The purpose of the study was to simulate skiing conditions in the laboratory and to analyse flexion in a ski boot, ankle and knee joints for a skier with a special above-knee prosthesis for alpine skiing.
Considering the initial flexion of the knee (40[degrees] in the prosthesis, 50.6 [+ or -] 5.9[degrees] in the intact leg and 35.4[+ or -]6.5[degrees] in the control group) and the associated RoMs, it can be estimated that the total flexion in the knee was near 85[degrees] in all cases.
This study presents the results of measurements of the flexion in ski boot, ankle and knee joints in simulations of different regimes of skiing with a special above-knee prosthesis with a multi-axis knee joint, which has been successfully used for actual skiing.
Smaller flexion in the ski boot on the side of the prosthetic leg can be attributed to the construction of the bottom part of the artificial limb, which does not allow flexion between the lower leg and the prosthetic foot (Reichel et al., 2008).
Despite the rigid connection between the lower part of the prosthesis and the prosthetic foot, virtual flexion in the ankle has been achieved.
At 60 degrees knee flexion, the differences of the tibial displacements for non-braced and braced conditions were only significant at 120 N and 150 N (p < 0.05).
If the knee flexion angle is less than 20[degrees] or the femoral sulcus angle is abnormally wide, the restraints will not be sufficient and the patellar mobility might produce test errors (Kupper et al., 2006).
The standard knee configuration for arthrometric diagnosis of knee instability, however, is the flexion range of 20[degrees] to 35[degrees] (Branch et al., 1988; Bach et al., 1995; Heydari et al., 2008).
However, considering the fact that the stability examination has been often limited to up to 30 degrees knee flexion in previous studies, it remains a question that whether this improvement is limited to knee extension and early flexion angles, or it is maintained during mid and deep flexion.
Another interesting finding of the present study was the pattern of variation of the knee stability with flexion angle following bracing.