Biomechanics in anthropology

Biomechanics is the set of tools that explain organismal movement and mechanical behavior and links the organism to the physicality of the world. As such, biomechanics can relate behaviors and culture to the physicality of the organism. Scale is critical to biomechanical analyses, as the constitutive equations that matter differ depending on the scale of the question. Within anthropology, biomechanics has had a wide range of applications, from understanding how we and other primates evolved to understanding the effects of technologies, such as the atlatl, and the relationship between identity, society, culture, and medical interventions, such as prosthetics. Like any other model, there is great utility in biomechanical models, but models should be used primarily for hypothesis testing and not data generation except in the rare case where models can be robustly validated. The application of biomechanics within anthropology has been extensive, and holds great potential for the future.

The mechanical failure of locally manufactured prosthetic feet from the Jaffna Jaipur Centre for Disability Rehabilitation (JJCDR), Sri Lanka

BACKGROUND

The International Organization for Standardization (ISO) 10328 standards are used to verify the safety of lower limb prosthetic devices. However, the ISO 10328 tests are performed in sterile laboratory settings and do not account for environmental or sociocultural factors associated with prosthetic use. Most locally manufactured prosthetic feet from low-income and middle-income countries, which are safely used for years, do not meet these standards. In this study, we investigate the modes of wear patterns of naturally worn prosthetic feet from Sri Lanka.

OBJECTIVE

To characterize wear patterns of locally manufactured prosthetic feet from low-income and middle-income countries.

METHODS

Sixty-six replaced prosthetic feet from the Jaffna Jaipur Center of Disability and Rehabilitation were analyzed. Delamination between the keel and rest of the foot could not be detected with ultrasound. Sole wear pattern was quantified by photographing soles and dividing them into 200 rectangles and scoring the rectangle's wear from 1 to 9 (no to extreme wear). Homologous scores were averaged to create a contour map of prosthetic foot wear.

RESULTS

The highest levels of wear occurred at the heel, end of the keel, and the perimeter of the prosthetic foot. All regions of the prosthetic feet had significantly different wear scores ( p < 0.005).

CONCLUSIONS

Locally manufactured solid ankle cushion heel feet display high levels of wear in localized areas of the sole of prosthetic feet, which can limit their life span. High levels of wear occur at the end of the keel, which would not be detectable in the ISO 10328 tests.