Legg-Calvé-Perthes Disease Clinical Trial
Official title:
Validation and Reliability Testing of the Western Ontario and McMaster Osteoarthritis Scale (WOMAC) Hip Score in Children and Adolescents With Perthes Disease
Patient oriented clinical outcomes have increased in use and popularity and provide a
comprehensive assessment of the level of symptoms and function experienced by a patient.
Though several measures have been developed and shown to be valid, reliable, and responsive
in adults, such efforts have only been rarely undertaken in pediatric populations.
Specifically, there has been no validation of the predominant adult hip specific outcome
measures, such as the WOMAC and Oxford-12, in children and adolescents. Prior to using such
measures in pediatric patients, it is necessary to establish the psychometric properties of
these measurements in this population.
The objective of this study is to determine the reliability and validity of the WOMAC hip
scores in a pediatric population, between five and nineteen years of age, with Perthes
disease. The results of this study will accomplish the above goal, thereby allowing either
for widespread use of these measures in pediatric hip disorders or emphasizing the necessity
for development of a pediatric hip specific outcome measure.
1. Purpose Perthes disease is a hip disorder most often affecting children with an onset
between four and eight years of age. The treatment options range from non-operative to
bracing to operative intervention. As the disease most often affects the head of the
femur, there is the potential for long-term conditions due to the residual hip joint
deformity, following resolution of Perthes disease, leading to early degenerative hip
osteoarthritis and potential impact on hip function, quality of life, and morbidity. A
valid and reliable means by which to assess function and outcome is essential to
determine the most effective means of treatment. Previous research has used different
methods in different subject groups, making comparisons of results very difficult. Both
the long-term outcome and change over time of a patient with Perthes disease could be
measured with a hip joint specific patient oriented outcome measure. Several such
measures have been developed in adults; specifically the Western Ontario and McMaster
Osteoarthritis Scale (WOMAC) hip score are used very often. Though these tools have
been well studied and validated in adults, they have not been tested or used in
pediatric populations. As they were developed and shown to be valid, reliable, and
responsive in adults, these measures require rigourous testing in pediatric populations
prior to their use.
2. Hypothesis There is no true global hypothesis for the study since it is a
validation/reliability study. There are hypotheses for each type of validity being
studied.
For construct validity (using convergence), the hypothesis would be a priori hypothesis
in this study related to convergent validity is that, assuming the WOMAC has construct
validity in this population, then the hip specific outcome scores should be different
for each Stulberg classification stage.
For construct validity (using extreme groups), the hypothesis would be a priori
hypothesis in this study is that, assuming the measures have adequate construct
validity in this population, the group of subjects being followed for treatment of an
upper extremity fracture should have significantly better function, as indicated by a
low score on the WOMAC and , compared to those with Perthes disease, who should have
higher scores indicating poorer function.
For criterion validity, the hypothesis would be a priori hypothesis related to
criterion validity in this study predicts that, assuming adequate concurrent validity
of these measures in this population, there should be a negative correlation between
the Activities Scale for Kids - Performance (ASK-p, an activity level outcome score)
and the WOMAC. The reason for a negative correlation is that high scores on the generic
measure indicate better function, whereas low scores on the hip specific measures
indicate better function.
3. Research Method All subjects enrolled in the study will be given the initial set of
questionnaires at the time of recruitment and asked to complete them at home, following
the clinical follow-up visit, and return the questionnaires by mail using a
self-addressed, stamped envelope which will be provided. All subjects will complete the
WOMAC. Those with healed Perthes disease will also complete the ASK-p at the first
visit to the clinic following consent into the study. Those in the comparison group
with an upper extremity fracture will not complete the generic measure. This will
comprise the initial time point of the study. Those subjects who do not complete all
required questionnaires, at this time point, will be excluded from the study.
Radiographs of the affected hip and pelvis will be obtained for each patient with
healed Perthes disease at the time of the clinic visit, which would be obtained
regardless of inclusion in the study in the course of standard clinical follow-up.
Those subjects with Perthes disease will also complete the WOMAC and measure two weeks
following the initial time point. The questionnaires will be mailed to the subjects and
they will be asked to complete the questionnaires and return them in a self-addressed,
stamped envelope which will be provided. This will comprise the follow-up time point of
the study. A reminder notification will be mailed at four weeks and a telephone call
reminder at six weeks following the initial time point if the second series of
questionnaires has not been returned. Those who do not complete the second series of
questionnaires will be excluded from the reliability component of the study but
maintained in the validity phase, provided the initial questionnaires were completed.
Those with an upper-extremity fracture will not complete any additional questionnaires
following the initial time point. The Stulberg classification will be determined, as
outlined, following the initial time point but prior to analysis of the data.
4. Statistical Analysis All statistical analysis will be performed by a blinded,
independent analyst. All analyses, with the exception of the weighted kappa statistic
which will be calculated manually, will be performed with the use of S-PLUS software
(version 6.2, Lucent Technologies, Inc.). The distribution of all questionnaire data
will be determined with the use of frequency histograms to allow for the use of
appropriate statistical tests. All statistical tests will be performed with α=0.05. The
reported values will be the mean and the corresponding 95% confidence interval. Where
two groups are compared, the mean difference between the groups and the 95% confidence
interval of the difference will be reported.
There have been no previous studies or data of the WOMAC in a pediatric population. Using
values obtained in studies of adults may not provide a good estimate for a power analysis in
this population since other outcome measures, which have been validated in adults, have been
shown to lack validity in children and adolescents. However, in order to estimate the sample
size required for the correlation between the ASK-p and the hip outcome measures the
previously reported adult derived values were required. On the basis of a minimum
correlation of 0.6, which would be considered adequate, with α=0.05 and 80 per cent power, a
total of 40 children are required for the study. Since there is no available evidence with
which to estimate the correlation between these outcome measures, a liberal sample size will
be recruited. In a similar study, except that generic as opposed to joint specific, outcome
measures were used, a sample size of 196 subjects was recruited. Young et al recruited 200
subjects for their study in which several psychometric properties of the ASK-p were
determined. A total of 200 subjects will be recruited across all centers participating in
this study. There will be 100 subjects with an upper extremity fracture and 100 with healed
Perthes disease. This sample size was chosen, in part, on the basis of the maximum number of
subjects with healed Perthes which would be feasible to recruit over the time horizon of the
study, which will be six months. It is anticipated that a minimum of four centers will
participate in the study.
;
Observational Model: Cohort, Time Perspective: Prospective
| Status | Clinical Trial | Phase | |
|---|---|---|---|
| Completed |
NCT02676271 -
The Long Term Outcome of Varus Derotational Osteotomy for Legg-Calvé-Perthes' Disease
|
N/A |