Abstract: The present disclosure provides knee prostheses that replicate at least a portion of the function of an individual patient's anterior cruciate ligament (ACL). An exemplary knee prosthesis includes a femoral component configured to be implanted on the distal end of the patient's femur and a tibial component configured to be implanted on the proximal end of the patient's tibia. In extension, the femoral component and the tibial component may cooperate to limit anterior movement of the tibial component relative to the femoral component. In flexion, the femoral component may be free to rotate relative to the tibial component.

Abstract: An electromagnetic emissions free optical signal based helicopter landing assistance arrangement wherein helicopter rotor wash dust cloud-caused obfuscation of the intended landing site and other landing threats are overcome. Real time optical sourced data is collected early and used during helicopter approach to the intended landing site. Upgrading of this data for use during dust cloud presence is accomplished with image processing techniques applied in response to such inputs as helicopter flight data. Military use of the invention especially in current theatre conflict environments is contemplated. Dust cloud related landing hazards are disclosed as a significant difficulty in such environments and generate need for the invention.