Determining educational assessment criteria for patellar-tendon-bearing impressions for transtibial prosthetic sockets: A Delphi study.

BACKGROUND: Validated criteria to guide assessment of student performance in clinical tasks in prosthetics and orthotics education have not been established. Lack of established criteria and assessment methods presents challenges in evaluating student performance on clinical tasks, such as taking impressions for patellar-tendon-bearing (PTB) sockets. OBJECTIVES: To establish assessment criteria for the PTB impression process for use in educational settings. STUDY DESIGN: Delphi consensus process. METHODS: Initial Delphi survey items were based on interviews with prosthetic instructors and focus groups with prosthetic students. Expert prosthetic educators were then identified by purposive sampling to complete multiple-round Internet-based Delphi surveys. The Delphi surveys asked experts to indicate their level of agreement on various assessment methods and criteria in PTB education. Consensus for survey items was reviewed after each survey round and used to determine the content of and need for subsequent rounds. RESULTS: Fourteen experts completed two Delphi survey rounds. Items were categorized into educational materials/strategies, impression stages/materials, measurement tools, measurements taken, assessment during impression, assessment after impression, feedback, student self-assessment, and grading. In two survey rounds, 40 items guiding assessment methods and criteria for PTB impressions achieved 80% consensus. CONCLUSIONS: A high level of consensus was achieved in two survey rounds. Lower levels of consensus were reached on specific objective criteria, such as use of measurement thresholds when evaluating student impressions. Standardized assessment of student performance on PTB impression-taking instead relies primarily on qualitative assessments based on instructor expertise.

Knee Swing Phase Flexion Resistance Affects Several Key Features of Leg Swing Important to Safe Transfemoral Prosthetic Gait.

We systematically investigate in-vivo the effect of increasing prosthetic knee flexion damping on key features of the swing phase of individuals with transfemoral amputation during walking. Five experienced prosthesis users walked using a prototype device in a motion capture laboratory. A range of interchangeable hydraulic rotary dampers was used to progressively modify swing phase flexion resistance in isolation. Toe clearance (TC; vertical distance toe to floor), effective leg length (ELL; distance hip to toe), and knee flexion angle during swing phase were computed, alongside the sensitivities of vertical toe position to angular displacements at the hip, knee and ankle. Key features of these profiles were compared across 5 damping conditions. With higher damping, knee extension occurred earlier in swing phase, promoting greater symmetry. However, with implications for toe catch, minimum TC reduced, and minimum TC and maximum ELL occurred earlier; temporally closer to mid-swing, when the limb must pass the stance limb. Further, TC became less sensitive to changes in hip flexion, suggesting a lesser ability to control toe clearance without employing proximal or contralateral compensations. There is a trade-off between key features related to gait safety when selecting an appropriate resistance for a mechanical prosthetic knee. In addition to highlighting broader implications surrounding swing phase damping selection for the optimization of mechanical knees, this work reveals design considerations that may be of utility in the formulation of control strategies for computerized devices.

Do Upper Limb Loss and Prosthesis Use Affect Lower Limb Gait Dynamics?

INTRODUCTION: Intentional interruption of upper and lower limb coordination of able-bodied subjects alters their gait biomechanics. However, the effect of upper-limb loss (ULL) on lower-limb gait biomechanics is not fully understood. The aim of this secondary study was to perform a follow-up analysis of a previous dataset to characterize the spatiotemporal parameters and lower-limb kinematics and kinetics of gait for persons with ULL when wearing and not wearing an upper limb prosthesis (ULP). We were particularly interested in quantifying the effects of matching the mass and inertia of the prosthetic limb to the sound limb. MATERIALS AND METHODS: Ten persons with unilateral ULL walked at a self-selected speed under three randomly presented conditions: 1) not wearing a prosthesis, 2) wearing their customary prosthesis, and 3) wearing a mock prosthesis that can be adjusted to match the length, mass, and inertial properties of each subject's sound limb. Walkway-embedded force plates and a 12-camera digital motion capture system recorded ground reaction forces (GRFs) and retroreflective marker position data, respectively. Average spatiotemporal (walking speed, cadence, stance time, swing time, step length, double support time), lower-limb kinematic (joint angles), and lower-limb kinetic (ground forces, joint moments and powers) data were processed and their statistical significance were analyzed. RESULT: Walking speed for each condition was nearly equivalent (1.20±0.01 m/s) and differences between condition were non-significant (p=0.769). The interaction effect (side× prosthesis) was significant for peak hip extension (p=0.01) and second peak (propulsive) vertical GRF (p=0.028), but separate follow-up analyses of both main effects were not significant (p≥0.099). All other main effect comparisons were not significant (p≥0.102). CONCLUSIONS: Although the sample cohort was small and heterogeneous, the results of this study suggest that persons with unilateral ULL did not display significant limb side asymmetry in lower-limb gait spatiotemporal, kinetic, and kinematic parameters, regardless of ULP use.