Congenital genu flexum is a condition in which the knee joint bends more than normal. It is caused by a variety of factors, including:
1. Abnormal development of the knee joint during fetal development.
2. Abnormalities in the structure of the knee joint, such as a shallow femoral groove or a shallow patellar groove.
3. Abnormalities in the muscles and ligaments that support the knee joint.
4. Abnormalities in the growth plates of the bones that make up the knee joint.
5. Trauma to the knee joint, such as a fracture or dislocation.
6. Connective tissue disorders, such as Ehlers-Danlos syndrome.
7. Neuromuscular disorders, such as cerebral palsy.