Gait mechanics are influenced by quadriceps strength, age, and sex after total knee arthroplasty.

Although most patients are satisfied with outcomes after total knee arthroplasty (TKA), many retain preoperative altered gait mechanics. Identifying patient characteristics associated with gait mechanics will improve rehabilitation strategies and enhance our understanding of movement disorders. Therefore, the purpose of this study was to identify which patient characteristics are related to gait mechanics in the surgical limb during walking post-TKA. Patient characteristics included age, body mass, sex, quadriceps strength, self-reported function, and knee pain. General linear regression was used to compare patient characteristics associated with gait mechanics, after controlling for gait speed, functional capacity and time from surgery. We tested 191 patients cross-sectionally at 6-24 months after primary, unilateral TKA. Quadriceps weakness in the surgical limb was associated with less peak vertical ground reaction force (PvGRF) (β = .245, p = .044), knee extension moment (β = .283, p = .049), and knee extension excursion (β = .298, p = .038). Older age (β = .168, p = .050) was associated with less PvGRF. Quadriceps strength in the nonsurgical limb (β = -.357, p = .021) was associated with greater knee extension excursion in the surgical limb. Females with TKA (β = -.276, p = .007) had less knee flexion excursion compared to males. Faster gait speed was also associated with greater PvGRF (β = .585, p < .001), knee extensor moment (β = .481, p < .001), and knee flexion excursion (β = .318, p < .001). Statement of Clinical Significance: This study showed quadriceps weakness, slower gait speed, older age and being female were related to altered gait mechanics post-TKA. These findings will help clinicians better educate patients and develop targeted interventions for improving care in patients post-TKA.