Related Experiment Video
Updated: Mar 22, 2026
Treatment with Locking Intramedullary Nailing for Intertrochanteric Fracture of the Femur Utilizing a New Awl with a Distal Positioner
Published on: June 6, 2025
Effect of varus and valgus alignment on implant loading after proximal femur fracture fixation
Meir Marmor1, Kate Liddle2, Jenni Buckley3
1Orthopaedic Trauma Institute, San Francisco General Hospital, University of California, San Francisco, 2550 23rd Street, Building 9, 2nd Floor, San Francisco, CA, 94110, USA.
Introduction:
More than 10 % of proximal femur fractures repaired with either a sliding hip screw and side plate (SHS-P) or a sliding hip screw and intramedullary nail (SHS-IMN) demonstrate varus malreduction. The purpose of this study was to compare the effect of varus or valgus loading on comminuted intertrochanteric fractures repaired with SHS-P or SHS-IMN constructs.
Methods:
Unstable intertrochanteric fractures with segmental comminution were generated in 12 cadaver proximal femurs, six of which were fixed with an SHS-P and six with an SHS-IMN. Both implants had a strain gauge at the lag screw-nail-plate interface to assess implant load bearing. The load on the implants was measured with the specimens in neutral position and at 5°, 10°, and 15° of varus and valgus.
Results:
Loads on both SHS-IMN and SHS-P constructs were significantly increased when loading the implants in varus and significantly decreased when loading the implants in valgus. Unlike the SHS-IMN, the SHS-P trended toward increased load bearing at 15° varus (159.1 vs. 118.5 %, P = .065) and trended toward less load bearing at 15° valgus (42.3 vs. 59.8 %, P = .06).
Conclusions:
Regardless of implant choice, avoiding varus loading on the fixation construct reduces the load on the implant. SHS-P constructs may be more affected by varus or valgus malalignment than SHS-IMN constructs.
