Why there is pain in the knee joint when flexing?

For a long time we do not even think about the fact that our joints can get sick - we mercilessly exploit them, as we please. Fortunately, the human body is designed in such a way that it can withstand enormous loads, but for the time being, until the time. If such a test lasts a long time, then sooner or later we begin to experience unpleasant sensations, which gradually turn into pain.

One of the most common complaints of patients with articular pathology is pain in the knee joint during flexion. It is not strange either. After all, this anatomical structure is superficial, every day withstands large dynamic and static loads. And if you take into account the fact that the knee joint has anatomical prerequisites for damage, it is not at all strange that sooner or later knees begin to ache.

Anatomical features of the knee joint

The knee belongs to the largest joints of the human body( more only the hip), but this does not make it strong, but, on the contrary, creates the prerequisites for damage.

Three bones are involved in the construction of the knee joint - the femur, the tibia and the knee cap, which makes the joint difficult to arrange. The anatomical form of the joint is unstable, because in the joint there are natural stabilizers - menisci, which are cartilaginous pads, located at the edges of the articular surface of the tibia to complement, increase congruence of the joint and fix it. Also, the surfaces of the bones are covered with hyaline cartilage, which protects the bone from damage, and also provides amortization properties of the knee.

These cartilage structures do not have their blood vessels, but are fed by synovial fluid, which is located in the joint cavity, bounded by a capsule. If the body has any causes that affect the composition and amount of this nutrient and protective fluid, or factors that lead to permanent cartilage injury, then soon the cartilaginous tissue will begin to die, which will inevitably lead to pain and other consequences.

Bones are strengthened by intra-articular ligaments, as well as by extraarticular and muscle tendons. Unfortunately, the muscular skeleton of the knee is poorly developed, because of which the joint has a superficial location and is prone to injury, which further exacerbates the situation.

knee structure
Because of the peculiarities of the anatomical structure, the knee joint is susceptible to various diseases.

. The main causes of chronic pain

. The causes of soreness in the knee joint are very many when bent. In this case, we are talking about the true diseases, and not the normal physiological state, when the pain when flexing or flexing appears after heavy physical labor.

Osgood-Schlatter osteochondropathy

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knee pain Why does the knee ache during flexion?

A typical disease, in which there is pain when bending at the knees, can be considered Oschud-Schlatter osteochondropathy. Osteochondropathy is a numerical group of abnormalities of the musculoskeletal system, in which apophyses of bones are affected( these are bony projections and tuberosity, to which tendons of muscles are attached).In the case of Osgood-Schlatter disease, the tibial tuberosity is affected by pathological changes, to which the tendon of the patella is attached( continuation of the tendon of the largest muscle of the leg - the quadriceps muscle of the thigh).

In the vast majority of cases, the disease develops in children and adolescents, especially in boys. Children who exercise regularly( active kinds with loads on their knees) are more prone to pathology than their peers who do not go in for sports.

The basis for the development of osteochondropathy is the discrepancy between the growth rates of bone tissue and blood vessels. With a jump in growth, the vessels do not keep up with the increase in bone tissue. This promotes local ischemia of the tuberosity of the tibia, plus constant loads on the knees lead to hypertrophy of the bone tissue and the formation of a cone, which is accompanied by pain under the knee during flexion.

Symptoms of pathology are typical enough:

  • formation of the knoll under the knee, the skin over it is not changed, signs of inflammation are absent;
  • pain occurs when kneeling and bending at the knees.

As a rule, the symptoms of the disease pass with age. In some cases, surgical treatment may be required, but this is rare.

bump under the knee
A typical and specific symptom of Osgood-Schlatter disease is the "lump" under the knee


Gonarthrosis doctors call deforming osteoarthritis of the knee joints. This disease is familiar to a large number of people, especially the mature age. But arthrosis can affect not only the elderly, but also young patients, while the main role is played not by age-related degenerative-dystrophic changes in intraarticular cartilage, but by risk factors( obesity, active sports, constant dynamic loads, sedentary lifestyle, endocrine and metabolic pathology).

Symptoms of gonarthrosis develop slowly and imperceptibly for the patient, which is the cunning nature of the disease. First, knees hurt after a hard working day, and after rest everything goes by itself. With the progression of pathological changes, the pain becomes permanent, increases with movement, it becomes painful to bend the leg in the knee, all movements are accompanied by a specific crunch.

If the process is not stopped in time, the joint eventually loses its function completely, persistent deformations and contractures develop, painkillers and symptomatic treatment do not help, and the only chance to get rid of pain remains the operation to replace the joint with an artificial endoprosthesis.

Useful exercises:

Rheumatoid arthritis

Rheumatoid arthritis often affects small joints, but there are forms of the disease in which the knee joint can be drawn into the pathological process.

At the same time the disease proceeds wavy - with periods of exacerbation and remission. At an aggravation the pain in the knees is very strong, accompanied by a feeling of stiffness( in the morning it is impossible to perform any movements in the knees).A characteristic sign of rheumatoid knee injury is inflammation - the knees turn red and swell.

Treatment of this disease - this is a very difficult task, which should only deal with a specialist rheumatologist. Since the therapeutic program requires a long-term intake of basic antirheumatological medications that have many contraindications and side effects, one can not do with an anesthetic pill in such cases.

Traumatic injuries

Since the knee refers to complex joints, there are many types of traumatic injuries to its structures. Most often, tension or rupture of intraarticular and extraarticular ligaments, fractures of intraarticular parts of bones, damage to menisci, rupture of the capsule, traumatic synovitis, hemarthrosis can be observed.

Pain syndrome is typical for each such injury, and pain can disturb the patient, both with knee flexion and at rest. Self-diagnosis of the type of injury is unlikely to work. The trauma doctor can do this after examining and conducting a number of additional examinations, which will necessarily include radiography.

swelling of the knee
If knee pain is accompanied by edema of the knee joint, it is absolutely necessary to consult a doctor

Inflammation of the

Inflammatory lesions of both the joint itself and the periarticular tissues can cause knee pain when flexing:

  • reactive arthritis;
  • infectious arthritis( bacterial, fungal, viral);
  • allergic arthritis;
  • inflammation of the joint capsule( synovitis), its pockets and twists( bursitis), inflammation of the meniscus, ligaments( tendinitis);
  • inflammation of the periarticular tissues( periarthritis).

Unfortunately, we do not always pay attention to the warning signs of knee injury until they develop into severe pain and significantly worsen the quality of our lives. But often it happens that in such cases it is already impossible to get rid of the disease and it is necessary to live with chronic pain or lie under the surgeon's knife. That this does not happen to you, be attentive to your body, because pain is a signal that he needs your help.

knee bending