A New System for Periprosthetic Fracture Stabilization-A Biomechanical Comparison.

Daniel Rau,Dag Wulsten,Werner Schmölz,Clemens Kösters,Sven Märdian,Gabriele Rußow,Mark Heyland

doi:10.3390/jcm11030892

Abstract

In recent years, an increase in periprosthetic femur fractures has become apparent due to the increased number of hip replacements. In the case of Vancouver type B1 fractures, locking plate systems offer safe procedures. This study compared the distal lateral femur plate (LOQTEQ®, aap Implantate AG) with a standard L.I.S.S. LCP® (DePuy Synthes) regarding their biomechanical properties in fixation of periprosthetic femur fractures after hip arthroplasty. We hypothesized that the new LOQTEQ system has superior stability and durability in comparison. Eighteen artificial left femurs were randomized in two groups (Group A: LOQTEQ®; Group B: L.I.S.S. LCP®) and tested until failure. Failure was defined as 10° varus deformity and catastrophic implant failure (loosening, breakage, progressive bending). Axial stiffness, loads of failure, cycles of failure, modes of failure were recorded. The axial stiffness in Group A with 73.4 N/mm (SD +/− 3.0) was significantly higher (p = 0.001) than in Group B (40.7 N/mm (SD +/− 2.8)). Group A resists more cycles than Group B until 10° varus deformity. Catastrophic failure mode was plate breakage in Group A and bending in Group B. In conclusion, LOQTEQ® provides higher primary stability and tends to have higher durability.

Highlights

Many authors agree that endoprosthetic hip replacement is probably the most successful innovation in orthopedic surgery to date [1,2]
The hydroxyapatite titanium alloy coating allows a high level of primary stability [21], which is necessary for biomechanical examinations with axial force application
We were able to show that the LOQTEQ® hinge system had a significantly higher axial stiffness than the control group of the standard implant

Summary

Introduction

Many authors agree that endoprosthetic hip replacement is probably the most successful innovation in orthopedic surgery to date [1,2]. With steadily increasing implantation rates of total hip and knee arthroplasty in an steadily aging population [3], the incidence of periprosthetic femoral fractures continues to rise [4,5]. The increase in life expectancy and a high level of activity, despite advanced age, contribute to the increased incidence of periprosthetic fractures [6]. Due to the different moduli of elasticity of the prosthesis stem and the surrounding bone, stress peaks occur in the area of the stem tip. In this transition area, in particular, these lead to most (approximately 75%) periprosthetic fractures around the hip [7]

Methods

Results

Discussion

Conclusion