Sex specific associations between biomechanical recovery and clinical recovery after total hip arthroplasty

BACKGROUND: There are sex-specific gait differences in men and women before and after total hip arthroplasty (THA) but we do not know their impact on clinical outcomes. The objective of this study was to identify sex-specific associations between pre- and postoperative changes in pain and function and (i) gait mechanics, (ii) passive range of motion, and (iii) abductor strength. METHODS: Pre- and one-year postoperative data were identified from a data repository (n = 124; 64 Women; Age 61 (SD 10); BMI 29 (SD 5)). We used linear regression analysis to identify sex-specific associations between Harris Hip Score pain and function subscores, and sagittal plane hip kinematics and 3D hip kinetics during gait, hip abductor strength, and passive hip range of motion (RoM). FINDINGS: Combinations of biomechanical variables predicted up to 24% of the variation in pain improvement and up to 27% of the variation in functional improvement. In men, increased peak external rotation moments were associated with pain improvement. Passive flexion RoM and peak extension moments were associated with functional improvement. In women, increased passive adduction RoM and peak external rotation moments were associated with pain improvement. Peak adduction moments and passive flexion RoM were associated with functional improvement. INTERPRETATIONS: The different associations between improvement in clinical outcomes and improvement in gait, passive RoM, and abductor strength suggest that the biomechanical path to recovery may be different in men and women

Split-Belt Treadmill Training Improves Mechanical Energetics and Metabolic Cost in Women with Unilateral Hip Osteoarthritis: A Proof-of-Concept Study

We have shown that step length asymmetry seen in hip osteoarthritis (OA) is associated with poorer mechanical energy exchange and higher metabolic cost. Thus, we conducted this proof-of-concept study to investigate whether modifying step length through split-belt treadmill training can improve walking energetics. We conducted split-belt treadmill training in four periods with simultaneous motion and metabolic analyses in 10 women with unilateral hip OA. Using repeated measures ANOVA, we evaluated changes across each period, in step length asymmetry, mechanical energy exchange, and O2 rate. We also examined changes in hip range of motion and peak plantarflexor moment. We used Spearman correlations (rho) to assess the strength of associations between variables at baseline and after adaptation. We found that step length asymmetry and O2 rate decreased (p = 0.007, p p 2 rate (rho = 0.732, p = 0.016). Hip range of motion increased (p p = 0.004), indicating a potential mechanism. These findings suggest that reducing step length asymmetry by split-belt treadmill training could improve walking energetics in hip OA people