The contour of cementless femoral stem has minor effect on initial periprosthetic von Mises stress distribution. A 3-dimensional finite element analysis

OBJECTIVE: To evaluate periprosthetic von Mises stress distribution with cementless femoral stems of various contours.

METHODS: The study was carried out at the Department of Orthopaedics, Shanghai 6th Hospital, Shanghai, China between May 2008 and February 2009. Finite element models of proximal femoral replacement with 4 cementless stems (Alloclassic, Ribbed Anatomic, VerSys, and Securi-fit) of various contours were set up. Under the loading conditions of walking and stair climbing, 3-dimensional periprosthetic von Mises stresses were calculated, and the stress distribution patterns were compared.

RESULTS: Periprosthetic stresses were increased in level 1, 2, and 3 under the 2 loading conditions, and more considerably in level 2 and 3. The stresses were higher on the medial side in all cases. No remarkable difference was found in the patterns between the 4 stems.

CONCLUSION: The contour design of femoral stem has minor effect on initial periprosthetic von Mises stress distribution.