The most common causes of thigh valgus may be congenital deformity, over-training, obesity, bone hernia, etc. If accompanied by any uncomfortable symptoms, it is recommended to consult a doctor in time for treatment. 1. Congenital deformity: some patients may be born with knee valgus, the deformity of the knee joint will make the muscles connected to it valgus, and then produce the performance of thigh valgus. 2. Over-training: some patients may be due to over-exercise, over-training of the lateral thigh muscles, making the lateral thigh muscles developed while the medial muscles are loose, which in turn can show thigh valgus. 3. Obesity: some patients whose weight is too obese, with more meat on the thighs, may also have the phenomenon of thigh ectropion, and patients should be instructed to lose weight. 4. muscle hernia: patients with thigh muscles if trauma or a history of trauma, resulting in thigh muscle fascia breakage, muscle pressure may be too large from the fascia out of the formation of thigh ectropion phenomenon. The causes of thigh ectropion are more, if the symptoms of thigh ectropion continue without relief, it is recommended that patients go to the hospital in time to find out the cause of the disease, and then carry out targeted treatment.