Prosthetic Components and Stability in Amputee Gait
Condition: Diabetes Mellitus; Leg Injuries; Traumatic Amputation
MeSH terms: Amputation, Traumatic; Leg Injuries
Study type: Interventional

Summary: 
      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 trans-tibial 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.

      The researchers 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.
    

Detailed description: 
      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 trans-tibial 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 hypotheses
      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 trans-tibial 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 trans-tibial amputee is the
      determination if transverse plane rotational adapter pylons can improve their comfort,
      mobility, and stability.
    

Intervention name(s): Transverse plane rotation adaptor pylon; Rigid pylon
Intervention type(s): Device; Device
Intervention description(s): Potential future practice; Current clinical practice
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: Amputation; Amputee; Artificial limbs; Gait; Locomotion; Walking