Lower Extremity AmputationAStrO-OINCT04934839
Instrumental Analysis of Walking in People With Osseointegrated Prostheses for Lower Extremity Amputation: Comparative Evaluation With Traditional Socket Prostheses
A study testing Test of standing balance (Equitest System). Test of walking in tied and split conditions on a force-sensorized split-belt treadmill. in people with Lower Extremity Amputation, run by Istituto Auxologico Italiano at 2 sites in Italy.
Trial summary
The currently accepted standard for rehabilitation and mobility following amputation is a socket-mounted prosthesis. Osseointegration is an alternative method that has gradually gained greater acceptance in the last 30 years. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Lower Extremity Amputation
- What is being tested?
- Test of standing balance (Equitest System). Test of walking in tied and split conditions on a force-sensorized split-belt treadmill.
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 2 participants
- Where
- 2 sitesItaly
- Study dates
- 7 Jun 2021to 9 Jun 2021
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- unilateral lower extremity amputation;
- age > 18 years;
- amputation-adjusted Body Mass Index between 18 and 25;
- ability to understand the instructions;
- ability to wittingly sign the informed consent form.
Who cannot join
- other previous knee injuries or major surgical interventions at the lower limbs;
- comorbidities, such as neurological conditions, vascular diseases, or diseases of orthopedic, cardiac, or pulmonary origin;
- cancer disease in the site under examination;
- other neurological pathologies with impact on balance and gait.
Trial locations and contacts
2 sites in 1 country.
Italy2 sites
Istituto Auxologico Italiano
Milan, MI, 20122
ASST Gaetano Pini-CTO
Milan, 20122
About this study
The currently accepted standard for rehabilitation and mobility following amputation is a socket-mounted prosthesis. Osseointegration is an alternative method that has gradually gained greater acceptance in the last 30 years. It is defined as a procedure in which a metal implant is directly anchored to the residual bone, attached to a prosthetic limb using a transcutaneous connector.
The advantages of osseointegrated prostheses over conventional socket prostheses include stable fixation, significant increases in walking ability, range of motion and control of the prosthesis, and health-related quality of life. Moreover, bodyweight distribution results more similar to physiological conditions.
Read more
No formal consensus exists for osseointegration surgery. However, based on the positive clinical experience, surgeons currently indicate this surgery for those patients who show poor tolerance of socket prostheses.
The present study investigates neuro-physiologic and mechanical parameters of walking and balance in patients with lower limb amputation and osseointegrated prostheses and in matched patients with traditional socket prostheses to highlight strengths and weaknesses of the alternative technique with respect to the present standard of care.
The primary endpoint is the investigation of the neurologic and mechanic adaptation in terms of a) kinematic and dynamic segmental analysis of walking and transfer of the body center of mass during walking; b) capacity to retain balance in response to different conditions of oscillation, tilt, and translation of a posturographic platform.
The secondary endpoint is investigating of adaptation to walking on a split-belt treadmill mounted on force sensors with the belts running at different velocities.
We hypothesize that:
- the deficit in joint power of the prosthetic limb is associated with a phenomenon of "learned non-use" both in balance and during gait. This behavior looks automatic and unconscious. It consists of the under recruitment of the impaired side as a form of unconscious protection, which is adopted when the contralateral side may be exploited to carry out the function;
- the joint power provided by the prosthetic limb may increase both by increasing treadmill velocity and by walking in split-belt modality with the prosthetic limb on the faster belt;
- an "after-effect" will be evidenced after the split-belt walking test when the two belts will return to the same velocity; patients with osseointegrated prostheses and patients with socket prostheses may show different behaviors in the adaptation to split-belt walking and the following post-adaptation, as a result of the residual proprioception of the amputated limb.
Results from the present study will allow:
- the identification of the possible advantages in walking and balance symmetry in patients with osseointegrated prostheses with respect to patients with socket prostheses;
- the estimate of the sample size for future experimental protocols and new rehabilitative programs.
- Conditions
- Lower Extremity Amputation
- Being tested
- Test of standing balance (Equitest System). Test of walking in tied and split conditions on a force-sensorized split-belt treadmill.
- Keywords
- Lower extremity amputation, Osseointegrated prostheses, Learned non-use, Rehabilitation, Walking, Gait analysis, Split-belt treadmill, Balance, Osseointegration
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Test of standing balance (Equitest System). Test of walking in tied and split conditions on a force-sensorized split-belt treadmill.Diagnostic test
Tests of standing balance will be performed using the EquiTest System posturographic platform. Individuals will be requested to perform three tasks within the EquiTest battery: Sensory Organization test, Motor Control test backward/forward, Adaptation Test upward/downward.
Gait analysis will be performed on a force sensorized split-belt treadmill. Participants will walk at increasing velocities from 0.2 m/s to the highest sustainable velocity in tied-belt condition. Velocity will be increased by 0.1 m/s every 20 consecutive strides.
During gait analysis in the split-belt condition, participants will walk for 30 seconds with both belts at 0.4 m/s. Then, the velocity of the belt under the prosthetic limb will be increased to 1.2 m/s. After 6 minutes, the velocity of the faster belt will be restored at 0.4 m/s for 6 more minutes. Different combinations of velocities could be tested based on the patients' characteristics, maintaining a ratio of 3:1 between the velocities of the 2 belts.
| Study group | Role | What they receive |
|---|---|---|
| Patients with osseointegrated prostheses | Experimental | Patients with an osseointegrated prosthesis following a lower limb amputation Receives: Diagnostic Test: Test of standing balance (Equitest System). Test of walking in tied and split conditions on a force-sensorized split-belt treadmill. |
| Patients with socket prostheses | Experimental | Patients with a socket-mounted prosthesis following a lower limb amputation Receives: Diagnostic Test: Test of standing balance (Equitest System). Test of walking in tied and split conditions on a force-sensorized split-belt treadmill. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Joint power
Joint kinematics will be recorded during walking through an optoelectronic method as per the Davis anthropometric model. The 3D displacement of the markers will be captured using 8 near-infrared stroboscopic cameras. Joint power will be computed through the spatiotemporal synchronization of ground reaction force vectors and the joint centers of rotation. The sagittal plane, only, will be considered for the analysis. Hip, knee, and ankle joint power will be computed as the product of joint torque and joint rotation speed. Power will be defined as positive or generated when the joint moment and rotation speed share the same directions (i. e., when agonist muscles are contracting while shortening), as negative or absorbed otherwise. Positive work will be computed as the integral of the generated (positive) power over time.
Measured: Day 1
Secondary outcomes (7)
Kinetic energy of the center of mass during walking
Changes in kinetic energy during walking due to the forward (Ekf), lateral (Ekl), and vertical (Ekv) velocity will be computed.
Measured: Day 1
Energy of the center of mass during walking due to vertical motion
Changes in gravitational potential energy (Ep), and changes of the mechanical energy due to the vertical motion, Ev = Ekv+Ep, will be computed.
Measured: Day 1
Total mechanical energy of the center of mass during walking
Changes in total mechanical energy (Etot = Ekf+Ekl +Ev) will be computed.
Measured: Day 1
Recovery of mechanical energy, R
The amount of recovery of mechanical energy, R, due to the passive exchange between Ekf, Ev and Ekl, during walking, will be computed according to the equation R = (Wf + Wv + Wl - Wext)/(Wf + Wv + Wl) × 100, where Wf for Ekf, Wv for Ev, Wl for Ekl and Wtot for Etot represents the corresponding work values calculated as the sum of the positive increments of these energy values during one step.
Measured: Day 1
SOT score
The patient's task is to maintain an upright stance during three 20 s trials under six different conditions, including movements of the platform and the visual surround 'tuned' with the individual's sagittal oscillation. The SOT score will be calculated by comparing the sagittal oscillation of the body's center of mass (COM) to the maximal sagittal oscillation. The score is averaged across the six conditions (range 0-100. The higher the score, the lower the oscillation).
Measured: Day 1
MCT score
The patient's capacity to recover upright stance when the platform suddenly shifts forward or backward, thus causing the subject to lean back or forward with respect to the ground. The score is the latency between the onset of translation and the rise of a compensatory torque. Average latency between legs, repetitions and stimulus amplitude (36 values overall) is computed. The score is given in ms (the lower, the better).
Measured: Day 1
ADT score
The patient's capacity to minimize body sway when the platform suddenly tilts upward or downward, thus causing the body to lean backward or forward with respect to the ground, respectively. A non-dimensional parameter from a 'sway-energy function' is calculated. The function provides an 'energy' parameter derived from the root mean square of speed and acceleration of the position of the centre of pressure on the force plate during the tilt (range 0 to infinite, the lower, the better).
Measured: Day 1
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Jun 2021
- Study start7 Jun 2021
- Primary completion9 Jun 2021
- Study completion9 Jun 2021
Why it stopped: Recruitment halted after enrollment of two participants because no additional eligible patients with the required osseointegrated prosthesis could be identified in Italy.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Lower Extremity AmputationStudies of the same condition, open and under way.
- More trials run by Istituto Auxologico ItalianoThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Diagnosis
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Model description
- Osseointegration for lower limb amputation is a rare procedure. Therefore, a convenience sample of patients will be enrolled. Efforts will be made to match the participants with controls, fitted with conventional socket prosthesis, by age, gender, height and weight without the prosthesis, prosthetic side, and type of prosthesis, but an exact matching is not considered a strict requirement.
- Masking
- None (open label)
- Enrolment
- 2 participants (actual)
Sponsor and investigators
- Lead sponsor
- Istituto Auxologico Italiano
- Sponsor type
- University, hospital or other
- Collaborators
- ASST Gaetano Pini-CTO
- Responsible party
- Sponsor
- Investigators
- Luigi Tesio, MD, Professor, Principal investigator, Istituto Auxologico Italiano
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04934839
- Sponsor's protocol ID
- 24X101
- Acronym
- AStrO-OI
- Status last verified
- Nov 2026
- First submitted
- 31 May 2021
- Last updated
- 6 Nov 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes
Study at a glance
From the registry record, last updated by the sponsor on 6 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Instrumental Analysis of Walking in People With Osseointegrated Prostheses for Lower Extremity Amputation: Comparative Evaluation With Traditional Socket Prostheses
- ClinicalTrials.gov ID
- NCT04934839
- Acronym / sponsor ID
- AStrO-OI / 24X101
- Conditions
- Lower Extremity Amputation
- Keywords
- Lower extremity amputation, Osseointegrated prostheses, Learned non-use, Rehabilitation, Walking, Gait analysis, Split-belt treadmill, Balance
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Recruitment halted after enrollment of two participants because no additional eligible patients with the required osseointegrated prosthesis could be identified in Italy.
- Enrolment
- 2 participants (actual)
- Lead sponsor
- Istituto Auxologico ItalianoUniversity, hospital or other
- Collaborators
- ASST Gaetano Pini-CTO
- Study start
- 7 Jun 2021 (actual)
- Primary completion
- 9 Jun 2021 (actual)
- Study completion
- 9 Jun 2021 (actual)
- First posted
- 22 Jun 2021 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The currently accepted standard for rehabilitation and mobility following amputation is a socket-mounted prosthesis. Osseointegration is an alternative method that has gradually gained greater acceptance in the last 30 years. It is defined as a procedure in which a metal implant is directly anchored to the residual bone, attached to a prosthetic limb using a transcutaneous connector.
The advantages of osseointegrated prostheses over conventional socket prostheses include stable fixation, significant increases in walking ability, range of motion and control of the prosthesis, and health-related quality of life. Moreover, bodyweight distribution results more similar to physiological conditions.
No formal consensus exists for osseointegration surgery. However, based on the positive clinical experience, surgeons currently indicate this surgery for those patients who show poor tolerance of socket prostheses.
The present study investigates neuro-physiologic and mechanical parameters of walking and balance in patients with lower limb amputation and osseointegrated prostheses and in matched patients with traditional socket prostheses to highlight strengths and weaknesses of the alternative technique with respect to the present standard of care.
The primary endpoint is the investigation of the neurologic and mechanic adaptation in terms of a) kinematic and dynamic segmental analysis of walking and transfer of the body center of mass during walking; b) capacity to retain balance in response to different conditions of oscillation, tilt, and translation of a posturographic platform.
The secondary endpoint is investigating of adaptation to walking on a split-belt treadmill mounted on force sensors with the belts running at different velocities.
We hypothesize that:
- the deficit in joint power of the prosthetic limb is associated with a phenomenon of "learned non-use" both in balance and during gait. This behavior looks automatic and unconscious. It consists of the under recruitment of the impaired side as a form of unconscious protection, which is adopted when the contralateral side may be exploited to carry out the function;
- the joint power provided by the prosthetic limb may increase both by increasing treadmill velocity and by walking in split-belt modality with the prosthetic limb on the faster belt;
- an "after-effect" will be evidenced after the split-belt walking test when the two belts will return to the same velocity; patients with osseointegrated prostheses and patients with socket prostheses may show different behaviors in the adaptation to split-belt walking and the following post-adaptation, as a result of the residual proprioception of the amputated limb.
Results from the present study will allow:
- the identification of the possible advantages in walking and balance symmetry in patients with osseointegrated prostheses with respect to patients with socket prostheses;
- the estimate of the sample size for future experimental protocols and new rehabilitative programs.
Study design
- Primary purpose
- Diagnosis
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Osseointegration for lower limb amputation is a rare procedure. Therefore, a convenience sample of patients will be enrolled. Efforts will be made to match the participants with controls, fitted with conventional socket prosthesis, by age, gender, height and weight without the prosthesis, prosthetic side, and type of prosthesis, but an exact matching is not considered a strict requirement.
| Arm | Type | Receives |
|---|---|---|
| Patients with osseointegrated prostheses | Experimental | Diagnostic Test: Test of standing balance (Equitest System). Test of walking in tied and split conditions on a force-sensorized split-belt treadmill.Patients with an osseointegrated prosthesis following a lower limb amputation |
| Patients with socket prostheses | Experimental | Diagnostic Test: Test of standing balance (Equitest System). Test of walking in tied and split conditions on a force-sensorized split-belt treadmill.Patients with a socket-mounted prosthesis following a lower limb amputation |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- unilateral lower extremity amputation;
- age > 18 years;
- amputation-adjusted Body Mass Index between 18 and 25;
- ability to understand the instructions;
- ability to wittingly sign the informed consent form.
Key exclusion criteria (4 listed)
- other previous knee injuries or major surgical interventions at the lower limbs;
- comorbidities, such as neurological conditions, vascular diseases, or diseases of orthopedic, cardiac, or pulmonary origin;
- cancer disease in the site under examination;
- other neurological pathologies with impact on balance and gait.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Test of standing balance (Equitest System). Test of walking in tied and split conditions on a force-sensorized split-belt treadmill.Tests of standing balance will be performed using the EquiTest System posturographic platform. Individuals will be requested to perform three tasks within the EquiTest battery: Sensory Organization test, Motor Control test backward/forward, Adaptation Test upward/downward. Gait analysis will be performed on a force sensorized split-belt treadmill. Participants will walk at increasing velocities from 0.2 m/s to the highest sustainable velocity in tied-belt condition. Velocity will be increased by 0.1 m/s every 20 consecutive strides. During gait analysis in the split-belt condition, participants will walk for 30 seconds with both belts at 0.4 m/s. Then, the velocity of the belt under the prosthetic limb will be increased to 1.2 m/s. After 6 minutes, the velocity of the faster belt will be restored at 0.4 m/s for 6 more minutes. Different combinations of velocities could be tested based on the patients' characteristics, maintaining a ratio of 3:1 between the velocities of the 2 belts. | Diagnostic test | Patients with osseointegrated prostheses, Patients with socket prostheses |
Primary outcome
Joint power
Time frame: Day 1
Joint kinematics will be recorded during walking through an optoelectronic method as per the Davis anthropometric model. The 3D displacement of the markers will be captured using 8 near-infrared stroboscopic cameras. Joint power will be computed through the spatiotemporal synchronization of ground reaction force vectors and the joint centers of rotation. The sagittal plane, only, will be considered for the analysis. Hip, knee, and ankle joint power will be computed as the product of joint torque and joint rotation speed. Power will be defined as positive or generated when the joint moment and rotation speed share the same directions (i. e., when agonist muscles are contracting while shortening), as negative or absorbed otherwise. Positive work will be computed as the integral of the generated (positive) power over time.
7 secondary outcomes
Kinetic energy of the center of mass during walking
Time frame: Day 1
Energy of the center of mass during walking due to vertical motion
Time frame: Day 1
Total mechanical energy of the center of mass during walking
Time frame: Day 1
Recovery of mechanical energy, R
Time frame: Day 1
SOT score
Time frame: Day 1
MCT score
Time frame: Day 1
ADT score
Time frame: Day 1
Results and safety
The study was stopped early (reason given: Recruitment halted after enrollment of two participants because no additional eligible patients with the required osseointegrated prosthesis could be identified in Italy.). Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Nov 2026.
- Individual participant dataSharing planned: Yes
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Luigi Tesio, MD, Professor principal investigator
Istituto Auxologico Italiano
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Test of standing balance (Equitest System). Test of walking in tied and split conditions on a force-sensorized split-belt treadmill. in people with Lower Extremity Amputation, run by Istituto Auxologico Italiano at 2 sites in Italy.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: stopped early, as of the sponsor's last update on 6 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Italy. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study was stopped early (reason given: Recruitment halted after enrollment of two participants because no additional eligible patients with the required osseointegrated prosthesis could be identified in Italy.). Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Joint power (time frame: Day 1). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 Nov 2026.