Postural control in patients with total hip replacement

The aim of this study was to investigate the balance of the standing position and the motor responses by means of dynamic posturography (DP) in patients affected by hip osteoarthritis and treated by total hip replacement (THR).

Data obtained from THR patients were compared with those of control adult groups ofage-matched subjects with normal hearing and no history of audio-vestibular symptoms. The statistical tests used were paired and unpaired Student's t-test. Significance was set for P<0.05. The study was carried out at the Department of Otorhinolaryngology and Department of Physiatrics and Rehabilitation of the A. Gemelli University Hospital of Rome (Italy). Twenty-three consecutive patients, without cochleo-vestibular or neurological pathologies (screened by accurate case-history), affected by hip osteoarthritis and treated by THR were enrolled. The main outcome measure were Sensory Organization Test (SOT), Motor control test (MCT) and Adaptation test (AT) obtained by means of Equi-Test Dynamic Posturography System by NeuroCom (Int. Inc., Clackamas, OR, USA).

When analysing the SOT and MCT, no statistically significant differences were observed between patients and controls. In the AT, the sway energy score decreased in the course of the test in an up and down perturbation both in healthy and in THR patients.

These data confirm a normal postural control and symmetrical responses in THR patients and confirm the absence of a detectable relationship between balance problems and fall risk. These results could be justified by an irrelevant role of intracapsular proprioceptors in maintaining balance. Moreover DP could be useful in osteo-articular diseases for understanding balance, evaluating surgical outcome and monitoring the rehabilitation program.