Pressure distribution at the stump/socket interface in transtibial amputees during walking on stairs, slope and non-flat road

Background Studies examining the stump/socket interface stresses have been restricted to unsupported stance and natural gait, i.e. walking at a comfortable speed on flat and straight walkway. However, the pressure behaviour as to the interface in unilateral transtibial amputees during walking on stairs, slope and non-flat road is unclear. Methods Pressure distribution changes at multiple points, expressed as mean peak stump/socket interface pressure, mean pressure level over 90% of peak pressure, time in which pressure exceeded 90% of peak pressure and time–pressure integral at the period of sustained sub-maximal load, were measured during natural ambulating and walking on stairs, slope and non-flat road. Findings Compared with natural gait, the mean peak pressure and sustained sub-maximal load increase notably over the patellar tendon during walking on stairs and non-flat road, and however decrease or change insignificantly at the patellar tendon on slope and over other measured areas in all conditions; moreover the time period of sustained sub-maximal load changes remarkably, except over the patellar tendon during walking up slope and over the popliteal area on non-flat road; finally, the time–pressure integral in the time period of sustained sub-maximal load changes considerably, except at the patellar tendon during walking up slope. Interpretation The pressure characteristics during natural ambulating seem not to be highly predictive of what occurs in the conditions of walking on stairs, slope and non-flat road, which leads to significant increase in amplitude domain of tissue loading only at the patellar tendon, and however to remarkable changes in temporal sequences of tissue (un-)loading almost in all measured regions.