Loosening of cementless femoral stems: a biomechanical analysis of immediate fixation with loading vertical, femur horizontal.

摘要: Abstract Large joint implants must have immediate fixation to be successful. Unfortunately, the magnitude and consistency of achieving this remains largely unknown. For cementless femoral components it is being increasingly appreciated that torsional loading as occurs during stair climbing or rising from a chair leads loosening thigh pain in some cases. A biomechanical test was developed evaluate position. Twelve pairs human cadaveric femora were press-fit with an AML stem. Each femur secured horizontal position, prosthetic head cyclically loaded vertically downward direction. The offset resulted combined compressive load applied stem within proximal femur. Loosening found consistently occur rapidly accelerate when subsided more than 0.2 mm 100 cycles. stem, at loads 62 171% body weight after few 800 This physiologic range normal daily activities measured by others instrumented prostheses. poses challenge ability stems tolerate vivo. Patients prosthesis should protected until porous ingrowth and/or bone remodelling had time occur. Testing same paired demonstrated no right vs left difference (p > 0.6).