When testing one leg standing position on the balance platform, the patients were asked to raise one foot half the level of the calf of the supporting leg but not touching the stance limb. The trial lasted for 5 s. The test was stopped when the subject used his arms (touched the handrail) or used the raised foot (touched the floor). Usually after 2 failed attempts or fear of falling down procedure was stopped and results was not recording. The results of the patients after THR when standing on the operated (1 O) and non operated (1 N) leg were compared to the index denoting the mean results of the control group (1 C).