Trochear dysplasia is a condition where the trochlear groove is abnormal, usually at its upper end, at which point the groove is abnormally flat or even heaped into a 'bump'.
Trochlear dysplasia and kneecap instability
|Mild trochlear dysplasia with a shallow trochlear groove.||More severe situation where the upper trochlea has no groove at all.||Instead of being convex, the trochlear forms a concave 'bump', and the patella finds no comfortable groove into which to slide.|
The effect of trochlear dysplasia on patellofemoral biomechanics: a cadaveric study with simulated trochlear deformities. Van Haver A, De Roo K, De Beule M, Labey L, De Baets P, Dejour D, Claessens T, Verdonk P. Am J Sports Med. 2015 Jun;43(6):1354-61.
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VIDEO putting trochlear dysplasia into context