System for intraoperative evaluation of soft-tissue-generated forces during total hip arthroplasty by measurement of the pressure distribution in artificial joints

Figures & data

Figure 1. CAD data of the customized femoral head component. The head compartment was designed using a 3D CAD system to allow 8 pressure sensors, including their wiring, to be embedded under the spherical surface. [Color version available online.]

Figure 2. The physical model of the femoral head component manufactured from the CAD data in plastic using a laminate molding technique. All sensors and wiring are collected within the head component, which has a diameter of 32 mm. [Color version available online.]

Figure 3. The displays of the measuring software. (a) Graphs indicating the transitions of the pressure values of each sensor. (b) Pressure direction (top) and distribution (bottom) over the spherical surface. (c) Real-time video captured by the digital video camera. (d) The window that controls the sensor system and records the data. [Color version available online.]

Figure 4. Examples of the estimated pressure distributions. The pressure distributions when the sensor receives loading from the cup component in three directions, designated a, b and c, are depicted. [Color version available online.]

Figure 5. System configuration for the clinical evaluation experiment. The sensor part was sterilized prior to surgery and connected to the control part just before the experiment. [Color version available online.]

Figure 6. Results of one trial of the accuracy test. The graph at right shows the measured and applied forces during a 30-second trial. The applied force direction is shown at left. [Color version available online.]

Figure 7. Display of measured pressure at a given moment. (a) Computer display of the software. The red arrow in the left window indicates the direction and intensity of the pressure. The pressure distributions were mapped using color. (b) and (c): 3D views from the posterior and looking diagonally backward. [Color version available online.]