title: Alterations in lower extremity movement and muscle activation patterns in individuals with knee osteoarthritis. The feasibility of creating a checklist for the assessment of the methodological quality both of randomised and non-randomised studies of health care interventions. Normalization of joint moments during gait: a comparison of two techniques. The knee adduction moment during gait in subjects with knee osteoarthritis is more closely correlated with static alignment than radiographic disease severity, toe out angle and pain. Comparison of hip and knee muscle moments in subjects with and without knee pain.
abstract: OBJECTIVE The purpose of this study was to investigate lower extremity movement and muscle activation patterns in individuals with knee osteoarthritis and healthy age- and gender-matched control subjects . DESIGN This study utilized a non-r and omized case-control design to compare 24 subjects with unilateral symptomatic knee osteoarthritis to 24 age- and gender-matched control subjects without knee osteoarthritis . BACKGROUND It is hypothesized that knee osteoarthritis is associated with altered lower extremity movement and muscle activation patterns . METHODS A gait analysis was performed to determine the lower extremity movement and muscle activation patterns when walking on a level surface at 1.12 to 1.34 m/s and while descending a 20 cm step . Paired t-tests were used to compare the average of five trials between the groups . RESULTS Subjects with knee osteoarthritis demonstrated less excursion of the knee in the sagittal plane from heelstrike to peak flexion before midstance ( i.e. during loading ) . Subjects with knee osteoarthritis also demonstrated reduced peak vertical ground reaction forces relative to body weight . The muscle activity patterns were also different between the groups . The vastus lateralis , medial hamstrings , tibialis anterior and medial gastrocnemius were on approximately 1.5 times longer than the same muscles in the control subjects . Additionally , significant increases in muscle co-activation were also observed in individuals with knee osteoarthritis during walking . Similar findings were observed when the subject descended a 20 cm step OBJECTIVE : To test the feasibility of creating a valid and reliable checklist with the following features : appropriate for assessing both r and omised and non-r and omised studies ; provision of both an overall score for study quality and a profile of scores not only for the quality of reporting , internal validity ( bias and confounding ) and power , but also for external validity . DESIGN : A pilot version was first developed , based on epidemiological principles , review s , and existing checklists for r and omised studies . Face and content validity were assessed by three experienced review ers and reliability was determined using two raters assessing 10 r and omised and 10 non-r and omised studies . Using different raters , the checklist was revised and tested for internal consistency ( Kuder-Richardson 20 ) , test-retest and inter-rater reliability ( Spearman correlation coefficient and sign rank test ; kappa statistics ) , criterion validity , and respondent burden . MAIN RESULTS : The performance of the checklist improved considerably after revision of a pilot version . The Quality Index had high internal consistency ( KR-20 : 0.89 ) as did the subscales apart from external validity ( KR-20 : 0.54 ) . Test-retest ( r 0.88 ) and inter-rater ( r 0.75 ) reliability of the Quality Index were good . Reliability of the subscales varied from good ( bias ) to poor ( external validity ) . The Quality Index correlated highly with an existing , established instrument for assessing r and omised studies ( r 0.90 ) . There was little difference between its performance with non-r and omised and with r and omised studies . Raters took about 20 minutes to assess each paper ( range 10 to 45 minutes ) . CONCLUSIONS : This study has shown that it is feasible to develop a checklist that can be used to assess the method ological quality not only of r and omised controlled trials but also non-r and omised studies . It has also shown that it is possible to produce a checklist that provides a profile of the paper , alerting review ers to its particular method ological strengths and weaknesses . Further work is required to improve the checklist and the training of raters in the assessment of external validity Joint moments are commonly used to characterize gait . Factors like height and weight influence these moments . This study determined which of two commonly used normalization methods , body mass or body weight times height , most reduced the effects of height and weight on peak hip , knee , and ankle external moments during walking . The effectiveness of each normalization method in reducing gender differences was then tested . Gait data from 158 normal subjects were analyzed using unnormalized values , body mass normalized values , and body weight times height normalized values . Without normalization , height or weight accounted for 7 - 82 % of the variance in all 10 peak components of the moments . With normalization , height and weight accounted for at most 6 % of the variance with the exception of the hip adduction moment normalized by body weight times height and the ankle dorsiflexion moment normalized by body mass . For the hip adduction moment normalized by body weight times height , height still accounted for 13 % of the variance ( p<0.001 ) and for the ankle dorsiflexion moment normalized by body mass , 22 % of the variance ( p<0.001 ) . After normalization , significant differences between males and females remained for only two out of 10 moments with the body weight times height method compared to six out of 10 moments with the body mass method . When compared to the unnormalized data , both normalization methods were highly effective in reducing height and weight differences . Even for the two cases where one normalization method was less effective than the other ( hip adduction-body weight times height ; ankle dorsiflexion-body mass ) the normalization process reduced the variance ascribed to height or weight by 48 % and 63 % , respectively , as compared to the unnormalized data This study tested whether the peak external knee adduction moments during walking in subjects with knee osteoarthritis ( OA ) were correlated with the mechanical axis of the leg , radiographic measures of OA severity , toe out angle or clinical assessment s of pain , stiffness or function .  Gait analysis was performed on 62 subjects with knee OA and 49 asymptomatic control subjects ( normal subjects ) . The subjects with OA walked with a greater than normal peak adduction moment during early stance ( p = 0.027 ) . In the OA group , the mechanical axis was the best single predictor of the peak adduction moment during both early and late stance ( R = 0.74 , p < 0.001 ) . The radiographic measures of OA severity in the medial compartment were also predictive of both peak adduction moments ( R = 0.43 to 0.48 , p < 0.001 ) along with the sum of the WOMAC subscales ( R = -0.33 to -0.31 , p < 0.017 ) . The toe out angle was predictive of the peak adduction moment only during late stance ( R = -0.45 , p < 0.001 ) . Once mechanical axis was accounted for , other factors only increased the ability to predict the peak knee adduction moments by 10 18 % . While the mechanical axis was indicative of the peak adduction moments , it only accounted for about 50 % of its variation , emphasizing the need for a dynamic evaluation of the knee joint loading environment . Underst and ing which clinical measures of OA are most closely associated with the dynamic knee joint loads may ultimately result in a better underst and ing of the disease process and the development of therapeutic interventions Elderly subjects with and without knee pain walked at a comfortable pace during gait analysis . Comparison of peak hip and knee internal extensor generalized muscle moments ( GMMs ) during loading response was made between groups . Walking velocity , peak hip internal extensor GMM , and knee range of motion ( ROM ) were significantly less for the group with knee pain than for the group without pain . Peak hip internal extensor GMM was strongly correlated with velocity , but peak knee internal extensor GMM was not . Knee ROM limitations may account for the increased peak knee internal extensor GMM in the knee pain group
target: The majority of consistent gait deviations associated with KOA were exhibited by those with severe disease in the temporospatial domain .
  There was a lack of evidence for alterations in the external knee adduction moment .
  Individuals with KOA exhibit a range of gait deviations compared with controls .
  Despite its common usage in KOA gait studies , we did not find consistent evidence that knee adduction moment differs between those with and without KOA or between disease severity levels .
background: OBJECTIVE To identify which gait deviations are consistently associated with knee osteoarthritis ( KOA ) and how these are influenced by disease severity , the involved compartment , and sex .