Clinical hip tests and a functional squat test in patients with knee osteoarthritis: reliability, prevalence of positive test findings, and short-term response to hip mobilization.

STUDY
DESIGN: One group pretest-posttest exploratory design.
OBJECTIVES: Primary purposes of this study were to examine the short-term effect of hip mobilizations on pain and range of motion (ROM) measurements in patients with knee osteoarthritis (OA) and to determine the prevalence of painful hip and squat test findings in both patients with knee OA and asymptomatic subjects. The secondary purposes were to assess intrarater reliability and to determine whether fewer subjects experienced painful test findings following hip mobilization.
BACKGROUND: Conservative intervention, including manual physical therapy applied to the lower extremity, has been shown to reduce impairments associated with knee OA. METHODS AND MEASURES: One rater pair administered 4 clinical hip tests to 22 patients with knee OA (mean age, 61.2 years; SD, 6.1 years) and 17 subjects without lower extremity symptoms or known pathology (mean age, 64.0 years; SD, 7.9 years). Intrarater reliability was examined for each clinical test. Patients with knee OA and painful-hip and squat test findings received hip mobilizations. Pain and ROM responses for each test were dependent variables.
RESULTS: Intraclass correlation coefficients for all tests were greater than 0.87. Composite and individual test pain scores and ROM scores improved significantly following hip mobilization. All clinical test findings were more frequent in the group with knee OA, except for those of the FABER test, and the number of subjects with painful test findings following hip mobilization was reduced for all tests except the hip flexion test.
CONCLUSIONS: Patients experienced increases in ROM, decreased pain, and fewer subjects had painful test findings immediately following a single session of hip mobilizations. Examination and intervention of the hip may be indicated in patients with knee OA.