Intraoperative computer-assisted prediction of intraarticular contact pressures in the knee during high tibial osteotomy.

Objectives: To develop an accurate intraoperative method to estimate changes in intraarticular contact pressures during high tibial osteotomy (HTO).

Methods: Changes in knee alignment and pressure were monitored in real time in seven cadaver specimens that received HTO. Intraarticular contact pressure (N/mm ) in each knee compartment was estimated based on extraarticularly acquired data (leg alignment, correction, and ankle tilt) and based on the application of an axial force of half bodyweight (400-450 N).

Effect of Femoral Antetorsion on Tibiofemoral Translation and Rotation in the Anterior Cruciate Ligament Deficient Knee.

We aimed to investigate how increased or decreased femoral antetorsion would affect the biomechanics of the knee in an anterior cruciate ligament (ACL)-deficient cadaveric model. We hypothesized that external or internal rotation of the distal femur, achieved through a femoral osteotomy, would affect the magnitude of tibiofemoral translation and rotation. Navigated measurements of tibiofemoral translation and rotation during the anterior drawer, Lachman, and pivot shift tests were performed on six whole-body cadaveric specimens in each of the following four conditions: native, ACL-deficient knee, ACL-deficient knee and 20-degree internal distal femur rotation, and ACL-deficient knee and 20-degree external distal femur rotation.

Computer navigation for total knee arthroplasty achieves better postoperative alignment compared to conventional and patient-specific instrumentation in a low-volume setting.

Background: Procedure volume is an important determinant of total knee arthroplasty (TKA) outcomes. We aimed to determine whether computer navigation or patient-specific instrumentation (PSI) would improve postoperative alignment in a low-volume setting.

Hypothesis: PSI for TKA achieves better limb and implant alignment compared to conventional TKA and to computer navigated TKA.

Improving the human-robot interface for telemanipulated robotic long bone fracture reduction: Joystick device vs. haptic manipulator.

Objectives: Intramedullary nailing is the treatment of choice for femoral shaft fractures. However, there are several problems associated with the technique, e.g.

Comparison of algorithms for automated femur fracture reduction.

Purpose: We designed an experiment to determine the comparative effectiveness of computer algorithms for performing automated long bone fracture reduction.

Methods: Automated reduction of 10 3D fracture models was performed using two computer algorithms, random sample matching (RANSAM) and Z-buffering (Z-Buffer), and one of five options of post-processing: none; iterative closest point algorithm (ICP); ICP-X1; ICP-X2; and ICP-X3. We measured the final alignment between the two fragments for each algorithm and post-processing option.