patellofemoral pain

Patellofemoral pain is a chronic condition in the kneecap region, which can occur around, behind or under the knee

What is patellofemoral pain?

Patellofemoral pain is a chronic condition in the kneecap region, which can occur around, behind or under the knee. The pain usually increases during some physical activity, and the risk of occurrence is particularly high in certain positions of the lower limbs. Patellofemoral tends to worsen during activities such as squatting, sitting, climbing stairs and running. It has been referred to as front knee joint pain, but this can be misleading as it can be felt anywhere, including the back hamstring.

What causes patellofemoral pain?

The following triggering factors usually cause pain in the knee:

  • running
  • walking
  • squatting
  • climbing stairs
  • sitting for an extended time

The primary cause of patellofemoral pain is the dislocation of the patella (kneecap) in relation to the groove of the femur block, to which its posterior surface is attached. This causes the patella to move sideways away from the limb axis on flexion and extension of the knee joint. The structures that support the patella become overstretched, manifested by painful sensations.

Subsequently, changes occur in the neuromuscular apparatus of the lower limb. The elasticity of the ligaments responsible for stabilising the patella is reduced due to long-term micro-trauma and inflammation. As a result, the normal biomechanics of movement is disturbed, and compensatory activation of the corresponding muscle structures occurs. As a result of these abnormalities, there is increased compression on the patellofemoral joint. This leads to accelerated destruction of the cartilage tissue of the articular surfaces.

Impaired patellar alignment in relation to the femur groove can be attributed to the knee joint’s valgus (X-shaped) position. In addition, foot malpositioning, weakness of the thigh muscles, muscle-tendon imbalance and contractures of the thigh muscles also cause patellofemoral pain. Pain occurs when the patellofemoral joint is overloaded during certain sports.

Symptoms and diagnosis

Patellofemoral pain can occur in one or both knees. The severity of the discomfort can vary. Patients often complain of a deep, dull pain that is not clearly localised. A crunching sound is heard when the lower limbs move. This sound occurs when the cartilage is missing or weak and when the bones in the joint start to touch each other. Patients also notice a subjective feeling of a “blockage” in the knee joint and stiffness in the joint after straightening the bent leg for a long time. 

On examination, the orthopaedist may detect a deviation from the normal biomechanical axis of the lower extremity. There is also an increased or reduced knee joint mobility and hypotrophy of the quadriceps femoris muscle.

What are the levels of patellofemoral pain?

Patellofemoral pain is a gradually progressive condition that can lead to disability if not treated in time. In the initial stages of the condition, symptoms are usually absent or minimal in intensity. There are three levels of patellofemoral pain, depending on the severity of the pathological changes in the knee joint.

  1. The first level is characterised by a slight destruction of the cartilage in the joint. It can be challenging to detect, even with an X-ray. Clinically, this is manifested by sharp, not intensive knee pain at increased physical activity, which disappears after rest.
  2. In the second level of patellofemoral pain, a radiograph may show already visible and widespread degenerative-dystrophic changes in the cartilage. The patient complains of intense pain in the knee after jogging, climbing stairs, standing up after a long sitting period, etc. In some cases, there is a slight limp when walking long distances. However, the patient doesn’t feel pain at rest.
  3. The third level of patellofemoral pain is diagnosed when there are extensive pathological changes in the cartilage tissue of the joint and its complete damage in some. The clinical picture includes pain in the knee during exercise as well as at rest. In addition, there is limited mobility in the knee joint, which is deformed externally. In the advanced levels of the condition, movement in the knee becomes almost impossible.

Treatment

First, the knee joint must be maximally unstressed if there is patellofemoral pain. This involves excluding sports training, wearing orthopaedic shoes, and wearing special bandages or knee pads.

Treatment with medication involves taking non-steroidal anti-inflammatory drugs to relieve the pain. For very severe pain, intraarticular injections of glucocorticosteroids are given.

In addition to this, the treatment plan is accompanied by:

  1. Exercise therapy
  2. Physiotherapy methods
  3. Surgery (it is indicated in the third stage of the patellofemoral pain)