BIOMECHANIC / MUSCULAR SKELETAL EXAMINATION (MSK)
Biomechanics is the study of human movement, as the feet and legs are the part of the body that move us from place to place, understanding how this is done is very important. Small changes in alignment can have a large impact on the whole system.
THE GAIT CYCLE
As we walk the first part of the foot to hit the ground is the outside of our heel (this is why we wear this part of our shoe first), as the rest of the foot comes in contact with the ground, we start to move our body weight over the foot. At this point the foot starts to pronate (the rolling and flattening of the arch) this is a normal part of the gait cycle and allows the foot to adapt to uneven surfaces and absorb shock. As the body continues to move over the foot the foot starts to supinate, the arch starts to rise and the foot becomes more of a rigid lever enabling us to pivot over the foot (or push off) so we can take our next step, and so the cycle continues. We take an average of 2500 steps a day which means we walk about 3000 miles a year.
It is not difficult to imagine that small changes in the gait cycle could have a significant impact on the whole system. If for example there is excessive pronation or flattening of the arch during the gait cycle, then we may be trying to pivot (push off) a foot that is a mobile adaptor rather than a rigid lever. Not only would this be less effective at moving us forward and therefore require more effort, but it may also have an impact on the structure doing the moving, i.e. the feet and legs. Excessive pronation can lead to many foot and leg conditions including, plantar fasciitis, tendonitis, shin splints, patella femoral problems and capsulitis to name a few. There may well be more remote symptoms including back pain and even tempro mandibular joint problems (jaw pain).
Equally if there is excessive supernation and the foot is a rigid lever when it should be a mobile adaptor then the feet will be poor shock absorbers and this may also lead to problems like ankle sprains, Morton’s neuroma and knee problems once again to name a few.
Even callous and corns can often be traced back to underlying biomechanical problems causing increased pressure and or friction on a certain part of the foot.
Part of the roll of a podiatrist is to assess the patient’s biomechanical problems when appropriate. This usually takes the form of a biomechanical assessment. The patient is examined to see how everything lines up, feet, legs, knees, and the rest of the body, lines may be drawn on the legs and feet and ranges of joint motion measured. Weakness or tightness of associated muscles will be noted. The gait may be observed and foot wear examined.
From this the podiatrist can then make a diagnosis and prescribe the appropriate care often in the form of a custom made orthotic, to reduce excessive pronation or supernation and align the legs and feet. Muscle stretching or strengthening may also be required and direct treatment to the injury or problem could be needed in the form of manipulation, strapping or laser treatment to the area.
Podiatric biomechanics is very technical and requires high skill to deal with problems of standing, walking and running. It is the use of this skill in performing a biomechanical examination that enables podiatrists to identify and treat functional faults.
A biomechanical examination involves taking a series of measurements of the feet and legs with the patient standing and lying down and may include checking joint movements and assessing muscle strength and flexibility. It will often include watching the patient walk to assess the way in which the foot works.
The results of a biomechanical examination enable the podiatrist to assess the relative positions of the feet and legs and the amount of excessive motion occurring. Once that is established, the podiatrist will be able to decide which treatment can help the feet to function more efficiently.
Orthotics refers to insoles that are fitted into your shoes. Often it is necessary to fit insoles into footwear to support and comfort a person’s feet and they are made precisely for the way their foot is shaped and how they walk.
The most common treatment for biomechanical problems is the use of orthoses. They assist the feet to function more efficiently. They do this by controlling joint movement, and by altering some joint angles to prevent excessive motion.
Many look like arch supports, but they are not intended to support the arch.
Orthotics are angled individually to control the heel and forefoot, and prevent excessive motion. The natural arch in the foot will in most case become more apparent whilst the orthotics are worn.
There are many different types of orthotics. The type that is used depends on the activity in which the patient is involved, the shoes they want to wear, and the underlying foot problem.
There are 3 main types of orthosis:
- Prefabricated but prescribed by the podiatrist, often heat mouldable for a more contoured fit
- semi-custom orthotic which is a pre-formed orthotic with personal adjustments made for individual requirements.
- custom made usually following a biomechanical assessment during which a mould has been taken of the feet. Specifically designed and manufactured for your feet,
There are many different manufactured shapes and sizes of orthotics but your podiatrist will know which will be best for you.