Whiteboard Cleaning Task Realization with HOAP-2

The controller has a motion feedback control loop for the four arm joints and a force feedback control loop for the ankle joint. The desired motion/force trajectories are obtained via kinesthetic teaching by a human, followed by a learning phase. During skill demonstration, the arm joints are made compliant while the robot balances using ankle/hip strategies. Experimental data demonstrate the feasibility of the method

Biomechanical considerations in the pathogenesis of osteoarthritis of the knee

Osteoarthritis is the most common joint disease and a major cause of disability. The knee is the large joint most affected. While chronological age is the single most important risk factor of osteoarthritis, the pathogenesis of knee osteoarthritis in the young patient is predominantly related to an unfavorable biomechanical environment at the joint. This results in mechanical demand that exceeds the ability of a joint to repair and maintain itself, predisposing the articular cartilage to premature degeneration. This review examines the available basic science, preclinical and clinical evidence regarding several such unfavorable biomechanical conditions about the knee: malalignment, loss of meniscal tissue, cartilage defects and joint instability or laxity

The computer-assisted sequential lateral soft-tissue release in total knee arthroplasty for valgus knees

Soft-tissue management is a critical factor in total knee arthroplasty, especially in valgus knees. The stepwise release has been based upon surgeon’s experience. Computer-assisted surgery has gained increasing scientific interest in recent times and allows the intraoperative measurement of leg axis and gap size in extension and flexion. We therefore aimed to analyse the effect of sequential lateral soft-tissue release and the resulting change in the a.p. limb axis on the one hand and the tibiofemoral gaps on the other hand in extension as well as in flexion in eight cadaveric knees. Measurements were obtained using a CT-free navigation system. In extension the highest increase compared to the previous release step was found for the first (iliotibial band, P = 0.002), second (popliteus muscle, P = 0.0003), third (LCL, 0.007) and the sixth (entire PCL, P = 0.001) release step. In 90° flexion all differences of the lateral release steps were statistically significant (P < 0.004). Massive progression of the lateral gap in flexion was found after the second (popliteus muscle, P = 0.004) and third (LCL, 0.007) release step. Computer-assisted surgery allows measurement of the effect of each release step of the sequential lateral release sequence and helps the surgeon to better assess the result

Patella Fractures by Different Techniques

International audiencePatellar fractures are common. Anatomic reduction and stable fixation is crucial to achieve satisfactory results and avoid early complications and articular cartilage degeneration. Open techniques represent the most common approach to these fractures. Unfortunately, they are associated with a variable rate of early complications often requiring reoperation. Arthroscopic-assisted techniques have been introduced to improve the outcomes and reduce the rate of complications that are associated with open approaches. The most common indication is a displaced transverse fracture. In those cases, arthroscopy ensures accurate articular structure integrity evaluation. In addition, precise visualization of the reduction of the fragments is possible allowing the use of minimally invasive osteosynthesis techniques. Several options have been described including screws, cerclage, tension band, and external fixators