Containment Socket Research Articles

Comparison of Ischial Containment and Subischial Sockets Effect on Gait Biomechanics in People With Transfemoral Amputation: A Randomized Crossover Trial

ObjectiveTo compare gait biomechanics of the Northwestern University Flexible Sub-Ischial Vacuum (NU-FlexSIV) Socket to the ischial containment (IC) socket. DesignRandomized crossover trial with 2, 7-week periods. SettingPrivate prosthetic clinics and university research laboratory. ParticipantsA total of 30 enrolled (n=30); 25 participants completed the study with full (n=18) or partial data (n=7). InterventionsTwo custom-fabricated sockets (IC and NU-FlexSIV), worn full-time for 7 weeks, with testing at 1, 4, and 7 weeks after socket delivery. Main Outcome MeasuresGait analyses were conducted at 1, 4, and 7 weeks post socket delivery. Differences between sockets in selected gait variables related to hip motion and coronal plane socket stability were assessed. ResultsFor participants with data for both sockets at week 7 (n=19), there were no significant differences in any gait variables between sockets at self-selected normal walking speed. However, when all participants and all study time points were assessed (n=25), there was a significant main effect of socket (P=.013), with prosthetic side sagittal plane hip range of motion being significantly greater for the NU-FlexSIV Socket at self-selected normal walking speed. There were no other significant effects. ConclusionsThe results suggest that, compared to the IC socket, the NU-FlexSIV Socket did not alter gait biomechanics related to hip motion and coronal plane socket stability in people with unilateral transfemoral amputation.

Effects of Prosthetic Socket Design on Residual Femur Motion Using Dynamic Stereo X-Ray - A Preliminary Analysis.

Individuals with transfemoral amputation experience relative motion between their residual limb and prosthetic socket, which can cause inefficient dynamic load transmission and secondary comorbidities that limit mobility. Accurately measuring the relative position and orientation of the residual limb relative to the prosthetic socket during dynamic activities can provide great insight into the complex mechanics of the socket/limb interface. Five participants with transfemoral amputation were recruited for this study. All participants had a well-fitting, ischial containment socket and were also fit with a compression/release stabilization socket. Participants underwent an 8-wk, randomized crossover trial to compare differences between socket types. Dynamic stereo x-ray was used to quantify three-dimensional residual bone kinematics relative to the prosthetic socket during treadmill walking at self-selected speed. Comfort, satisfaction, and utility were also assessed. There were no significant differences in relative femur kinematics between socket types in the three rotational degrees of freedom, as well as anterior-posterior and medial-lateral translation (p > 0.05). The ischial containment socket demonstrated significantly less proximal-distal translation (pistoning) of the femur compared to the compression/release stabilization socket during the gait cycle (p < 0.05), suggesting that the compression/release stabilization socket provided less control of the residual femur during distal translation. No significant differences in comfort and utility were found between socket types (p > 0.05). The quantitative, dynamic analytical tools used in the study were sensitive to distinguish differences in three-dimensional residual femur motion between two socket types, which can serve as a platform for future comparative effectiveness studies of socket technology.

Comparison of Ischial Containment and Subischial Sockets on Comfort, Function, Quality of Life, and Satisfaction With Device in Persons With Unilateral Transfemoral Amputation: A Randomized Crossover Trial

ObjectiveTo compare comfort and functional performance of the Northwestern University Flexible Subischial Vacuum (NU-FlexSIV) Socket with the ischial containment (IC) socket in persons with unilateral transfemoral amputation. DesignRandomized crossover trial with two 7-week periods. SettingPrivate prosthetic clinics and university research laboratory. ParticipantsA total of 30 enrolled (N=30); 25 participants completed the study with full (n=18) or partial data (n=7). InterventionsTwo custom-fabricated sockets (IC and NU-FlexSIV), worn full-time for 7 weeks, with testing at 1, 4, and 7 weeks after socket delivery. Main Outcome MeasuresThe primary outcome was change in Socket Comfort Score (SCS) at 7 weeks. Secondary outcomes at 7 weeks included the Orthotic and Prosthetic Users’ Survey (OPUS) to assess lower extremity functional status, health-related quality of life, and satisfaction with device, as well as the 5-Times Rapid Sit-to-Stand Test, Four Square Step Test, and T-Test of Agility to assess functional performance. ResultsAt 7 weeks, the mean SCS for IC (7.0±1.7) and NU-FlexSIV (8.4±1.1) Sockets were significantly different (P<.001; 95% confidence interval, 0.8-2.3). Results from a linear mixed-effects model, accounting for data from all time points, indicated that the SCS was 1.7 (SE=0.45) points higher for the NU-FlexSIV Socket (P<.001). For the secondary outcomes, only OPUS satisfaction with device was significantly better in the NU-FlexSIV Socket after accounting for all data points. ConclusionsThe results suggest that after 7 weeks’ accommodation, the NU-FlexSIV Socket was more comfortable and led to greater satisfaction with device than the IC socket in persons with unilateral transfemoral amputation and K3/K4 mobility. Other patient-reported outcomes and function were no different between sockets.

Prediction of ischial ramal angle for transfemoral ischial containment sockets.

A well-fitting and comfortable ischial containment socket relies on accurately replicating the transverse plane angle of the ischium and ischial ramus angle, inside the medial socket brim. Prediction of the ischial ramus angle, may provide a way to determine the ischial ramus angle without in vivo measurement. To determine the accuracy with which the ischial ramus angle could be predicted and identify which variables contributed significantly to the prediction. Cross-sectional study. Computed tomography scans were randomly sampled from a cadaveric database (n = 200). Standard multiple regression models were developed to predict the ischial ramus angle based on pelvic measures. The regression model explained 10.5% of the variance in ischial ramus angle (p = 0.018). The standard error of the estimate was 11.32°. While regression models by sex explained a larger proportion of the variance, the resulting accuracy was not improved. The regression models explained a small proportion of variance in ischial ramus angle. The average error associated with the prediction was too large to accurately predict the ischial ramus angle for use in clinical practice. Contrary to commonly held beliefs, there was no statistically significant difference in ischial ramus angle between sexes. Prediction of ischial ramus angle does not have sufficient accuracy to be clinically useful, but descriptive data may help clinicians identify casting errors and correct these in a plaster positive, knowing that the average ischial ramus angle was 32.65°±5.59° (relative to mid-sagittal plane) and does not vary between sexes.

P 036 - Pressure mapping analysis for forward and backward gait

To compare comfort and functional performance of the Northwestern University Flexible Subischial Vacuum (NU-FlexSIV) Socket with the ischial containment (IC) socket in persons with unilateral transfemoral amputation.Randomized crossover trial with two 7-week periods.Private prosthetic clinics and university research laboratory.A total of 30 enrolled (N=30); 25 participants completed the study with full (n=18) or partial data (n=7).Two custom-fabricated sockets (IC and NU-FlexSIV), worn full-time for 7 weeks, with testing at 1, 4, and 7 weeks after socket delivery.The primary outcome was change in Socket Comfort Score (SCS) at 7 weeks. Secondary outcomes at 7 weeks included the Orthotic and Prosthetic Users’ Survey (OPUS) to assess lower extremity functional status, health-related quality of life, and satisfaction with device, as well as the 5-Times Rapid Sit-to-Stand Test, Four Square Step Test, and T-Test of Agility to assess functional performance.At 7 weeks, the mean SCS for IC (7.0±1.7) and NU-FlexSIV (8.4±1.1) Sockets were significantly different (P<.001; 95% confidence interval, 0.8-2.3). Results from a linear mixed-effects model, accounting for data from all time points, indicated that the SCS was 1.7 (SE=0.45) points higher for the NU-FlexSIV Socket (P<.001). For the secondary outcomes, only OPUS satisfaction with device was significantly better in the NU-FlexSIV Socket after accounting for all data points.The results suggest that after 7 weeks’ accommodation, the NU-FlexSIV Socket was more comfortable and led to greater satisfaction with device than the IC socket in persons with unilateral transfemoral amputation and K3/K4 mobility. Other patient-reported outcomes and function were no different between sockets.

Comparative Efficacy of Transfemoral Prosthetic Interfaces: Analysis of Gait and Perceived Disability

ABSTRACT Introduction The High-Fidelity (HiFi) interface is an emerging transfemoral interface technology. However, no comparison of this interface to traditional transfemoral interface designs is currently available. The purpose of this study is to measure the effects of the HiFi system on gait and perceived disability compared with a traditional socket design in a subject with transfemoral amputation. Methods The subject was first tested with a traditional ischial containment socket, then fit with the HiFi system, and tested again after a 30-day accommodation period. Three-dimensional motion analysis was performed using an 8-camera Vicon Motion Capture system. The Oswestry Low Back Pain Disability Questionnaire v2.0 and Western Ontario and McMaster University Osteoarthritis index were administered at initial and secondary testing to evaluate perceived disability. A one-way analysis of variance and Fischer's least significant difference were used to determine statistical difference between conditions. The level of significance for all tests was set at P ≤ 0.05. Results Notable results included an increase in self-selected gait velocity, prosthetic hip adduction, and hip extension. Reductions in lateral center of mass deviation during gait and in perceived disability was also shown with use of the HiFi condition. Discussion This study analyzed the effects of the HiFi Interface System on biomechanical parameters of gait and perceived disability compared with a baseline IRC condition in this elderly subject with history of TF amputation. Several improvements and markers of increased stability with use of the HiFi were noted. Perceived disability was also greatly improved comparatively. Conclusions The HiFi Interface System presented some biomechanical advantages to traditional IRC socket designs in this case, which may allow for increased stability in patients utilizing a TF prosthesis. Further research with larger samples is warranted.

Shuttle Lock Suspension Supplemented with Suction for a Person with Transfemoral Amputation

Traditional suction suspension is well documented for fitting amputees with transfemoral amputation. Volume fluctuation and shape change in the transfemoral residual limb can impact the quality of linkage obtained with this type of suspension. Poor linkage can have a negative impact on activity level, confidence, and overall ability of the transfemoral amputee to use the prosthesis. The purpose of this case report was to document the change in the ability to ambulate for persons with transfemoral amputation as they transition from a prosthesis with traditional suction to one with shuttle lock suspension supplemented with suction (passive vacuum [PV]). A 59-year-old male subject with a unilateral transfemoral amputation experienced a decline in participation activity level and decreased confidence while using a prosthesis with suction suspension and ischial containment (IC) socket design. The Amputee Mobility Predictor with prosthesis (AMPpro) was administered while he used the suction-only prosthesis and after 5, 9, and 12 months with a prosthesis featuring shuttle lock suspension combined with PV along with a total surface bearing (TSB) socket interface (SI). His AMPpro scores increased 5 points in the first 5 months with the PV prosthesis and improved slightly in the final 7 months of testing. Performance in reaching, transfers, and static balance tasks improved, allowing the subject to transition from an activity level K2 to activity level K3. The subject’s improved capability can likely be attributed to the combination of the prosthesis with the PV SI along with physical therapy.

Prediction of the skeletal medio-lateral dimension using non-invasive anthropometric measurements for the provision of ischial containment sockets

Great emphasis is placed on the skeletal medio-lateral to maintain the normal adduction of the remnant femur and to ensure coronal plane stability in an ischial containment socket. Given the invasiveness of the skeletal medio-lateral measurement, an alternative approach using prediction based on non-invasive measures would be welcomed. Determine the accuracy with which the skeletal medio-lateral dimension could be predicted using sex, stature, anterior-posterior dimension and iliofemoral angle. Cross-sectional. Anthropometric measurements on 77 persons were recorded and used as input data into a standard multiple regression. The regression model explained 59% of the variance in skeletal medio-lateral (r(2) = 0.59) that was statistically significant (F(4,72) = 25.37, p = 0.000). Only sex contributed significantly to the prediction of skeletal medio-lateral (β = 0.67, t = 6.15, p = 0.00). The degree of error associated with the regression model (sum of squared errors = 0.009) indicated that the actual skeletal medio-lateral could be predicted within ±18 mm in 95% of the cases. The regression model is not sufficiently accurate to predict skeletal medio-lateral for clinical purposes. Accuracy of the prediction could be improved with more accurate input data from computed tomography scans and use of other independent variables that explain the unique variance not already described by the participants' sex. Clinical relevance This pilot study demonstrates potential for the skeletal medio-lateral to be predicted using non-invasive anthropometric measurements. Given this proof of concept, future investigators should use more accurate input data from computed tomography scans and identify alternative independent variables that explain the variance in the skeletal medio-lateral not attributable to sex.

Influence of different types of sockets on the range of motion of the hip joint by the transfemoral amputee

Purpose To compare the individual influence of different types of socket designs on the hip's range of motion in transfemoral amputees. Patients and methods We studied the kinematic parameters of the hip joint for patients with transfemoral amputation under four experimental conditions: without a socket, with a quadrilateral socket, an ischial containment socket, an ischial-ramal containment socket. An opto-electronic system was used to record the movements in the frontal and sagittal planes for a 3D movement analysis. Results The hip's range of motion is always significantly restricted with the sockets, regardless of their type, compared to the situation without a socket ( P < 0.05). The adduction and extension movements are the most restricted. The global amplitude (i.e., the sum of all the ranges of motion) is significantly higher for the ischial-ramal containment socket (139.5°) compared to the ischial containment socket (125.4°, P = 0.002) and the quadrilateral socket (127.3°, P = 0.01). No comparable study exists in the literature, especially for the ischial-ramal containment socket. Conclusion The ischial-ramal containment socket seems to be the most interesting type of socket in terms of the criterion studied. It still remains to identify the possible functional improvements that this design would provoke during gait and during daily activities.

Energy cost of walking in transfemoral amputees: Comparison between Marlo Anatomical Socket and Ischial Containment Socket

Objective To compare energy cost of walking (ECW) and prosthesis-related perceived mobility with the Marlo Anatomical Socket (MAS ®) and the Ischial Containment (IC) Socket. Method Transfemoral (TF) amputees were enrolled in the study. ECW tests were conducted inside, in a hallway with a regular floor surface. Subjects had to walk back and forth on a 61 m linear course at their own self-selected speed. Metabolic and heart rate data were collected during the walking test using a portable gas analyzer. All measurements were made at steady state (SS). The tests were performed first using the IC socket and then after 30 days of MAS ® use; the last test was carried out after 60 days of MAS ® use. The amputees were also administered the Prosthetic Evaluation Questionnaire Mobility Section (PEQ MS) at the first and the last test to assess perceived potential for mobility using the prosthesis. Results Seven long-term prosthesis users were analyzed. Their mean age was 33.9 ± 9.3 years; all were employed, active, and used IC sockets. At the third walking test, the ECW with the MAS ® was significantly lower than that with the IC socket ( p = .016). PEQ MS data also improved significantly at the last evaluation ( p < .018). Conclusion Results suggest that using the MAS ®, lowering the ECW and improving PEQ MS, could be a valid prosthesis design for active TF amputees compared to their usual IC socket.

Modern research and the forgotten prosthetic history of the Vietnam war

Clinicians and researchers have become aware that achieving normal anatomical adduction of the femoral remnant is an important objective in transfemoral amputation surgery [1-3]. Achieving anatomical adduction has also been a long-established design goal of the transfemoral prosthetic limb [4-11]. The rationale for attaining normal anatomic adduction in the transfemoral amputee is to provide pelvic stabilization [4-6], provide efficient rest-length action of the abductor muscle group [4,8], and reduce the lateral motion of the center of mass of the body, thus producing a smoother and more energy-efficient gait [3]. The degree to which the prosthetic socket can influence the position of the femoral remnant has been disputed. The promotion of surgical stabilization of the through myodesis has been presented on the basis that the prosthesis does little to influence adduction [1-3]. * In 1989, the concept that socket shape and alignment do not affect the position of the femoral remnant in transfemoral amputations was introduced into the body of prosthetic thought. In their research article, Does socket configuration influence the position of the in above-knee amputation? Gottschalk et al. concluded from observations of 50 weight-bearing X-rays of transfemoral prosthetic sockets that no amount of lateral pressure can change the position of the femur and stated the belief that proper anatomical adduction is achieved through specific applied surgical techniques [1]. The sockets X-rayed in Gottschalk et al.'s study comprised both quadrilateral and ischial containment socket designs, and measurements revealed a reported average of 2[degrees] of abduction for all sockets surveyed. In 1989, the contention that socket shape and alignment do not influence the position of the femoral remnant was hotly debated at presentations at the annual meetings of the American Academy of Orthopaedic Surgeons (AAOS) and American Orthotic and Prosthetic Association (AOPA) [1,12,13 (p. 2)]. As of 2009, with numerous meeting presentations having been given and accepting literature having been published [14-15], the debate has cooled considerably. * Two publications from the 1970s, which resulted from an checkout protocol adopted by Fitzsimons Army Medical Center (FAMC) (Figure 1) after the end of America's military involvement in Vietnam, suggest that Gottschalk et al.'s conclusion is incomplete. The publications, as they exist, can be arguably dismissed and were not cited in Gottschalk et al.'s 1989 research. They comprise a two-page technical note in a 1975 prosthetics journal [9] and an abstract published in 1977 [16]. Combined, the publications are slightly more than 1,000 words. However, they serve as provenance for a collection of recently recovered documents related to FAMC's checkout of the transfemoral limb. These previously unpublished documents indicate that femoral adduction was improved, as per clinical practice, with intervention during prosthetic limb manufacture. These documents, gathered from private collections and presented in a special section of the Orthotics and Prosthetics Virtual Library, the FAMC Institutional Memory Preservation Project (http://www.oandplibrary.org/famc/), suggest that our understanding of the relationship between alignment, socket design, and femoral adduction requires further research. [FIGURE 1 OMITTED] The first published reference to FAMC's use of roentgenograms occurs in the second sentence of Long's Allowing normal adduction of in above-knee amputations, which appeared in the December 1975 issue of Orthotics and Prosthetics. Long wrote, X-ray studies carried out at Fitzsimons Army Hospital since March 1974 show that very few above-knee prostheses built in the United States today achieve proper adduction of the femoral stump [9]. It is of interest that the data from Gottschalk et al.'s research support that observation; the divergence and controversy emerge from the conclusion from that data. …

Rehabilitation of a US Army Soldier With Traumatic Triple Major Limb Amputations: A Case Report

In Brief A 22-year-old male US Army soldier injured during combat operations in Iraq. The soldier was struck by a rocket propelled grenade and his life was saved through the efforts of fellow infantrymen, combat medics, and combat support hospital staff. His treatment crossed international boundaries from Iraq, Germany, and to the United States. He arrived in Washington, DC, on the sixth day after his injury. The following amputations were performed: left transradial amputation, right hip disarticulation, and left knee disarticulation. He was fitted with a myoelectric arm, a body-powered arm, and a passive/cosmetic arm along with multiple terminal devices. He was also fitted with a right bucket hip socket and left thigh ischial containment socket with bilateral C-legs. At 1-year postinjury, the patient was functioning at a modified independent level for mobility, transfers, ambulation, and activities of daily living. He was able to walk using axillary crutches for community distances. He had exceeded all initial functional goals. Rehabilitation of a triple amputee is an uncommon challenge that will likely become more common with the improved survivability of the modern battlefield (increased protection of personal body armor, advanced training of combat medics, forward positioned surgical trauma teams, rapid medical evacuation out of theater, and advanced lifesaving techniques). As more patients with severe, multiple trauma and amputations survive, there will be a greater need for innovative and comprehensive interdisciplinary approaches to their life-saving acute care and lifelong rehabilitation. A US Army soldier who was struck by a rocket-propelled grenade in Iraq underwent a left transradial amputation, a right hip disarticulation, and left knee disarticulation. He was fitted with a myoelectric arm, a body-powered arm, and a passive/cosmetic arm, along with multiple terminal devices. He also was fitted with a right bucket hip socket and left thigh ischial containment socket with bilateral Otto Bock C-Legs. At one year post-injury, he had exceeded all initial functional goals.

Concepts of Pressure in an Ischial Containment Socket: Measurement

In Brief The goal of this study was to develop a methodology for obtaining and mapping the pressures occurring inside a “comfortable” ischial containment socket during gait for later use in studies of the perception of pressure magnitude. F-Socket (Tekscan, Inc., South Boston, MA) was used to obtain the pressure measurements for a single subject, and pressure maps displaying the dynamics of socket pressure during gait in the muscle compartments and high pressure regions of the socket were developed by windowing regions of the sensor and taking average pressures over five steps during gait. Data for the muscle compartments were plotted as splines using polar coordinates for loading response, midstance, terminal stance, and midswing. Data for regions of higher pressure concentration were plotted as points using polar coordinates. The maps revealed patterns that were in general agreement with those hypothesized by Radcliffe (Radcliffe CW. Prosthetics. In: Rose J, Gamble JG, eds. Human Walking. Baltimore: Williams & Wilkins, 1994:168–173.) to maintain anterior-posterior stability of the knee and medial-lateral stability of the pelvis, but some differences were found. Pressures in the distal compartments are hypothesized to have been influenced by downward movement of the femur and proximal tissues during gait and the morphology of the residual limb, which had fairly mobile adipose tissues distally. Data suggest a “quasi-hydrostatic” form of loading may have occurred distally, which would occur only in a snug-fitting socket. The mappings provided valuable insight into the dynamics of the socket. The authors sought to develop a methodology for obtaining and mapping the pressures occurring inside a “comfortable” ischial containment socket during gait for later use in studies of the perception of pressure magnitude. Pressure maps displaying the dynamics of socket pressure during gait in the muscle compartments and high pressure regions of the socket of one subject were developed. The maps revealed patterns that were in general agreement with those previously hypothesized, but some differences were found.

Concepts of Pressure in an Ischial Containment Socket: Perception

Concepts of Pressure in an Ischial Containment Socket: Perception

Poster 153: Knee disarticulation in a patient with an ipsilateral girdlestone hip: a case report.

Setting: Tertiary care medical center. Patient: A 66-year-old man with spindle cell sarcoma of the right lower-extremity requiring amputation. Case Description: The patient presented for preoperative consultation to an outpatient amputee clinic on an appropriate level of amputation to achieve best functional outcome. He had a Girdlestone hip on the ipsilateral side of the sarcoma. Due to the proximity of the sarcoma to the knee, a below-knee amputation was not an option. The patient suffered from multiple comorbidities, including diabetes, peripheral vascular disease, and degenerative joint disease. Preoperatively, the patient was an independent household ambulator, but used a wheelchair for longer distances. He was independent with transfers, toileting, and activities of daily living. The patient’s goal was to continue ambulation after the amputation. We recommended a knee disarticulation for the following reasons: a longer residual limb provides a better base of support for sitting, a longer lever arm is better for transfers, and less energy is expended during gait as compared with hip disarticulation or above-knee amputation. Regarding prosthetic fitting issues, the knee disarticulation would provide greater stability with the longer residual limb and partial distribution of weight bearing at the femoral condyles. Assessment/Results: The patient underwent a knee disarticulation without complication. The prosthesis included an ischial containment socket with a manual locking knee. Inpatient rehabilitation was planned for gait training. Discussion: This is the first reported case, to our knowledge, of a knee disarticulation with an ipsilateral Girdlestone hip. Conclusion: This exemplifies the importance of physiatric preoperative functional assessment, with attention to patient goals and consideration of prosthetic-fitting issues.

Transfemoral Socket Design and Suspension Options

The transfemoral socket is the interface between the patient's residual limb and the remaining prosthesis. Whether the patient uses a technologically advanced knee mechanism and foot or a single axis, constant friction knee and solid ankle cushioned heel, no other prosthetic component is as crucial in assuring a comfortable and well-functioning prosthesis as the socket. This article discusses the rationale of quadrilateral and ischial containment socket designs and reviews suspension options.

Current transfemoral sockets.

Clinicians have two types of prosthetic sockets for patients with a transfemoral amputation: the quadrilateral socket introduced in the 1950s and the ischial containment socket introduced in the 1980s. For many years, the quadrilateral socket was acceptable to clinicians and patients alike. With the introduction of the ischial containment socket claims were made that the quadrilateral socket had been inadequate from its inception. It also was claimed that the ischial containment design was the answer to all problems than patients with transfemoral amputations may have. Unfortunately, there is only one scientific study that lends any support to claims of the ischial containment socket's superiority and its findings are limited. Still, clinicians must make recommendation and prescription decisions daily regarding what is best for their patients. There are two acceptable socket designs for patients with transfemoral amputations. Experience with both supports the concept that they have more similarities than differences and that each has a legitimate place in the treatment of patients with transfemoral amputations. A comprehensive understanding of each socket design and its biomechanical intentions is essential for successful clinical application and treatment of patients with amputations.

Energy cost of walking: Comparison of “intelligent prosthesis” with conventional mechanism

Objective: To determine physiological energy cost with Blatchford's “Intelligent Prosthesis” (IP) compared to energy cost with a conventional pnuematic swing phase control (PSPC) mechanism. Design: Before-After trial: subjects fitted with IP walked on programmable treadmill at speeds: 6min slow, 6min fast, 8min while speed changed, between slow, normal, and fast, every minute, and 6min normal. Breath-by-breath analysis of subject's expired air determined average Vo 2 (L/min) within each period. Procedure repeated after 1-week interval using PSPC prosthesis. Testing sessions supervised by experienced prosthetist. Setting: Rehabilitation centre. Subjects: Volunteer sample. Three men, unilateral transfemoral traumatic amputee patients, ages 39 to 59 years. Normally used ischial containment socket, Blatchford Endolite Stabilised Stance Flex knee with PSPC and Multiflex foot and ankle. Interventions: Fitting, programming, and alignment of IP (own socket) by Bioengineering Unit's resident prosthetist. IP's microprocessor programmed to facilitate five walking speeds. Main Outcome Measure: Physiological energy cost (Vo 2), of using IP compared to using PSPC mechanism. Results: Two subjects displayed reduced Vo 2 of between 5.6% and 9.0% using IP compared to PSPC prosthesis at a pace either faster or slower than their normal pace. Third subject showed no significant change in oxygen consumption despite IP unit being heavier. All subjects displayed reduced Vo 2 (averaging 4.1%) using IP for period of variable speed walking. Conclusions: Although differences were small, they tend to indicate that use of the heavier IP unit lowered the energy cost of walking at speeds other than the amputee's normal pace.

Biomechanics and shape of the above-knee socket considered in light of the ischial containment concept

In recent years considerable interest has been generated in the United States and abroad about new style above-knee prosthetic sockets, variously referred to as Narrow M-L, NASNA, CAT-CAM and SCAT-CAM. More than a little confusion has attended the process. Moreover, the impression has been created that they are not governed by the basic biomechanical rules identified by Radcliffe as affecting the quadrilateral socket. Attention has come to be focused on the role of ischial containment and the term Ischial Containment (IC) socket is enjoying widespread use. This paper reviews many of the critical features of such sockets with the goal of first demonstrating that many of these features are dictated by the requirements of ischial containment, and second that the principles set forth by Radcliffe are fully applicable. The paper concludes with a brief discussion of the alignment principles associated with Long's Line.

Clinical Aspects and Indications of the Ischial-Ramal Containment Socket for Above-Knee Amputees

Clinical Aspects and Indications of the Ischial-Ramal Containment Socket for Above-Knee Amputees