Influences of knee osteoarthritis and walking difficulty on knee kinematics and kinetics

Abstract

Background: Self-reported walking difficulty is a problem among patients with knee osteoarthritis (OA), however, these patients have never been studied as a subgroup population.

Objective: The purpose of this study is to examine known knee OA gait mechanics among those with knee OA, with (Diff) and without (NoDiff) self-reported walking difficulty, as compared to age- and sex-matched controls without knee OA.

Methods: A total of 39 subjects in three groups of 13 individuals walked at a controlled gait speed during instrumented gait analysis. Gait mechanics were compared between a priori determined groups using the independent t-test.

Results: The results of the study found that among those with knee OA, knee excursion angles were not significantly different between the Diff and NoDiff groups. Whereas, external knee moments were significantly different between the Diff and NoDiff groups but not between the NoDiff and the control groups. The lack of difference between the NoDiff and control groups were especially interesting because of the moderate to severe OA in the NoDiff group. Therefore, the findings of this study suggest the importance of considering self-reported walking difficulty among those with knee OA. Perhaps patients with knee OA-related walking difficulties use alternative gait parameters that may need to be clinically addressed. Strengths of the study included a matched design and controlled walking speed, whereas limitations were the small sample size and cross-sectional design.

Conclusions: Given the relationships found among self-reported walking difficulty, OA presence, and gait parameters, addressing gait parameters specifically related to walking difficulty may be indicated in this sub-group knee OA population.

Keywords: Biomechanics; Gait; Knee osteoarthritis; Walking difficulty.

Fig. 1.

Average Knee Excursion Angle. Average flexion (Panel A), extension (Panel B), and adduction (Panel C) excursion angles for the Difficult (Diff): □ Not Difficult (NoDiff); and Control groups. Greater positive values represent larger knee excursion angles. Top whisker represents the highest quartile, box represents the 2nd and 3rd quartile separated by the median, and bottom whisker represents the lowest quartile. (*) Significant group differences, p ≤ 0.05.

Fig. 2.

Average knee moments. Peak knee flexion moment (Panel A), extension moment (Panel B), and adduction moments (Panel C and D) for the Difficult (Diff); □ Not Difficult (NoDiff); and Control groups. Positive values represent larger knee moments normalized by body weight times height. Top whisker represents the highest quartile, box represents the 2nd and 3rd quartiles separated by the median, and bottom whisker represents the lowest quartile. (*) Significant group differences, p ≤ 0.05.

Fig. 3.

Radiographic OA severity versus knee adduction moment. Subjects’ OA severity, or Kellgren-Lawrence (KL) score, versus first peak knee adduction moment normalized by body weight times height for each subject in the Difficult (Diff) and ● Not Difficult (NoDiff) group and the associated relationships for the Diff and NoDiff groups.