Effects of a sensory-motor exercise program for older adults with osteoarthritis or prosthesis of the hip using measurements made by the Posturomed oscillatory platform.

OBJECTIVES: To assess changes in balance capacities after a 12-week sensory-motor training program for older adults with osteoarthritis or prosthesis of the hip. BACKGROUND: Sensory-motor training is recommended to help aging adults with osteoarthritis maintain activity, avoid injurious falls, and improve functioning. Up to now, however, there has been no standard training protocol for sensory-motor training. METHODS AND MEASURES: Thirty-five participants in a hip exercise group who had a mean age of 58 years (SD 12) were quasi-randomized into a training group (TG) and a control group (CG) by the month they applied for the Hip School program. The TG performed balance exercises using balance pads and received Hip School training once a week. The CG did not receive any training intervention. Balance was measured by recording center-of-pressure excursion while participants were in 1-legged stance on the oscillatory Posturomed platform. Outcome measures were the total path of center of pressure on the platform during balance recovery and the percentage of failed attempts. RESULTS: The TG had a lower percentage of failed attempts (TG 5%, CG 18%, P = .001) and required fewer balance recovery movements to maintain balance (TG: mean [SD] measurement is 59 [36] mm; CG: 96 [68] mm, P = .036] after completing the 12-week training program. After the training period, participants in the TG compensated better for perturbations in the nondisplaced medial-lateral (ML) direction (pretest [SD] measurement was 48 [18] mm; posttest, 36 [14] mm; P= .001]. CONCLUSIONS: Participants could successfully cope with more disturbances and improved their reactions to sudden displacements after training intervention. This exercise setting improves balance abilities and should be included in Hip School programs for patients with osteoarthritis.

Pelvic tilt makes acetabular cup navigation inaccurate.

BACKGROUND: Modern navigation techniques allow precise positioning of the acetabular cup relative to the anterior pelvic plane. Variations in pelvic tilt will affect the resulting spatial orientation of the cup. METHODS: We measured pelvic tilt in 30 volunteers with an inclinometer combined with an ultrasonographic position measurement system. A mathematical algorithm was developed to calculate the resulting cup position measured on standard radiographs, depending on pelvic tilt. RESULTS: Average pelvic tilt at rest was -4 degrees in the lying position and -8 degrees in the standing position, and ranged from -27 degrees to +3 degrees. Pelvic reclination of 1 degree will lead to functional anteversion of the cup of approximately 0.7 degree. INTERPRETATION: Pelvic tilt makes navigation systems referring to the anterior plane inaccurate.