Gait analysis in hip and knee surgery

An objective method of gait analysis is presented. It is characterized by: Two five metre long force plates, thus giving possibility of registering several consecutive steps for each foot. Additional equipment has been provided and the whole system has been computerized. Reliability was found to be great and reproducibility good. The method has been used in registering gait variables like time and distance variables, vertical ground reaction forces and sagittal angular movement of hips and knees and these have been correlated to clinical findings. The method has been used in analysis of individuals after pelvic resections preserving the lower extremity, before and after total hip replacement, after total knee replacement and in comparison of two different methods for THR, one cemented (Charnley) and one non-cemented (HP Garches).

The gait variables most sensitive in giving evidence of a change in a patient's ambulatory status were maximal vertical force and average velocity followed by step rate, single limb support, and weight acceptance - all measurements of weight bearing capacity. Maximal vertical force and average velocity were the only gait variables that could distinguish the one type of THR from the other. In correlations between the clinical impression of gait function and its objective registration the strongest correlations were found in maximal vertical force and average velocity. Thus, gait analysis is considered a useful tool in the evaluation of locomotor function after surgical procedures.