The knee is made with two degrees of freedom of movement. It folds and unfolds, thus lengthening and shortening the lower limb and positioning the lower leg and foot exactly in space. The knee joint is an intermediate link that articulates the femur and calf bones. It is an anatomically complex joint. It is dynamically supported mainly by the strong thigh muscles, and statically by the joint ligaments. It is often subject to traumatic injuries, such as patellar luxation. As a rule, patellar dislocation is characteristic of women due to the greater elasticity of the ligaments. Patellar subluxation is also known as patellar instability.
Anatomical features of the patella
The patella is a sesamoid bone, located in front of the knee joint. It covers and protects the joint. The cap is woven deep into the tendon of the quadriceps muscle. When the thigh muscle is contracted, the cap moves upward in the direction of contraction and vice versa. When folded, it falls into the intercondylar fossa. This mechanism suggests that the correct positioning of the patella is directly dependent on the strength of the thigh muscles. It is a dynamic stabilizer that ensures the correct fit of the cap in the intercondylar space and the preservation of retropatellar cartilage. Static stabilizers are the lateral knee joints, which are located on both sides. They prevent the cap from coming out laterally, which is essentially a dislocation of the patella or a sprain of the knee cap.
Types of patellar luxation
- Congenital dislocation due to abnormal development or underdevelopment of joint components. Old diseases or pathological changes in the knee joint can also create preconditions for injury.
- Traumatic dislocation. It is obtained as a result of extreme activity or sports contact leading to displacement of the patella. The mechanism of the injury is twisting with a slightly bent knee. Mostly young and active sports people suffer. It mainly affects girls and women due to the looser joints in them. Often the dislocated patella adjusts spontaneously. But there are also cases of severe rupture of the stabilizing retinal connection. The knee is painful with limited volume and impaired function. Hemarthrosis is observed. The pain is in the area of the medial retinaculum and the lateral edge of the patella.
- Habitual luxation. Dislocation of the cap is observed when bending at the knee, followed by spontaneous repositioning.
- According to the direction of displacement we observe: vertical, torsional and lateral luxation of the patella, as well as subluxation.
Diagnosis and treatment
If patellar dislocation is suspected, it is necessary to consult an orthopedist-traumatologist. He will examine joint stability, take into account the location of pain and functional deficit. In the presence of a traumatic moment, you will be referred for an X-ray of the joint. If you need more complete research, you may be referred for magnetic resonance imaging. Depending on the clinical picture and the results of imaging studies, you can focus on conservative or surgical treatment.
In both cases, the course of recovery goes through physiotherapy and kinesitherapy, whose tasks and goals are to quickly restore the affected limb and return the patient to normal rhythm and course of life. For more information you can contact us.