Total hip arthroplasty (THA) is an effective treatment to remove the pain for patients who suffer from rheumatoid arthritis or osteoarthritis of the hip joint. In THA, the artificial hip joint dislocation is one of the most serious problems to be solved. The dislocation of the artificial hip joint occurs depending on the hip joint angles and hip contact force. Specifically, the muscle forces of the patients who suffer from hip osteoarthritis become weaker because they cannot move the hip joint enough due to pain. In this paper, we discuss the influence of the hip contact force on artificial hip joint dislocation when the muscle forces around the hip joint become weaker. To clarify the influence, the experiments are carried out using the hip joint simulator which can generate the desired hip joint angle and the joint contact force simultaneously.
