What Is an Orthosis? Why Is an Orthosis Used?

Orthoses are auxiliary medical devices used to compensate for functional losses in the musculoskeletal system, externally support weakened tissues, and keep body segments in the correct position. They are mainly preferred to reduce pain that occurs during movement, provide stabilization after surgery or trauma, increase mobility in cases of muscle strength loss, and stop the progression of anatomical deformities. These devices, based on biomechanical principles, allow tissues to heal by distributing the load placed on joints in a balanced way. Today, these systems, which both support rehabilitation processes and increase daily comfort, play a critical role in restoring physical independence.

What Is the Origin of the Word Orthosis and What Does It Mean?

The origin of many terms used in the medical world actually reveals the basic philosophy and purpose of that concept very clearly. The word orthosis, just like the words orthopedics or orthodontics, is derived from the Ancient Greek root “ortho,” meaning straight, correct, normal, and in accordance with rules. This etymological meaning of the word perfectly summarizes the device’s basic function in the body.

When looking at the logic of naming, the aim is to correct curvatures in the body, bring faulty postures into normal anatomical alignment, and rebuild natural body mechanics. In daily life, many different names such as splint, brace, knee support, wrist support, or corset are used among patients for these devices. However, in universal medical language, these devices are named according to the body regions they include and support. For example, a device that includes only the wrist and fingers is called a wrist-hand orthosis, while a device extending from the knee to the foot is called a knee-ankle-foot orthosis. This standard naming method ensures complete and error-free communication between different healthcare professionals involved in the patient’s treatment process.

What Are the Main Differences Between Orthosis and Prosthesis?

The two basic concepts most commonly confused and frequently misused in society are orthosis and prosthesis. Although both types of devices are used to improve people’s quality of life, restore their mobility, and provide independence, the purposes they serve and their working principles are completely different from each other.

The easiest way to understand this difference is to think of the example of eyeglasses and a glass eye. Prosthesis is the name given to devices that artificially replace an organ or limb that is completely missing in the body, was absent from birth, or was later removed by a surgical procedure. In other words, a prosthesis imitates the shape and function of a body part that does not exist. The artificial system attached to the leg of a person whose leg has been amputated below the knee so that they can walk is called a prosthesis. Just like a glass eye placed instead of a missing eye.

An orthosis, on the other hand, is a device that externally supports a limb that already exists and is in place but cannot perform its function for various reasons. The limb is there, it is a part of the body, but due to nerve paralysis, muscle wasting, bone fracture, or advanced joint arthritis, it needs external support, protection, or guidance. Eyeglasses worn in front of an eye that has difficulty seeing and that allow the existing eye to see better are actually a perfect example of an orthosis.

In Which Situations Is Orthosis Use Needed?

The design of these devices and their application to the patient’s body may serve more than one medical purpose depending on the patient’s current condition. Depending on the type and severity of the disease, whether it is acute or chronic, and which stage of the healing process it is in, the expected functions of the devices vary greatly.

The main purposes of these devices in clinical practice are:

• Immobilization
• Load distribution
• Prevention of deformity
• Assisting movement

Immobilization, meaning fixation, is vitally important especially in acute traumas. When a bone is broken or a ligament is completely torn, that region must remain completely immobile for a certain period in order to repair itself. Static devices, which are modern and comfortable alternatives to casts, completely immobilize the relevant region and prepare the ground for tissue healing.

The load distribution feature comes into play in weakened or damaged joints. When a damaged joint becomes unable to carry body weight, these devices take the load placed on that region and transfer it to surrounding tissues or neighboring joints that are in better condition, stopping the progression of damage.

The function of preventing and correcting deformity is used especially in paralysis, muscle diseases, or congenital bone anomalies. When the balance between muscles is disrupted, permanent contractions and deformities develop in the joints over time. With devices that apply appropriate force, the formation of these disorders can be prevented, or existing curvatures can be gradually and controllably corrected.

Assisting movement is frequently used in nerve paralysis. When some muscles do not work due to nerve damage, dynamic devices mechanically take over the task of that non-functioning muscle with the help of springs, elastic bands, or special hinges, allowing the person to move normally.

Which Materials Are Preferred in Modern Orthosis Production?

When looking at the earliest periods of history, primitive splints made with tree branches, reeds, and linen fabrics are found even in mummies dating back thousands of years. Treatment of fractures and dislocations has existed throughout human history. Today, however, these devices are produced with modern, lightweight, and extremely durable materials used in the aviation industry and advanced engineering fields. The choice of material to be used is carefully determined according to how much load the device will carry on the patient’s body, the patient’s expectations, the duration of use of the device, and skin structure.

The main materials used in the production of these devices are:

• Thermoplastics
• Titanium alloys
• Aluminum
• Carbon fiber
• Leather and sponge-like tissues

Thermoplastics are special plastics that soften when heated in hot water or special ovens, can take shape like dough, and can be molded exactly on the patient’s skin, then preserve that shape rigidly when cooled. Because they are very light, do not absorb water, can be easily washed and cleaned, and fully adapt to the patient’s own body contours, they have created a revolution in modern production processes.

Metals such as titanium and aluminum come into play in systems that need to carry load. Although stainless steel is a very strong metal, it is quite heavy. Carrying a heavy mass of steel on the leg in daily life is extremely tiring for the patient. Therefore, lightweight but steel-strong titanium and special aluminum alloys, also used in aircraft production, are preferred. These durable metals are indispensable especially in the mechanical joint areas of walking devices at the leg and hip level.

Carbon fiber is one of the peak points of today’s technology. Carbon fiber structures, although as light as paper, have much higher durability than steel and offer tremendous freedom of movement to the patient, especially in long-term use. The greatest advantage of carbon fiber is its ability to store and return energy; while the patient walks, the device flexes and traps energy, then gives this energy back when lifting the foot off the ground, pushing the patient forward without tiring them.

How Do Orthoses Support Our Body and With Which Physical Rules Do They Work?

Although these devices may look from the outside like a simple mold or plastic sheath placed on the patient’s arm or leg, they actually contain a very serious science of physics, anatomy, and biomechanics in the background. These devices provide treatment by manipulating, directing, or changing muscle and joint forces in the body.

One of the most commonly used working principles is the three-point principle. While force is applied from one direction to the exact peak point of a curvature or bending that needs to be corrected, two counterforces are applied in the exact opposite direction from below and above that curvature. Just like the logic we use when tying a young tree sapling bent by the wind to a strong stake to straighten it, the device corrects the curvatures in the body with calculated pressure applied from these three different points.

Another vital principle is directing the ground reaction force. When a person steps on the ground while walking, according to gravity and physical rules, the ground also applies a reaction force toward the human body. Orthoses produced for the leg adjust the angle at which the foot steps on the ground so precisely that they ensure this force coming from the ground prevents the knee or hip from suddenly bending in an unwanted direction. Thanks to this biomechanical play, even a patient whose leg muscles are completely paralyzed and weak can safely stand and take steps without collapsing onto the knee.

How Does Orthosis Provide Benefit in Arm and Wrist Problems?

The arms, wrists, and hands, called the upper extremity, are regions that allow humans to interact with their environment in daily life, work, eat, and express themselves, and that perform very sensitive and complex movements. The main purpose of devices used in this region is to preserve the fine motor skills and gripping function of the hand, relieve pain if present, and correctly adjust the position of the hand in space.

Common conditions requiring device support in the arm and hand region are as follows:

• Carpal tunnel syndrome
• Tendon cuts
• Rheumatic joint inflammations
• Elbow dislocations
• Post-fracture healing period

Carpal tunnel syndrome is a problem very common in office workers and housewives of the modern age, caused by compression of the median nerve passing through a narrow canal in the wrist, and manifests with electrification, numbness, and pain in the fingers. For these pains, especially those waking the patient from sleep at night, lightweight and practical night splints are used that rest the wrist in a straight position called neutral and physically minimize pressure on the nerve. In this way, the tissues rest, edema in the nerve decreases, and the patient sleeps comfortably.

In tendon injuries and cuts, a much more delicate process operates. After the movement tendons in the hand rupture and are surgically repaired, a very critical healing phase begins. If the fingers are completely immobilized with a cast while the tendon is still weak, the tendon sticks to surrounding tissues. If the fingers are left completely free, the stitches that have not yet healed rupture. Dynamic hand orthoses are used to provide this difficult balance. These devices allow the fingers controlled movement only within safe limits with the help of elastics, pulleys, and springs on them, accelerating healing and preventing adhesions.

How Does Orthosis Use in Leg and Foot Problems Make Walking Easier?

Anatomical problems or neurological damage in the legs and feet directly affect a person’s ability to stand up, maintain balance, walk, and therefore independence in life. Devices designed for this region, which carries the entire body weight, must be much more resistant to high loads than the upper body and must be produced with very accurate mechanical calculations.

The main problems requiring support in the leg and foot region are:

• Foot drop
• Ligament injuries
• Polio sequelae
• Spinal cord injuries
• Meniscus tears

Foot drop deformity is the condition in which the muscles that lift the foot upward from the ankle stop working in cases such as lumbar disc herniation ruptures, paralysis, or cutting of the nerve behind the kneecap. These patients cannot pull their toes upward when trying to walk; the foot hangs down like a flipper and constantly catches on carpets and thresholds. In order not to fall, the patient has to walk by lifting the leg upward in an exaggerated way. Plastic or carbon devices specially molded for foot drop keep the foot at a fixed 90-degree angle, mechanically prevent the foot from catching on the ground during walking, and make walking extremely fluid, aesthetic, and most importantly safe.

In polio sequelae, spinal cord injuries due to traffic accidents, or progressive muscle diseases, the leg muscles may become too weak to keep the body upright. In these cases, larger and more comprehensive walking systems extending from the hip joint or knee to the sole of the foot are used. These devices, which have unique mechanical hinges and locking systems, lock the leg straight when the patient takes a step, allow the foot to step on the ground firmly and without bending, and when moving to the next step, the lock opens and allows the leg to bend comfortably.

How Does Orthosis Use in Knee Arthritis Relieve Pain?

Knee osteoarthritis, popularly known as calcification, is the condition in which the slippery cartilage tissue inside the knee joint wears down and disappears due to the aging process, genetic predisposition, severe traumas in the past, or excessive weight carried for many years. Usually, the cartilage on the inner side of the knee wears down faster and collapses over time. As a result of this collapse, the legs begin to bend outward in an “O” shape. The bones rub against each other, causing unbearable pain and limitation of movement.

In this case, specially designed, engineering-marvel unloading knee orthoses are used. The working logic of these devices is similar to placing support under the shorter leg of a wobbling table. The device takes the pressure from the region on the inner side of the knee where the bones rub against each other and are crushed under excessive load, and transfers that load to the stronger outer part of the knee thanks to its special angle-adjustable hinges. Thus, friction between the bones decreases during walking, the patient’s pain is dramatically relieved, walking distance increases, and in many patients, the need for knee replacement surgery can be delayed for years.

What Are Corset-Type Orthoses Used for in Scoliosis and Spinal Curvatures?

When viewed from behind, the human spine should descend like a straight column. However, deformities may occur in this column due to traumas, diseases, or structural problems of unknown cause in the spinal region. In such cases, spinal orthoses called corsets, which surround and support the trunk and reduce the load on the spine, are used.

The main conditions requiring device use in the spinal region are:

• Scoliosis
• Lumbar disc herniation
• Spinal fractures
• Postural disorders
• Neck injuries

One of the most critical and transformative areas of use of these devices is scoliosis disease, which is frequently encountered in childhood and early adolescence. Scoliosis is the condition in which the spine curves to the right or left in a “C” or “S” shape and also rotates around itself. In children during rapid growth, this curvature can progress very quickly within months and reach levels that put pressure on internal organs. In curvatures below a certain degree, the worldwide gold standard of non-surgical treatment is the use of a properly designed scoliosis brace.

Scoliosis braces apply firm but targeted external pressure to the convex regions where the spine curves, using the child’s own natural growth potential as a corrective force. Working exactly opposite to the logic of bending a tree while it is young, they push the growing spine toward a straight line. In past years, children’s bodies were wrapped in heavy plaster casts and very laborious measurements were taken, while today this production process is carried out entirely with computer-assisted digital technologies. The child is scanned within seconds with three-dimensional contactless laser scanners. Corrections are made virtually on the obtained digital millimetric model, and the brace is produced by robotic devices. In this way, much lighter, more aesthetic braces that are not noticeable under clothing and have much higher correction capacity are obtained for our children.

What Should Be Considered in Orthosis Use in Children and Babies?

Babies and growing children cannot be considered physically as miniature copies of adults. Their skeletal systems are still cartilage-based structures that have not yet ossified, continue to grow and change shape rapidly, their joints are much more flexible, and their skin tissues are extremely thin. Therefore, devices used in children require a very different medical approach and extra sensitivity compared to adults.

The most striking example of this is the treatment of developmental hip dysplasia, that is, hip dislocation seen in babies. In babies diagnosed early by ultrasonic screenings performed after birth, bandages made of special fabrics and soft straps are used to keep the hip joint in the correct position in its socket. These systems keep the baby’s legs in an open and bent angle called the frog position. The important point is that these bandages do not completely eliminate the baby’s movements; on the contrary, by offering a safe range of motion, they encourage the hip socket to carve itself, deepen, and develop healthily as the leg moves. Device treatment correctly applied in the first months, when the ossification process continues rapidly, saves the child from very severe hip surgeries and lifelong disabilities that may occur in later ages.

Why Are Skin Care and Cleaning Very Important When Using an Orthosis?

No matter how perfect the design of the device is from an engineering perspective, if it cannot adapt to the patient’s skin, that treatment is doomed to fail. Since these devices are in contact with the skin directly or through a thin fabric for a large part of the day, they can cause serious dermatological problems if not used carefully. The biggest factor causing treatment to be interrupted is deep irritation and pressure sores caused by excessive pressure of the device on the bony areas of the body.

The basic care steps to be considered in the daily routine are:

• Skin control
• Cleaning
• Drying
• Exercise
• Use of cotton socks

The skin surface should be checked in detail every time the device is removed from the body. Mild redness on the skin after the device is removed is generally considered normal, but if this redness does not disappear within half an hour or if the skin color begins to darken, this means that the device is applying excessive pressure to that region enough to disrupt tissue nutrition, and it must be modified immediately by a specialist. In addition, the inside of the device should always be kept clean and moisture-free. Sweating creates a suitable ground for bacterial growth and fungal infections in a closed environment. Patients are advised to wear seamless cotton fabrics with high sweat absorption capacity under plastic surfaces. In order to prevent muscle laziness in regions that remain fixed for a long time, joint movement exercises recommended by specialists should be performed without interruption when the device is removed.

Who Plans Orthosis Treatment and How Does the Process Work?

The diagnosis, evaluation, and planning of how biomechanical problems involving the muscle, skeletal, and nervous systems will be treated are directly within the authority and responsibility of specialist physicians. Orthosis applications are an extremely serious medical process, just like the decision for a surgical operation or long-term drug treatment, and should not be started without a detailed examination by a physician.

As a result of establishing the definitive diagnosis of the disease, determining the degree of the problem with radiological images, and analyzing the patient’s daily life activities, age, and physical capacity, the most appropriate device type for the patient is prescribed by the specialist doctor. This medical prescription is a very detailed treatment map specifying which materials the device will be produced from, which joints it will include, how many degrees of movement it will allow those joints, and how many hours a day it will be used. After this stage, technical healthcare professionals called orthotists, who have received special training in the design and production of these devices, come into play. The orthotist takes the measurements of the device in accordance with the doctor’s prescription and the clinical limits determined, produces it individually, performs its fittings on the patient’s body, and delivers the device.

Why Should Orthoses Under Specialist Control Be Preferred Instead of Buying Ready-Made Orthoses?

Today, there are many ready-made support products that can be purchased randomly according to body size from pharmacies, websites, or medical markets without any medical evaluation. These products, which can provide short-term relief in simple sprains, may cause existing diseases to progress much faster and irreversible tissue damage rather than benefit when used unconsciously in serious diseases.

Human anatomy is as individual as a fingerprint. It is physically impossible for a mass-produced, one-size-fits-all device to fit everyone’s leg curvature, neck structure, or spinal angle. A standard knee brace that fixes the joint at the wrong angle may accelerate cartilage wear even more; a standard lumbar corset that applies unnecessary pressure from wrong points may increase spinal curvature or crush superficially passing nerves, causing permanent numbness. Therefore, especially in chronic conditions and structural disorders, custom-made devices molded according to the person’s own anatomical measurements must be used.

Why Are Regular Orthosis Checks and Follow-Up Process Vitally Important?

The human body is not a static structure; it constantly changes and adapts. During the treatment process, as the body heals, as children grow taller, as swellings and edema decrease, or as weak muscles strengthen, the device that fit perfectly on the first day begins to loosen or become tight over time.

Orthosis treatment is not a treatment method in which the device is delivered to the patient and the process is finished. The device must be constantly updated in parallel with the changes in the patient’s body, its angles changed, and support points readjusted. Therefore, patients must definitely go to clinical examinations at certain intervals, and when necessary, the condition of curvatures or bone structures must be checked with low-radiation X-rays.