Takaaki Chin

Physical fitness of lower limb amputees.

Chin T, Sawamura S, Fujita H, Nakajima S, Oyabu H, Nagakura Y, Ojima I, Otsuka H, Nakagawa A: Physical fitness of lower limb amputees. Am J Phys Med Rehabil 2002;81:321–325. Objective To investigate the cardiorespiratory endurance of the physical fitness of amputees and able-bodied subjects of the same ages and to demonstrate deterioration of the physical fitness of the amputees. Design The test subjects were 31 amputees. Eighteen able-bodied persons served as controls. The incremental exercise test was performed to evaluate physical fitness. Sixteen of 31 amputees underwent endurance training by using a cycle ergometer driven by the intact leg, and their physical fitness was evaluated after completion of the endurance training program. Results The &OV0312;o2max, anaerobic threshold, and maximum workload for the amputees were significantly lower than those of the able-bodied group. The equivalent values for the endurance training group before exercise treatment were 18.0, 12.1, and 63.9, respectively. After exercise treatment, these values significantly increased, and there was no significant difference from the able-bodied subjects. Conclusions This study showed that the physical fitness of amputees was clearly lower than that of the able-bodied subjects and that the amputees were able to recover from a poorly conditioned status after endurance training.

VO2max as an indicator of prosthetic rehabilitation outcome after dysvascular amputation

In this study, independent ambulation of at least 100 metres with/without a cane was regarded as successful prosthetic rehabilitation. The subjects were classified into two groups according to this criterion at the time of discharge. The successful group attained this performance, the other group failed to reach this level. The successful group included 8 unilateral trans-femoral amputees aged 72.2 ± 2.1 years who underwent amputation at more than 70 years, and succeeded in walking with a prosthesis. The group which failed included 9 unilateral trans-femoral amputees aged 63.2 ± 2.1 years who underwent amputation between the ages of 60–65 years, and had great difficulty in walking with a prosthesis. The purpose of this research was to investigate whether or not %VO2max as an indicator of physical fitness is useful in predicting prosthetic rehabilitation outcome after dysvascular amputation by comparing these two groups. Evaluation of physical fitness was conducted before the subjects began prosthetic rehabilitation. Information about each subject before fitting with a prosthesis was collected retrospectively from clinical charts made during admission. The successful group were capable of strenuous exercise, reaching the intensity of 50% V02max or more. In the group which failed only one reached the intensity of 50% V02max. The working capacity of 50% VO2max or greater would appear to be a valid initial guideline level of physical fitness at which an amputee can expect to succeed in walking with a prosthesis. Apart from physical fitness, a lesser number of comorbidity, good ability to stand on the remaining leg, and a strong will to walk were found to be important factors contributing to successful prosthetic rehabilitation. This study also showed that age alone was not an important factor.

The efficacy of physiological cost index (PCI) measurement of a subject walking with an Intelligent Prosthesis

The Intelligent Prosthesis may enable lower limb amputees to walk faster than with conventionally damped prostheses and as a result the physical burden involved in walking could be expected to be considerably higher. The aim of this study was to investigate whether or not physiological cost index (PCI) is applicable as an indicator for monitoring the amount of exercise load involved in walking with an Intelligent Prosthesis. The method used a treadmill and monitored gas exchange, ventilation and heart rate (HR) in 6 unilateral trans-femoral amputees, ages were between 17 and 34 with an average age of 23.1. The exercise protocol was as follows: for each person speeds at 0.8 times the subjects free level walking speed, 1.0 times, 1.2 times, 1.4 times and for some 1.6 times were applied. In each case the index of correlation between PCI and oxygen uptake in response to walking speed was calculated. A significant correlation was observed between PCI and oxygen uptake in each case, which indicated a close relationship between cardiopulmonary factor and energy consumption while walking. These results suggest that PCI is of use as an indicator for ascertaining the amount of exercise load in walking with an Intelligent Prosthesis.

The efficacy of the one-leg cycling test for determining the anaerobic threshold (AT) of lower limb amputees

The aim of this study was to investigate whether or not the one-leg cycling test driven by the subjects sound leg as the exercise load method is an applicable method for determining the anaerobic threshold (AT) of lower limb amputees. To evaluate physical fitness, a graded exercise test that monitored gas exchange, ventilation and heart rate (HR) was performed in 51 unilateral lower limb amputees. AT was successfully measured for 42 out of 51 subjects, an 82.3% success rate. The average AT was 12.7 ± 2.2 ml/kg/min, and the average HR at AT point was 117.7 ± 16.2 beats/min. The average peak oxygen uptake was 20.1 ± 5.6 ml/kg/min, and the average peak HR was 145.1 ± 22.4 beats/min. The peak HR exceeded the HR at AT by an average 27.4 beats/min, which indicates that a comparatively intense exercise load above the AT level is possible. The average AT was 40.9% of the predicted maximum oxygen uptake, which seems reasonable when compared to the reports of other researchers. These results suggested that the one-leg cycling test driven by the sound limb is of use as a method for determining the AT of lower limb amputees.

Effect of physical fitness on prosthetic ambulation in elderly amputees.

Chin T, Sawamura S, Shiba R: Effect of physical fitness on prosthetic ambulation in elderly amputees. Am J Phys Med Rehabil 2006;85:992–996. Objective:To evaluate the physical fitness and prosthetic ambulation ability of high-level (hip disarticulation, transfemoral) lower-limb amputees aged 60 and above, and to investigate the level of fitness required for successful prosthetic ambulation. Design:The test subjects were 49 amputees aged 60 and above. Subjects were permitted to use any necessary ambulatory aids and were asked to walk at their most comfortable walking speed for evaluation of prosthetic ambulation ability. An incremental exercise test was performed to evaluate physical fitness. Results:The average %VO2max value for the successful user group was 64.4%, and the average %VO2max value for the failed user group was 44.8%, a statistically significant difference (P < 0.01). Of the amputees with %VO2max ≥50, 93.7% were in the successful user group. Of the amputees with %VO2max <50, only 23.5% were in the successful user group. Conclusion:This study showed that the ability to sustain an exercise intensity of ≥50%VO2max can be regarded as a guideline value for the level of fitness required for successful prosthetic ambulation in elderly amputees.

Energy consumption during prosthetic walking and wheelchair locomotion by elderly hip disarticulation amputees.

Chin T, Oyabu H, Maeda Y, Takase I, Machida K: Energy consumption during prosthetic walking and wheelchair locomotion by elderly hip disarticulation amputees. Am J Phys Med Rehabil 2009;88:399–403. Objective:To investigate the differences in energy consumption by patients with hip disarticulation between prosthetic walking and wheelchair locomotion. Design:The subjects consisted of seven amputees, all older than 60, with unilateral hip disarticulation. Energy consumption when walking with prosthesis and when propelling a wheelchair, each at the respective comfortable movement speed, was measured by means of a portable telemetric system. Results:The average comfortable movement speed for prosthetic walking was 30.5 m/min, which was much slower than the 63.1 m/min average for wheelchair locomotion (P < 0.01). The average oxygen cost value for prosthetic walking was 0.639 ml/kg/m, and the average for wheelchair locomotion was 0.175 ml/kg/m, indicating that oxygen cost was significantly higher for prosthetic walking than for wheelchair locomotion (P < 0.01). Conclusions:The results of this research clearly showed that the efficiency of prosthetic walking for elderly hip disarticulation amputees was very low. When the subject is judged not to be a candidate for practical prosthetic walking after a careful multidisciplinary evaluation, wheelchair locomotion may be an alternative to prosthetic walking as a realistic goal.

Successful prosthetic fitting of elderly trans-femoral amputees with Intelligent Prosthesis (IP): a clinical pilot study.

The objective of the study was to compare the Physiological Cost Index (PCI) and walking speeds during walking in two elderly trans-femoral amputees when using knee joints which emphasized stance-phase control and Intelligent Prosthesis, and to provide some bibliographic observations on factors behind their success in improving walking ability despite their age. It was a within-subject comparison. The subjects comprised two patients, aged 75 and 81 years, with trans-femoral amputations. On admission subjects were subjected to one-leg cycling test driven by their non-amputated leg in order to evaluate their physical fitness. The PCI and speed during free level walking was measured using their original knee joints. The knee joint was then changed to IP and the subjects received prosthetic walking training programs using it. The PCI and speed measurements were taken during free level walking on completion of the training program. Both subjects showed a decreased PCI and an increased free walking speed when using the IP compared with the original knee joints. It was concluded that elderly trans-femoral amputees who are judged to be in good physical condition appear to merit the application of knee joints with superior swing phase control functions such as IP, regardless of their age.