The test is afraid of the patella: why and the mechanism of formation
There is still a lack of evidence regarding the validity of patellar studies as a finding for the patella to be unstable. A small study was completed, showing a sensitivity of only 39%.
The patient lies on their back with knees slightly folded (usually 20-30 °). The examiner then applies force with both hands, pushing the kneecap from the medial position to the side, while the patient is instructed to incorporate quadriceps muscle contraction. This test is considered positive if pain develops or if the patient refuses to contract the quadriceps muscle due to the prediction of pain or mild dislocations.
Figure. The test is afraid of the kneecap
The patient experiences a dislocated kneecap as an external force is pushed into the kneecap when the knee is folded.
Patty bone cell.
Petaloid pain syndrome.
The kneecap is placed in the kneecaps, sliding up and down in the groove as the knee is folded and stretched.
It is stored in this groove by a series of tendons and ligaments, including the quadriceps and the patella ligaments as well as other support structures. If any of the structures become damaged or loose, the kneecap is more easily removed and doing so will cause pain.
By pushing sideways, the examiner actively attempts to move the kneecap out of the furrow and, by contracting the quadriceps (causing the patella to move toward the centre), the displacement is exacerbated. and more pain.
There is still a lack of evidence regarding the validity of patellar studies as a finding for the patella to be unstable. A small study was completed, showing a sensitivity of only 39%. However, the simple and CT images we get are just static tests and are often of limited value in emergency installations and MRI is more expensive, not readily available, and also problematic in Non-emergency installation context, the health check is still important.
A newer test called the patella anxiety test motion for lateral patellar instability showed better sensitivity and specificity.