Direct anterior total hip arthroplasty and the relationship between hip abduction torque and external hip adduction moment

Abstract

Purpose--The Direct Anterior Total Hip Arthroplasty (DA THA) is a variation of Minimally Invasive Total Hip Arthroplasty procedures. This surgical approach does not transect the abductor musculature and is classified as a muscle sparing procedure. The muscle sparing procedure goal is to limit the damage to the hip abductors and thereby allowing patients faster recovery times. Hip abduction torque as it relates to hip external adduction moment is considered an important factor of THA function before and after surgery. Therefore the purpose of this study was to determine the relationship hip abduction torque had on external hip adduction moment in DA-THA and Control groups. Methods--Two 2x3 analysis of variance (ANOVA) with repeated measures (RM) were used to compare 16 participants, 8 direct anterior (DA)-THA procedure participants and 8 controls. Pearson's Correlation was used to test the relationship of hip abduction strength and hip external adduction moment. Pearson's Chi-square test was used to evaluate the Trendelenburg test grade. External hip adduction moment, function, (Trendelenburg test) and hip abduction torque data were collected at the following three time periods: pre-operation (PRE/initial), three months post-surgery (POST3) and six months post-surgery (POST6). Results--Results revealed non-significant Pearson Correlation (r = 0.15) between involved hip abduction isometric torque and external hip adduction moments. ANOVA results revealed a decrease in control group hip abduction torque from PRE to POST6. Conclusion--Within the limitations of the present study DA-THA and control groups failed to demonstrate a significant relationship between hip abductor torque and external hip adduction moment.