Lower Extremity Prostheses Research Articles

Afferent Sensory Feedback for Lower Extremity Prosthesis

Electrical stimulation has been applied to sciatic nerves of patients to achieve sensory feedback after lower limb amputation for periods of up to six years. Patients used the sensory feedback device daily. Pain, infection and electrode displacement have not been problems. The immediate postoperative benefits are that pain is minimized after amputation and stump healing is improved. Furthermore, the stimulus affords the patient increased confidence when walking due to renewed awareness of the center of gravity. Improved ability to function in the dark and when walking up and down stairways makes the application of sciatic nerve stimulation after amputation very rewarding.

FOOT-ANKLE ASSEMBLIES SUITABLE FOR THE JAPANESE

Almost everyone in Japan normally wears shoes outdoors, but does not use any kind of foot-wear except for socks or Japanese “tabi” socks inside his home. Not only is the temperature very high in Japan during summer, but it is also very humid. Therefore, there is need for special lower extremity prosthesis which is more suitable for the Japanese in their daily life. Research on foot-ankle assemblies is being carried out as our initial work.1. Commercially available foot-ankle assemblies which are made in both foreign countries and Japan were listed and evaluated. Almost all foot-ankle assemblies made in foreign countries are good in quality, but they are not suitable for walking on ;“tatami mat;”; whereas, the domestically produced assemblies do not fit shoes snugly and are also poor in overall quality compared to the imported assemblies. No foot-ankle assemblies which are considered suitable for Japanese A. D. L. could be found among both the foreign and domestically assemblies.2. A survey was made on 159 lower extremity amputees who are receiving pension in the Kansai area. Among the many different types of foot-ankle assemblies in use, the conventional single axis assemblies are most extensively used in Japan, numbering about 87%. The SACH foot is used somewhat less extensively which is only almost 5%. Most of the amputees have complaints in using their foot-ankle assemblies, which included trouble with the single axis joint, excessive noise, etc. Most female amputees want to wear shoes with high heels.3. The above survey shows that lower extremity amputees in Japan need foot-ankle assemblies which are suitable for walking with both shoes (high heels in case of women) and barefoot. We are now making two kinds of experimental foot-ankle assemblies which will be most suitable for the Japanese. One of them has an adjustable coupling for variable ankle angle fitting both shoes and barefoot. The other has a connector for various prosthetic feet which completely fits with any types of footwear. Both of them incorporate the SACH foot.

On the dynamic stability of biped locomotion.

While biped locomotion involves very complicated dynamical processes, a good deal can be learned about stability and feedback control from an analysis of simplified mathematical models. This paper treats locomotion dynamics relative to planar motion under an assumption that leg mass can be ignored in comparison to body mass. Thus the hypothetical biped possesses one rotational degree of freedom and two translational degrees, leading to a sixth-order system of nonlinear differential equations. These equations are linearized and feedback control laws are then derived to produce the desired stable forward motion. The feedback laws proposed involve a combination of continuous and discrete concepts to produce both step length and step period control as well as control of body attitude and altitude. The applicability of the control laws to the nonlinear system in the presence of large disturbances is verified by computer simulation. Hopefully, the results presented are significant relative to control processes arising in lower extremity prostheses and orthoses as well as to the design of biped robots.

Establishment of a theoretical base-design of a lower extremity prosthesis.

AbstractA conceptual model that relates the phenomenological stimuli responsible for bone remodeling has been developed as a preliminary exercise in a study designed to quantify Wolff's Law. In this regard, a set of thermodynamic and chemical kinetic equations have been formulated and their use in describing and predicting the formulation of crystalline hydroxypatite is presented.As a parallel activity, a macrocopic structural analysis of the bone‐pylon interface has been conducted using a finite element representation and the results of this investigation are discussed as they relate to establishing a set of pylon design criteria.Finally, a modular, endoskeletal prosthetic system is described. The design of this appliance is based on the concept of total cosmesis and provides the present amputee with increased comfort and functionality as well as providing a system that can be effectively interfaced with a bone pylon when direct skeletal attachment (DSA) becomes a clinically accepted procedure.

Upper and Lower Extremity Prostheses

Upper and Lower Extremity Prostheses

PROSTHETIC MANUFACTURE AND FITTING PROBLEMS

One of the most rewarding patients in surgical practice is the completely treated amputee. From the fearful, despondent and apparently inconsolable patient there can gradually emerge an individual proud of his achievement and often surpassing his former ability. While good surgery is a normal prerequisite, the final result is not so much dependent upon surgical procedures as on the treatment by paramedical personnel. In my own experience, the necessity to refer a patient for revisionary surgery is extremely rare, despite my seeing many ex-soldiers who have what would be called very poor stumps as the result of emergency surgery performed under the worst conditions of warfare. It is the part played by the paramedical personnel which I propose to discuss, and the discussion will be further confined to lower extremity prostheses.

Clinical Experiences with the S.A.C.H. Foot Prosthesis

The solid ankle cushion heel, or S.A.C.H., foot has proved to be a valuable component for lower-extremity prostheses; it can be used with all prostheses that require a full artificial foot. There is significantly less irritation of the amputation stump with use of the S.A.C.H. foot, especially in below-the-knee amputees, because of the diminished torsion upon the stump and less jarring from heel impact. The degree of comfort for the amputee using an artificial lower limb with a S.A.C.H. foot is increased as a result of the cushioned heel and smooth rocker action. The continued use of an improperly aligned prosthesis often occurs with a conventional wooden foot which has become loose at the articulated ankle joint. Tightening and repairs to the wooden foot and ankle joint are often postponed or deferred by the amputee until stump irritation finally forces him to seek repairs; the skin ulceration or abrasion may then result in unnecessary deprivation of the use of the prosthesis until the stump has healed. Such problems are definitely diminished with the use of a S.A.C.H. foot. The S.A.C.H. foot represents a significant advance in prosthetic research. It is now being prescribed extensively for all lower-extremity amputees, and appears likely to replace the wooden foot and articulated ankle joint as the conventional component for all lower-extremity prostheses.

Neuromuscular performance and sensory receptivity in a triple congenital amputee; report of a case.

This report of a 22-year-old man, born without lower arms and hands and without the distal end of the right leg, supports Adrian's observation that nervous system reacts to relations between stimuli and performs the appropriate task with any part of the motor system that is available. We cannot represent it as a series of machines for operating on the map of events unless we add a number of devices to make good this fundamental difference. On the sensory side there must be something to abstract the significant elements of a pattern and on the motor side something to do just the reverse, to convert the abstraction into a concrete movement.1 The patient, when standing, carries his weight on the left lower extremity and on the right lower extremity prosthesis. X-rays reveal an abnormal skeletal structure of the left foot (figure,A). Despite his multiple deformity, this patient,

Alignment and fitting of lower extremity prostheses.

Alignment and fitting of lower extremity prostheses.