How does an orthosis work?

Despite the variety of different orthoses and the differences in shape and size, orthoses are usually based on a common principle of action. This is the so-called three-force principle. Here, the effect of the orthosis is achieved by having three points of contact on the corresponding part of the body, two of which serve to stabilize and exert pressure.

With so-called active orthoses, this effect is best achieved in motion, which means that the activity of the user is necessary. Passive orthoses, on the other hand, support the joint completely even when at rest. The most important prerequisite for any orthosis to have a good effect is that it fits exactly and is adjusted to the patient’s measurements if necessary.

In addition, the individual requirements for the aid should also be taken into account. It is also important that the orthosis is comfortable to wear and that pressure points, for example, are recognized and compensated for in good time. To achieve the best possible effect, it is important that the orthosis is not only individually fitted, for example by an orthopedic technician in a medical supply store, but also instructed on how to put the orthosis on correctly.

Which orthoses are available?

Orthoses can be classified according to various categories. A classification is made according to the body part on which they are used. Thus there are orthoses for arms and hands, legs and feet as well as for the trunk, i.e. back or neck.

In addition, a distinction is made between orthoses that only work actively and those that also provide passive support. In the case of the only actively effective orthoses, the effect only occurs when the wearer moves. A further important classification is based on the purpose the orthosis is intended to fulfill.

For example, the aim can be to immobilize a joint after an operation, so that the wounds can heal. These orthoses are often referred to as positioning splints. On the other hand, when ligaments are injured, orthoses are often used that serve to stabilize the joint from the outside, for example after a torn cruciate ligament in the knee joint.So-called retention or redression splints are used to compensate or correct malpositions.

Another group of orthoses are used for length compensation, for example, when one leg is longer than the other. In addition, the various orthoses differ due to the materials of which they are made. Besides different types of plastic, carbon (carbon fibers) can also be used.

The knee joint is the largest joint in the human body and it has a complex structure with various ligaments that serve to stabilize the knee while providing mobility. If ligament structures are damaged, for example in an accident, it is therefore often necessary to use a knee joint orthosis. From the outside, this forms a stable frame around the joint and thus replaces the stability lost through the injuries as far as possible.

In addition, knee orthoses are usually equipped with axial joints. These can be fixed at different angles and thus limit the extent of movement in the knee. By releasing the movement more and more over several weeks, the damaged structures can recover and the knee joint becomes stable again even without the orthosis.

On the other hand, if an operation is performed on the knee, complete immobilization of the joint is usually required first. This ensures that the wound as well as the internal structures can heal and that premature movements do not lead to renewed damage. The orthoses used for this purpose are so-called knee support splints.

Here the knee is not stretched, but usually fixed at a certain angle of flexion, depending on the operation performed and the structures that were injured. Since swelling of the tissue can occur after an operation, it is also important that the width of the knee orthosis can be adjusted. A lower leg orthosis is prescribed, for example, if a tear and partial tear of the Achilles tendon has occurred.

The lower leg orthosis fixes the foot in an arched foot position. This allows the tendon to grow back together again and also prevents further injury from occurring due to lowering of the foot. The angle between the lower leg and foot is achieved by the use of a wedge and is greatest at the beginning of the orthosis treatment, since this is the best way to bring the ends of the tendon together.

Over the coming weeks, the angle is gradually reduced by changing to ever smaller wedges until the foot is back in its neutral position of 90 degrees. This prevents the tendon from shortening. Other reasons why a lower leg orthosis is used are, for example, fractures of the tibia or calf bone.

In addition, ligaments on the foot can also tear or be overstretched by bending them over, making it necessary to wear an orthosis temporarily. Injuries to the ankle joint are among the most common injuries to the musculoskeletal system in humans. The mechanism of the accident is usually a twisting inwards or outwards.

This can lead to overstretching or a tearing of ligaments as well as to a fracture of the inner or outer ankle. Often an ankle joint orthosis must be worn for some time after the injury. This can be the actual treatment for minor injuries.

A so-called stabilizing splint prevents the foot from buckling again while maintaining mobility in the ankle joint. In cases with larger injuries, surgery may be necessary first. Subsequently, an orthosis is often required to immobilize the ankle joint area so that the wounds and injured structures can heal.

A wrist orthosis usually consists of a splint that runs from the palm of the hand to the wrist to the forearm and is fixed with ligaments or straps. This fixes the joint in a neutral position. In this position, optimal blood circulation is ensured and immobilization is made as comfortable as possible.

A wrist orthosis to immobilize the joint is required, for example, after a fracture of the radius or an operation. A wrist orthosis can also be used as an aid after severe sprains in the wrist or irritations in the thumb or forearm area. In cases of wear and tear, a wrist orthosis can also help to stabilize and maintain functionality.An elbow orthosis is used to immobilize the arm in a flexed position.

This is necessary, for example, after a fracture in the area of the elbow so that healing is not hindered by movements in the joint. In addition, in some cases the elbow joint is affected by a wearing disease (arthrosis) or an inflammation. In this case, immobilization with an elbow orthosis can also help to relieve pain and allow the joint to recover.

A thumb orthosis is usually prescribed in cases of wear and tear of the thumb saddle joint between the carpus and the first metacarpal. This disease, known as rhizarthrosis, primarily affects older people. Due to a loss of articular cartilage, the bony surfaces rub directly against each other in the advanced stages, resulting in a painful restriction of movement of the affected thumb.

A thumb orthosis serves to stabilize the joint by fixing it in a functional position. The mobility of adjacent joints is hardly affected. As a result, the hand’s ability to grasp things can often be maintained and there is significantly less pain.

In most cases, permanent use of a thumb orthosis is indicated in such cases. Trunk or back orthoses are usually also called corsets. A distinction can be made between active and passive corsets.

Passive support orthoses primarily serve to relieve and support people who suffer from instability of the spine due to a disease, which can be accompanied by severe pain. Examples of this are cancers that have blasted into the bones or severe bone loss, which can affect older women in particular. The corset is intended to relieve pain and stabilize the back in order to prevent bone fractures and paraplegia.

The active back orthoses, on the other hand, are used for the treatment of diseases where there is a false statics of the spine, which should be corrected if possible. The treatment of children and adolescents is particularly important and promising in this context, since at this age, poor posture can still be best corrected or at least its development can be positively influenced. The most common example where treatment with an active back orthosis becomes necessary is scoliosis.

In this case, the spine is curved when viewed from behind and deviates to the left or right. In addition, vertebral bodies are twisted against each other. The active back orthosis can only be effective if it is worn during physical activity.

However, it must also be worn at night. As a rule, it must be worn 23 hours a day to achieve the best possible treatment results. Another disease for which back orthoses are used for treatment is Scheuermann’s disease.

In this case, the spine becomes increasingly stiff due to bony attachments and hardening of ligament structures. Mostly young men are affected and timely and consistent treatment with a back orthosis is important to counteract the stiffening of the spine. Immobilization splints for the cervical spine are a special type of back orthosis with a completely different area of application.

These are applied after a traffic accident, for example, to prevent consequential damage to the cervical spine in the event of a possible injury during transport. Another disease for which back orthoses are used for treatment is Scheuermann’s disease. In this case, the spine becomes increasingly stiff due to bony attachments and hardening of ligament structures.

Mostly young men are affected and timely and consistent treatment with a back orthosis is important to counteract the stiffening of the spine. Immobilization splints for the cervical spine are a special type of back orthosis with a completely different area of application. These are applied after a traffic accident, for example, to prevent consequential damage to the cervical spine in the event of a possible injury during transport.

Orthotic shoes are shoes that can be put on when an orthosis has to be worn on the foot or lower leg that do not allow normal shoes to be put on. They are wider than normal shoes and offer various adjustment options, thus enabling individual adaptation to the foot and the orthosis. It is important that the orthosis is as comfortable as possible to wear so that no pressure points are created and no conductive pathways are left behind.Orthotic shoes are used especially for children who receive long-term treatment with orthoses due to a treatment of foot malpositions.

However, there are also a variety of orthotic shoes for adults, which are especially necessary when the orthosis has to be worn for a long period of time. Another type of aid, sometimes referred to as orthotic shoes, is special shoes that serve to compensate for a difference in leg length. Strictly speaking, however, this is not an orthosis.