Artificial hip joint

Definition

What is an artificial hip joint?

An artificial hip joint – also known as a hip prosthesis, hip endoprosthesis or hip TEP – is a medical hip replacement that partially or completely replaces the diseased or damaged hip. During hip joint surgery, the worn joint surfaces on the femoral head and in the hip socket are removed and replaced with artificial hip joints made of metal, ceramic or plastic. Such a new hip restores the sliding and movement function when conservative treatments are not sufficiently successful or severe hip pain occurs.

An artificial hip joint mimics the natural movement of the hip joint: the prosthesis surfaces are designed to provide stable guidance while enabling movement with as little friction as possible. Depending on the disease and condition of the joint, the following are used:

• ◉ Total hip replacement (THR)

  A total hip replacement completely replaces the hip socket and femoral head. It is the standard treatment for osteoarthritis, joint wear or chronic pain, as both joint partners are damaged. THR surgery generally offers the best stability, long-term durability and mobility.

• ◉ Partial prosthesis (hemiprosthesis/duo-head prosthesis)

  A partial prosthesis only replaces the femoral head, while the natural hip socket remains intact. It is mainly used for femoral neck fractures in older people when the hip socket is undamaged. It allows for rapid mobilisation, but is not suitable for osteoarthritis or damage to the socket.

Regardless of the model, every artificial hip joint operation aims to reduce pain, restore stability and improve long-term mobility of the hip. For an artificial hip joint to function optimally, the choice of material, positioning and individual anatomy must be precisely coordinated. The actual lifespan of an artificial hip depends on the quality of the materials, the course of the hip surgery, the subsequent rehabilitation, the patient’s physical constitution and the strain placed on the joint in everyday life.

Targeted exercises after hip replacement, structured mobilisation and reliable aftercare contribute significantly to the proper functioning and problem-free healing of the artificial hip joint. Regular check-ups also help to identify potential problems, such as loosening of the hip prosthesis, at an early stage.

Reasons for an artificial hip joint

The need for an artificial hip often arises from years of incorrect use and excessive strain on the hip, as well as natural wear and tear on the joint cartilage. Lack of exercise, sedentary activities and monotonous everyday stresses lead to premature degeneration of the hip joint. Muscles and fasciae around the hip become tense and sticky, which limits the mobility of the hip joint. As a result, the hip joint is only used to a limited extent during movement, which puts additional strain on the cartilage.

Whereas hip joints used to be ideally exercised through a variety of movements on softer surfaces such as forest and meadow floors, today hard, flat surfaces such as asphalt or concrete and stiff, supportive shoes have an unfavourable effect on the hip joints. These conditions weaken the muscles of the feet, legs and buttocks and impair the stabilisation of the hips, accelerating wear and tear and potentially necessitating hip replacement surgery at a later stage.
The reduced muscle strength transfers the load directly to the cartilage, which intensifies the degradation process in the hip joint. The hard everyday stresses also mean that the impact forces of each step act on the hip without being filtered. This overload accelerates the degenerative changes, so that hip replacement may be necessary in the long term. Foot deformities – such as flat feet or bent feet – also affect the leg axis and can cause uneven stress on the hip, which also accelerates wear and tear.
As the joint cartilage of the hip has no direct blood supply, it is supplied with nutrients through movement and the alternation of pressure and relief. A lack of movement reduces this supply, causing the cartilage to lose elasticity and become less resistant. In addition, tense or hardened fasciae in the legs and hips can increase pressure on the joint. At the same time, a lack of movement reduces the overall mobility of the hip joint, which further increases the strain. Combinations of muscular weakness, hard floors, limited mobility and misalignments therefore increase the risk of the hip joint becoming so severely damaged that artificial hip replacement surgery becomes necessary. There are also other factors that can lead to an artificial hip joint, such as obesity, genetic predisposition or rheumatic diseases, which further accelerate joint wear.

Consequences and risks of an artificial hip joint

An artificial hip joint can significantly improve quality of life, but – like any hip operation – it also carries risks and possible consequences. After artificial hip joint surgery, patients report pain, especially in the first few weeks or months after the hip prosthesis is implanted. This hip pain is often caused by the healing of the surrounding tissue, the muscles adapting to the new hip joint and the temporary increase in strain. Some patients describe pain after a hip implant that worsens when walking, standing or climbing stairs for long periods of time.

Another possible consequence is temporarily limited mobility of the hip. Depending on the model and individual anatomy, an artificial hip joint has a slightly limited range of motion compared to a natural hip joint. This can lead to a change in gait due to compensatory postures or muscular imbalances, resulting in incorrect or excessive strain on surrounding structures. Despite modern materials and techniques, even an artificial hip can only withstand limited impact loads, which is why high-impact sports are often not recommended.

The lifespan of an artificial hip is also not unlimited. Many artificial hip joints last 15 to 25 years, depending on age, activity level, weight and the material used in the hip prosthesis. After this time, replacement – another hip joint operation – may be necessary. Possible complications include infections, thrombosis or loosening of the hip prosthesis. Loosening of the hip prosthesis can manifest itself in pain, instability, restricted movement or swelling and, in some cases, requires another hip operation. Malalignment during implantation can also occur and impair the function of the artificial hip joint, which can cause additional discomfort. Regular follow-up checks are therefore important in order to detect signs of loosening of the hip prosthesis at an early stage and to ensure the long-term functionality of the implant.

Conventional therapy – what helps with artificial hip joints

After artificial hip joint surgery or in preparation for a hip prosthesis, there are numerous measures that can be taken to alleviate pain associated with artificial hip joints, improve hip function and support healing of the hip prosthesis:

• ◉ Physiotherapy: Special exercises after hip replacement promote mobility, strengthen the muscles around the new hip and thus relieve the artificial hip joints.
• ◉ Exercise therapy: Gentle activities such as swimming, cycling or yoga strengthen the muscles and promote blood circulation without overloading the artificial hip.
• ◉ Weight reduction: Reduces the strain on the hip prosthesis and alleviates pain after hip surgery.
• ◉ Muscle building: Strengthening exercises for the thigh, buttock and core muscles stabilise the new hip and support the healing process after hip replacement surgery.
• ◉ Orthopaedic aids: Bandages, orthoses or special shoe inserts can stabilise the artificial hip and provide targeted relief.
• ◉ Dietary changes: An anti-inflammatory diet supports the healing and function of the artificial hip joint.
• ◉ Acupuncture: Can promote pain reduction after hip replacement surgery.
• ◉ Heat or cold applications: Heat relaxes tense structures, cold reduces swelling.
• ◉ Electrotherapy: Promotes blood circulation and supports regeneration after hip replacement surgery.
• ◉ Drug therapy: Painkillers and anti-inflammatory drugs can shorten the healing time of the hip joint and alleviate discomfort.
• ◉ Gentle daily routine: Avoid climbing stairs, standing for long periods or heavy lifting to relieve the artificial hip.
• ◉ Check-ups: Regular follow-up care after hip replacement surgery detects early signs of loosening of the hip prosthesis or malalignment and contributes to the long-term function of the hip prosthesis.

kybun mode of action – what helps with artificial hip joints

The kybun products offer an effective way to improve hip function and reduce pain in hip prostheses after artificial hip joint surgery or in existing hip prostheses. The elastic, springy soles significantly reduce the strain on the artificial hip joint, while activating, stabilising and evenly distributing the load on the muscles. This supports both healing after hip replacement surgery and long-term protection of the implant, and can help to extend the life of the artificial hip. kybun shoes help artificial hip joints in the following ways:

• ◉ Muscle activation and stabilisation of the hip joint

  When walking in kybun shoes, the heels can sink deep into the elastic, springy material thanks to the compressible sole. This means that the load is built up slowly, in a controlled and physiological manner, so that the muscles around the artificial hip joint are optimally activated. Well-toned muscles stabilise the implant, protect the surrounding structures and support the natural movement of the hip. In comparison, on hard surfaces or in stiff, highly supportive shoes, the forces acting on artificial hip joints are virtually undamped. The muscles often react too late to cushion the load, which can lead to uneven force distribution and incorrect or excessive loading. In the long term, this can cause pain, slow down healing or impair the function of the hip prosthesis.

• ◉ Reduction of force exerted on the artificial hip joint

  The compressible sole of kybun shoes acts like a dynamic shock absorber. When the heel strikes the ground, the elastic, springy material is compressed, significantly reducing the forces exerted on the artificial hip and surrounding structures. This slow, controlled cushioning minimises the peak loads that would occur with every step and protects the implant from incorrect loading in the long term. Similar to an airbag in a car, the kybun sole helps to minimise the impact of force through its cushioning effect. This relief also allows the tendons, fasciae, ligaments and muscles around the hip to regenerate better, which supports healing after hip replacement and maintains mobility in the long term.

• ◉ Activation and strengthening of deep muscles

  The slightly unstable surface of the elastic, springy base continuously activates the deep muscles in the feet, legs, buttocks and torso. These muscles are crucial for stabilising the artificial hip joint, posture and balance. At the same time, coordination between the nervous system and muscles improves, making movements more physiological and controlled. Strong deep muscles ensure that the artificial hip joint is loaded within a natural range of motion, which prevents selective overload. This protects the hip prosthesis from premature wear and tear and supports the long-term functionality of the implant.

Balance and EMG

Balance ability was measured with a force plate by movement of the center of mass from front to back (ant-post) and sideways (med-lat) while standing. In parallel, electromyography (EMG) recorded muscle activity.

Furthermore, activation helps to strengthen the foot muscles. Foot deformities such as splayfoot, flatfoot or pes valgus are often associated with weakened foot muscles and can significantly increase the strain on the artificial hip. Activating the foot muscles in kybun shoes stabilises the longitudinal arch, prevents the foot from bending inwards or outwards and keeps the leg axis physiologically aligned. The correct alignment of the leg axis not only relieves the new hip, but also has a positive effect on the knee and spine. This reduces the risk of secondary damage and supports the long-term function of the artificial hip joint, while at the same time strengthening the muscles in the long term.

• ◉ Natural rolling motion

  Thanks to the elastic, springy kybun shoes with their rebound effect and the associated muscular pre-tensioning and reduced acceleration, the foot can be placed on the ground in a controlled manner when the heel strikes. This prevents unphysiological flat feet, which would otherwise transfer increased impact forces to the hip prosthesis with every step. In addition, active rolling on the elastic, springy kybun material utilises the entire range of motion of the foot. The movement begins when the heel makes contact with the ground and ends when the toes push off. Using the entire range of motion in the feet automatically results in more movement in the hip joints. This means that the hip is not always moved in the same restricted range, which can lead to incorrect loading with a prosthesis, but is used across a natural range of motion. The result is a reduction in the amount of stress on specific points.
  
  By using the full range of motion, the tissue around the hip prosthesis remains mobile and is better protected against tension and blockages. This additional movement with a natural and physiological gait can activate and strengthen the muscles and promote blood circulation, which can have a positive effect on the stability and function of the hip prosthesis.

• ◉ Promotion of blood circulation

  The elastic, springy materials activate the muscles when walking and standing, which improves blood circulation around the artificial hip joint. Good blood circulation supports the supply of nutrients, promotes metabolism and helps to distribute anti-inflammatory substances in the tissue. At the same time, waste products are efficiently removed, keeping the tissue elastic, resilient and functionally active. This increases wearing comfort, reduces pain and contributes to overall hip stability and health after hip replacement surgery.

• ◉ Reduction of lack of exercise

  Walking and standing in kybun shoes motivates you to move more in everyday life. Shortened hip flexors and tense thigh and calf muscles are stretched, the angle of the hip is improved and the strain on the artificial hip joint is reduced. More movement supports healing after hip replacement surgery, promotes muscle function and protects the implant from uneven or excessive strain.

• ◉ Fascia care

  Healthy fasciae distribute stress evenly and protect artificial hip joints and surrounding structures from excessive strain. The natural movement sequence in kybun shoes keeps fasciae elastic, reduces tension and promotes long-term hip mobility. Regular activation of the fascia can also reduce the risk of pain in the hip, knee or back.

• ◉ Optimised pressure distribution

  When walking and standing in kybun shoes, the entire sole of the foot is surrounded by elastic, springy material. This ensures even pressure distribution across the foot, reduces pressure points and protects the artificial hip joint from excessive strain. Even pressure distribution helps to maintain the stability of the hip implant and promotes healing and long-term comfort.

Application tips for use with artificial hip joints

Before wearing kybun shoes for the first time with an artificial hip, it is worth noting a few tips for use. Appropriate use can help to support movement after hip surgery and reduce possible artificial hip joint pain when walking. In addition, it is recommended that you continue to follow your rehabilitation programme consistently after hip replacement surgery.

• ◉ Initially, only wear kybun shoes for as long as your body allows. If you experience increasing fatigue or discomfort around the artificial hip joint, take breaks from wearing them. Especially after hip joint surgery, the musculoskeletal system needs time to adjust, as the activating effect of the kybun sole can cause initial reactions.
• ◉ Walk more often than you stand. After a hip replacement, standing for long periods of time can put more strain on the joint area, while movement promotes blood circulation, relieves tense structures and distributes pressure more evenly across the hip joints.
• ◉ Consciously press your heel into the elastic, springy material and find a pressure point where the artificial hip joint remains as comfortable as possible.
• ◉ Actively roll over the ball of your foot and toes. A greater range of motion in the foot area often enables mobility that is gentle on the gait – helpful for people with artificial hip joints. The goal is a foot-oriented rather than hip-dominated gait. Test the possible range of motion of your feet in conjunction with the mobility of the artificial hip.
• ◉ After a period of adjustment, vary your walking speed. Alternating between brisk walking, light jogging and a normal pace (approx. 15 seconds each) can reduce tension around the hip implant and improve movement.
• ◉ Enhance the effectiveness of kybun shoes with additional exercises, such as those often recommended after hip replacement surgery as part of rehabilitation.

Helpful exercises for an artificial hip joint

To enhance the effect of kybun shoes and support recovery after hip replacement surgery, it is advisable to perform specific exercises for the hip joint. The exercises presented here are an example programme and can be supplemented with other movement exercises. As a general rule, pain in the artificial hip joint should not increase during the exercises. However, soothing, relieving ‘pain’ in surrounding areas such as the thighs or buttocks, as well as muscle fatigue, are desirable. Discuss the exercises with your doctor beforehand. The exercises are divided into the following areas: ‘Walking correctly in kybun shoes’, ‘Muscle length training’, ‘Fascia training’ and ‘Strengthening’.

Walking correctly in kybun shoes

The quality of each individual step is crucial in reducing the strain on the hip prosthesis, avoiding incorrect posture and excessive strain, and activating the muscles around the artificial hip joint. kybun shoes offer ideal support in this regard.

Controlled heel strike

• ◉ Carefully press your heel into the elastic, springy material to find the point at which you can apply pressure without causing pain in your hip prosthesis.
• ◉ Roll your midfoot and forefoot slowly and in a controlled manner.
• ◉ Consciously control the position of your foot so that it does not tilt inwards or outwards.
• ◉ Roll your forefoot slowly and in a controlled manner.
• ◉ Slow exercises help to build up the stabilising muscles around the new hip.
• ◉ Perform these exercises consciously every day when walking in kybun shoes.

Quick step frequency

• ◉ The movement sequence is identical to that of the controlled foot movement.
• ◉ Now incorporate short steps with a high step frequency to promote mobility in the hip joint. Use the full range of motion of your feet.
• ◉ If you experience hip pain, increase your stride length and reduce your step frequency.
• ◉ Maintain an upright posture to relieve pressure on the spine and place physiological stress on the new hip.
• ◉ Perform these exercises consciously every day while wearing kybun shoes.

Muscle length training

Muscle length training is particularly important for artificial hip joints, as discomfort often arises from shortening, tension or blockages in the myofascial structures. Targeted stretching of these structures can improve mobility, reduce pain and have a positive effect on the function of the artificial hip joint.

Hip opener

• ◉ Start in a quadruped position.
• ◉ Place your left foot forward next to your arms.
• ◉ Extend your right leg backwards and place your foot flat on the floor. Ensure that your hips and spine are aligned.
• ◉ To increase the stretch, push your hips forwards and downwards. Depending on your individual flexibility.
• ◉ Perform 1–2 times daily.
• ◉ Hold the exercise for 3 x 30 seconds.

Seated

• ◉ Starting position: lying on your back.
• ◉ Extend both arms out to the sides at a 90-degree angle and bend your left leg, placing it on your right side.
• ◉ Press down on your bent knee with your right hand.
• ◉ Make sure that both shoulder blades remain on the floor.
• ◉ Perform 1–2 times daily.
• ◉ Hold the exercise for 3 x 30 seconds.

Fascial rolling

Regular fascia training loosens adhesions and tension in the myofascial structures and improves mobility around the hip prosthesis. This supports healing and reduces hip pain.

Gluteal muscles

• ◉ Starting position: sitting with both legs bent.
• ◉ Roll out the corresponding buttock with the fascia ball. Increase the pressure by placing one leg on top of the other. If you experience pain in your wrist, you can also perform the exercise on your forearms.
• ◉ Perform the exercise slowly and in a controlled manner.
• ◉ Adjust the pressure to suit your personal comfort level, but go as far as you can tolerate without pain.
• ◉ Roll out any specific adhesions more intensively or hold the position at this point.
• ◉ 3 minutes per side.
• ◉ Perform 1–2 times daily.

Side thigh muscles

• ◉ Start in a side-lying position.
• ◉ Place a large roller between your outer thigh and the floor.
• ◉ Place your upper leg at a right angle for stabilisation and to guide the movement.
• ◉ Actively roll out your side thigh from your hip to above your knee joint.
• ◉ Perform the exercises slowly and in a controlled manner.
• ◉ Adjust the pressure to suit your personal comfort level, but go as far as you can tolerate without pain.
• ◉ Roll out any specific adhesions more intensively or hold the position at this point.
• ◉ The exercise can be intensified by straightening the upper leg.
• ◉ 3 minutes per side.
• ◉ Perform 1–2 times daily.

Strengthening the hip muscles

Targeted strength training strengthens the muscles around the new hip, relieves pressure on the artificial joint and protects against incorrect loading and excessive strain. Strong muscles absorb the forces acting on the joint, stabilise the hip joint and help to relieve pain.

Hip thrust

• ◉ Starting position: Lie on your back with your legs bent (hip-width apart). Arms are stretched out towards your feet, shoulder-width apart.
• ◉ Actively lift your hips off the floor and move them towards the ceiling (your hips should be fully extended at the highest point of the exercise).
• ◉ Hold the position at the highest point for 4 seconds.
• ◉ Make sure that the force comes from your buttocks (not from your heels or the back of your thighs).
• ◉ Slowly lower your hips again without your buttocks touching the floor.
• ◉ 3 sets of 8–12 repetitions.
• ◉ Perform 2–3 times a week.

Squats

• ◉ Starting position: standing, feet slightly wider than hip-width apart and slightly rotated outwards.
• ◉ Slowly and in a controlled manner, lower yourself into a deep squat. Push your bottom backwards and shift your weight onto your heels.
• ◉ Make sure that the force comes from your bottom. Stabilise your knees so that they do not buckle inwards or outwards.
• ◉ Slowly and in a controlled manner, stand up again. If you have balance problems, you can hold on to a stable object with your hands.
• ◉ 3 sets of 8–12 repetitions.
• ◉ Perform 2–3 times a week.