An expert system feedback tool improves the reliability of clinical gait kinematics for older adults with lower limb osteoarthritis.

Recently, an expert system was developed to provide feedback to examiners with the aim of improving reliability of marker-based gait analysis. The purpose of the current study was to evaluate the effectiveness of this novel feedback tool in improving the reliability of gait analysis for individuals with lower limb osteoarthritis. Three-dimensional gait analysis was conducted for n=27 individuals, at two different time points, and during each session the feedback tool was used to refine marker placement. Results for both discrete variables and support vector machine classifications demonstrated improved reliability of the data with the feedback tool.

Kinematic gait patterns and their relationship to pain in mild-to-moderate hip osteoarthritis.

BACKGROUND: Mild-to-moderate hip osteoarthritis is often managed clinically in a non-surgical manner. Effective non-surgical management of this population requires characterizing the specific impairments within this group. To date, a complete description of all lower extremity kinematics in mild-to-moderate hip osteoarthritis patients has not been presented. The aim of the present study is to describe the lower extremity gait kinematics in mild-to-moderate hip osteoarthritis patients and explore the relationship between kinematics and pain. METHODS: 22 subjects with mild-to-moderate radiographic hip osteoarthritis (Kellgren-Lawrence grade 2-3) and 22 healthy age and BMI matched control subjects participated. Kinematic treadmill walking data were collected across all lower extremity joints. A two-way repeated measures analysis of variance estimated mean differences in gait kinematics between groups. Correlations between gait kinematics and pain were assessed using a Spearman correlation coefficient. FINDINGS: Hip osteoarthritis subjects hiked their unsupported hemi-pelvis 1.40° (P<0.001) more than controls and tilted their pelvis 4.65° more anteriorly (P=0.01). Osteoarthritis subjects walked with 4.30° more peak hip abduction (P<0.001), 8.57° less peak hip extension (P<0.001), and 10.54° more peak hip external rotation (P<0.001). Kinematics were related to pain in the ankle frontal plane only (r=-0.43, P<0.05). INTERPRETATION: Individuals with mild-to-moderate hip osteoarthritis demonstrate altered gait biomechanics not related to pain. These altered biomechanics may represent effective therapeutic targets by clinicians working with this population. Understanding the underlying patho-anatomic changes that lead to these biomechanical changes requires further investigation.

Does tester experience influence the reliability with which 3D gait kinematics are collected in healthy adults?

OBJECTIVES: To determine whether tester experience influences the reliability of three-dimensional gait collections. DESIGN: Reliability study. PARTICIPANTS: Ten healthy subjects visited a university gait laboratory on two separate days and underwent a walking gait analysis. During each visit, kinematic data were collected by a biomechanist with 8 years of 3D gait analysis experience (EXP) and a physical therapist with no previous 3D gait analysis experience (NOV). MAIN OUTCOME MEASURES: Joint kinematic angles were calculated using either a functional or predictive joint identification method. Within-tester and between-tester measures of reliability were determined by calculating the root mean square error (RMS) and coefficient of multiple correlations (CMC). RESULTS: Within-tester RMS and CMC values were not significantly different (P > 0.05) between the EXP and NOV testers using either a functional or predictive joint approach. Within-tester CMC values exceeded 0.90 for both testers across all kinematic variables. Between-tester CMC reliability values were greater than 0.85 for all variables measured. CONCLUSIONS: Following basic training, a physiotherapy clinician with no previous 3D gait experience is as reliable as an experienced gait biomechanist with respect to marker placement accuracy. In addition, reliability comparisons between an experienced and novice tester appear independent of the joint identification method chosen.

Hyperventilation-induced hypocapnic alkalosis slows the adaptation of pulmonary O2 uptake during the transition to moderate-intensity exercise.

The effect of voluntary hyperventilation-induced hypocapnic alkalosis (RALK) on pulmonary O2 uptake (VO2) kinetics and muscle deoxygenation was examined in young male adults (n=8) during moderate-intensity exercise. Subjects performed five repetitions of a step-transition in work rate from 20 W cycling to a work rate corresponding to 90% of the estimated lactate threshold during control (CON; PET,CO2, approximately 40 mmHg) and during hyperventilation (RALK; PET,CO2, approximately 20 mmHg). was measured breath-by-breath and relative concentration changes in muscle deoxy- (DeltaHHb), oxy- (DeltaO2Hb) and total (DeltaHbtot) haemoglobin were measured continuously using near-infrared (NIR) spectroscopy (Hamamatsu, NIRO 300). The time constant for the fundamental, phase 2, VO2 response (tau VO2) was greater (P<0.05) in RALK (48+/-11 s) than CON (31+/-9 s), while tauHHb was similar between conditions (RALK, 12+/-4 s; CON, 11+/-4 s). The DeltaHb(tot) was lower (P<0.05) in RALK than CON, prior to (RALK, -3+/-5 micromol l(-1); CON, -1+/-4 micromol l(-1)) and at the end (RALK, 1+/-6 micromol l(-1); CON, 5+/-5 micromol l(-1)) of moderate-intensity exercise. Although slower adaptation of during RALK may be related to an attenuated activation of PDH (and other enzymes) and provision of oxidizable substrate to the mitochondria (i.e. metabolic inertia), the present findings also suggest a role for a reduction in local muscle perfusion and O2 delivery.