Four-dimensional patient-specific musculoskeletal model of the patient after Total Hip Arthroplasty

We constructed a four-dimensional (4D) patient-specific musculoskeletal model of the patient having had Total Hip Arthroplasty (THA). The model includes the three-dimensional skeletal structures, the muscles and the movement data from optical motion capture system. This model reflects the patient-specific characteristics of the bone geometry, implant alignment and the characteristics of the movement. The muscle model proposed in this paper is the string-typed model representing the route of the muscles. The strings expands and contracts according to the movement of the origin and insertion location of the muscle and we can estimate the direction of the muscle force and the length of the muscles. We developed models of the seven muscles and muscle groups related to the movement of the hip joint. By using this model, clinicians can predict the potential for dislocation or recognize the causes of dislocation, including the influence of the muscles.