Military Medicine International Journal of amsus raising the bar: extremity trauma care guest editors
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was to determine the presence of gait deviations and their prevalence in a group of service members with a TTA. METHODS Subjects
Data from 40 AB males and 16 male individuals with a TTA are presented in this study. The AB group included service members between the ages of 18 and 45 years with no pain at time of data collection and no history of lower extremity injury requiring surgery. The TTA group included service members between the ages of 18 and 45 years who used an energy-storing-and-returning ankle-foot prosthesis, were able to ambulate without an assistive device, and had been ambu- lating for approximately 4 months. In order to detect devia- tions not associated with acute pain, the TTA group could not have pain of greater than 4 out of 10 anywhere on their body at the time of data collection. The TTA group was a convenience sample of patients within a military treatment facility who met the inclusion criteria without bias toward their mechanism of injury or level of physical fitness. All participants provided written informed consent before partic- ipating in this institutional review board –approved study. Procedures Participants underwent a biomechanical gait assessment on level ground at a prede fined walking speed scaled to leg length using a Froude number 24 of 0.16. A full-body, six- degree-of-freedom marker set comprised of 57 retrore flective
markers was placed on 13 body segments. 25 A 26 camera motion capture system (Motion Analysis Corp., Santa Rosa, California) recorded marker trajectories as participants walked across a 10-m walkway embedded with eight AMTI force plates (AMTI, Inc., Watertown, Massachusetts) operating at 1,200 Hz. Temporal spatial, kinematic, and kinetic data were normalized to 100% step cycle using Visual 3D (C-Motion Inc., Rockville, Maryland). Five representative strides from each participant were exported into MATLAB (Mathworks, Natick, Massachusetts). Key kinematic and kinetic measures for the ankle, knee, hip, pelvis, and trunk were de fined as pre- viously described. 25 Joint range of motion (ROM) was de fined as the difference between the maximum and minimum joint angle values during one gait cycle. On the prosthetic side, ankle sagittal ROM was de fined as the difference between the maximum and minimum joint angle values during stance. Temporal spatial measures were determined using kinetic gait events and foot kinematics. Step length was de fined as the distance between the foot centers in the anterior-posterior direction at heel strike. Step width was calculated as the medial-lateral distance between the heel markers on each foot during double-limb stance. Step time was quanti fied as
the duration between heel strike of the ipsilateral limb and heel strike of the contralateral limb. Stance time was deter- mined as the duration between heel strike and toe off of the same limb. Swing time was quanti fied as the duration between toe off and heel strike of the same limb. Stride length was de fined as the distance between the foot centers in the anterior-posterior direction on successive heel strikes of the same limb. Stride time was quanti fied as the duration between successive heel strikes of the same limb. Statistical Analysis SPSS v.19 (SPSS Inc., Chicago, Illinois) was used for all statistical analyses. AB and TTA group means and standard deviations were calculated for demographic, anthropometric, temporal spatial, kinematic, and kinetic measures. Due to differences in sample size, and a desire to retain all avail- able data, Mann –Whitney non parametric tests were used to identify differences between AB and TTA groups for demographic-anthropometric, temporal spatial, and kinematic- kinetic measures. The AB group ’s right lower limb was used in comparisons made to the TTA group ’s lower limbs (e.g., AB vs. prosthetic limb and AB vs. intact limb). Bonferroni –Holm corrections were performed to correct for multiple comparisons across all measures. The Bonferroni – Holm method uses a step-down approach to account for multiple comparisons by arranging p values from the smallest to the largest and comparing them to sequential signi ficance
cutoffs. 26 Signi ficance was set at a p value of 0.05. Thus, correction factors accounting for 6, 6, and 53 comparisons yielded minimum p-value cutoffs of 0.0083, 0.0083, and 0.0009 for demographic-anthropometric, temporal spatial, and kinematic-kinetic measures, respectively. Similar to the work of O ’Sullivan, 20 the NRR for each measure was de fined as two standard deviations greater than and less than the AB group mean. Microsoft Excel 2007 (Microsoft Corp., Redmond, Washington) was used to deter- mine the upper and lower bounds of the NRR for the AB group and the prevalence of deviations in the TTA group. The deviation prevalence for each measure was calculated as the percentage of participants from the TTA group with indi- vidual mean values outside the NRR. To facilitate visualiza- tion of the data and ease of presentation, prevalence values were categorized into three groups; high (>50%), moderate (25
–49%), and low (<25%). RESULTS
Participant demographics and anthropometrics including age, height, weight, body mass index, leg length, walking speed, and time since independent ambulation ( TTA group only) are listed in Table I. Only age demonstrated a signi fi- cant difference between groups with the TTA group being an average of 4 years older than the AB group ( p = 0.006). Figure 1A provides an example of a measure that demon- strates high deviation prevalence in the TTA group with sig- ni ficant between group difference; 5.4% of all measures presented here were in this category. In addition, 7.1% of measures showed moderate deviation prevalence in the TTA group with signi ficant between group differences (Fig. 1B) MILITARY MEDICINE, Vol. 181, November/December Supplement 2016 31 The Prevalence of Gait Deviations in Individuals With Transtibial Amputation Yüklə 1,64 Mb. Dostları ilə paylaş:
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