Functional Gait Features in Standard Individuals and Patients After Total Hip Arthroplasty

Abstract

Functional gait asymmetry can be quantified using vertical ground reaction forces (vGRF). Although gait characteristics in healthy and post-total hip arthroplasty (THA) populations have been separately described, direct comparisons between young adults, older adults without THA, and uncomplicated THA patients remain limited. This study aimed to establish normative vGRF reference values and assess differences in gait loading patterns across these groups. vGRF data were collected from 287 participants using an instrumented treadmill: adults aged <50 years ( n =178), adults aged ≥50 years without THA ( n =34), and THA patients ( n =75). All THAs were performed by the senior author using a posterior approach. Participants walked on level ground at 4-7 km/h and on 5-15% inclines at 4 km/h. vGRF values were normalized to body weight. Weight acceptance, midstance, push-off, and symmetry indices were analyzed using paired and unpaired t-tests (α=0.05). Increasing walking speed increased weight acceptance and push-off forces, while reducing midstance forces across all groups. Compared with older and THA participants, the <50 group demonstrated significantly lower weight acceptance at 6 km/h ( p= 0.03, p= 0.04) and 7 km/h ( p= 0.0003, p= 0.001). Push-off forces were consistently greater in younger adults, whereas midstance differences were inconsistent. Symmetry indices increased with both speed and incline, indicating greater asymmetry during more demanding walking conditions. These findings provide normative vGRF reference ranges for healthy and post-THA populations. Age was associated with reduced concentric and increased eccentric loading patterns, supporting the use of vGRF analysis for objective assessment of gait asymmetry and postoperative functional recovery following THA. These data may assist clinicians in interpreting postoperative gait performance, identifying persistent asymmetry, and benchmarking rehabilitation outcomes against age-matched controls during routine functional assessment after hip arthroplasty in practice.