The Foot - Part Two
The shoes in which we encase our feet in almost all circumstances may be partly to blame for some of the foot pathologies we experience. The unstable ground surfaces we now encounter much less often were the normal environment for the feet to evolve, gripping the ground and stressing the foot''s small muscles. Now most of our surfaces are flat and smooth and with the foot in a shoe with a flat smooth sole, the foot has a much less varied and challenging job to do of coping with what is underfoot. As the foot has been deprived of its natural environment its muscles, the foot intrinsics, weaken.
The arches of the foot and the function of the toes alter as the intrinsic muscles of the foot weaken as the toes lose the ability to hold themselves straight when gripping the surface. Due to this they start to bend or claw, and as this progresses the muscles which extend the toes can shorten in sympathy, drawing the toes up in a flexed position. This takes the pads of the toes away from any possible contact with the ground, obliging them to take force on the tips perhaps. Overall the foot becomes less functional and the arches decrease in height.
As the inside and long ways arch loses height, perhaps connected to the tendency to roll the foot inwards excessively in walking, the tissues under the arch become strained as they are put under tension stretch. This can cause pain and aching with time on the feet such as standing or walking for a while. The smaller front arch across the foot can also give problems if it loses some of its strength and tension. This allows the underneath of the head of the second metatarsal to contact the ground and take body weight pressure, a job it is not designed to do.
The second metatarsal does not have a great degree of fatty padding underneath it so it does not suit the job of bearing the weight whilst walking or standing, with patients often reporting they feel they have a stone under the forefoot. Areas of hard skin known as calluses can develop over these areas and show where abnormal weight is being taken. The weight of the body can be thrown forward onto the fronts of the feet by wearing high heels and the ability to push off with the toes can be compromised by the narrow fronts of the shoes.
Another abnormality which might develop is a bunion, an enlarged and often unsightly joint between the big toe and the first metatarsal. This can be something which is familial to some degree as many patients report their relatives are similar to them. As the joint enlarges it can become painful and the big toe deviates gradually towards the outside. Along with the loss of the strength of the foot arches this turns the foot from a dynamic movement tool to a static platform which is difficult and often painful to use.
The relationship between the big toe joint and the first metatarsal is not the whole determinant of a bunion problem, as the first metatarsal is typically angled towards the inside and this makes the abnormality worse. Orthopaedic surgeons can approach these problems with a number of operations with differing goals, the first metatarsal osteotomy being a common intervention to restore the natural alignment between it and the big toe. Day case surgery has taken over from overnight admission or longer in cases where the patient can learn to mobilise quickly either weight bearing on the heel or hopping and if the pain can be well controlled.
Physiotherapists who specialise in the area of foot assessment and subsequent treatment manage many of the less severe foot disorders due to abnormal foot postures. This needs specific training in the assessment and the use of the large variety of pre-formed insoles, typically called orthotics, to correct the postures of the hind foot or to give support to the arches of the foot. Exercises are often prescribed at the same time to attempt to restore strength and function in the intrinsic muscles which maintain the foot arches.