Postural Balance During Quiet Standing in Patients With Total Hip Arthroplasty With Large Diameter Femoral Head and Surface Replacement Arthroplasty

Abstract 

Nantel J, Termoz N, Ganapathi M, Vendittoli P-A, Lavigne M, Prince F. Postural balance during quiet standing in patients with total hip arthroplasty with large diameter femoral head and surface replacement arthroplasty.

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.

Key Words: Arthroplasty, Biomechanics, Hip, Posture, Rehabilitation

List of Abbreviations: COM, center of mass, COP, center of pressure, RMS, root-mean-square, SRA, surface hip arthroplasty, THA, total hip arthroplasty