Small movements which allow a glide and a slide inside a joint are essential for the normal use of the joint but cannot be done in isolation, occurring with other movements. These are called accessory movements and their presence is vital to joint function, a reduction in available range or a pain problem resulting if they are lost or reduced. The hip is a deep joint with significant stability so the accessory movements are rather subtle, with the main one being compression and distraction, the pushing in to and pulling out of the ball from the socket.
Walking and bearing weight involve reciprocal cycles of relaxation and compression, which promotes the nutrition and health of the articular cartilage. On compression the cartilage will be indented to a degree and once the force is released it will move back towards its normal shape. In this way fluid is forced out of the tissue under compression and sucked back in again on relaxation of the pressure. This pumps fluid from inside the articular cartilage and from the bone under it, setting up a system of fluid replacement.
The typical mechanical stresses through the joints stimulate the production of new cartilage cells, with the on-off stresses being important to counter the high forces involved when we put our heels down in gait. Bigger movements in larger amplitudes may encourage cartilage growth whilst absence of stresses or sustained loads may impede synthesis of cartilage. Cartilage breakdown may be encouraged by high bodyweight, static loading for long periods or by reducing loads such as by use of a stick.
When a joint is painful it may not always be the best idea to rest it although pain will be reduced at least initially. Without normal forces the cartilage regrowth stimulation does not occur and there may be a tightening of the joint capsule and a loss of the full movement of the joint. The joint may then become more painful as the tightness increases compressive forces. Respecting a painful joint is important but overall it is better to keep an arthritic joint moving than to keep it static. The normal cyclical rhythm of gait is very important in maintaining movement and good blood supply to the upper hip area.
The ligamentum teres, a band like structure running from the head of the femur to the socket, has blood vessels which may be affected by the cycle of gait which produces a effect of pumping fluid through. This may allow better blood supply to the head of the femur and keep the bone healthy. To maintain the density and normal composition of the bone in the upper femur it is important for this area to be subject to normal forces such as walking. Use of a walking aid or resting in bed can cause loss of bone density and mineralisation, with the bone becoming less flexible and less resistant to jars and strains.
In western societies we typically use little of the relatively large available ranges of movement of the hip joint. We walk in a limited, repetitive range and when we sit we typically do so at a mostly high level so our hips don't go beyond 90 degrees flexion. We seldom push our hips to the extremes of movement of which they are capable and this tendency increases greatly with age. Overall the hip will benefit from maintaining a variety of its movements and from placing it at the ends of its ranges at times. Eastern peoples typically squat or sit cross legged, even to iron, and seem to have lower levels of hip arthritis.
A lack of use in the end ranges of a joint can mean the joint capsule will exhibit some tightening and in this way increase the compressive forces suffered by the head. Extension of the hip can be particularly affected by a difference in leg length. The longer leg in standing will tend to bend slightly at the hip and knee to keep the head level for the eyes to function best. This compensation can lead to stiffness developing with some loss of hip and knee extension as the hip develops a fixed flexion deformity. - 14130
Walking and bearing weight involve reciprocal cycles of relaxation and compression, which promotes the nutrition and health of the articular cartilage. On compression the cartilage will be indented to a degree and once the force is released it will move back towards its normal shape. In this way fluid is forced out of the tissue under compression and sucked back in again on relaxation of the pressure. This pumps fluid from inside the articular cartilage and from the bone under it, setting up a system of fluid replacement.
The typical mechanical stresses through the joints stimulate the production of new cartilage cells, with the on-off stresses being important to counter the high forces involved when we put our heels down in gait. Bigger movements in larger amplitudes may encourage cartilage growth whilst absence of stresses or sustained loads may impede synthesis of cartilage. Cartilage breakdown may be encouraged by high bodyweight, static loading for long periods or by reducing loads such as by use of a stick.
When a joint is painful it may not always be the best idea to rest it although pain will be reduced at least initially. Without normal forces the cartilage regrowth stimulation does not occur and there may be a tightening of the joint capsule and a loss of the full movement of the joint. The joint may then become more painful as the tightness increases compressive forces. Respecting a painful joint is important but overall it is better to keep an arthritic joint moving than to keep it static. The normal cyclical rhythm of gait is very important in maintaining movement and good blood supply to the upper hip area.
The ligamentum teres, a band like structure running from the head of the femur to the socket, has blood vessels which may be affected by the cycle of gait which produces a effect of pumping fluid through. This may allow better blood supply to the head of the femur and keep the bone healthy. To maintain the density and normal composition of the bone in the upper femur it is important for this area to be subject to normal forces such as walking. Use of a walking aid or resting in bed can cause loss of bone density and mineralisation, with the bone becoming less flexible and less resistant to jars and strains.
In western societies we typically use little of the relatively large available ranges of movement of the hip joint. We walk in a limited, repetitive range and when we sit we typically do so at a mostly high level so our hips don't go beyond 90 degrees flexion. We seldom push our hips to the extremes of movement of which they are capable and this tendency increases greatly with age. Overall the hip will benefit from maintaining a variety of its movements and from placing it at the ends of its ranges at times. Eastern peoples typically squat or sit cross legged, even to iron, and seem to have lower levels of hip arthritis.
A lack of use in the end ranges of a joint can mean the joint capsule will exhibit some tightening and in this way increase the compressive forces suffered by the head. Extension of the hip can be particularly affected by a difference in leg length. The longer leg in standing will tend to bend slightly at the hip and knee to keep the head level for the eyes to function best. This compensation can lead to stiffness developing with some loss of hip and knee extension as the hip develops a fixed flexion deformity. - 14130
About the Author:
Jonathan Blood Smyth is the Superintendent of Physiotherapists at an NHS hospital in the South-West of the UK. He writes articles about back pain, neck pain, and injury management. If you are looking for physiotherapists in Bolton visit his website.
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