The reliability and validity of visual rating of dynamic alignment during lower extremity functional screening tests: a review of the literature

Background: Musculoskeletal assessment of lower extremity dynamic alignment during functional screening tests is important. Clinicians must consider the reliability and validity of visual assessment and the reliability of kinematics during the tests. Aim: To review studies reporting on the reliability and validity of visual and kinematic assessments of dynamic alignment during lower extremity functional screening tests. Methods: One relevant book and 39 journal articles were reviewed after searches of electronic databases. Findings: Reliability of lower extremity joint kinematics during functional tests ranged from fair to excellent [intraclass correlation coefficient (ICC) = 0.46–1.0]. The best evidence of reliable kinematics from 3D motion analysis exists for the single leg squat, small knee bend and drop jump/land. Intra-rater and inter-rater agreement with visual rating of functional tests ranged from slight to excellent (AC1 = 0.01–0.96; κ = 0.00–0.92). Visual assessment can differentiate groups with kinematics and hip muscle function that may place them at increased risk of injury. Clinician's visual ratings agreed sufficiently with those of an expert consensus panel. Reliability and validity of visual assessment may improve with clinical experience, training, simple dichotomous rating methods and slower velocity tests. Conclusion: The most valid clinical assessment of lower extremity dynamic alignment will be achieved with the use of a single leg squat, single or double leg small knee bend or drop jump, rating knee position relative to the foot on a dichotomous scale. If using more complex rating methods, example ratings and/or additional rater training are needed to gain acceptable agreement.