Background/Purpose: Assessments of symptomatic knee osteoarthritis (KOA) rely on physical measures for clinical decision-making. However, there is limited literature on the association between examination procedures and reported KOA symptoms and activity limitations.  This study aims to: (1) provide a rich clinical description of patients with KOA and (2) correlate examination findings with self-reported measures to determine the most efficient exam procedures to classify disease severity. 

Methods: This is a secondary analysis of baseline data from 47 patients with symptomatic and radiographic KOA recruited for a randomized clinical trial comparing tai chi and physical therapy. Patients completed self-reported outcome surveys (e.g., WOMAC Osteoarthritis Index [VAS scale]), performance tests (Timed Walk, repeated Sit-to-Stand, 6-min Walk Test, Berg balance), and a standardized physical examination by a physical therapist.  The exam included: an interview, muscle flexibility (Ober and Ely), muscle strength testing, ligamentous stability and meniscus integrity tests (e.g., Lachman, McMurray), pain provocation (patella compression), range-of-motion and functional assessments (Waldron squat test). Descriptive statistics and correlations were used to characterize the sample and determine associations between exam procedures, performance tests and outcome measures.

Results: Patients were 58 years of age (SD=9.8), 68% were female, 54% were Caucasian. Most (78%) had a high school education/some college and 30% were employed. 83% had unilateral knee involvement and 25% used an ambulatory device.  Patients reported limited function (mean WOMAC function =879.5 [SD= 376]) and pain (mean WOMAC pain = 254.5 [SD=99]) and were at low fall risk (mean Berg= 53.8[SD=2.7]).  Few patients tested positive for ligament instability and 2/3 tested positive for patellofemoral involvement.  There was a low to moderate correlation between self-reported pain and subject performance on tests of functional strength, aerobic fitness and walking speed. Iliotibial band tightness (based on a positive Ober test) was significantly correlated with increased pain, stiffness and self-reported functional limitations. (TABLE 1)   

Conclusion: Patients with symptomatic KOA had varied clinical presentations.  Those with iliotibial band tightness reported more knee pain, stiffness, and functional limitations. Pain provocation tests were not associated with greater dysfunction or symptoms although most patients tested positive with these tests. Self-reported pain correlated significantly with physical performance test outcomes.  The Ober test appears to be a useful clinical maneuver that is associated with KOA related functional difficulties and symptoms. Clinical performance tests of gait speed and aerobic capacity may help identify patients with more severe disease and are less costly than radiographic tests.