A biomechanical study of the effect of weight loading conditions on the mechanical environment of the hip joint endoprosthesis. (December 2019)

• Record Type: Journal Article
• Authors: Farmakis, Ioannis-Ilias K.; Potsika, Vassiliki T.; Smyris, Andreas-Foivos; Gelalis, Ioannis D.; Fotiadis, Dimitrios I.; Pakos, Emilios E.
• Is Part Of: Clinical biomechanics. Volume 70(2019)
• Page Start: 197
• Page End: 202
• Publication Date: 2019-12
• Subjects: Total hip arthroplasty -- Prosthesis -- Obesity -- Strain gages -- Complications; Biomechanics -- Periodicals; Osteopathic medicine -- Periodicals; Biomechanics -- Periodicals; Osteopathic Medicine -- Periodicals; 612.76
• DOI: 10.1016/j.clinbiomech.2019.10.002
• Languages: English
• ISSNs: 0268-0033

Abstract

Abstract: Background: Total hip arthroplasty is one of the most successful orthopedic surgical procedures aiming to eliminate pain related to several types of hip arthritis and restore mobility. Obesity has been associated with an increased risk of complications after a total hip arthroplasty such as poor wound healing, periprosthetic joint infection, instability, and aseptic loosening. Methods: This paper presents an in-vitro study on composite femoral models to investigate the impact of different weight loading conditions on the mechanical environment of the hip joint endoprosthesis considering normal-weight and overweight individuals from 70 to 110 kg. The micro strains on the femur during single-leg stance of gait were measured on critical stress points based on the Gruen femoral zones. Findings: The micro strains increase as the weight increases implying that the displacement in the hip joint endoprosthesis is higher for overweight subjects enhancing the risk of failure. The highest increase was measured in Gruen zone 1 by 5.60% indicating that the great trochanter is subjected to higher stress shielding with increasing the weight. Also, the statistically significant increase of the micro strain values with increasing the weight in Gruen Zones 3 (2.91%), 5 (1.56%), and 11 (1.75%) may enhance the risk for a periprosthetic fracture at the lower region of the prosthesis. Interpretation: This is the first biomechanical study which quantifies the effect of increasing weight loading conditions on the mechanical environment of the hip joint endoprosthesis considering different positions of evaluation. Highlights: The highest micro strain increase was measured in Gruen zone 1. The great trochanter is subject to higher stress shielding as the weight increases. The increase of weight may lead to complications after a total hip arthroplasty. The increase of weight may have a negative impact on the prosthesis longevity.