Objective. There are no Dutch language disease-specific questionnaires for patients with patellofemoral pain syndrome available that could help Dutch physiotherapists to assess and monitor these symptoms and functional limitations. The aim of this study was to translate the original disease-specific Kujala Patellofemoral Score into Dutch and evaluate its reliability. Methods. The questionnaire was translated from English into Dutch in accordance with internationally recommended guidelines. Reliability was determined in 50 stable subjects with an interval of 1 week. The patient inclusion criteria were age between 14 and 60 years; knowledge of the Dutch language; and the presence of at least three of the following symptoms: pain while taking the stairs, pain when squatting, pain when running, pain when cycling, pain when sitting with knees flexed for a prolonged period, grinding of the patella and a positive clinical patella test. The internal consistency, test–retest reliability, measurement error and limits of agreement were calculated. Results. Internal consistency was 0.78 for the first assessment and 0.80 for the second assessment. The intraclass correlation coefficient (ICCagreement) between the first and second assessments was 0.98. The mean difference between the first and second measurements was 0.64, and standard deviation was 5.51. The standard error measurement was 3.9, and the smallest detectable change was 11. The Bland and Altman plot shows that the limits of agreement are 10.37 and 11.65. Conclusions. The results of the present study indicated that the test–retest reliability translated Dutch version of the Kujala Patellofemoral Score questionnaire is equivalent of the test– retest original English language version and has good internal consistency. Trial registration NTR (TC = 3258). Copyright © 2015 John Wiley & Sons, Ltd.
PURPOSE: The patients diagnosed with Ehlers-Danlos Syndrome Hypermobility Type (EDS-HT) are characterized by pain, proprioceptive inacuity, muscle weakness, potentially leading to activity limitations. In EDS-HT, a direct relationship between muscle strength, proprioception and activity limitations has never been studied. The objective of the study was to establish the association between muscle strength and activity limitations and the impact of proprioception on this association in EDS-HT patients.METHODS: Twenty-four EDS-HT patients were compared with 24 controls. Activity limitations were quantified by Health Assessment Questionnaire (HAQ), Six-Minute Walk test (6MWT) and 30-s chair-rise test (30CRT). Muscle strength was quantified by handheld dynamometry. Proprioception was quantified by movement detection paradigm. In analyses, the association between muscle strength and activity limitations was controlled for proprioception and confounders.RESULTS: Muscle strength was associated with 30CRT (r = 0.67, p = <0.001), 6MWT (r = 0.58, p = <0.001) and HAQ (r = 0.63, p= <0.001). Proprioception was associated with 30CRT (r = 0.55, p < 0.001), 6MWT (r = 0.40, p = <0.05) and HAQ (r = 0.46, p < 0.05). Muscle strength was found to be associated with activity limitations, however, proprioceptive inacuity confounded this association.CONCLUSIONS: Muscle strength is associated with activity limitations in EDS-HT patients. Joint proprioception is of influence on this association and should be considered in the development of new treatment strategies for patients with EDS-HT. Implications for rehabilitation Reducing activity limitations by enhancing muscle strength is frequently applied in the treatment of EDS-HT patients. Although evidence regarding treatment efficacy is scarce, the current paper confirms the rationality that muscle strength is an important factor in the occurrence of activity limitations in EDS-HT patients. Although muscle strength is the most dominant factor that is associated with activity limitations, this association is confounded by proprioception. In contrast to common belief proprioception was not directly associated with activity limitations but confounded this association. Controlling muscle strength on the bases of proprioceptive input may be more important for reducing activity limitations than just enhancing sheer muscle strength.