Asymmetry of leg creases on the inner side of the thigh, the frog sign test is mainly a clinical examination method to distinguish whether the patient has congenital hip dislocation. However, from another perspective, it cannot be concluded that there is congenital hip dislocation just because the test is positive. It should be further confirmed by hospital-related ultrasound or X-ray examination. The key examination method is that the patient lies flat, the lower limbs are flexed at the patella and placed on the same plane and straight line. The key positive reaction is that the patella height ratio is different, and there is a manifestation of asymmetry of the leg creases on the inner side of the thigh. In some cases of congenital hip dislocation, there may be a significant sound of entry during the process of lifting the patella, or there may be significant resistance when performing this posture.

The frog sign is used to examine the structure and function of the baby’s hip joint. Specific method: the examiner lies on his back, the operator supports the child’s knees with one hand, flexes the hips and knees to 90 degrees, and then performs external abduction and external rotation of both hips to form a frog-like position. If the thigh root cannot reach the bed surface, it is positive, indicating congenital hip dislocation. Leg crease asymmetry is also a manifestation of congenital hip dislocation, with a higher possibility of unilateral dislocation.

Congenital hip dislocation, also known as developmental dysplasia of the hip (DDH) or hip dysplasia, is a congenital hip growth disorder that can affect the growth and development of patients if not treated promptly. Health screening after birth is of great significance, and basic diagnosis of developmental dysplasia of the hip can be made through leg crease status and frog sign tests, so as to facilitate early treatment.

Asymmetry in leg creases is a condition that is more common in infants. This kind of condition usually reminds us that there may be congenital hip dislocation. Therefore, for infants with leg crease asymmetry, great attention should be paid. This kind of condition requires hospitalization for medical treatment and an X-ray examination of the hip joint to determine the position of the femoral head. This is beneficial for determining whether there is a congenital hip dislocation. If it is confirmed that the femoral head is dislocated, this condition should require joint reduction and external fixation with a plaster cast.