Angela Schlager: Defining generalised joint hypermobility: Aspects of reliability, validity and the association to pregnancy induced pain

Abstract

The aim of this thesis was to evaluate the definition of joint hypermobility and generalised joint hypermobility with aspects of reliability, validity and the association between generalised joint hypermobility and pregnancy-induced pain. Generalised joint hypermobility is used to reflect hereditary systematic connective tissue fragility. In study I, the inter-rater and intra-rater reliability, were evaluated in 49 women and men through 12 joint mobility tests included in three instruments for defining generalised joint hypermobility. In study II, the criterion validity was evaluated in 339 women in early pregnancy between the self-reported five-part questionnaire to identify generalised joint hypermobility, with the Beighton score. In study III, 255 women in early pregnancy were included to evaluate if a subset of joint mobility tests could define generalised joint hypermobility and establish limits for joint hypermobility. In study IV, 99 women pain-free before pregnancy were included to investigate the first onset of self-reported pain during pregnancy comparing women with and without generalised joint hypermobility, by parity and pain location. The reliability was good-to-excellent for both inter- and intra-rater reliability, for the majority of the joint mobility tests. The five-part questionnaire to identify generalised joint hypermobility with a cut-off level of ≥ 2 entailed the highest clinimetric values. However, the odds of having generalised joint hypermobility with a positive self-reported five-part questionnaire were low and yielding a false positive rate of 38%. No subset of joint mobility tests could define generalised joint hypermobility. Different combinations of joint mobility tests in upper- and lower limbs and the axial skeleton were compiled and evaluated for different standard deviation levels, where plus two standard deviations were most difficult to achieve. Women with generalised joint hypermobility and multiparous women experienced substantial earlier onset of self-reported pain during pregnancy, mainly in the lower back region. Thoroughly measured joint mobility and defining generalised joint hypermobility through different combinations of joint mobility tests, probably increased the precision of defining generalised joint hypermobility. Generalised joint hypermobility seems to be important for early development of pain during pregnancy. To identify women with generalised joint hypermobility in early pregnancy might be important in order to offer proper information, advice and rehabilitation.