OBJECTIVETo determine how selected gait parameters may change as a result of total hip arthroplasty (THA).

METHODSFrom February 2006 to February 2007 the study was performed on 53 osteonecrosis of femoral head subjects prior to and 6 weeks, 3, 6 and 12 months after total hip arthroplasty surgery. Gait analysis was performed using the three-dimensional Infrared-based system (Dalian Dong Fang Xin Rui Company, China). Kinematic data were recorded for the lower limb. The results obtained from the osteonecrosis of femoral head subjects were compared with those of 40 individuals without osteonecrosis. Using a three-dimensional motion analyzer, the following were measured: (1) gait speed, stride length, cadence; (2) step length, stride width; (3) standing phase time, walking phase time; (4) gait cycle time, Joint movement angular.

RESULTSCompared with persons before total hip arthroplasty, THA patients showed significantly increased gait speed, gait frequency, step length and affected limb stand phase (P < 0.01). Angle timetable: preoperative hip-maximum flexion was 15 degrees, post-extension was 8 degrees, knee-maximum flexion was 70 degrees, ankle-maximum flexion was 15 degrees. Postop hip-maximum flexion was 27, post-extension was 17 degrees, knee-maximum flexion was 50 degrees, ankle-maximum flexion was 14 degrees; parameters of hip, knee between preoperative and postoperative was significance (P < 0.01).

CONCLUSIONThese results suggest that 3-D gait analysis before and after total hip arthroplasty can evaluate precisely hip vitodynamics variation.