The foot in health
Even in health the foot is a very complicated structure. There are 26 bones, more than 30 small joints, and more than 100 muscles, tendons and ligaments that must all work together in order for the foot to function properly. The foot also has to cope with varying roles at different times in the walking cycle; needing to be mobile to absorb shock when landing but to be rigid and efficient when springing forward to the next step. The timing of these motions is also vitally important and there is plenty that can go wrong, especially where joints are more or less mobile than normal. The foot is exposed to very high stresses. During normal walking, the forces in the foot can be a third greater than when standing still and this can increase when running to result in forces equivalent to 3-4 times body weight. With more than a million steps to be taken per year, it is no surprise that mechanical aches and pains are common in the feet.
Unique features of the foot in EDS
While there is a good deal of accepted wisdom about the foot and its related problems in EDS it is fair to say that there is relatively little that is supported by good science. We think that in people with hypermobile joints some of the subtle timing mechanisms are altered and that this results in changes to the way that groups of joints work together. Many people with the hypermobile variants of EDS have low arched or ﬂat feet but this finding is not universal and not yet fully understood. Paradoxically, in some people with a Marfan-type presentation the foot type can sometimes go the other way resulting in a high arched foot that is overly rigid.
Whether or not due specifically to changes in the joint mobility, we do know that problems with the internal function of the foot can increase the strain on the joints and the soft tissues (the muscles, tendons, ligaments) that hold everything together. As well as the direct consequences of altered joint function, there are a range of other features that can cause foot problems but which are secondary to the underlying problem. These include skin callus over exposed prominences, contractures of tendons (e.g. causing clawing of the toes), and problems with scar tissue.
While many of the above features have been noted but never measured formally, there are a few facts that have been established through scientific investigations. We know to begin with that ankle and foot hypermobility has been reported to affect as many as two- thirds or more of adults with the hypermobility types of EDS. We also know that compared with a control (healthy) population, people with hypermobile joints due to EDS or ‘benign’ hypermobility report:
• Measurably poorer general health and quality of life
• Worse lower limb pain
• Greater lower limb disability
• A tendency towards multiple joints being involved, with the lower limbs affected more than the upper limbs
Manifestations of EDS in the bones, joints and soft tissues
The most common conditions occurring in the bones, joints and soft tissues tend to be many of those that we see in the otherwise healthy population and are classed very loosely as ‘overuse’ type problems. In this context overuse does not mean doing too much activity overall, but rather overusing a specific tissue or a structure to the point that it becomes injured. The most common ‘overuse’ problems around the foot and ankle are damage to a tendon or its protecting sheath, ‘sprains and strains’ of muscles and ligaments around joints, and specific problems around the heel (most often plantar fasciitis). There is a rough rule of thumb used by many health professionals that people with hypermobile joints experience largely the same type of overuse type problems as their healthy counterparts but do so more frequently and more severely. This is a sweeping generalisation that has attracted some criticism but is nonetheless a useful way of understanding the types of foot problems that can be encountered by people with EDS.
Damage to a tendon or tendon sheath can be caused when the structures are over-stressed by a neighbouring part not performing properly. In the first instance the tendon sheath can become inﬂamed causing pain and stiffness. This can often be managed by taking mild anti-inﬂammatory tablets such as ibuprofen, or through home-based physical therapies (ice etc.) as described later. If the stress goes on for a long period the body of the tendon can become involved and this requires the intervention of a suitable health professional (see over). Modern imaging techniques such as diagnostic ultrasound allow us to look inside the tendons and have helped us understand and treat these conditions much better. Sprains and strains usually occur when a joint (or part of a limb) is moved rapidly to near the end of its stable range of movement. The mechanism is the same as for a sprain or a strain in an otherwise healthy person but these are a good example of where people with EDS can experience an injury more frequently or more severely than usual.
Finally, heel pain is so common that it warrants a special mention. The most common type of heel pain is the so-called plantar fasciitis, which is damage caused to the plantar fascia, a long fibrous band that helps maintain the foot’s long arch. There are other causes also but these are beyond the scope of this book. Plantar fasciitis/heel pain is usually felt as pain on the underside of the heel, typically worse when first standing in the morning or after a period of sitting during the day. Plantar fasciitis will resolve without treatment in many people, but for others it can persist for some years and be very resistant to treatment. In the early stages home-based remedies are worth trying but for resistant or long-standing heel pain a consultation with your GP, physiotherapist or podiatrist is required.
One common question we are asked is about bunions and clawed toes. A bunion is where the big toe twists out of normal alignment and is sometimes accompanied by the development of a lump at the base of the toe. Clawing of the toes is where the lesser toes bunch up due to the tendons tightening. Toe clawing is not hugely problematic in itself but can create hotspots of pressure on the tops of the toes or underneath the ball of the foot that can lead to discomfort. Both bunions and clawed toes are caused by problems with the internal mechanics of the foot combining with the deforming effects of shoes to create the forces that result in these changes becoming fixed.
Obviously over time, stresses and strains can build up to cause lasting damage to joints. People with hypermobile joints can find that the joints themselves can be uncomfortable but this is not necessarily a sign of permanent damage or arthritis. Where there is no lasting damage then exercise and orthoses can help protect the foot joints and these are discussed later. There is debate about the role of hypermobility in causing or even protecting joints from arthritis. There is some evidence that having extra joint mobility may actually reduce the risk of arthritis in joints such as the wrists and hands although the risk may be increased in other joints such as the knees. There is no good scientific data about the effect on foot joints. Arthritis can occur in any of the foot joints but the most common sites are: the ankle after one or more sprains, the base of the big toe as noted above, or less commonly in the joints of the middle of the foot. At present arthritic damage is not reversible and so the treatment options are limited. Some people will get relief from shoes, splints or orthoses that brace the affected joint, or from anti-inﬂammatory medication. Where there is frank arthritis however there will usually be some ongoing discomfort and while something ‘can always be done’ this may not result in the removal all of the symptoms entirely.
Common foot health problems
In a dedicated foot health service, nail care, callus reduction; footwear advice and provision; and orthoses/insole prescriptions are the mainstays of management. Podiatrists and chiropodists will also provide patients with advice to encourage and enable self-management of simple foot problems.
Abnormalities of the nails are frequently seen in clinical practice although there has been no specific study of these in patients with EDS. Difficulty with hand function coupled with painful upper and lower limb joints may also make it difficult for the patient to reach and cut the toenails. Inappropriate cutting of nails may lead to infection around the nail bed and ingrowing toenails, in such cases patients are advised to seek help from a private or NHS HPC registered chiropodist or podiatrist. We recommend that patients cut their nails straight across, filing afterwards and avoid cutting or digging down the sides of nails.
Like other warts, verrucas/verrucae are caused by strains of papillomavirus, which many people carry on the surface of their skin. It does not cause any harm unless it penetrates into the skin, where it can cause a wart. This is most likely to happen if the surface of your skin is already damaged, with tiny cracks. Most people believe that verrucas are caught in the changing rooms of swimming pools and the pool surrounds, but only one scientific study has shown that people who use swimming pools regularly are more likely to get verrucas. Other studies have shown no link.
There are a variety of treatments available for verrucas, however the clinical evidence available for their effectiveness is very sparse and very often verrucas will disappear on their own. For patients with EDS, whose skin is particularly fragile we would recommend that they avoid acid based treatments and freezing techniques due to the risk of delayed healing and infection. Instead applying pure tea tree oil with lemon oil may be of benefit, however once again the evidence is poor.
The prevalence of painful callus (hard skin) in patients with EDS is unknown. Compressive and shearing forces acting on the skin can lead to corn and callus formation, and the presence of scarring from surgical interventions will also increase the chances of a person with EDS developing painful calluses. Calluses usually become problematic only when the callus becomes thick and limits skin elasticity and this is usually made worse if a corn develops in the centre of the callus. Regular treatment of the callus can be carried out by a chiropodist/podiatrist, but the callus can be expected to re-grow within one to six weeks, creating a need for ongoing care. Using emollients (moisturisers) to soften the skin and ofﬂoading of the area may be helpful in limiting callus regrowth. Ofﬂoading can be achieved through the use of foot orthoses (insoles) to redistribute forces or simple cushioning insoles in the shoes.
Fungal infections (Tinea Pedis)
Also known as athlete’s foot, this may be more common in patients with EDS who have significant forefoot deformities. Where the toes are deformed and very difficult to separate and dry thoroughly in between after showering/bathing or in particularly in warm weather then fungal infections may develop in this ideal warm, moist environment. Antifungal sprays are available from the chemist and these have proved useful. We recommend avoid using powders or creams in between the toes as they can build up and cause a reoccurrence of the infection. Prevention is always best and daily application of surgical spirit to the skin between the toes using cotton wool or buds can prevent the build up of moisture in the skin and is ideal in this situation.
Impaired wound healing is a typical feature of EDS; this may be exacerbated with the weight bearing nature of the foot particularly if someone has a wound on the underside of their foot. If people with EDS have a wound the area may require ofﬂoading, for example with a surgical boot for a longer period of time to allow the area to fully heal. New scar tissue that forms subsequently will need to be treated with care, which includes protecting it from repeated trauma to the area (see below) and moisturising the area daily.
In an era of increased patient empowerment, education programmes have become more commonplace. People can manage many foot conditions themselves with appropriate advice and support. Leaﬂets and online resources are increasingly available for a range of conditions and one-to-one advice is often available from the GP’s surgery or podiatry clinic. Where safe and appropriate, self-management and personal empowerment is known to result in better health.
Sensible footwear choices are extremely important and simple changes here can make a significant difference to many people with hypermobility. Unstable ankles and overly ﬂexible feet can benefit from greater control provided by the shoe, and the impact of overloaded joints and soft tissues can be offset to a significant degree through the judicious use of shock absorbing and cushioning materials. In essence, the characteristics of the ideal shoe are seen in the more solid types of trainers readily available in the high street. A strong heel counter for stability, a robust upper and strong fastening for midfoot control, combined with a cushioned midsole are all ideal. Many trainer-type shoes now come in colours easier to reconcile with the workplace and in settings where trainers are not appropriate; consideration of any of these features will likely to be helpful even when more conventional shoes are required.
Hosiery can be used to protect deformed joints and tissues (skin) at risk of breakdown as well as footwear. ‘Silipos’TM or other silicone-based products are available as socks or protective sleeves for areas such as the tops of toes, the ball of the foot and heel areas. They are easy to put on, reusable on a daily basis and can be washed. These provide additional protection for fragile areas or those areas that have recently healed following a wound, as well as providing cushioning for painful areas under increased pressure due to deformity.
Limitations in joint movement for those patients who have developed arthritis with their EDS may cause difficulty in managing their own foot care needs including basic foot hygiene. Washing feet and changing of socks daily will help improve foot hygiene as well as moisturising areas of dry hard skin and using surgical spirit in between the toes.
Foot orthoses are insoles worn in the shoes that are intended to limit excessive joint motions or to produce specific functional effects. They can be custom-made to a cast of the foot or can be provided ‘off-the-shelf’ or bought from pharmacies or sports shops. Some people with hypermobile foot or ankle joints will benefit from the functional control provided by foot orthoses although they not a panacea for all foot problems. The functional orthoses most widely recommended combine three key characteristics; a contoured shell, a heel cup and one or more wedges to inﬂuence joint positions. Standard foot orthoses can be obtained over the counter for between £20-£50 and may suit many people. More tailored devices may be required for significant instability or more complex problems and these are obtained through consultation with a health professional such as a podiatrist. These will usually have a deeper heel cup and more pronounced wedging. Customised devices can cost between £100-£500 and so it is worth checking firstly that the practitioner you are consulting is familiar with EDS and the subtleties of the problems that may be encountered and secondly it is worth discussing what the various alternative treatment options might be. Notwithstanding, it is essential that foot orthoses for people with EDS are provided in conjunction with other physical therapies (e.g. strengthening etc) as set out later. They may have little effect if used in isolation.
Ankle and rear foot braces are commonly provided for patients with EDS who are prone to dislocation, to limit excess movements, particularly excessive inversion and eversion (swinging in or swinging out of the heel when walking). Braces can be provided by your local orthotics or podiatry department following a referral from your GP, consultant rheumatologist, physiotherapist or OT. Braces are also available from sports shops, however it is unlikely that they will provide enough support for someone with EDS, particularly if the joints are very unstable or poorly aligned.
Braces, as with foot orthoses, should not be used in isolation. It is important that these external devices are used in conjunction with relevant strengthening exercises (see below), otherwise joints and soft tissue are likely to become even more unstable once the brace is removed.
The benefits of improving joint stability generally are well recognised in the management of hypermobility of all causes. For the body ‘core’ many people find a Pilates-type approach helpful especially when combined with specific exercises. Foot exercises are of relatively limited use because of the large forces acting on the foot and the small size of most of the local muscles. Nevertheless, conditioning of muscles under natural loads may help somewhat as long as the exercises do not themselves cause undue discomfort. Barefoot walking is encouraged where safe and comfortable, and exercises involving repeated raising onto tip-toe may help strengthen the small muscles of the foot.
Many people do not think that stretching and hypermobile joints go together but there is an interesting paradox in that hypermobile joints may cause to excessive tightness of surrounding muscles and tendons in (over) compensation. Controlled stretching of the calf muscles, hamstrings and arch area may be useful if undertaken cautiously. If stretching causes pain or discomfort then the exercise should be performed or modified under the direction of a health professional familiar with the complexities of EDS. Potentially useful exercises are: stretching of the calf and arch muscles by leaning towards a wall with the feet on the ﬂoor, or through standing with only the front of the foot on small step and dropping the heels down. These stretches can be combined with non-weightbearing ﬂexibility exercises (e.g. circling of feet, splaying of toes, picking up small objects with the toes).
Joint position sense
We know that joint position sense can be reduced in some people with hypermobile joints. The precise cause is not known but may arise because of looseness or damage to the joint capsule. Improving joint position sense may have a positive impact on instability in joints such as the ankle. Tiptoe standing is an easy way to (re) train the joint position sense starting with bearing weight on both feet simultaneously and raising onto tip toes for 5-6 repetitions of 30 seconds. If safe and appropriate this can be increased to more repetitions and ultimately to standing only on one leg at a time.
Many people with problems in the bones, joints and muscles may be offered or may consider surgical treatments. While some surgical foot procedures (e.g. for removing bunions or fixing damaged tendons) may well be appropriate, there are a few specific things that people with EDS should bear in mind.
Many foot procedures are now conducted under local anaesthetic, which we know is sometimes less effective in people with EDS. Fragile skin can make it difficult for the surgeon to achieve a clean scar following surgery and even when the initial wound closes well, stitches can also pull later. This is particularly troublesome for structures such as the feet where the load causes the skin to stretch more than on other parts of the body. Depending on skin condition healing (and therefore the period off-weightbearing) may be extended by weeks after surgery.
The foot is very complex and so there is plenty that can go wrong in people with systemic conditions like EDS. There is evidence that people with EDS do get more foot problems than the rest of the population, but importantly many of these problems will respond very well to better footwear, or self-management programmes based on exercise and staged activities. Insoles can help stabilise foot joints but should be used in conjunction with exercises and changes to footwear etc.
If you do have foot problems that you think may be a direct consequence of your EDS you should consult your GP, hospital consultant or HPC registered podiatrist. They will be able to advise you on what you can safely do to help yourself and should be able to point you towards any extra treatments you might need.