Patients with soreness in the thigh groove, especially when the pain is significantly worse with activity and there is significant tenderness without significant localized redness or swelling, are most likely due to inguinal ligament strain. If there is localized redness and swelling and enlarged lymph nodes are palpable, this is usually due to inguinal lymphadenitis. If the pain is significant with activity but there is no significant pressure, it is most likely due to synovitis of the hip joint. If the patient has soreness in the thigh groove either during activity or inactivity, it is usually caused by femoral head necrosis or degeneration or osteoarthritis of the hip joint in middle-aged and elderly people. Therefore, after a patient develops soreness in the thigh groove, an MRI of the hip joint must be performed to rule out femoral head necrosis. Once femoral head necrosis occurs, it will easily lead to the collapse of the cartilage surface of the femoral head, which will cause significant limb shortening and limitation of hip joint movement and seriously affect the quality of life of the patient.