An estimation of geometric changes in the proximal femurs of US adults from 1988-2014

Open Access
- Author:
- Aydogan, Beytullah
- Graduate Program:
- Mechanical Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- March 27, 2018
- Committee Members:
- Matthew B Parkinson, Thesis Advisor/Co-Advisor
- Keywords:
- statistical shape modeling
poximal femur
population-based design - Abstract:
- Total hip replacement (THR) is one of the most common operations in the world. As a result, there are a number of studies focused on improved femur implant design. Among these are studies focused on the measurement of femur geometry. Many of these use data from cadavers and/or scanned data to collect information about femur geometry. However, these data are not widely available and are typically from a convenience sample. As a result, data on the range of geometries across a population are scarce. This project aims to mitigate this by using a statistical shape model to quantify the range of variability. Body mass index (BMI, a measure of weight-for-stature), age, gender, and stature are predictor variables in the model. To generate a representative sample of femurs, the data from NHANES (National Health and Nutrition Examination Survey) III and NHANES 07-14 were used. A total of 36,019 femurs were generated using NHANES population demographics. A sample population containing 216,509 individuals was generated using weighted data in NHANES 07-14. Measurements of the proximal femur (head diameter, neck diameter, shaft diameter and neck-shaft angle) were made on the synthesized femurs using shape fitting algorithms. Gender different were investigated with controlling input variables. The males measurements were found significantly bigger than females except for neck-shaft angle. The measurements collected from synthesized NHANES III are compared with data from the real NHANES III proximal femur measurements gathered from 2D x-ray images. The synthesized NHANES III measurements were compared with synthesized NHANES 1314 and, the recent population measurements were found slightly bigger except neck-shaft angle. Correlation tests between input demographics and output measurements were performed. The neck-shaft angle was found strongly correlated and decreasing with age. The changes of measurement were investigated between years and races pairs. The significant changes were found in most of the year pairs except head diameter. Most of the race pairs were also found significantly different. Additionally, the relationship between bone geometry and hip fracture was investigated using NHANES 07-10 & 13-14 questionnaire data. The neck shaft angle was found significantly different between non-fractured and fractured individuals. The results can be used to improve implant design for the US and other populations.