In recent years technical innovations have combined to make artificial limbs much more comfortable, efficient, and lifelike than earlier versions. Future innovations are likely to depend on the interaction between three powerful forces—amputees' demands, advances in surgery and engineering, and healthcare funding sufficient to sustain development and application of technological solutions. This article looks at the innovative new prostheses that are currently available and discusses future developments. Advances in prosthetic technology
Prosthetic technology has advanced to a remarkable degree in the past two decades, driven largely by amputees' demand. Today, otherwise healthy individuals with mid-calf amputation should be able to participate in a full range of normal responsibilities, to walk without any perceptible limp, and to engage in recreational and sports activities.
Shock absorbing mechanisms to reduce impact forces
Once amputees worldwide began to regularly jog, run, and jump, it became apparent that the lack of shock absorption in artificial limbs was a limiting factor. Flex-Foot introduced the Re-Flex shin-foot design in 1993, coupling a spring loaded shock absorber with the dynamic response foot. Recently, gait studies have confirmed that this type of component improves the biomechanical performance of artificial limbs, which may explain the enthusiastic acceptance of such devices by non-athletes too Until this past decade, thigh amputees have been forced to hold their prosthetic knee in full extension throughout most of the stance phase of the gait cycle to prevent the leg from collapsing. This not only results in an unnatural gait but also eliminates the primary mechanism for shock absorption offered by the biological knee. To address this shortcoming, a growing number of prosthetic knee designs now include a “stance flexion feature.” The UK company Blatchford was the first to offer this capability, termed the “bouncy knee.”10 As the amputee bears weight on the limb a friction brake engages automatically and stabilises the knee, while a small rubber element allows a few degrees of motion to absorb shock and simulate knee flexion during the early stance phase.
Microprocessor controlled movement
The first artificial knee with an “on board” computer to improve the symmetry of amputees' gait across a wide range of walking speeds was developed by Blatchford in the early 1990s. Studies have confirmed that these “intelligent prostheses” offer amputees a more reliable gait pattern during the swing phase of the gait cycle, permitting them to walk with more confidence and in a more energy efficient manner.
The potential of low cost, limited function prostheses
Modern industrial fabrication, particularly with injection moulded plastics, can create lightweight, low cost components with sufficient function for limited walking, and this might be quite sufficient for today's typical elderly amputee. Some designs may also be made moisture resistant and therefore suitable for use in the shower or on the beach. The lower manufacturing costs of such devices may permit their use in developing economies, where the cost of more complex technology is prohibitive. The Shower Limb, developed by Blatchford, is an example of this trend. The company has also developed a special line of plastic Atlas Prostheses designed specifically for use in tropical climates.
The International Committee of the Red Cross has established an initiative to produce low cost polypropylene plastic prostheses, made by unskilled local workers, for areas where conflict or environmental catastrophes have resulted in large numbers of traumatic amputations (see www.icrc.org). These devices are well accepted clinically, although some problems have been reported with their durability. i finished my simester through this website https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1121287/
