Pain below the patella

Pain below the patella is a relatively common disease, especially in female athletes, and it is very likely related to abnormal alignment. Generally, the occurrence of this disease requires a physical examination first, and then the corresponding diagnosis, because only through accurate examination can we know what stage the patient's body is currently in, so that we will not be too blind when treating.

reason

Patellofemoral pain syndrome (PFPS) is a common disease, especially in athletes and women. The cause of the disease is not yet clear, but it is closely related to abnormal alignment of the patella.

The cause of PFSP is still unclear, but there are two possible explanations.

(1) The patella deviates from the trochlear groove, causing the patella to be off track, resulting in anterior knee pain.

(2) The synovium around the patella is richly innervated by nerves and may be stimulated by chemicals or pressure. Once inflamed, it will cause symptoms during activities.

examine

Physical examination:

1. There is friction sound under the patella when the knee joint moves, and the position is not fixed.

2. There is diffuse pain behind the patella, the legs feel weak when walking, and there is obvious discomfort when going up and down stairs.

3. When in half squat position, the knee joints feel sore and weak, and the patella feels tender.

4. The patellar pressure quadriceps contraction test is positive.

5. Patellar compression and grinding test: During the examination, the patella and the corresponding femoral condyle articular surface are squeezed and ground against each other or slid up and down and left and right, which causes a rough friction feeling, grinding sound and pain and discomfort; or the examiner pushes the patella to one side with one hand and presses the back of the edge of the patella with the thumb of the other hand, which may cause pain.

6. Single-leg squat test: The patient holds weight on one leg and gradually squats to 90°-135°. Pain and weakness occur, and the patient cannot stand up on one leg after squatting.

Imaging examinations: X-ray, arthroscopy, internal patellar venography, CT: They are valuable in diagnosing patellofemoral malalignment and femoral condylar dysplasia, to determine the cause and severity of patellar pain.

Differential Diagnosis

Usually, if there is only knee pain and no fibrosis of the patellar cartilage is found in the pathological examination, it can only be called "patellofemoral pain syndrome". If the cartilage has changed, it is called "chondromalacia patella".

In fact, most knee pains among young people are of this type; but if knee pains among the elderly are present, most of them are caused by degenerative arthritis. But the two are still related, because if the patellar cartilage is painful for a long time, the cartilage will easily wear out and turn into degenerative arthritis.

(1) The patient will experience pain when sitting for a long time, squatting, kneeling or going up and down stairs.

(2) In some cases, there may be crepitus when the knee is flexed or straightened.

(3) Patients may experience improper soft tissue pressure due to incorrect patellar tracking, which in turn affects their proprioception.