Hossein Gholizadeh

Evaluation of new suspension system for limb prosthetics

BackgroundGood prosthetic suspension system secures the residual limb inside the prosthetic socket and enables easy donning and doffing. This study aimed to introduce, evaluate and compare a newly designed prosthetic suspension system (HOLO) with the current suspension systems (suction, pin/lock and magnetic systems).MethodsAll the suspension systems were tested (tensile testing machine) in terms of the degree of the shear strength and the patient’s comfort. Nine transtibial amputees participated in this study. The patients were asked to use four different suspension systems. Afterwards, each participant completed a questionnaire for each system to evaluate their comfort. Furthermore, the systems were compared in terms of the cost.ResultsThe maximum tensile load that the new system could bear was 490 N (SD, 5.5) before the system failed. Pin/lock, magnetic and suction suspension systems could tolerate loads of580 N (SD, 8.5), 350.9 (SD, 7) and 310 N (SD, 8.4), respectively. Our subjects were satisfied with the new hook and loop system, particularly in terms of easy donning and doffing. Furthermore, the new system is considerably cheaper (35 times) than the current locking systems in the market.ConclusionsThe new suspension system could successfully retain the prosthesis on the residual limb as a good alternative for lower limb amputees. In addition, the new system addresses some problems of the existing systems and is more cost effective than its counterparts.

Transtibial prosthetic socket pistoning: Static evaluation of Seal-In ® X5 and Dermo ® Liner using motion analysis system

BACKGROUND The method of attachment of prosthesis to the residual limb (suspension) and socket fitting is a critical issue in the process of providing an amputee with prosthesis. Different suspension methods try to minimize the pistoning movement inside the socket. The Seal-In(®) X5 and Dermo(®) Liner by Ossur are new suspension liners that intend to reduce pistoning between the socket and liner. Since the effects of these new liners on suspension are unclear, the objective of this study was to compare the pistoning effect of Seal-In(®) X5 and Dermo(®) Liner by using Vicon Motion System. METHODS Six transtibial amputees, using both the Iceross Seal-In(®) X5 and the Iceross Dermo(®) Liner, participated in the study. The vertical displacement (pistoning) was measured between the liner and socket in single limb support on the prosthetic limb (full-weight bearing), double limb support (semi-weight bearing), and non-weight bearing on the prosthetic limb, and also under three static vertical loading conditions (30 N, 60 N, and 90 N). FINDINGS The results demonstrated that the pistoning within the socket when Seal-In(®) X5 was used, decreased by 71% in comparison to the Iceross Dermo(®) Liner. In addition, a significant difference between the two liners under different static conditions was found (p<0.05). INTERPRETATION Participants needed to put in extra effort for donning and doffing the prosthesis with Seal-In(®) X5; however, this type of liner provided less pistoning. The new approach that uses the motion analysis system in this study might be an alternative for measuring the pistoning effect in the prosthetic socket.

Pistoning assessment in lower limb prosthetic sockets

Background: One of the main indicators of the suspension system efficiency in lower limb prostheses is vertical displacement or pistoning within the socket. Decreasing pistoning and introducing an effective system for evaluating pistoning could contribute to the amputees’ rehabilitation process. Objectives: The main objective of this study was to review existing research studies that examine the occurrence of pistoning in lower limb prosthesis with different techniques in static (standing) and dynamic (walking and jumping) positions. Study Design: Literature review. Methods: Keywords related to slippage, suspension, pistoning and vertical movement in lower limb prosthetics were used to search the literature available in PubMed, ScienceDirect, Web of Science and Google Scholar databases. Sixteen articles were selected for further analysis according to the selection criteria. Results: The following methods have been used to measure the occurrence of pistoning in prosthetic limbs: radiological methods, photographic technique, motion analysis system, sensor and spiral computerized tomography (CT). Pistoning was measured both in standing and walking. Conclusions: The results of this review reveal that further research is needed to develop and evaluate easy, accurate and safe methods of measuring pistoning. Future studies should provide a gold standard for the acceptable range of pistoning in a prosthetic socket. Clinical relevance This literature review contributes to a further understanding of lower limb prosthetic biomechanics by highlighting the strengths and weaknesses of the techniques that are currently available for evaluating the occurrence of pistoning in a prosthetic socket. It provides a useful overview of the current methods of measuring residual limb movements relative to the socket and liner, and will be of use for both practitioners and researchers in prosthetics and orthotics fields.

Clinical investigation of the interface pressure in the trans-tibial socket with Dermo and Seal-In X5 liner during walking and their effect on patient satisfaction

BACKGROUND The interface pressure between the residual limb and prosthetic socket has a significant effect on an amputees satisfaction and comfort. Liners provide a comfortable interface by adding a soft cushion between the residual limb and the socket. The Dermo and the Seal-In X5 liner are two new interface systems and, due to their relative infancy, very little are known about their effect on patient satisfaction. The aim of this study was to compare the interface pressure with these two liners and their effect on patient satisfaction. METHODS Nine unilateral transtibial amputees participated in the study. Two prostheses were fabricated for each amputee, one with the Seal-In liner and one with the Dermo liner. Interface pressure was measured at the anterior, posterior, medial and lateral regions during walking on the level ground. Each subject filled in a Prosthetic Evaluation Questionnaire (PEQ) regarding the satisfaction with the two liners. Findings The mean peak pressures with the Seal-In liner was 34.0% higher at the anterior, 24.0% higher at the posterior and 7.0% higher at the medial regions of the socket (P=0.008, P=0.046, P=0.025) than it was with the Dermo Liner. There were no significant differences in the mean peak pressures between the two liners at the lateral regions. In addition, significant difference was found between the two liners both for satisfaction and problems (P<0.05). Interpretation There was less interface pressure between the socket and the residual limb with the Dermo liner. The results indicated that the Dermo liner provides more comfort in the socket than the Seal-In liner.

A new approach for the pistoning measurement in transtibial prosthesis

Background: Good suspension lessens the pistoning (vertical displacement) of the residual limb inside the prosthetic socket. Several methods are used for measuring the pistoning. Study Design: Clinical trial. Objectives: To introduce and evaluate a new simple method for measuring the pistoning between the soft liner and socket in transtibial prostheses. Methods: Five transtibial prostheses with Iceross silicone liner and shuttle lock were made for the subjects. The pistoning was measured between the liner and socket by a photographic method in single limb support on the prosthetic limb (full weight bearing), non-weight bearing and under three static axial loading conditions (30, 60 and 90 N). Results: This new method enabled us to measure the pistoning between the liner and prosthetic socket. The reproducibility of measurements in different trials of one session and between two sessions by two observers was shown to be high. The average of displacement between the liner and socket was about 9 mm in non-weight bearing compared with full weight bearing. Furthermore, as we expected, the average of pistoning increased consistently by adding the loads. Conclusions: This new method provides for easy and inexpensive determination of pistoning between the liner and socket by every prosthetist in clinical settings.

An experimental study of the interface pressure profile during level walking of a new suspension system for lower limb amputees

BACKGROUND Different suspension systems that are used within prosthetic devices may alter the distribution of pressure inside the prosthetic socket in lower limb amputees. This study aimed to compare the interface pressure of a new magnetic suspension system with the pin/lock and Seal-In suspension systems. METHODS Twelve unilateral transtibial amputees participated in the study. The subjects walked on a level walkway at a self-selected speed. The resultant peak pressure with the three different suspension systems was recorded using F-socket transducers. FINDINGS There were significant statistical differences between the three studied suspension systems. Pair-wise analyses revealed that the mean peak pressure (kPa) was lower with the magnetic system than it was with the pin/lock system over the anterior and posterior aspects during one gait cycle (89.89 vs. 79.26 and 47.22 vs. 26.01, respectively). Overall, the average peak pressure values were higher with the Seal-In system than they were with the new magnetic lock and pin/lock system. INTERPRETATION The new magnetic system might reduce the pressure within the prosthetic socket in comparison to the pin/lock and Seal-In system during one gait cycle. This is particularly important during the swing phase of gait and may reduce the pain and discomfort at the distal residual limb in comparison to the pin/lock system.

100 top-cited scientific papers in limb prosthetics

Research has tremendously contributed to the developments in both practical and fundamental aspects of limb prosthetics. These advancements are reflected in scientific articles, particularly in the most cited papers. This article aimed to identify the 100 top-cited articles in the field of limb prosthetics and to investigate their main characteristics. Articles related to the field of limb prosthetics and published in the Web of Knowledge database of the Institute for Scientific Information (ISI) from the period of 1980 to 2012. The 100 most cited articles in limb prosthetics were selected based on the citation index report. All types of articles except for proceedings and letters were included in the study. The study design and level of evidence were determined using Sackett’s initial rules of evidence. The level of evidence was categorized either as a systematic review or meta-analysis, randomized controlled trial, cohort study, case–control study, case series, expert opinion, or design and development. The top cited articles in prosthetics were published from 1980 to 2012 with a citation range of 11 to 90 times since publication. The mean citation rate was 24.43 (SD 16.7) times. Eighty-four percent of the articles were original publications and were most commonly prospective (76%) and case series studies (67%) that used human subjects (96%) providing level 4 evidence. Among the various fields, rehabilitation (47%), orthopedics (29%), and sport sciences (28%) were the most common fields of study. The study established that studies conducted in North America and were written in English had the highest citations. Top cited articles primarily dealt with lower limb prosthetics, specifically, on transtibial and transradial prosthetic limbs. Majority of the articles were experimental studies.

Satisfaction and problems experienced with transfemoral suspension systems: a comparison between common suction socket and seal-in liner.

OBJECTIVE To compare a seal-in liner with the common suction socket with regards to patient satisfaction and problems experienced with the prosthesis. DESIGN Retrospective survey. SETTING A medical and engineering research center and a department of biomechanical engineering. PARTICIPANTS Men (N=90) with traumatic transfemoral amputation who used both suspension systems participated in the study. INTERVENTION Two prosthetic suspension systems: a seal-in liner and common suction socket. MAIN OUTCOME MEASURES Two questionnaires were completed by each subject to evaluate their satisfaction and problems experienced with the 2 suspension systems. Satisfaction and problems with the prosthetic suspension systems were analyzed in terms of fitting, donning and doffing, sitting, walking, stair negotiation, appearance, sweating, wounds, pain, irritation, pistoning, edema, smell, sound, and durability. RESULTS The study revealed that the respondents were more satisfied with a seal-in liner with regards to fitting, sitting, and donning and doffing. Overall satisfaction increased with the use of a seal-in liner compared with the suction socket (P<.05). However, satisfaction with the prosthesis showed no significant differences in terms of walking (flat and uneven surfaces), appearance, and stair negotiation. Furthermore, problems experienced differed significantly between the 2 suspension systems (P<.05). Sweating, wounds, pain, irritation, pistoning, edema, smell, and sound were less problematic with the use of a seal-in liner, whereas durability was significantly better with the suction socket. CONCLUSIONS The results of the survey suggest that satisfaction and problems with prosthetic suspension in persons with transfemoral amputation can be improved with a seal-in liner compared with the suction socket, provided that the durability of the liner is enhanced.

Review of the Socket Design and Interface Pressure Measurement for Transtibial Prosthesis

Socket is an important part of every prosthetic limb as an interface between the residual limb and prosthetic components. Biomechanics of socket-residual limb interface, especially the pressure and force distribution, have effect on patient satisfaction and function. This paper aimed to review and evaluate studies conducted in the last decades on the design of socket, in-socket interface pressure measurement, and socket biomechanics. Literature was searched to find related keywords with transtibial amputation, socket-residual limb interface, socket measurement, socket design, modeling, computational modeling, and suspension system. In accordance with the selection criteria, 19 articles were selected for further analysis. It was revealed that pressure and stress have been studied in the last decaeds, but quantitative evaluations remain inapplicable in clinical settings. This study also illustrates prevailing systems, which may facilitate improvements in socket design for improved quality of life for individuals ambulating with transtibial prosthesis. It is hoped that the review will better facilitate the understanding and determine the clinical relevance of quantitative evaluations.

Gait Biomechanics of Individuals with Transtibial Amputation: Effect of Suspension System

Prosthetic suspension system is an important component of lower limb prostheses. Suspension efficiency can be best evaluated during one of the vital activities of daily living, i.e. walking. A new magnetic prosthetic suspension system has been developed, but its effects on gait biomechanics have not been studied. This study aimed to explore the effect of suspension type on kinetic and kinematic gait parameters during level walking with the new suspension system as well as two other commonly used systems (the Seal-In and pin/lock). Thirteen persons with transtibial amputation participated in this study. A Vicon motion system (six cameras, two force platforms) was utilized to obtain gait kinetic and kinematic variables, as well as pistoning within the prosthetic socket. The gait deviation index was also calculated based on the kinematic data. The findings indicated significant difference in the pistoning values among the three suspension systems. The Seal-In system resulted in the least pistoning compared with the other two systems. Several kinetic and kinematic variables were also affected by the suspension type. The ground reaction force data showed that lower load was applied to the limb joints with the magnetic suspension system compared with the pin/lock suspension. The gait deviation index showed significant deviation from the normal with all the systems, but the systems did not differ significantly. Main significant effects of the suspension type were seen in the GRF (vertical and fore-aft), knee and ankle angles. The new magnetic suspension system showed comparable effects in the remaining kinetic and kinematic gait parameters to the other studied systems. This study may have implications on the selection of suspension systems for transtibial prostheses. Trial Registration Iranian Registry of Clinical Trials IRCT2013061813706N1.