Ultra 3, you’ll find that that HA moves very easily within the tissues and you don’t get any hard lumps or bumps.
I ask the patients to wear comfortable sports shoes for 24-48 hours. However, it’s not unusual for the patients to go straight into their heels again immediately after the treatment. It can be very frustrating when patients don’t come prepared with their flat shoes, particularly since we try to give them that information beforehand. However, many people are really keen just to get back into heels and back to normal again, and that’s why I use products like the Belotero Basic, the very soft fillers, because it will allow patients to get straight back into wearing their shoes again. Sometimes we ask them to just use common sense oral analgesia, if the pain is a little more than they’re expecting, and a slow introduction to high heels as comfort dictates.
Try not to use too much filler all in one session—a couple of mils of a soft HA filler are perfect in one session. You may end up having to go back and add a few more after a few months, and that’s fine, but in my experience it’s always been much easier to add a little more filler, or do a little more treatment a month or two later than regret doing too much all in one session.
Be aware of intra-articular injection. However, if you’re injecting the face and you’re familiar with straightforward injections, you should have no problem injecting the foot.
Correct patient selection is really important. It’s generally not possible to help older patients, who have arthritis in their feet. Many patients have very high expectations for this treatment. It’s wise to advise patients that this is just a comfortable treatment that should increase the comfort of wearing high heels, but that you’re not going to eliminate all of the pain.
Is there some benefit from using toxins? Personally, I don’t use toxins in the feet. I can understand some of the logic behind using it in the feet—you can relax some of the muscles in the feet that are in spasm in high heels, and actually give some analgesic effect. Although the mechanisms are not completely understood for everyone a paper in Neurology Journal showed that patients who were injected with Botox in the soles of their feet experienced significant reduction in pain after 12 weeks, so it’s something definitely to look at but not something that I personally use.
Dr Mark Hamilton is a full time cosmetic doctor and surgeon, published author and conference speaker working in the UK and Ireland who has been practicing in aesthetics for the last 12 years. He has recently opened a new clinic in Merrion Square, Dublin city centre.