A pilot study to test the influence of specific prosthetic features in preventing trans-tibial amputees from walking like able-bodied subjects.

The purpose of this pilot investigation was to develop a method to test the influence of specific prosthetic features in preventing trans-tibial amputees from walking like able-bodied subjects. An able-bodied subject was fitted with a patellar-tendon-bearing orthosis incorporating several features of an amputee's prosthesis. Kinetic, kinematic and metabolic data were collected as features were systematically removed from the orthosis. While wearing the orthosis the gait of the able-bodied subject closely simulated trans-tibial amputee gait kinematically, kinetically and metabolically. Although it was obvious that the various prosthetic features influenced the kinetics and kinematics of gait, they were difficult to quantify with only a single subject. However, the two features which appeared to have the largest influence in preventing trans-tibial amputees from walking like able-bodied subjects were patellar tendon loading and a solid ankle.

A comparison of oxygen consumption during walking between children with and without below-knee amputations.

BACKGROUND AND PURPOSE: Differences, if any, in energy costs during walking of children with below-knee amputations (BKAs) and those of children without amputations have not been quantified. The purpose of this investigation was to compare measures of heart rate and oxygen consumption during walking (1) between children with BKAs and long residual limbs and children with BKAs and short residual limbs and (2) between children with BKAs and children without amputations. SUBJECTS: Twenty-four children volunteered to participate in this investigation. Ten of the children, aged 6 to 18 years, had BKAs, and 14 children, aged 6 to 17 years, were without amputations. METHODS: The subjects walked for 2 minutes at each of the following four speeds: (1) chosen walking speed (CWS), (2) 20% below CWS, (3) 20% above CWS, and (4) fixed speed of 1.2 m/s. Heart rate and oxygen uptake were measured at each speed. RESULTS: The results indicated (1) that there were no significant differences between children with long residual limbs and those with short residual limbs; (2) that oxygen consumption was 15% greater for children with BKAs compared with children without amputations; (3) that there were no differences in heart rates between children without amputations and those with BKAs or within children with BKAs; and (4) that children with BKAs did not choose speeds different from their peers without amputations, regardless of stump length. CONCLUSION AND DISCUSSION: The results indicated that children with BKAs had higher energy needs for walking than children who had no amputation. Whether the increased energy needs prevent or inhibit children with BKAs from having a lifestyle comparable to that of children without amputations is currently unknown and warrants further research. [Herbert LM, Engsberg JR, Tedford KG, Grimston SK. A comparison of oxygen consumption during walking between children with and without below-knee amputations.

Normative ground reaction force data for able-bodied and trans-tibial amputee children during running.

The purpose of this investigation was to develop normative ground reaction force data for able-bodied (AB) and trans-tibial amputee (TTA) children during running. Two hundred AB (mean age 9.4 years, range 7-12) and 21 TTA (mean age 11.1 years, range 5-17) children ran (2.2 m/s +/- 10%) over a force platform. Ground reaction force data were normalized, averaged within groups and plotted to produce force-time curves characterizing the different leg types (i.e. able-bodied, non-prosthetic and prosthetic). In addition, discrete variables characterizing the leg type differences were determined. One way ANOVA determined significant differences between variables and a TukeyB Post Hoc analysis defined which variables were significantly different (p < 0.05). Results generally indicated differences between the three leg types with the non-prosthetic leg indicating greater forces than the prosthetic and AB legs. The results of this investigation provide normative ground reaction force data for both AB and TTA children during running and can be used for comparison with other groups of children.

Normative ground reaction force data for able-bodied and below-knee-amputee children during walking.

We determined normative ground reaction force data for able-bodied (AB) and below-knee-amputee (BKA) children during walking. Twenty-two BKA and 225 able-bodied children walked over two adjacent force platforms. Average normalized force-time curves were determined for legs of the children for subjective comparisons, and discrete variables were determined for statistical comparisons. No significant differences existed between (a) right and left legs, (b) gender, and (c) age for the AB children. BKA children had an asymmetrical gait pattern with a dominant role of the nonprosthetic limb. This dominant role was related to a greater rate of loading, magnitude of loading, impulse, and time of loading as compared with prosthetic limbs and with the limbs of AB children.

Weight distribution of below-knee amputee and able-bodied children during standing.

The purpose of this investigation was to compare weight distributions of a relatively large number of below-knee (BK) amputee and able-bodied children during two different standing positions. Twenty-one BK amputees and 200 able-bodied children volunteered as subjects for this investigation. Each child stood on a pressure plate and three sets of trial data were collected. One set of trial data was collected with both feet together on the pressure plate and two were collected with feet placed 20cm apart. The total force applied by each foot to the pressure plate was normalised by dividing by subject weight to yield foot force to body weight ratios. Data were separated into forefoot and rearfoot areas, force for the forefoot area was then calculated and normalised by dividing by total foot force to yield forefoot to whole-foot force ratios. Ratios for the two foot placement conditions and for non-prosthetic, prosthetic, dominant, and non-dominant feet were compared using paired t-tests (p < 0.05). Results indicated that: 1) BK amputee children placed more weight on their non-prosthetic limb than their prosthetic limb, yet this was not different from able-bodied children in respect of weight distribution between dominant and non-dominant limbs; 2) approximately 90% of the load on the prosthetic foot was placed on the forefoot; and 3) the load on the non-prosthetic foot was evenly distributed between the forefoot and rearfoot like that of able-bodied children. It was concluded that except for substantially more weight on the forefoot of the prosthetic leg BK amputee children stood in the same way as able-bodied children.

Center of mass location and segment angular orientation of below-knee-amputee and able-bodied children during walking.

This investigation compared the center of mass (COM) locations and segment angular orientations of the gait of below-knee-amputee (BKA) children to those of able-bodied (AB) children. Eleven AB children (mean age, 8.4 years) and three BKA children (mean age, 7.5 years) volunteered to participate as subjects. Film data (100 frames per second) of a typical walking stride, were collected for the children during four experimental sessions held at six-month intervals. Two 16mm cameras were used to obtain frontal and lateral views of the subjects. The same approximate rate of walking (1.2m/s +/- 10%) was enforced for all testing sessions and at least three trials of data were collected for each subject during each session. Segmental endpoints of each subject from the film of each camera were digitized and the direct linear transformation (DLT) method was used to obtain three-dimensional segmental location-time data for a complete stride. These data were then used to determine whole body COM locations and angular orientations for the segments. Discrete values describing normalized locations at touchdown, midsupport, and takeoff were determined for whole body COM and the angular orientation of the trunk, thighs, and legs. In the sagittal plane the COM was lower and more anterior for the BKA children when compared to that of the AB children. This was primarily due to the greater forward flexion of the trunk.(ABSTRACT TRUNCATED AT 250 WORDS)