Abstract: A cementless femoral stem prosthesis for use in hip replacement surgery is disclosed. The stem has a collar and a body having a fixed end and a shank end. The shank end is divided into a pair of adjustable endosteal plates that are secured to the cortical bone of the femur by screws. The present invention provides an improved femoral stem structure because the screws through the endosteal plates transfer the load to the cortical bone rather than the cancellous bone, the medial endosteal plate has a plurality of spurs to engage with the cancellous bone to increase the number of stress-strain points, and the collar transfers the load directly to the cortical bone. All of these features work in tandem to reduce the risk of stress shielding, bone resorption, prosthetic loosening, and other difficulties associated with femoral stem prostheses.

Abstract: A cementless femoral stem prosthesis for use in hip replacement surgery is disclosed. The stem has a collar and a body having a fixed end and a shank end. The shank end is divided into a pair of adjustable endosteal plates that are secured to the cortical bone of the femur by screws. The present invention provides an improved femoral stem structure because the screws through the endosteal plates transfer the load to the cortical bone rather than the cancellous bone, the medial endosteal plate has a plurality of spurs to engage with the cancellous bone to increase the number of stress-strain points, and the collar transfers the load directly to the cortical bone. All of these features work in tandem to reduce the risk of stress shielding, bone resorption, prosthetic loosening, and other difficulties associated with femoral stem prostheses.