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Computer-aided design and computer-aided manufacturing (CAD/CAM) systems for the design and manufacture of limb prostheses have recently become commercially available. However, rigorous evaluations of these systems have not been performed to determine whether they produce sockets that fit as well as or better than sockets made using conventional design methods. A controlled evaluation protocol, in which computer-designed sockets are compared with conventionally designed sockets, has been developed and pilot tested at the authors' facility. A full trial of one of the commercially available systems for transtibial sockets is currently in progress. In preliminary findings, the CAD/CAM socket was preferred by one-half of the first 20 subjects. During the course of this trial, it was noted that the CAD/CAM technique seems to be better suited to some prosthetists than others.

The postural sway of amputees was investigated quantitatively in fifty patients with above-the-knee amputations and in twenty-nine patients with below-the-knee amputations. The factors evaluated were: (1) the mean speed of sway: (2) the range of movement in the sagittal and coronal planes; and (3) the dependence on vision as indicated by the ratio of eyes-open to eyes-closed values. The results demonstrated that in amputees there is an increased dependence on vision for maintenance of the erect posture. Postural sway in patients with below-the-knee amputations was found to be significantly greater than that in those with above-the-knee amputations. Postural sway increased with age; but the visual dependence for the control of postural sway was independent of age.

A new system for measuring the cross-sectional area profiles of amputation stumps and whole limbs has been designed at the Amputee Research Centre. The instrument consists of a cylindrical tank supported on an elevator. The tank is raised to the height of the amputation stump and filled with water. A graph of the cross-sectional area profile of the amputation stump is generated by a mini-computer as the elevator descends. The cross-sectional area (A) is calculated from the expression: formula: (see text) where Hw = height of water in the tank He = height of the elevator Ac = a constant, related to the size of the measuring tank. This paper describes the instrument, which may find application in many other areas where there is a need to study shape.

This study evaluated residual limb volume fluctuations of new and mature amputees in order to better plan for definitive limb prostheses. A measurement system based on a water displacement technique was used to measure cross-sectional area profiles of lower extremity amputation residual limbs. Reliable data were obtained for 32 of the 49 subjects participating in this study. Residual limb shrinkage cannot be characterized by any single pattern and therefore the date for fitting of a final prosthesis cannot be predicted precisely from regular volume measurements. Every amputee studied demonstrated an increase in body weight. Changes in residual limb volume early postoperatively were dictated by interaction of shrinkage and opposite effect of weight gain . Mature amputation limbs were observed to fluctuate in volume, and these fluctuations tended to correspond to body weight changes. For 3 general patterns of volume change observed early postoperatively, the best estimate of time to fit a final prosthesis appears to be about 150 days postamputation.

Eine Statistik des offentlichen Gesundheitswesen in den USA berichtet (zwischen 1953 und 1965) uber 1,35 Amputierte auf 1000 Personen (nicht eingeschlossen solche, die in Heimen oder Heilstatten leben). In Grosbritannien wurden 1,58 Amputierte auf 1000 Personen gezahlt (hier sind solche in Heimen oder Instituten mitgezahlt) (Le Blanc 1973).

Der Gangzyklus wird in 2 Phasen unterteilt: die Standphase, in welcher der Fus Kontakt mit dem Boden hat, sowie die Schwungphase, wahrend der der Fus nach vorn geschwungen wird zur Vorbereitung des nachsten Schrittes. Beim normalen Gehen sind wahrend einer kurzen Zeit gleichzeitig beide Fuse in Beruhrung mit dem Boden; infolgedessen betragt auch der Prozentsatz der Standphase am ganzen Schritt mehr als 50%. Diese uberschneidende Phase, wahrend welcher beide Fuse den Boden beruhren, nimmt zeitlich ab mit zunehmender Ganggeschwindigkeit. Sobald sich kein solches gleichzeitiges Beruhren des Bodens mehr ereignet, spricht man von Laufschritt.

Die Belastungen eines Amputationsstumpfes durch eine Prothese hangen sowohl von der Pasform des Schafts als auch von seiner Ausrichtung ab, wie in Kap. 25 erwahnt wurde. Neben der Anpassung und dem achsengerechten Aufbau des Schafts hangt die Funktionstuchtigkeit der Prothese von der Wahl des Materials und der Konstruktion ab. In diesem Kapitel soll der Leser einige grundlegende Tatsachen uber diese Themen erfahren. Von wenigen Ausnahmen abgesehen soll kein Katalog von Einzelheiten geliefert werden, sondern wir wollen uns auf einige Grundprinzipien beschranken.

A percutaneous implant for the attachment of an artificial limb has been designed and tested in 14 pigs. Firm fixation to beone was achieved with the porous-surface layered metal intramedullary stem design in some cases. Dacron velour was used at the soft tissue interface. Evidence of soft tissue ingrowth was seen. However, the velour was unable to maintain adequate epithelial adhesion to form an anatomical seal and a barrier to bacteria.

Periodically a new method of treating decubitus ulceration is introduced, with accounts of its proven efficacy. Each new method, whether mechanical or chemical, results in accelerated healing initially but many are eventually discarded because of an inability to sustain performance. This pattern, over the years, has resulted in numerous claims for new and effective methods of treatment. One variable, which appears to have been overlooked in most studies, is the increased interest generated in both staff and the patients involved. In an effort to assess this factor a placebo device was constructed that was claimed to emit a healing electromagnetic radiation. The machine was introduced into a large teaching hospital as a double blind study (neither the staff nor the patients were aware that it was inoperative). The patients’ sores were exposed to this `radiation’ for half an hour in every two hours. The sores healed rapidly and the staff were convinced of the machine’s efficacy. The authors concuded that an effective method of treating decubiti is by heightening and main­taining the interest of staff involved. It is also concluded that any clinical trial of a new system, to be valid, must take into account the increased enthusiasm and the stimulus to the nursing routine.

A new and measurable parameter in the study of static equilibrium is described. Using a minicomputer, the locus of postural sway was measured during 1 minute periods in 144 volunteer subjects, including 105 control subjects and 39 persons with above-knee amputations. It was hypothesized that the above-knee amputee group had lost a relatively predictable degree of proprioception and kinesthetic sense. Vestibular mechanisms were normal and, therefore, constant in both groups. Using a simple arithmetic formula, the effect of such loss of proprioception was estimated by comparing the amputee group with the nonamputee group, while the contribution of visual input was estimated by comparing both groups with their eyes open and closed. Using this parameter, no clear age dependency was demonstrated. The mean locus of sway for the amputee group was the same as the nonamputee group with the eyes open. However, a comparison of the eyes open/eyes closed ratio in both groups demonstrated a significantly greater increase for the amputee group than for control subjects (p less than 0.001). In the future, mean locus of sway might provide a useful clinical method of measurement and the eyes open/eyes closed ratio might provide a simple and useful method to communicate the dependency upon vision in individual patients.

A method of measuring human postural movement is described, using measurement of the total length of the locus of postural sway in 60-second epochs with the eyes open and with the eyes closed and expressed as average speed in centimetres per minute. The ratio of the overall mean speed values derived with the eyes open to that with the eyes closed provides an indication of the subject’s dependence upon vision. Two sample case studies indicate clinical applications of the method.

The postural sway of amputees was investigated quantitatively in fifty patients with above-the-knee amputations and in twenty-nine patients with below-the-knee amputations. The factors evaluated were: (1) the mean speed of sway: (2) the range of movement in the sagittal and coronal planes; and (3) the dependence on vision as indicated by the ratio of eyes-open to eyes-closed values. The results demonstrated that in amputees there is an increased dependence on vision for maintenance of the erect posture. Postural sway in patients with below-the-knee amputations was found to be significantly greater than that in those with above-the-knee amputations. Postural sway increased with age; but the visual dependence for the control of postural sway was independent of age.