Abstract
Abstract
Objectives
The objective of this proof of concept study was to explore whether some total hip arthroplasty (THA) patients with well-functioning implants achieve normal sagittal plane hip kinematics during walking gait.
Methods
Sagittal plane hip kinematics were recorded in eleven people with well-functioning THA (71 ± 8 years, Oxford Hip Score = 46 ± 3) and ten healthy controls (61 ± 5 years) using a three-dimensional motion capture system as they walked over-ground at a self-selected velocity. THA patients were classified as high- or low-functioning (HF and LF, respectively) depending on whether the mean absolute difference between their sagittal plane hip kinematics was within one standard deviation of the control group (5.4°) or not. Hedge's g effect size was used to compare the magnitude of the difference from the control group for the HF and LF THA groups.
Results
Five THA patients were identified as HF and 6 as LF. The mean absolute difference in sagittal plane hip kinematics between the THA groups and the control group was on average 6.2° larger for the LF THA patients compared to the HF, with this difference associated with a large effect size (g = 1.84).
Conclusions
The findings of this study challenge the findings of previous work which suggests THA patients do not achieve normal sagittal plane hip kinematics. Five patients were classified as HR and achieved motion patterns that were on average within the variance of the asymptomatic control group, suggesting normative sagittal plane hip kinematics. Understanding why some THA patients achieve motion patterns more comparable to healthy controls than others would help to develop means of maximising functional recovery, and potentially enhance both patient quality of life and implant survivorship through more normal loading of the implant.
