The extensor mechanism of the knee can be assessed through the following steps:
1. Physical examination: Observing the knee while the patient extends, flexes, and walks can help identify any abnormal movements or weakness.
2. Palpation: The affected area should be palpated to identify areas of tenderness, swelling or crepitus.
3. Testing quadriceps strength: Manual muscle testing can be performed for quadriceps strength using the Medical Research Council grading system.
4. Patellar tracking test: Assessing patellar position and movement while the knee joint is passively extended and flexed.
5. Imaging studies: X-ray, MRI, and ultrasound studies can provide more detailed information on any anatomical abnormalities, such as patellar malalignment or tears in the quadriceps or patellar tendons.
6. Biomechanical tests: Video gait analysis and other biomechanical evaluations can identify any abnormal movements, such as knee valgus, that may contribute to extensor mechanism dysfunction.