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VOLUME 4, ISSUE 1 

 2021 

 

CASE STUDY/CASE SERIES 

Pellegrini R, Denza G, Brunelli S, Zenardi D, Imperio M, Vannozzi G, Traballesi M. The hybrid subischial socket for persons with transfemoral amputation: gait 

parameters and clinical assessment of a case series. Canadian Prosthetics & Orthotics Journal. 2021; Volume 4, Issue 1, No.9. 

https://doi.org/10.33137/cpoj.v4i1.36252 

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https://doi.org/10.33137/cpoj.v4i1.36252


 

1 

Pellegrini R, Denza G, Brunelli S, Zenardi D, Imperio M, Vannozzi G, Traballesi M. The hybrid subischial socket for persons with transfemoral amputation: gait 
parameters and clinical assessment of a case series. Canadian Prosthetics & Orthotics Journal. 2021; Volume 4, Issue 1, No.9. 
https://doi.org/10.33137/cpoj.v4i1.36252 

 

 

 
CASE STUDY/CASE SERIES 

 

THE HYBRID SUBISCHIAL SOCKET FOR PERSONS WITH TRANSFEMORAL AMPUTATION: GAIT 

PARAMETERS AND CLINICAL ASSESSMENT OF A CASE SERIES 

Pellegrini R1, Denza G1, Brunelli S2 *, Zenardi D1, Imperio M3, Vannozzi G3, Traballesi M2
 

 

1 ITOP Spa, Officine Ortopediche, Palestrina, Rome, Italy. 
2 Fondazione Santa Lucia, Scientific Institute for Research, Hospitalization and Health Care, Rome, Italy. 
3 Department of Movement, Human and Health Sciences, Foro Italico, University of Rome, Rome, Italy. 

 

 

 

 

  

 

 

 

 

 

 

 

 
 

 

 

 

INTRODUCTION   

Current trends relating to the design of the prosthesis for 

persons with transfemoral (TF) amputation lead to sockets 

and suspension systems that allow for a hip range of motion 

that is as close as possible to the physiological one, and that 

do not interfere with muscle activity. A socket with these 

characteristics should improve walking of persons with TF 

amputation.1,2  

The socket is the interface between the prosthesis and the 

appendicular skeleton via residual limb soft tissue. The 

socket shape aims to ensure a comfortable use of the 

prosthesis both in static and in dynamic phases without 
causing pain.3 Despite  the  improvement  in  technology  in  

 

recent years, about 20% of persons with TF amputation are 

reported not walking at all at home while about 50% do not 

use the prosthesis outside.4 

The most common transfemoral sockets is the Ischial 

Containment Socket (ICS).5 One drawback is the limitation 

of hip motion, in particular the hip extension, because it 

encloses the ischial tuberosity and the ramus within the 

socket. This shape is also reported to cause discomfort 

when the user is sitting.6  

The Marlo Anatomical Socket (MAS) is an evolution of the 

ICS. MAS users have shown a significant improvement of 

 
OPEN  ACCESS Volume 4, Issue 1, Article No.9. 2021 

 

 

Journal Homepage: https://jps.library.utoronto.ca/index.php/cpoj/index 

 

ABSTRACT 

BACKGROUND: The subischial socket interface design is a promising new shape of socket for persons 

with transfemoral amputation. Typically, the proximal trim line is located distal to the ischial tuberosity, 

improving comfort in prosthetic users without interfering with gait parameters compared to Ischial 

Containment Socket (ICS). No studies have investigated the performances of a subischial sockets with 

suction suspension system. A new subischial socket (Hybrid Subischial Socket - HySS) combined with 

a hypobaric passive suspension system has been recently developed. 

OBJECTIVE: To assess the effects of HySS in terms of comfort, hip range-of-motion and gait 

parameters. 

METHODOLOGY: Three persons with transfemoral amputation were tested first using their usual ICS 

and then after one month of continuous use of HySS. 

FINDINGS: The following parameters improved in all participants using HySS: 1) hip range-of-motion, 

2) walking speed and distance, 3) Timed-Up-and-Go-Test time, 4) stride length, 5) double support 

duration, 6) peak value of hip extension during stance, 7) satisfaction with the prosthesis. 

CONCLUSION: These findings suggest that the use of HySS could allow improvements for prosthetic 

use. 

ARTICLE INFO 

Received: March 25, 2021 

Accepted: July 1, 2021 

Published: July 14, 2021 

CITATION 

Pellegrini R, Denza G, Brunelli 

S, Zenardi D, Imperio M, 

Vannozzi G, Traballesi M. The 

hybrid subischial socket for 

persons with transfemoral 

amputation: gait parameters and 

clinical assessment of a case 

series. Canadian Prosthetics & 

Orthotics Journal. 2021; Volume 

4, Issue 1, No.9. 

https://doi.org/10.33137/cpoj.v4i

1.36252 

KEYWORDS 

Artificial Limb, Prosthetic Socket, 

Gait Analysis, Transfemoral 

Amputation, Locomotion, Ischial 

Containment, Socket Comfort 

 

 

* CORRESPONDING AUTHOR 

Stefano Brunelli, MD 

Fondazione Santa Lucia, Scientific Institute for Research, Hospitalization and Health Care, Rome, Italy. 

E-Mail: s.brunelli@hsantalucia.it 

ORCID ID: https://orcid.org/0000-0002-5986-1564 

https://doi.org/10.33137/cpoj.v4i1.36252
https://jps.library.utoronto.ca/index.php/cpoj/index
https://doi.org/10.33137/cpoj.v4i1.36252
https://doi.org/10.33137/cpoj.v4i1.36252
mailto:s.brunelli@hsantalucia.it
https://orcid.org/0000-0002-5986-1564


 

2 

Pellegrini R, Denza G, Brunelli S, Zenardi D, Imperio M, Vannozzi G, Traballesi M. The hybrid subischial socket for persons with transfemoral amputation: gait 
parameters and clinical assessment of a case series. Canadian Prosthetics & Orthotics Journal. 2021; Volume 4, Issue 1, No.9. 
https://doi.org/10.33137/cpoj.v4i1.36252 

ISSN: 2561-987X THE HYBRID SUBISCHIAL SOCKET FOR PERSONS WITH TRANSFEMORAL AMPUTATION   

Pellegrini et al. 2021 CPOJ 

 
gait efficiency and prosthesis-related perceived mobility 

compared to ICS. Although the ischium and gluteus 

maximum are not included in the MAS because of the 

lowered posterior shelf, even requires an interaction with 

the pelvis due to lateral containment.2 

The subischial socket has been a recent development in 

socket design.7 In this socket the proximal trim line is 

located distal to the ischial tuberosity and it does not interact 

with the pelvis.  

In the last decade some studies had shown how the 

subischial socket could improve the spatiotemporal gait 

parameters, the functional performance with the prosthesis 

and the comfort compared to the ICS.2,8-11 The vacuum 

assisted suspension system was used in all these studies. 

More recently the Northwestern University, Prosthetic 

Orthotic Center, Chicago, Illinois, USA has described the 

construction technique necessary to create a subischial 

socket with a suction suspension system: the NU-FLEX 

SIS.12 This technical note showed that suspension systems 

can involve differences in socket shape compared to the 

subischial socket ensured by vacuum. A subischial socket 

(Hybrid Subischial Socket - HySS) has been developed, 

embedding a suspension system that is ensured by a 

hypobaric liner Seal-In X® without an external sleeve and 

without vacuum. Its internal shape has four areas of tissue 

compression obtained with a casting technique and without 

rectification procedures as previously described in the 

literature.7,12 The HySS includes an inner socket made of 

biomedical silicone and an external carbon fiber frame. 

Figure 1 shows the differences between ICS and HySS. 

 

Figure 1: Differences between Ischial Containment Socket (left 

side - grey socket) and Hybrid Subischial Socket (right side - blue 

socket). Top left: frontal view. Top right: posterior view. Bottom left: 

medial view: Bottom right: lateral view. 

The shape and the principles of manufacturing of HySS, as 

in the other subischial sockets, may represent a benefit for 

the ICS prosthesis users. The pelvis is free from the contact 

with the socket, thus an increase in hip range of motion 

(RoM) should be observed (Figure 2).13 

An increase in RoM should “free” the hip during walking with 

better performances in terms of speed, endurance, motor 

ability and comfort during prosthesis use. 

 

Figure 2: Posterior view of HySS. In this case, the socket is coated 

with silicone for aesthetic purposes. 

To the best of our knowledge, no previous studies have 

investigated the functional effects of a subischial socket with 

suction suspension system. This report describes the 

differences in terms of gait parameters, hip RoM and 

satisfaction with the prosthesis following the change of the 

socket (from ICS to HySS) in three persons affected by TF 

amputation. 

METHODOLOGY 

2.1 Participants  

We randomly selected the persons with TF amputation 

among those accessing the local Prosthetics-Orthotics 

Center, informing them about the opportunity to try the new 

socket. The inclusion criteria included being over the age of 

18, being able to provide informed consent, having a 

transfemoral amputation, and being a prosthesis user. 

Informed consent was obtained from the participants after 

they were provided with an accurate description of the HySS 

and the purpose of the tests they would be subjected to. 

This case study was a pilot study; a forthcoming larger study 

is planned for which ethics committee approval is pending. 

2.2 Testing protocols 

Gait kinematic was measured using a SMART DX700 from 

BTS Bioengineering (Milan, Italy), which consisted of eight 

infrared cameras, used to record the position of 22 passive 

markers, applied on the subjects following the Davis 

https://doi.org/10.33137/cpoj.v4i1.36252


 

3 

Pellegrini R, Denza G, Brunelli S, Zenardi D, Imperio M, Vannozzi G, Traballesi M. The hybrid subischial socket for persons with transfemoral amputation: gait 
parameters and clinical assessment of a case series. Canadian Prosthetics & Orthotics Journal. 2021; Volume 4, Issue 1, No.9. 
https://doi.org/10.33137/cpoj.v4i1.36252 

ISSN: 2561-987X THE HYBRID SUBISCHIAL SOCKET FOR PERSONS WITH TRANSFEMORAL AMPUTATION   

Pellegrini et al. 2021 CPOJ 

 
protocol,14 at a rate of 250 Hz. Kinematics data were then 

combined with the kinetic one obtained using four force 

plates (BTS P-6000), each one containing four load cells 

that use strain gauges.15 A recording is also done with two 

optical cameras BTS Vixta (sampling rate: 25 Hz) to 

combine each test with a real-time video recording. Data 

analysis was performed using BTS SMART software, which 

is associated to the used devices; it calculates 

spatiotemporal parameters, joint kinematics and kinetics 

from the raw data acquired by the cameras and the force 

plates. The covered distance during Six-Minute Walking 

Test (6MWT) and duration of the Timed-Up-and-Go-Test 

(TUG) were obtained using one inertial measurement unit 

(G-Sensor, BTS), firmly attached on the pelvis of the 

participant16 and the relevant gait parameters 

calculated.17,18 For analysis subset of them, the Degree of 

Asymmetry (DoA) was calculated as in previous studies,9,19 

because it allows for the assessment of the differences 

between the contralateral and prosthetic leg during 

locomotion tasks. In a healthy individual, the asymmetry is 

lower compared to a person with unilateral lower limb 

amputation, thus an effective prosthesis should lead to DoA 

for all measured values as low as possible. The DoA 

represents the variation between the sound leg (S) and the 

prosthetic leg (P) which is obtained using the following 

formula:  

𝐷𝑜𝐴 = (
𝑆−𝑃

𝑆+𝑃
) ∗ 100 

2.2.1 Hip range of motion 

Maximum values of hip extension, flexion and abduction on 

the prosthetic side were measured using a long arm 

goniometer and the protocol proposed by Norkin.20 Four 

measurements were performed for each variable and, then, 

the relevant mean values were calculated (Figure 3). 

 

Figure 3: Measurement of hip flexion of the prosthetic side.  

2.2.2 Gait analysis 

Subjects were asked to walk on a straight line at a self-

selected speed inside the measurement area defined by the 

cameras. Five trials were recorded, during which at least 

one gait cycle could be identified using the force plate data. 

Focusing on a full gait cycle for each leg, based on both 

kinematics and kinetics measurements and the 

identification of the heel strike and toe-off events, the mean 

value of the following parameters was calculated:21,22   

1) Walking speed (m/s),  

2) Cadence (steps/min),  

3) Step width (m),  

4) Stride length (m),  

5) Double support (%),  

6) Hip extension (degrees).23 

 

For a subset of the above mentioned gait analysis 

parameters, the DoA was also calculated:9  

1) Step Length (DoA),  

2) Stance Duration (DoA),  

3) Swing Duration (DoA),  

4) Single Support Duration (DoA). 

 

Hip angles on the sagittal plane of both legs were exported 

in MATLAB. An algorithm was implemented to identify the 

peak value of the extension of the prosthetic hip and sound 

leg during the stance phase, as in a study by Tranberg et 

al.13  

2.2.3 Performance tests using a wearable sensor 

With an inertial sensor placed on the L5 vertebra, each 

subject walked on a straight line back and forth for six 

minutes.24 The path was 10 meters long inside the 

laboratory. The proprietary software (G-Studio) provided the 

total distance traveled (6MWT). 

With the same set-up, the participants were asked to stand 

up from a chair, to walk for three meters and, then, to turn 

back and sit down again, recording the amount of time 

necessary for the patient to perform the task (TUG).25 

2.2.4 Self-evaluation test 

To determine comfort and improvement of quality of life 

provided by the use of the prosthesis, the participants        

completed the SATPRO questionnaire which involves 15 

items related to the use of the prosthesis in daily life 

measured using a four-level scale (score 0-45, where 45 

means maximum satisfaction).26   

2.3 Timing and socket change 

All the mentioned evaluation tools were administered twice. 

The first measurement occurred after the first evaluation 

https://doi.org/10.33137/cpoj.v4i1.36252


 

4 

Pellegrini R, Denza G, Brunelli S, Zenardi D, Imperio M, Vannozzi G, Traballesi M. The hybrid subischial socket for persons with transfemoral amputation: gait 
parameters and clinical assessment of a case series. Canadian Prosthetics & Orthotics Journal. 2021; Volume 4, Issue 1, No.9. 
https://doi.org/10.33137/cpoj.v4i1.36252 

ISSN: 2561-987X THE HYBRID SUBISCHIAL SOCKET FOR PERSONS WITH TRANSFEMORAL AMPUTATION   

Pellegrini et al. 2021 CPOJ 

 
session performed with the ICS socket. Participants were 

also fit with the HySS at this first appointment. After one 

month of acclimation to the new socket, participants 

performed the second evaluation session while wearing the 

HySS socket. Only the sockets were changed between 

sessions. Socket alignment was performed by a team of 

certified experienced prosthetists. 

RESULTS  

In this preliminary study, 3 males with TF amputation were 

enrolled. All of them were K-level 4 prosthetic users, fitted 

with an ICS socket and a Seal-In suspension system. 

Proper fit and function of the existing prosthesis were 

confirmed by a certified prosthetist. The demographic and 

prosthetic information is reported in Table 1. 

As shown in Table 2, no difference was found in terms of 

variation of cadence, step width and all DoAs in each 

participant while wearing the ICS or HySS socket. An 

improvement was observed in the following parameters in 

all participants donning HySS: 1) passive hip RoM, 2) the 

distance covered during 6MWT, 3) the time of TUG and the 

following kinematic and temporal parameters related to gait, 

4) stride length, 5) double support duration, 6) walking 

speed and 7) peak value of hip extension during stance 

phase for both legs (Table 2). 

Table 1: Demographic and prosthetic information of the sample. BMI= Body Mass Index. 

Patient 
Age 

(yrs.) 
BMI (kg/m2) Side K- Level Cause of amputation 

Time since 

amputation 

Suspension 

System 
Knee Foot 

1 18 19.58 Right 4 Cancer 10 months Seal-In Genium Pro-Flex 

2 35 21.26 Left 4 Trauma 18 years Seal-In Genium Vari-Flex 

3 32 26.69 Left 4 Trauma 7 months Seal-In Genium Pro-Flex 

 

Table 2: Results obtained for each participant with both sockets. The difference (DIF%) is expressed as percentage variation. ICS: Ischial 

Containment Socket. HySS: Hybrid Subischial Socket. DoA: Degree of Asymmetry. 

Measure 
Patient 1 Patient 2 Patient 3 

ICS HySS DIF% ICS HySS DIF% ICS HySS DIF% 

Hip Range of Motion 

Abduction° 30 ± 6 45 ± 6 +50 18 ± 6 32 ± 5 +77.78 34 ± 4 40 ± 4 +17.65 

Flexion° 88 ± 11 96 ± 11 +9.09 65 ± 10 95 ± 13 +46.15 77 ± 12 110 ± 12 +42.86 

Extension°  21 ± 7 25 ± 6 +19.05 10 ± 7 21 ± 9 +110 10 ± 8 20 ± 8 +100 

Gait Analysis (global temporal parameters) 

Walking Speed 
(m/s) 

1.1 ± 0.0 1.2 ± 0.0 +9.09 0.9 ± 0.1 1.1 ± 0 +22.22 1.1 ± 0 1.2 ± 0 +9.09 

Cadence 
(steps/min) 

101.8 ± 1.7 104.8 ± 2.6 +2.95 97 ± 3 100.2 ± 1.1 +3.3 108.7 ± 0.8 109.9 ± 2.6 +1.1 

Gait Analysis (global spatial parameters) 

Step Width (m) 0.10 ± 0.01 0.11 ± 0.01 +10 0.12 ± 0.01 0.10 ± 0.01 -16.67 0.17 ± 0.01 0.16 ± 0.03 -5.88 

Gait Analysis (P-Leg temporal and spatial parameters) 

Stride Length (m) 1.29 ± 0.04 1.42 ± 0.6 +10.0 1.11 ± 0.03 1.29 ± 0.03 +16.2 1.21 ± 0.01 1.31 ± 0.03 +8.2 

Double Support 
Duration (%) 

15.1 ± 0.8 13.2 ± 0.9 -12.5 17.9 ± 1.3 11.4 ± 0.8 
 

-36.3 
19.5 ± 0.4 14.2 ± 1.1 -27.1 

Gait Analysis (peak angles during stance phase) 

P-Leg Hip 
Extension° 

-19.9 ± 0.8 -19.7 ± 1.7 -1.0 -3.5 ± 0.9 -8.2 ± 0.6 -134.2 3.4 ± 1.1 1.2 ± 0.9 -64.7 

S-Leg Hip 
Extension°  

-14.2 ± 1.7 -14.7 ± 2.2 -3.4 -6.3 ± 1.2 -8.1 ± 0.9 -28.5 1.5 ± 1.9 -4 ± 3 -366.6 

Gait Analysis (asymmetry between legs) 

Step Length (DoA) 4 ± 3 -3.9 ± 1.9 -8.18 -1 ± 6 0.1 ± 0.8 1.14 -0.7 ± 0.5 0.9 ± 1.2 1,66 

Stance Duration 
(DoA)  

6.2 ± 1.7 6.3 ± 1.4 0.09 5.3 ± 2.2 3.2 ± 1.9 -2.20 1.7 ± 0.9 4.5 ± 2.8 2,85 

Swing Duration 
(DoA) 

-10.9 ± 2.8 -10.8 ± 2.9 0,16 -10 ± 5 -5 ± 3 5.31 -3.9 ± 1.8 -8 ± 5 -4.75 

Single Support 
Duration (DoA) 

8 ± 6 11 ± 3 2,35 9 ± 6 5 ± 6 -3.99 1.0 ± 2.5 8 ± 7 7.20 

Timed-Up and Go 

Duration (s) 15.2 ± 0.5 13.1 ± 1.5 -13.82 15.3 ± 0.7 13.6 ± 0.8 -11.11 10.7 ± 0.7 9.1 ± 0.3 -14.95 

6-Minute Walking Test 

Distance (m) 300 340 +13.33 NA 320  270 380 +40.74 

SAT-PRO 

Score 43 45 +4.6 35 43 +22.8 28 34 +21.4 

 

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5 

Pellegrini R, Denza G, Brunelli S, Zenardi D, Imperio M, Vannozzi G, Traballesi M. The hybrid subischial socket for persons with transfemoral amputation: gait 
parameters and clinical assessment of a case series. Canadian Prosthetics & Orthotics Journal. 2021; Volume 4, Issue 1, No.9. 
https://doi.org/10.33137/cpoj.v4i1.36252 

ISSN: 2561-987X THE HYBRID SUBISCHIAL SOCKET FOR PERSONS WITH TRANSFEMORAL AMPUTATION   

Pellegrini et al. 2021 CPOJ 

 
Based on self-evaluation tests that are known to be 

indicative of the participants’ opinion of the sockets, all 

participants reported greater satisfaction with HySS (Table 

2) 

DISCUSSION 

All three participants in this case series demonstrated 

improvement in hip RoM, some gait parameters, and 

satisfaction with the prosthesis when using the HySS 

compared to the ICS. 

The increase in passive hip RoM confirms the sub-ischial 

design overcomes one disadvantage of the ischial 

containment socket, which is characterized by an increased 

constraint on the hip of the affected limb, as shown by other 

authors.2,8,26 Our results clearly indicate increased RoM in 

both ab/adduction and flexion-extension of the hip, 

obtaining higher maximum angles, with percentage change 

that reaches +110% in hip extension for one patient. 

Greater degree of hip flexion is also achieved during walking 

and for both the prosthetic and the sound limbs, with values 

obtained for all patients that are closer to those observed in 

normal gait. 

The SATPRO results suggest an increased overall comfort 

using the HySS, probably due to the greater RoM. Two 

patients reported a remarkable improvement in SATPRO 

answers (+22% and +21%), while the third one had a lower 

improvement (+4%) probably due to his higher ICS score.  

Parameters obtained during clinical performance tests 

indicate an improved involvement of the prosthetic leg while 

performing common daily tasks, which were performed at 

increased speed. For both 6MWT and TUG, a positive 

variation was observed, above the minimum detectable 

change in amputated individuals (MDC) of 45.0 m and 

1.28s, respectively, as reported in literature.27,28 

Certain biomechanical characteristics, like cadence, step 

width and all gait phase durations express as DoA are 

characterized by values that do not vary consistently or with 

a remarkable increment or decrement. Thus, the effect of 

the socket on these aspects of the gait can be considered 

minimal. 

While presenting these main advantages over ICS sockets, 

this new hybrid sub-ischial design does not present any 

remarkably negative variation on typical gait parameters. 

Asymmetry between legs does not vary significantly and 

consistently, with non-negligible percentage variation 

typically associated with a higher standard deviation that 

does not allow to interpret the results obtained with different 

sockets as different. Improvements on gait velocity and 

stride length (around +10% or more for both measures and 

for each patient) with a negligible cadence variation 

(between +1% and +3%) could indicate a safer gait, with an 

improvement in walking speed mainly caused by longer 

footsteps. 

Another interesting result is the change in the duration of 

double support phase within the gait cycle of the affected 

limb expressed as percentage of the whole cycle. In fact, it 

is shown how double support phase occupies a smaller 

amount of the gait cycle because of the increase in 

velocity.29 This can be considered as another sign of 

improvement in subjects’ walking, since increased values of 

double support duration in healthy subjects is typically found 

in the elderly.30 

These results are in line with the those obtained with the 

NU-FlexSIV socket, where gait analysis parameters are 

unaffected by a lower brim, while hip RoMs are improved as 

expected by a design that does not contain the ischial ramus 

inside the prosthesis.2 New sub-ischial sockets represent a 

new possibility to improve the quality of life of the individuals 

affected by lower limb amputations. The material used for 

HySS, biomedical silicone, allows to precisely customize 

the morphology, thickness, stiffness and color to produce 

socket that combine desirable features.31 The results 

obtained from this case series should be considered 

preliminary due to the low number of participants involved. 

Future work will consist of a larger cohort of individuals with 

limb loss.  

CONCLUSION 

The HySS can be considered an improvement over ischial 

containment sockets, because of the potential to overcome 

some common problems with ICS designs while achieving 

similar performance in other aspects of use. 

ACKNOWLEDGEMENTS 

Thanks to ITOP Spa, Officine Ortopediche, Palestrina, Rome, Italy 

for the design and fabrication of custom HySS. 

DECLARATION OF CONFLICTING 

INTERESTS 

All the authors declare to have no conflicts of interest to declare. 

AUTHOR CONTRIBUTION 

• Roberto Pellegrini: design and fabrication of HySS, supported 

the writing of the manuscript. 

• Gabriele Denza: acquisition, analysis of the data, led the writing 

of the manuscript. 

• Stefano Brunelli: conceived idea of the work, led the writing of 

the manuscript. 

• Daniele Zenardi: design and fabrication of HySS, supported the 

writing of the manuscript. 

https://doi.org/10.33137/cpoj.v4i1.36252


 

6 

Pellegrini R, Denza G, Brunelli S, Zenardi D, Imperio M, Vannozzi G, Traballesi M. The hybrid subischial socket for persons with transfemoral amputation: gait 
parameters and clinical assessment of a case series. Canadian Prosthetics & Orthotics Journal. 2021; Volume 4, Issue 1, No.9. 
https://doi.org/10.33137/cpoj.v4i1.36252 

ISSN: 2561-987X THE HYBRID SUBISCHIAL SOCKET FOR PERSONS WITH TRANSFEMORAL AMPUTATION   

Pellegrini et al. 2021 CPOJ 

 
• Matteo Imperio: acquisition, managed the data files, drafted the 

manuscript. 

• Giuseppe Vannozzi: revised the manuscript critically for 

important intellectual content, supported the data analysis, 

interpretation of the data. 

• Marco Traballesi: revised the manuscript critically for important 

intellectual content. 

SOURCES OF SUPPORT 

The authors received no financial support for the research, 

authorship or publication of this article. 

ETHICAL APPROVAL 

This case study was a pilot study; a forthcoming larger study is 

planned for which ethics committee approval is pending. 

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