Knee pain

Anatomy

Causes

Treatment

Tips & exercises

Do you suffer from knee pain?

In Germany, almost one person in eight is affected by knee pain. Are you one of them?

With every step, every leg movement and even when resting – the knee joint is subjected to varying strain every day that can often amount to several times a person’s body weight. Studies have shown that, when climbing the stairs, the knee joint is subjected to three times a person’s body weight.¹ When squatting or kneeling, a contact pressure of 80 to 100% of the body weight is exerted on the patella. Furthermore, joint forces of about 400% can be generated in the area of the patella when getting up.²

Knee pain is always a warning. The knee is one of the body’s joints most prone to injuries. Despite its size, it’s very vulnerable. That's why symptoms of knee problems should always be taken seriously. If they are ignored for a long time, treated too late or incorrectly, subsequent damage to the knee joint can be caused that can result in severe and ongoing problems. If you have persistent knee pain, you should consult a doctor to diagnose and treat the cause early. So get active today! Support your knee to prevent pain.

_{¹Source: Duda et al. 2011, "AE-Manual der Endoprothetik" (AE manual of endoprosthetics),}
_{²Source: Glitsch et al. 2009, "Belastung des Kniegelenks beim Knien und Hocken" (Strain on the knee joint when kneeling and squatting)}

The knee

The pivotal point of our mobility

The knee joint (articulatio genus) is the largest joint in the human body. It ensures stability when standing, cushions the body weight and is part of practically all movements. Most of the time, we only notice how much the knee does when pain occurs that restricts movement.
This hinge joint allows the knee to perform movements in two directions: flexion or extension of the leg, but also the option of turning the lower leg slightly outwards or inwards when the leg is bent. The structure of the knee joint is highly complex, which means it is very vulnerable and prone to injuries.

Knee anatomy and functions

Bony structure

Three bones join in the knee: the two longest bones in the human body, the thigh bone (femur) and the shin bone (tibia), as well as the kneecap (patella).

These three bones form two joints: the patellofemoral joint (articulatio femoropatellaris) between the thigh and the patella, as well as the femorotibial joint (articulatio femorotibialis) between the thigh and the tibial plateau (caput tibiae). Where the femur and tibia meet, they have cylindrical joint bodies covered with cartilage. These allow the low-friction rolling-gliding motion of the knee joint, and therefore a smooth gait.

Based on its bony structure, the knee itself is very unstable. It is therefore secured with tendons, ligaments, muscles and cartilage structures. This provides the joint with the required stability in all directions and enables upright standing and walking.

Anatomy of the knee, lateral view — Right knee, lateral view

Kneecap (patella)
The kneecap has a triangular shape, slightly convex at the front, and it protects the front of the knee joint. It is the insertion point of the thigh muscle (quadriceps femoris) and, similar to a pulley, it is responsible for the thigh muscles’ ideal transmission of forces to the lower leg. In this way, the patella makes bending and stretching of the leg easier and additionally guides the patellar tendon.
The back of the knee (fossa poplitea)
Important blood vessels and nerves run through the popliteal fossa, supplying the lower leg.

Menisci
Because the joint bodies of the femur and tibia do not directly fit into each other, cartilage structures, the menisci, lie between them. On the one hand, the menisci (medial and lateral menisci) extend the contact area of the two joint surfaces. On the other hand, they function as shock absorbers. The fibrous cartilage disks can cushion severe impact, compensate for heavy loads on the knee joint and evenly distribute the strain of weight. This provides additional protection to the joint surfaces.

Bursae
The bursae are elasticated, mobile pads filled with fluid. They lie between moving muscles, tendons and bones to reduce friction and pressure.

Menisci
Because the joint bodies of the femur and tibia do not directly fit into each other, cartilage structures, the menisci, lie between them. On the one hand, the menisci (medial and lateral menisci) extend the contact area of the two joint surfaces. On the other hand, they function as shock absorbers. The fibrous cartilage disks can cushion severe impact, compensate for heavy loads on the knee joint and evenly distribute the strain of weight. This provides additional protection to the joint surfaces.

Bursae
The bursae are elasticated, mobile pads filled with fluid. They lie between moving muscles, tendons and bones to reduce friction and pressure.

Ligaments and tendons

In addition to the menisci, the knee is protected by complex and firm ligament structures. Together with tendons, they are responsible for the exact guidance of the knee joint, and stabilise it in combination with the muscles. They consist of firm connective tissue fibres and feature hardly any blood vessels or nerves. This means their capacity for regeneration is limited.

Anatomy of the knee, frontal view — Right knee, proximal view

Collateral ligaments (lig. collaterale)
In order to prevent movement in a sideways direction, the knee joint is stabilised by the medial and lateral collateral ligaments.

Cruciate ligaments (lig. cruciata genus)
The cruciate ligaments, on the inside of the joint, are particularly important for the stabilisation of the knee joint. They stop the femur and tibia from shifting forwards or backwards and limit rotation.

Patellar tendon (lig. patellae)
The patellar tendon links the lower leg with the kneecap and ensures that it is guided precisely. It also connects the large anterior thigh muscles with the tibia via the kneecap.

Causes of knee pain

Knee injuries and conditions

About 10 million people in Germany regularly suffer from knee pain. This pain has many causes.

Triggers can include:

acute injuries caused by an accident, such as broken bones, capsular injuries, injuries to the ligaments, menisci and cartilage. The number of knee injuries constitutes about a quarter of all sports injuries and it is constantly increasing due to a lack of physical fitness.
Inflammation and rheumatoid conditions, such as arthritis, rheumatism, inflammation of the bursa, Baker’s cyst and Morbus Bechterew, are the most common causes of knee pain.
Metabolic disorders or blood disorders, such as gout, pseudo gout, haemochromatosis or haemophilia, can also trigger knee problems.
Wear and degenerative conditions, such as meniscus damage and osteoarthritis of the knee, usually result in chronic problems without ongoing treatment.
Excessive strain and misalignments, such as a high-riding patella, patellar lateralisation, knock knees or bandy legs, are causes of patellofemoral pain syndrome, patella tip syndrome (also known as jumper’s knee), Osgood-Schlatter disease and the well-known runner’s knee.
Congenital factors and auto-immune disorders, such as chronic polyarthritis, lupus erythematodes, osteochondrosis, patellar dysplasia or Ehlers-Danlos syndrome are possible triggers of knee pain.

Externally, knee pain may manifest with swelling, reddening or bruising. Pulling or piercing pain is then sometimes felt with every step.

The areas where pain occurs most obviously can give an initial indication as to the cause.

The following overview is arranged by pain localisation and is designed only as an initial source of information and non-binding guide.

To obtain a definitive diagnosis and appropriate treatment, medical advice is essential!

Localisation: where does knee pain occur?

Anterior (patella)

Posterior (back of the knee)

Medial (knee joint)

Lateral (knee joint)

Entire knee (no localisation possible)

Anterior knee pain (patella)

If the pain is mainly concentrated in the area of the patella, the front of the thigh and lower leg, as well as the patellar tendon insertion below the patella, this is referred to as anterior knee pain. When the pain occurred for the first time or which situations trigger it can provide an indication of the cause of the condition.

In which situation does pain occur?

During or after strain

Patella tip syndrome (jumper’s knee)
Patella tip syndrome is an irritation of the patellar tendon in the area of the lower insertion of the kneecap, usually caused by excessive strain. In the beginning, pain typically doesn't occur during strain, but instead after. The painful area is right underneath the kneecap and is very sensitive to pressure.
More about patella tip syndrome

Patellofemoral pain syndrome
It is often impossible to precisely identify what causes patellofemoral pain syndrome. Pain usually occurs behind the kneecap, but it can also radiate to the surrounding areas. It primarily occurs during sporting activities with the knee joint being subjected to a high degree of strain, when going downhill, climbing the stairs and after extended periods of sitting down.
More about patellofemoral pain syndrome

Patellar dysplasia
The kneecap has an asymmetrical shape in cases of patellar dysplasia. This means it wears the cartilage layer at the back of the patella unevenly. This is usually a congenital malformation that causes pain on exertion, such as walking, bending, sitting down or getting up.

Patellar lateralisation
Patellar lateralisation is a misalignment where the kneecap has shifted to the side and no longer moves smoothly in its dedicated guidance channel. The uneven load-bearing results in increased wear of the joint cartilage at the back of the patella. Pain is often noticed for the fist time when going downhill or downstairs.

High-riding patella (patella alta)
In cases of high-riding patella, the kneecap has shifted upwards, thus exerting increased tensile force on the patellar tendon when the knee is bent. A high-riding patella can be congenital or caused by trauma, a tear of the patellar tendon or patellar luxation. A high-riding patella manifests with significant pain that increases when climbing the stairs or pursuing intense sporting activities.

Osteoarthritis of the patella (retropatellar arthrosis)
Osteoarthritis of the patella is a condition of wear related to the kneecap and the trochlea. It is caused by wear of the cartilage under the patella and can lead to an audible crunching during movement. Pain typically occurs first when climbing the stairs or going uphill.

While growing/during adolescence

Osgood-Schlatter disease
Osgood-Schlatter disease is a painful irritation of the patellar tendon insertion on the tibia that mainly occurs in boys when they are growing. Pieces of shin bone can detach from the insertion point of the patellar tendon and die.

Sinding-Larsen-Johansson syndrome
Sinding-Larsen-Johansson syndrome is a painful inflammatory response in the area of the patellar tendon insertion on the kneecap. It is caused by excessive strain during the growth phase. A piece of bone can detach from the patella and die.

After an injury/trauma

Patellar luxation
In cases of patellar luxation, the patella jumps out of its groove, which can cause injuries to the cartilage and ligament structures. Patellar luxation usually occurs in women and for the first time before the age of 20 when the slightly bent knee is sprained. Those affected suffer from severe pain and can no longer move their lower leg.

At night when resting

Osteoarthritis of the patella (retropatellar arthrosis)
Osteoarthritis of the patella is a condition of wear related to the kneecap and the trochlea. It is caused by wear of the cartilage under the patella. Initially, pain mainly occurs when subjected to strain, later also at rest.

Inflammation of the bursa (prepatellar bursitis)
If a bursa becomes inflamed, it swells up and exerts pressure on the surrounding structures. Prepatellar bursitis can manifest with piercing knee pain, tenderness or an inability to stretch the knee joint.

Posterior knee pain (back of the knee)

Pain at the back of the knee can have various causes. The situation in which pain occurs for the first time or repeatedly can provide an indication of a certain condition.

In which situation does pain occur?

During or after strain

Knock knees (genu valgum)
The condition known as knock knees is an axial misalignment of the knee joint. This is usually caused by a congenital misalignment of the feet. Those affected suffer from severe restrictions in movement.

Osteoarthritis of the knee
Osteoarthritis of the knee is a degenerative knee condition (osteoarthritis) that mainly affects older patients. During this degenerative disorder, the knee’s cartilage layer wears down. This layer is a buffer between the bones that stops them from directly rubbing on each other.

More about osteoarthritis of the knee

Genu recurvatum
Genu recurvatum is an unnatural ability to hyper-extend the knee joint. Pain can occur in areas where the tissue is subjected to strain because of the hyper-extension. Common symptoms of this misalignment include joint instability and limping.

Baker’s cyst
There are two bursae on the inside of the popliteal fossa (back of the knee). If they merge into one large bursa and fill with fluid from the knee joint, this condition is called Baker’s cyst. This painful accumulation of fluid causes a swelling at the back of the knee. Pain primarily occurs when the leg is stretched or bent.

While growing/during adolescence

Growing pains
Growing pains occur between the ages of 3 and 14. In general, both knees are affected and there is no reddening or heat that would indicate swelling or inflammation. When stretching the leg (hyper-extension of the knee), pain can generally be alleviated a little.

After an injury/trauma

Tear of the posterior cruciate ligament
The posterior cruciate ligament connects the femur with the tibia and is the thickest, most important ligament in the knee joint. A tear can occur when considerable force is exerted on the bent knee joint, but this is much more common in the anterior cruciate ligament. The injury is usually associated with swelling and significant pain.

Injuries to the medial meniscus (meniscus medialis)
The medial meniscus is fused to the medial collateral ligament and is therefore only mobile to a certain extent, yet prone to injuries. A torn meniscus can be caused by forceful twisting or bending of the knee joint, resulting in pain when the knee is rotated or bent, as well as in knee instability.

At night when resting

More about osteoarthritis of the knee

Injuries to the medial meniscus (meniscus medialis)
The medial meniscus is fused to the medial collateral ligament and is therefore only mobile to a certain extent, yet prone to injuries. A torn meniscus can be caused by forceful twisting or bending of the knee joint, resulting in, as well as pain when the knee is rotated or bent, pain at night when the knees lie on top of each other.

Knee pain on the inside of the knee joint

If the pain primarily occurs on the inside of the knee joint, in the surrounding soft tissue, the medial collateral ligament as well as the inner thigh and lower leg, this is referred to as medial knee pain. When the pain occurred for the first time or in which situations it is very noticeable, can provide an indication of the cause of the condition.

In which situation does pain occur?

During or after strain

Pes anserinus syndrome
Pes anserinus syndrome is an inflammation of the tendon insertions on the inside of the lower leg below the knee caused by excessive strain. Initially, pain occurs on the inside of the tibial plateau. Later on, constant pain on exertion with swelling and local tenderness is also noticed.

Bandy legs (genu varum)
In cases of a varus misalignment, the knee joint deviates to the outside in relation to the load-bearing axis. This subjects the insides of the knees to particular strain. Pain is more severe in the mornings and generally increases with strain.

Ahlbäck’s disease
Ahlbäck’s disease is a spontaneous reduction in bone tissue in the lower part of the femur. This rare condition usually occurs later on in life. Symptoms include severe pain during movement as well as at rest.

Medial osteoarthritis of the knee
Medial osteoarthritis of the knee occurs when the osteoarthritis is limited to the side of the joint facing the centre of the body. During this degenerative condition, one-sided wear of the knee joint cartilage occurs. Because the buffers are missing, pain initially occurs, for example, when going downhill.

More about osteoarthritis of the knee

During rotation

Injuries to the medial meniscus (meniscus medialis)
The medial meniscus is located on the medial side between the joint surfaces of the femur and tibia. Injuries often cause the meniscus cartilage to tear or tear off, resulting in piercing pain and swelling of the knee.

After an injury/trauma

Injuries to the medial collateral ligament
The medial collateral ligament connects the tibia and the femur. Excessive stretching, straining and tearing of the medial collateral ligament are the most common knee ligament injuries. They are usually caused by lateral impact during sports. In addition to severe pain and swelling, instability of the knee occurs.

At night when resting

Medial osteoarthritis of the knee
Medial osteoarthritis of the knee occurs when the osteoarthritis is limited to the side of the joint facing the centre of the body. In advanced stages, wear of the buffering cartilage can also cause pain at night.

More about osteoarthritis of the knee

Knee pain on the outside of the knee joint

If the pain primarily occurs on the outside of the knee joint, in the surrounding soft tissue, the lateral collateral ligament as well as the outer thigh and lower leg, this is referred to as lateral knee pain. The situation in which pain occurs for the first time or repeatedly can provide an indication of a certain condition.

In which situation does pain occur?

During or after strain

Runner’s knee (IT band syndrome)
Runner’s knee is a common condition caused by the group of tendons on the outside of the thigh being subjected to excessive strain or inappropriate mechanical stress. Piercing pain on the outside of the knee joint initially occurs during running.

Lateral osteoarthritis of the knee
If the osteoarthritis is limited to the outside of the knee joint, this is referred to as lateral osteoarthritis of the knee. During this degenerative condition, one-sided wear of the buffering knee joint cartilage occurs, with pain mainly caused when going downhill or downstairs.

More about osteoarthritis of the knee

During rotation

Injuries to the lateral meniscus (meniscus lateralis)
The lateral meniscus is located on the lateral side of the knee joint between the joint surfaces of the femur and tibia. Injuries often cause the meniscus cartilage to tear or tear off, resulting in piercing pain and swelling.

After an injury/trauma

Injuries to the lateral collateral ligament
The lateral collateral ligament connects the thigh and the calf. Together with its counterpart, the medial collateral ligament, it provides the knee with stability. The most common causes of pain on the outside of the knee include the lateral collateral ligament hyper-extending, straining or tearing off. This results in severe pain, swelling and instability of the knee joint.

Pain in the entire knee

In these cases, no precise localisation of the pain is possible. It affects the entire knee and may even radiate into the surrounding areas. When pain occurred for the first time or when it primarily occurs can provide an indication of the condition.

In which situation does pain occur?

During or after strain

Cartilage damage
Cartilage damage causes dull, diffuse pain when the knee joint is subjected to strain. This pain can generally not be pinpointed and initially occurs when climbing the stairs, standing in an awkward position or extended periods of walking on hard or uneven terrain.

Pangonarthrosis
If wear of the cartilage layer between the bones affects all three parts of the joint, this is referred to as pangonarthrosis (osteoarthritis of the whole knee joint). This is associated with pain, swelling and inflammation as well as severe restrictions in movement. If parts of the bone or cartilage also detach, the joint can become blocked.

After an injury/trauma

Tear of the anterior cruciate ligament
A torn anterior cruciate ligament is a typical sports injury caused by impact on the cruciate ligament when it is under tension. Because the feet are fixed in a ski boot or studs are used on football boots, the most common knee ligament injury occurs during sports like football or skiing. During the accident, a tearing or shifting sensation can be felt and cracking sounds heard. In addition to pain, this injury results in bruising, swelling and instability.

At night when resting

Rheumatoid arthritis
Rheumatoid arthritis is the most common inflammatory joint condition that can affect various joints. In cases of this auto-immune disorder, the patient’s own immune system attacks the mucous membrane of the joints by mistake. The inflammation is associated with reddening, swelling and pain, but can also manifest with the development of heat.

Suddenly and in bouts

Gout
Gout is a metabolic disorder where increased levels of uric acid cause the formation of sharp crystals. They can result in swelling, piercing pain and an extreme sensitivity to touch.

What options are there to treat knee pain?

Supports and orthoses for relief and stabilisation

Juzo offers a comprehensive range of specialised medical aids for numerous different indications.

Knee supports

Knee supports stabilise the knee joint in cases of sprains or strains, after surgery or for particular misalignments. Thanks to a combination of different innovative and sophisticated knitting techniques, Juzo knee supports provide an excellent fit. The highly functional materials wick moisture away from the body particularly quickly. This provides you with maximum wearing comfort, the perfect fit and ideal freedom of movement.

Discover knee supports

Knee orthoses

Knee orthoses allow an even more effective influence on movement than is possible with flexible knee supports. Rigid elements help to relieve, stabilise and guide the injured knee joint. Knee orthoses also make it possible to allow movement only within a specific individually defined range, or to completely immobilise the joint. Orthoses can be adapted to treatment requirements as needed and thus help to achieve the desired outcome.

Discover knee orthoses

Medication to combat knee pain

If pain occurs only temporarily, it can be treated with pain medication for a limited time. Some drugs counteract inflammation and swelling. Pain medication is available in the form of tablets, as pain plasters, creams or cooling gels. The cause of the pain should always be clarified by a doctor first though.

Physical therapy in cases of knee pain

Physical therapy is an essential component of a comprehensive treatment concept in cases of knee pain. Physical therapy includes active as well as passive exercises in cases of knee pain. This means movements that patients perform themselves as well as exercises and stretches where the physical therapist guides and controls the movements. In addition to acute cases, physical therapy is also used for prevention and rehabilitation.

Heat treatment and cryotherapy in cases of knee pain

Whether heat or cooling is more beneficial in cases of knee pain will depend on the individual cause, but the general rule applies that acute pain and inflammation are usually alleviated more effectively by cooling the affected area. The cold also reduces swelling and inhibits inflammation. Ice or cooling compresses should be wrapped in a thin towel and never be applied directly to the skin to prevent frostbite. In cases of chronic conditions, such as osteoarthritis, heat is more beneficial because improved circulation more quickly removes metabolic waste and products that cause pain.

What you can do yourself in cases of knee pain

Everyday tips for stable knees

To ensure comprehensive treatment of your knee pain, you should get active.

Regular exercise
Healthy legs with strong, stretched muscles, ligaments and fasciae are less prone to knee problems and pain. Therefore, regularly train the co-ordination of your legs and your leg muscles with sports that are gentle on your knees, and carry out specific exercises to strengthen the knees.

Exercise vs strain
Movement is crucial for a healthy knee joint. Make sure, however, that your movements are gentle. Avoid excessive, one-sided and, in particular, constant strain.

Carrying heavy loads
Do not carry heavy loads on one side only and ensure your carrying method is gentle on your knees, by using a backpack, for example.

Appropriate footwear
Footwear has a significant impact on healthy knees. Your shoes should therefore have cushioning soles. High heels can lead to problems and should therefore only be worn for a limited time. Orthopaedic foot orthoses can compensate for misalignments.

A healthy diet
A healthy diet is absolutely essential. Every additional pound also puts extra strain on your knees. Make sure your dietary fibre intake is sufficient, and cut down on sugar and fat as much as possible.

Female runner wearing the JuzoPro Patella Xtec Plus knee orthosis

Exercises for strengthening the knees

We have put together a few exercises for you that help to strengthen your legs and therefore your knees or to support recovery after an injury. They are easy to do and you can incorporate them into your daily routine for the best results. If you are suffering from an acute injury, please consult your doctor first to find out which exercises are suitable for you.

Lunge

Do 12 lunges and repeat this exercise three times.

Stand with your legs hip-distance apart, keeping your upper body straight.
Tense your abdominal muscles.
Take one long step forwards.
Your lower leg and thigh of the front leg must be at a right angle.
The back leg lowers and stops just before touching the ground.
Hold this position briefly, then return to the start point.
Change legs after each lunge.

Please note: your back must remain straight during this exercise.

Squat

Do 12 squats and repeat this strengthening exercise three times.

Stand up straight with your legs a little wider than hip-distance apart.
Distribute your weight equally on both legs.
Slightly bend your legs and push your bottom back.
Squat only so far that your knees remain behind your toes.
Hold this position briefly, then straighten your body again.

Please note: keep your back straight during this strengthening exercise and tense your abdominal muscles.

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International

Knee pain

Do you suffer from knee pain?

The knee

The pivotal point of our mobility

Knee anatomy and functions

Bony structure

Ligaments and tendons

Causes of knee pain

Knee injuries and conditions

Localisation: where does knee pain occur?

Anterior knee pain (patella)

Posterior knee pain (back of the knee)

Knee pain on the inside of the knee joint

Knee pain on the outside of the knee joint

Pain in the entire knee

What options are there to treat knee pain?

Supports and orthoses for relief and stabilisation

Knee supports

Knee orthoses

Medication to combat knee pain

Physical therapy in cases of knee pain

Heat treatment and cryotherapy in cases of knee pain

What you can do yourself in cases of knee pain

Everyday tips for stable knees

Exercises for strengthening the knees

Lunge

Squat