Longitudinal and cross-sectional validity of the DynaPort® Knee Test in adults with nontraumatic knee complaints in general practice

Objective: The aim of the study was to determine the cross-sectional and longitudinal validity of a performance-based assessment of knee function, DynaPort (R) KneeTest (DPKT), in first-time consulters with nontraumatic knee complaints in general practice. Methods: Patients consulting for nontraumatic knee pain in general practice aged > 18 years were enrolled in the study. At baseline and 6-months follow-up knee function was assessed by questionnaires and the DPKT; a physical examination was also performed at baseline. Hypothesis testing assessed the cross-sectional and longitudinal validity of the DPKT. Results: Eighty-seven patients were included for the DPKT, 86 were available for analysis. The studied population included 44 women (51.2%), the median age was 54 (range 18-81) years. At follow up, 77 patients (89.5%) were available for the DPKT. Only 3 out of I I (27%) predetermined hypotheses concerning the cross-sectional and longitudinal validity were confirmed. Comparison of the general practice and secondary care population showed a major difference in baseline characteristics, DynaPort Knee Score, internal consistency, and hypotheses confirmation concerning the construct validity. Conclusion: The validity of the DPKT Could not be demonstrated for first-time consulters with nontraumatic knee complaints in general practice. Measurement instruments developed and validated in secondary care are therefore not automatically also valid in primary care setting. (C) 2008 Elsevier Inc. All rights reserved.