Pain in the kneecap

Introduction

The patella is a flat, disc-shaped, bony structure located directly in front of the knee joint. As a bone embedded in the tendon of the quadriceps femoris muscle, the patella is involved in the formation of the articular surfaces of the knee joint. The main function of the kneecap is to protect the knee joint.

In addition, the kneecap serves to increase the strength of the quadriceps femoral muscle by extending the lever arm. In the area of the kneecap, pain phenomena can often occur (especially in young women). Compared to other joints, the knee joint and/or the kneecap in particular causes problems for many people. Approximately every second person complains of pain in the area of the front knee (pain kneecap) at least once in the course of his life. Pain in the kneecap can be observed not only in older people, but often as early as childhood and adolescence.

Most frequent causes

Pain in the area of the kneecap is often caused by direct overloading or incorrect loading of this bony structure. Sporting activities, strenuous physical work and postural defects can be the cause. In addition, it can be observed that especially very overweight people often suffer from pain in the patella.

One of the most common causes of pain in the area of the kneecap is the so-called “unstable kneecap” which is characterized by lateral slipping out (lat. luxation). In addition, it can be observed in everyday clinical practice that pronounced cartilage damage and valgus malpositions can lead to patella pain.

Especially older women (>50 years) are often affected by such cartilage damage. Reasons for their development are knee arthrosis, injuries and genetically caused cartilage weaknesses. Patellar arthrosis (synonym: retropatellar arthrosis) itself is considered one of the most commonly observed causes of pain, which is mainly located behind the kneecap.

In many cases, other orthopedic clinical pictures also affect the stability of the knee joint and the patella. In this context, pain of the kneecap can be observed in the case of disease-related, increased external rotation of the thigh or tibia. Patients with malpositioning of the leg axis or lifting of the arch of the foot (so-called flat foot) also complain of increased pain in the area of the kneecap.

Since the bony patella contributes to a multiplication of the strength development of the quadriceps femoris muscle by extending its lever arm, pain in the patella can also be provoked by muscular disorders of the thigh. In perfectly healthy people, such pain phenomena are often triggered by temporary overloading of the knee joint, for example, by excessive training intensity. Stabbing, bright pain, which is acutely observed after a dislocation of the patella, can be an indication of the presence of a patella fracture (fracture of the patella).

Affected patients particularly report the occurrence of severe symptoms after walking down stairs. In addition, pain can be provoked by the displacement of the patella (so-called displacement pain). In addition, pain in the area of the kneecap is more common in people who often sit with a bent knee for a long time.

Acute trauma can cause the kneecap to spring out of its guide groove on the thigh bone. The kneecap usually shifts outwards. This often damages the back of the kneecap or part of the thigh bone.

In addition, holding ligaments and capsule apparatuses can tear. All this leads to pain in the kneecap. Bleeding and water retention can also occur.

This causes restricted movement and further pain. If you have a loose ligamentous apparatus, you must expect the kneecap to pop out more often. The more often this happens, the more pronounced the damage to the cartilage of the kneecap and thigh bone in particular can be.

Wear of the cartilaginous surface on the back of the patella results in so-called patellar arthrosis. It can occur as part of general knee arthrosis or in isolation. Symptoms such as stabbing pain behind the kneecap usually develop gradually and increase over time.

On the one hand, older people (>50 years) are affected; the causes are usually degenerative joint changes or injuries caused by falls.On the other hand, young people can also be affected; here the causes are often injuries/accidents, broken kneecaps, hereditary cartilage weakness or anatomical malpositions. The Springer knee, also known as patellar tip syndrome, is caused by overloading or incorrect loading of the patella and quadriceps as well as the lower end of the patella. It can also be caused by inflammation of the patella or the quadriceps tendon.

Stinging pain also occurs gradually, usually directly during or after sporting activity. Affected are mainly people who are active in sports (volleyball players, basketball players, long and high jumpers). In Sinding-Larsen(-Johannson) disease, the lower part of the kneecap is affected by an overstrain reaction.

Sportsmen and women (especially those involved in stop-and-go sports such as basketball, badminton, etc., but also running sports) are frequently affected by Sinding-Larsen’s disease. In this case, an overload on the knee joint, or more precisely on the patella tendon, leads to an inflammatory reaction. The inflammation spreads to the base of the patella tendon at the patella, i.e. to the lower pole.

In advanced stages, parts of the bone can detach from the patella and die off. Pes anserinus tendinitis is an inflammation of the tendon on the inner side of the lower leg just below the knee. Pain often occurs in the morning and under stress and is of a pulling/puncturing character.

Drunk people are mostly athletes, especially runners, and people after knee prosthesis implantation. There are various bursae in the area of the kneecap, both above the kneecap (B. prepatellaris) and along the patellar tendon (B. infrapatellaris). Bursae are pads filled with fluid that reduce friction and pressure on the joints.

If germs enter the joint as a result of external injuries, more fluid is produced. The knee joint swells, the skin is taut and overheated. A pressure pain is to be triggered over the affected bursae.

Furthermore, the mobility in the knee joint is restricted. Painful pain occurs under stress and is of a stabbing nature. Patellofemoral pain syndrome is characterized by pain between the patella and the thigh muscles, as well as around the patella, which cannot be precisely assigned.

The pain occurs mainly when climbing stairs, after sitting for long periods or during physical activity. However, pain at rest can also occur. The causes are overloading of the cartilage, underdevelopment of the patella or patella bearing (patellar dysplasia), excessively tight patella guidance, incorrect loading by knock-knees, muscular causes (shortened or weakened thigh muscles). Young people and athletes are particularly affected.