10 internal causes of knee pain

Knee pain often causes great discomfort in people by limiting walking and daily tasks. Fortunately, most of these conditions have effective and safe treatment.

Last update: February 11, 2022

The knee is one of the joints in the human body with the highest risk of presenting injuries and inflammatory or degenerative conditions. In general, they manifest with pain and difficulty walking. Next, we tell you 10 internal causes of knee pain.

The knee joint is made up of the femur, tibia, and patella or patella. Inside, it is covered with articular cartilage and synovial fluid that limits friction between the bones. Similarly, it has two cushioning pads called menisci, as well as several stabilizing ligaments and tendons.

In most cases, knee discomfort is associated with some kind of damage or injury to its internal structures. These conditions are often the result of trauma, a sports injury, or aging. Timely professional care determines greater pain relief and lower risk of complications.

10 Common Internal Causes of Knee Pain

Most knee problems can be treated by seeing a doctor right away.

Knee pain can manifest acutely as a result of a direct blow or injury from a fall, a sharp turn on the foot, or poor posture. Similarly, Discomfort in this joint can also appear progressively and increase in intensity over time.

Currently, there are several internal causes that explain the pain in the knees. Fortunately, these can be resolved in a short time under continuous medical supervision. Among the 10 most common causes are the following.

1. Medial collateral ligament (MCL) injury

The medial collateral ligament (MCL) is an elastic band that extends from the femur to the tibia on the inside of the knee. Like its counterpart, the lateral collateral ligament (LCL), its function is to stabilize the knee and align the leg with the thigh.

Studies affirm that injuries to the MCL represent 42% of ligamentous conditions of the knee. These injuries occur when the ligament is overstretched by a blow or direct compression on the outside of the knee, as occurs in contact sports.

In mild cases, a sprain of the MCL occurs, while In more serious cases, it can suffer a partial or total tear.. All of these situations are common internal causes of knee pain. Other symptoms associated with this condition include the following:

  • Stiffness and feeling of locking when moving the knee.
  • Instability and weakness when walking.
  • joint swelling.
  • Clicking in the knee.

2. Medial meniscus tear

The menisci are small, rubbery, C-shaped cartilages., located inside the knees. There are two menisci in each knee, one on the lateral side and one on the medial border of the joint. Its main function is to absorb and cushion the shocks generated by walking, running or jumping.

In this sense, the menisci may tear or tear from quick, jerky turns over the knee with the foot planted on the ground or in direct trauma. In this way, lifting heavy objects, sports with great physical demand and jumping from great heights are common causes of this condition.

Sharp inner knee pain and swelling are common symptoms of a medial meniscus tear. In addition, people may have the following symptoms:

  • Inability to flex and straighten the knee.
  • Stiffness and locking of the joint when walking.
  • Crunch when moving the knee.
  • Unstable or “wobbly” knee feeling.

3. Subluxation of the patella

Patellar subluxation is the most common type of dislocation in the knee.. This occurs before the sudden and abnormal displacement of the patella when leaving its normal position in the anterior part of the joint. It is one of the many internal causes of knee pain.

Research suggests that this type of subluxation is the result of sudden rotational movements of the knee with sustained contraction of the quadriceps. In general, severe pain, limitation of movement and knee deformity are the most common symptoms of this condition.

4. Knee fracture

Knee fractures involve any bony break that occurs in the patella, distal femur, or proximal tibia. They can have a wide variety of forms of presentation and are associated with direct trauma to the area.

In general, the symptoms vary according to the type of fracture, the degree of displacement of the bone pieces and the severity of the condition. This is one of the most common internal causes of severe knee pain after a fall or hard blow. Other signs of this condition are deformity and swelling of the knee..

Studies suggest that fractures of the patella represent between 0.5 and 1.5% of all bone fractures, being common in adults between 30 and 60 years. If you suspect a fracture, do not hesitate to seek medical attention as soon as possible.



5. Bursitis

Knee bursitis is nothing more than the inflammation of the bursa located in the knee joint. The bursa is a small rubbery sac, filled with synovial fluid, which works by reducing friction and cushioning pressure between bones, tendons, and muscles.

In most cases, the most affected bursae are those located above the patella or inside the joint. This condition is usually accompanied by mild to moderate pain when moving the leg or at rest, increased tenderness in the area, and swelling of the knee.

6. Tendinitis

Patellar tendinitis is also called “jumper’s knee”. This is a common condition in people who play sports like basketball and volleyball. However, it can also occur in people who do not play sports with jumps.

This condition occurs due to inflammation of the patellar tendon, responsible for connecting the patella with the tibia. In most cases, knee pain is the first symptom to appear. Initially, this discomfort appears when doing physical exercise, but over time it can even limit walking, sitting or climbing stairs.

Older people can suffer from knee problems due to aging.

7. Patellofemoral pain syndrome (PFPS)

This is one of the most common musculoskeletal disorders in adolescents and physically active adults. Studies estimate that PFPS represents between 11 and 17% of cases of knee pain. It is also more common in women. As usual, the discomfort is in the front and inner aspect of the knee.

The main cause of this pain syndrome is the overuse of the knee joint when practicing high intensity sports. In most cases, pain occurs when squatting, running, climbing stairs, or sitting for a long time.

8. Knee contusion

Direct blows to the knees from rigid objects or falls from a height are a popular cause of contusions at this level. In these cases, knees tend to swell and turn bright red to, then, turn purple and, finally, present a yellow-green color.

Similarly, mild to moderate pain that worsens with pressure on the area is common. These injuries can usually be treated at home with the help of cold compresses, pain medications, and rest.

9. Osteoarthritis

Osteoarthritis, or “wear and tear osteoarthritis”, is the most common degenerative disease in the knees. It generates wear and progressive destruction of the cartilage of the joint that causes pain and difficulty moving the knee.

Habitually, the pain worsens over time, as the cartilage wears away completely. Similarly, stiffness and discomfort in the knees are usually worse in the morning or after a long period without moving.



10. Rheumatoid Arthritis (RA)

Is about an autoimmune disorder characterized by symmetrical and progressive inflammation of the peripheral joints. This is one of the internal causes of knee pain in women and older adults.

Rheumatoid arthritis usually presents with pain, swelling, stiffness, and loss of motion in the joints. In addition, knee discomfort often worsens with rest. Thus, it is more intense at night and interferes with people’s sleep.

When to seek medical attention?

Today, There is a wide variety of internal causes of pain in the knees. In general, this symptom is associated with overuse of the joint, direct blows and degenerative processes typical of aging.

Ligament and meniscal injuries, dislocations, and fractures of the knee generally require medical attention as soon as possible. Early professional attention relieves discomfort and reduces the rate of short-term complications. Also, immediate help should be sought if the affected person is bleeding or loses consciousness.

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