Postural Balance during Quiet Standing in Patients with Total Hip Arthroplasty with Large Diameter Femoral Head and Surface Replacement Arthroplasty
Résumé
OBJECTIVE: To compare postural balance between patients who have had either a large diameter head total hip arthroplasty or surface replacement arthroplasty.
DESIGN: Observational study.
SETTING: Outpatient biomechanical laboratory.
PARTICIPANTS: Two groups of 14 patients with surface replacement or large diameter head total hip arthroplasties recruited from a larger randomized study and 14 control subjects.
INTERVENTIONS: Not applicable.
MAIN OUTCOME MEASURES: Postural balance during quiet standing in dual and one-leg stance (operated leg), hip abductor muscle strength, clinical outcomes, and radiographic analyses were compared between groups.
RESULTS: Compared to the control group, patients in both groups showed smaller center of pressure displacement amplitude in the medial-lateral direction in dual stance. Patients with large diameter head total hip arthroplasty showed lower hip abductor muscle strength compared to control subjects. There was statistical difference between the 2 patient groups in biomechanical reconstruction of the hip. Despite these differences, there was no significant difference in the ability to complete the one-leg stance task between the 3 groups.
CONCLUSIONS: The muscular strength in the operated limb could be mainly responsible for the lower center of pressure displacement amplitude compared to control subjects. However, the ability to complete the one-leg stance demonstrates that patients do not fear to load the hip prosthesis when needed. The large diameter femoral head may be a major mechanical factor contributing to these results.