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 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 11 (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.


CONCLUSIONS
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.
Belo
J N
JN
Department of General Practice, Erasmus Medical Center, Rotterdam, The Netherlands. Electronic address: j.belo@erasmusmc.nl.
Bierma-Zeinstra
S M A
SMA
Department of General Practice, Erasmus Medical Center, Rotterdam, The Netherlands.
Terwee
C B
CB
Institute of Research in Extramural Medicine, VU University Medical Center, Amsterdam, The Netherlands.
Heintjes
E M
EM
Department of General Practice, Erasmus Medical Center, Rotterdam, The Netherlands.
Koes
B W
BW
Department of General Practice, Erasmus Medical Center, Rotterdam, The Netherlands.
D000054:Acceleration; D000203:Activities of Daily Living; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D018771:Arthralgia / Q000503:physiopathology*; D004812:Epidemiologic Methods; D005194:Family Practice / Q000379:methods; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D017770:Lifting; D008297:Male; D008875:Middle Aged; D010808:Physical Examination; D016059:Range of Motion, Articular; D012737:Sex Factors; D016138:Walking; D055815:Young Adult