The C-Leg ® (Otto Bock, Duderstadt, Germany) is a microprocessor-controlled prosthetic knee that may enhance amputee gait. This intrasubject randomized study compared the gait biomechanics of transfemoral amputees wearing the C-Leg ® with those wearing a common noncomputerized prosthesis, the Mauch SNS ® (Ossur, Reykjavik, Iceland). After subjects had a 3-month acclimation period with each prosthetic knee, typical gait biomechanical data were collected in a gait laboratory. At a controlled walking speed (CWS), peak swing phase knee-flexion angle decreased for the C-Leg ® group compared with the Mauch SNS ® group (55.2° ± 6.5° vs 64.41° ± 5.8°, respectively; p = 0.005); the C-Leg ® group was similar to control subjects' peak swing knee-flexion angle (56.0° ± 3.4°). Stance knee-flexion moment increased for the C-Leg ® group compared with the Mauch SNS ® group (0.142 ± 0.05 vs 0.067 ± 0.07 N•m, respectively; p = 0.01), but remained significantly reduced compared with control subjects (0.477 ± 0.1 N•m). Prosthetic limb step length at CWS was less for the C-Leg ® group compared with the Mauch SNS ® group (0.66 ± 0.04 vs 0.70 ± 0.06 m, respectively; p = 0.005), which resulted in increased symmetry between limbs for the C-Leg ® group. Subjects also walked faster with the C-Leg ® versus the Mauch SNS ® (1.30 ± 0.1 vs 1.21 ± 0.1 m/s, respectively; p = 0.004). The C-Leg ® prosthetic limb vertical ground reaction force decreased compared with the Mauch SNS ® (96.3 ± 4.7 vs 100.3 ± 7.5 % body weight, respectively; p = 0.0092).

The movement of the center of mass (COM) during human walking has been hypothesized to follow a sinusoidal pattern in the vertical and mediolateral directions. The vertical COM displacement has been shown to increase with velocity, but little is known about the mediolateral movement of the COM. In our evaluation of the mediolateral COM displacement at several walking speeds, 10 normal subjects walked at their self-selected speed and then at 0.7, 1.0, 1.2, and 1.6 m/s in random order. We calculated COM location from a 15segment, full-body kinematic model using segmental analysis. Mediolateral COM displacement was 6.99 +/-1.34 cm at the slowest walking speed and decreased to 3.85 +/-1.41 cm at the fastest speed (p < 0.05). Vertical COM excursion increased from 2.74 +/-0.52 at the slowest speed to 4.83 +/-0.92 at the fastest speed (p < 0.05). The data suggest that the relationship between the vertical and mediolateral COM excursions changes substantially with walking speed. Clinicians who use observational gait analysis to assess walking problems should be aware that even normal individuals show significant mediolateral COM displacement at slow speeds. Excessive vertical COM displacement that is obvious at moderate walking speeds may be masked at slow walking speeds.Abbreviations: ANOVA = analysis of variance, COM = center of mass, fps = frames per second, SS = self-selected.

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Abstract-Much is known about human walking, but it is not known how walking is used during typical activities. Since improving walking ability is a key goal in many surgical, pharmacological, and physiotherapeutic interventions, understanding typical community mobility demands regarding the length of walking bouts, the number of sequential steps frequently performed, and the duration of common nonwalking (rest) behavior seems prudent. This study documents the gait of daily living in 10 nondisabled employed adults to define walking bout duration, sequential step counts, and length of rest periods over a 2-week period. Subjects wore a StepWatch™ Activity Monitor (OrthoCare Innovations; Mountlake Terrace, Washington) that counted steps in each 10-second time window. Custom code summed sequential steps, periods of walking behavior (bouts), and periods without steps (rest). Sixty percent of all walking bouts lasted just 30 seconds or less; a 2-minute walking bout was just 1 percent of total walking bouts. Forty percent of all walking bouts were less than 12 steps in a row, and 75 percent of all walking bouts were less than 40 steps in a row. Rest periods were predominantly very short, with half of all rests periods lasting 20 seconds or less. The community mobility demand for nondisabled employed adults appears to involve frequent short-duration walking behavior with low numbers of sequential steps strung together and many shortduration nonwalking (rest) behaviors.

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There is not a clear clinical recommendation for the determination of prosthetic candidacy. Guidelines do not delineate which member(s) of the multidisciplinary team are responsible for prosthetic candidacy decisions and which factors will best predict a positive outcome. Also not clearly addressed is a patient-centered decision-making role. In a previous systematic review (SR), Sansam et al. reported on the prediction of walking ability following lower limb amputation using literature up to 2007. The search strategy was designed from the previous Sansam SR as an update of previously valuable predictive factors of prosthetic candidacy. An electronic literature search was executed from August 8, 2007, to December 31, 2015, using MEDLINE (Pubmed), Embase, The Cumulative Index to Nursing and Allied Health Literature (CINAHL) (Ovid), and Cochrane. A total of 319 studies were identified through the electronic search. Of these, 298 were eliminated, leaving a total of 21 for full evaluation. Conclusions from this updated study are drawn from a total recruited sample (n) of 15,207 subjects. A total of 12,410 subjects completed the respective studies (18% attrition). This updated study increases the size of the original Sansam et al. report by including 137% more subjects for a total of 21,490 between the two articles Etiology, physical fitness, pre-amputation living status, amputation level, age, physical fitness, and comorbidities are included as moderate to strongly supported predictive factors of prosthetic candidacy. These factors are supported in an earlier literature review and should be strongly considered in a complete history and physical examination by a multidisciplinary team. Predictive factors should be part of the patient’s healthcare record.

The effect of walking speed on peak plantar pressure varied with plantar region. To achieve more robust peak plantar pressure measurements, walking speed should be controlled. Determining the normal plantar function across a range of speeds can aid in the development of shoes and foot orthoses. The pressure-speed relationships presented in this study can be used as a comparative tool for evaluating the efficacy of clinical interventions for pressure reduction, especially when walking speed changes may confound the outcomes.