Abstract
To quantify normal motion, medial and lateral passive patellar motion limits were measured in 67 high school athletes randomly selected from a group of 1340 ath letes undergoing preseason physical examinations. Pa tellar displacement was measured at knee flexion an gles of 0° and 35°, using both a Patella Pusher (a hand held force gauge) and a manual technique, and the results were compared. Demographic data and physical examination of the deceleration mechanism (Q angle, vastus medialis obliquus dysplasia, patella alta and baja, and valgus and varus alignment) were correlated with patellar motion limits.
With the knee in extension, passive displacement of the patella averaged 9.6 mm medially and 5.4 mm laterally. In flexion, medial displacement averaged 9.4 mm and lateral displacement averaged 10.0 mm. No positive correlations were found between demographic data or deceleration mechanism examination parame ters and patellar motion limits, suggesting that motion produced by the displacement force was limited by ligamentous restraints only.
The clinical assessment of the passive limits of pa tellar motion should include examination at knee flexion angles of 0° and 35°. The manually produced displace ment was found to be more reproducible than displace ment by the Patella Pusher (P < 0.05).
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