Reliability of the lateral pull test and tilt test to assess patellar alignment in subjects with symptomatic knees: student raters.

STUDY DESIGN

Test-retest reliability with blinded testers.

OBJECTIVES

To determine the inter- and intra-rater reliability of the lateral pull test and patellar tilt test.

BACKGROUND

If patellar malalignment can be detected by clinical examination, then condition-specific treatment interventions may be implemented in patients with patellofemoral pain syndrome. However, several clinical tests used to assess patellar mobility have recently been shown to have poor to fair reliability. Because the lateral pull test and the patellar tilt test are widely used clinically as diagnostic tests for patellofemoral pain syndrome but have not been previously tested for reliability, we examined these tests.

METHODS AND MEASURES

Fifty-two subjects (age range, 21-48 years) provided 95 knees (19 symptomatic and 76 asymptomatic) for assessment of the lateral pull test. Two testers, blinded to the presence or absence of symptoms, independently performed the lateral pull test in random order. Fifty-five subjects (age range, 22-42 years) provided 99 knees (73 asymptomatic and 26 symptomatic) for assessment of the patellar tilt test. Three blinded testers independently performed the patellar tilt test in random order. All subjects were tested and retested within 3-5 days. A kappa (kappa) statistic was used to assess the agreement of findings within each tester and between testers.

RESULTS

The kappa coefficients for intrarater reliability varied from 0.39 to 0.47 for the lateral pull test and from 0.44 to 0.50 for the patellar tilt test, while the coefficients for interrater reliability were 0.31 for the lateral pull test and varied from 0.20 to 0.35 for the tilt test.

CONCLUSIONS

Repeated lateral pull tests and patellar tilt tests had fair intrarater and poor interrater reliability. Our results suggest that care must be taken in placing too much emphasis on these tests when making clinical decisions.