The biomechanics of changing direction while walking has been largely neglected despite its relevancy to functional mobility. In addition, an increased risk of injury can be associated with turning due to a decrease in stability. The objective of this study is to understand the biomechanics of turning gait in sample populations of intact and transtibial amputees and the capacity of prosthetic components to facilitate transverse plane movement. The clinical impact of this investigation is the development of interventions that increase functional mobility, stability and safety while turning.

We propose to investigate three sets of hypotheses. The first set addresses the fundamental biomechanical mechanisms associated with walking along a circular trajectory, how intact subjects differ from amputees, and the effect of a rotation adaptor pylon. The second set of hypotheses addresses dynamic stability and the potential influence of prosthetic interventions. The third set of hypotheses addresses how the rotational properties of the prosthetic pylon can influence comfort and mobility during daily activities.

Condition	Intervention
Amputation Traumatic Amputation Diabetes Leg Injuries	Device: Transverse plane rotation adaptor pylon

Further Study Details: 

Primary Outcomes: Dynamic stability index at 3 weeks
Secondary Outcomes: A 3 weeks:; Lateral impulse; Outside limb external moment; Inside limb external moment; Outside stride length; Inside stride length; Outside effective limb length; Inside effective limb length; Step counts between weeks 3 & 4; At 4 weeks:; Pain questinnaire at 4 week; Distance during six-minute walk
Expected Total Enrollment:  40

Most of what is known about how amputees walk and how the properties of prosthetic components affect their gait has been discovered through sagittal plane observations while amputees walk back and forth along a straight line. Abnormal limb loading, thought to be a principal factor in the occurrence of residual limb pain which in turn may cause instability and limit mobility, can certainly occur while walking in a straight line. However, the incidence of abnormal limb loading is likely amplified when performing more complex gait activities, such as turning or avoiding obstacles; activities that are so very common in everyday life.

The specific aims of this investigation are to (1) discover the biomechanical strategies used and the stability of both intact individuals and transtibial amputees walking along a circular trajectory and (2) explore the effects of a prosthetic intervention on turning biomechanics, stability, comfort, and mobility.

We propose to investigate three sets of hypotheses:

The first set of hypotheses addresses the fundamental biomechanical mechanisms associated with walking along a circular trajectory, how intact subjects differ from amputees, and the effect of a rotation adaptor pylon. We will conduct experiments to test three hypothese related to achieving a change of heading, orientation, and balancing of centripetal forces necessary to walk along a circular trajectory.

The second set of hypotheses seeks to identify whether transtibial amputees with a rigid pylon are more unstable during a turning task than non-amputees and whether or not the rotation adaptors enhance stability. We will conduct experiments to calculate an index of dynamic stability that measures the rate at which a person can respond to a perturbation and return to a stable gait pattern.

The third set of hypotheses addresses how the rotational properties of the prosthetic pylon can influence comfort and mobility during daily activities. To measure comfort and mobility, we will solicit questionnaire responses and step count measures from amputees after a one-month period of wearing a rigid pylon and after a one-month period of wearing a transverse plane rotation adaptor (within-subject comparison). In addition to these field measurements, we will also compare the distance traveled during a six-minute walk. Patient opinions about their prosthesis and mobility measures over long periods of time can play a significant role in prosthesis evaluation.

For veteran amputees who experience discomfort and increased risk for residual limb skin problems, it seems reasonable to suppose that these problems might occur when walking along a curved trajectory rather than just a straight line. The joint forces and moments of turning may differ significantly from those exhibited while walking in a straight line. The proposed research will create a new knowledge base with which to understand prosthetic intervention effectiveness. The immediate clinical impact for the transtibial amputee is the determination if transverse plane rotational adapter pylons can improve their comfort, mobility, and stability.

Ages Eligible for Study:  25 Years   -   55 Years,  Genders Eligible for Study:  Both

Accepts Healthy Volunteers

Criteria

Inclusion Criteria:

1) be a unilateral transtibial amputee between the ages of 25 and 55, (2) wear a patellar-tendon bearing socket and gel liner with a distal locking pin suspension, (3) been a prosthetic user for at least one year, (4) wear the prosthesis at least 6 hours per day and be moderately active, (5) ambulate without upper extremity aids, (6) have no history of injurious falls within the previous six months, (7) must be a community ambulatory (Medicare activity level 3), and (8) must not utilize any prosthetic foot/ankle or pylon components that include rotation adapters, (9) must not have a significant neurological deficit that might impact gait characteristics, (10) must not have an underlying musculoskeletal disorder that might alter gait characteristics, (11) must not have a history of skin breakdown on the residual limb, and (12) exhibit no diabetic changes to the sound limb.

Non-amputee subjects participating in this investigation will meet similar inclusion criteria except for those related to prosthesis use.

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Exclusion Criteria:

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Please refer to this study by ClinicalTrials.gov identifier  NCT00167778

Janice A Pecoraro, RN      (206)-764-2962    janice.pecoraro@med.va.gov
Wesley D Edmundson      206-764-2991    wesley.edmunson.va.gov

Washington
      VA Puget Sound Health Care System, Seattle,  Washington,  98108,  United States

Study chairs or principal investigators

Glenn K Klute, PhD,  Principal Investigator,  VA Puget Sound Health Care System   

Study ID Numbers:  A3611R
Last Updated:  September 13, 2005
Record first received:  July 1, 2005
ClinicalTrials.gov Identifier:  NCT00167778
Health Authority: United States: Federal Government
ClinicalTrials.gov processed this record on 2005-09-20