Scientific studies have been conducted to quantify attributes that may be important in the creation of more functional and comfortable lower-limb prostheses. The prosthesis socket, a human-machine interface, has to be designed properly to achieve satisfactory load transmission, stability, and efficient control for mobility. The biomechanical understanding of the interaction between prosthetic socket and the residual limb is fundamental to such goals. The purpose of this paper is to review the recent research literature on socket biomechanics, including socket pressure measurement, friction-related phenomena and associated properties, computational modeling, and limb tissue responses to external mechanical loads and other physical conditions at the interface. There is no doubt that improved biomechanical understanding has advanced the science of socket fitting. However, the most recent advances in the understanding of stresses experienced at the residual limb have not yet led to enough clinical consensus that could fundamentally alter clinical practice. Efforts should be made to systematically identify the major discrepancies. Further research should be directed to address the critical controversies and the associated technical challenges. Developments should be guided to offer clinicians the quantification and visualization of the interaction between the residual limb and the prosthetic socket. An understanding of comfort and optimal load transfer as patterns of socket interface stress could culminate in socket design expert systems.

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State-of-the-art research in lower-limb prosthetic biomechanics-socket interface: a review.

Microclimate: A critical review in the context of pressure ulcer prevention.

Parameters related to use of a prosthesis by a patient with a limb amputation are monitored using a tool that includes one or more piezoelectric force sensors. The resulting data are processed for use both in short and long term management of amputee patients. The sensor is a small modular unit that fits within or between traditional prosthetic components, e.g., below a prosthesis socket. The data produced by the tool are collected, processed, and stored. Optionally, the data are periodically communicated to a remote site via a network, e.g., over the Internet. The device and associated software used to process the data can be used to characterize activities conducted by a prosthesis user, to determine pistoning or threatening interface stress distributions between the limb and socket, mal-alignment of the socket, use of improper components, and other possibly undesired conditions that the amputee patient using the prosthesis may be experiencing.

Prosthetic limb monitoring system

Susceptibility to decubitus ulcer formation

The relationship between pressure ulcers and skin blood flow response after a local cold provocation

A method for measuring the susceptibility of a patient to develop decubitus ulcers is described and initially evaluated. It is based on an indirect, noninvasive measurement of the transient regional blood flow response after a test pressure load which simulates the external stimulus for pressure-sore formation. This method was developed to determine the individual risk of a patient and to study the subfactors which contribute to the susceptibility. This would also offer the possibility of evaluating the effect of preventive treatment aimed at reducing the susceptibility. The method was found to discriminate between preselected elderly patients at risk on the one hand, and non-risk patients and healthy young adults on the other hand. No differences in blood flow responses were found between the non-risk elderly patients and the healthy young adults. This suggests that age per se is not a factor in the formation of pressure sores. In the risk group the recovery time after pressure relief was found to be three times as long as the duration of the pressure exercise. This indicates that the recovery time after pressure exercise may be as important as the period of pressure exercise in deducing the risk of developing decubitus ulcers.

M. W. Ribbe

Papers

Method for the measurement of susceptibility to decubitus ulcer formation.