Despite increasingly widespread adoption of vacuum-assisted suspension systems in prosthetic clinical practices, there remain gaps in the body of scientific knowledge guiding clinicians' choices of existing products. In this study, we identified important pump-performance metrics and developed techniques to objectively characterize the evacuation performance of prosthetic vacuum pumps. The sensitivity of the proposed techniques was assessed by characterizing the evacuation performance of two electrical (Harmony e-Pulse [Ottobock; Duderstadt, Germany] and LimbLogic VS [Ohio Willow Wood; Mt. Sterling, Ohio]) and three mechanical (Harmony P2, Harmony HD, and Harmony P3 [Ottobock]) prosthetic pumps in bench-top testing. Five fixed volume chambers ranging from 33 cm(3) (2 in.(3)) to 197 cm(3) (12 in.(3)) were used to represent different air volume spaces between a prosthetic socket and a liner-clad residual limb. All measurements were obtained at a vacuum gauge pressure of 57.6 kPa (17 inHg). The proposed techniques demonstrated sensitivity to the different electrical and mechanical pumps and, to a lesser degree, to the different setting adjustments of each pump. The sensitivity was less pronounced for the mechanical pumps, and future improvements for testing of mechanical vacuum pumps were proposed. Overall, this study successfully offers techniques feasible as standards for assessing the evacuation performance of prosthetic vacuum pump devices.

Although the overall bulk properties of the Achilles tendon have been measured, there is little information detailing the properties of individual fascicles or their interactions. The knowledge of biomechanical properties at the fascicle-scale is critical in understanding the biomechanical behavior of tendons and for the construction of accurate and detailed computational models. Seven tissue samples (approximately 15x4x1 mm(3)) harvested from four freshly thawed human (all male) tendons, each sample having four to six fascicles, were tested in uniaxial tension. A sequential sectioning protocol was used to isolate interaction effects between adjacent fascicles and to obtain the loading response for a single fascicle. The specimen deformation was measured directly using a novel polarized light imaging system with digital image correlation (DIC) for marker-free deformation measurement. The modulus of the single fascicle was significantly higher compared with the intact fascicle group (single: 226 MPa (SD 179), group: 68 MPa (SD 33)). The interaction effect between the adjacent fascicles was less than 10% of the applied load and evidence of sub- and postfailure fascicle sliding was clearly visible. The DIC direct deformation measurements revealed that the modulus of single fascicles could be as much as three to four times the intact specimen. The consistently higher moduli values of the single (strongest) fascicle indicate that the overall response of the tendon may be dominated by a subset of "strongest" fascicles. Also, fascicle-to-fascicle interactions were small, which was <10% of the overall response. This knowledge is useful for developing computational models representing single fascicle and/or fascicle group mechanical behavior and provides valuable insights into fascicle-scale Achilles tendon material properties.

Collodiaphyseal angle (CDA) is the angle formed between the femoral neck axis and the diaphysis axis. The aims of this study were to determine the normal range of collodiaphyseal angle in adults and to determine any difference in the collodiaphyseal angle between right and left femur and also between sexes. 340 subjects consisting of 170 (50%) males and 170 (50%) females were included in this study. Plain radiographs were taken with the patients lying supine and the medial malleoli touching each other to prevent the hips being laterally rotated. Films were shot at a film focal distance (FFD) of 90 cm to minimize magnification. Measurements were taken with calibrated ruler and the collodiaphyseal angle was measured using goniometer. Results showed a normal range of CDA among Nigerian males as mean ± SD of (133.2° ± 7.6) for the right and mean ± SD of (131.1° ± 7.3) for the left. In females, it was (125.1° ± 6.9) on the right and (123.0° ± 6.9) on the left. Based on the study, coxa vara and coxa valga could be diagnosed on the normal range of collodiaphyseal angle in Ile-Ife (118°-145° in males and 110°-138° females). There is also sex variation and difference in CDA between right and left femur.

Soft tissues such as tendons and ligaments are made up of groups of collagen fascicles surrounded by a sheath of epitenon. The friction between these structural fibers and their surrounding ground substance has been suggested to be the main contributor to the observed viscoelastic response of the tissue[1]. During normal daily activities such as walking, climbing stairs or jumping, these tissues are subjected to alternating loading and unloading conditions. Depending on the load and tissue orientation, this alternating loading condition may not be uniformly applied over the entire volume of the tissue. In some instances, certain fiber bundles are in tension (loaded) while others might be unloading. Hence, the development of accurate predictive models requires characterization of not only the loading behavior, but also the unloading behavior. To our knowledge, there are few models that specifically address the unloading behavior of the tissue.

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