Joint dislocation Abnormality of the lower limb Patellar dislocation The kneecap normally is located within the groove termed trochlea on the distal femur and can slide up and down in it. Patellar dislocation occurs if the patella fully dislocates out of the groove. Dislocation of patella Dislocated kneecap SNOMEDCT_US:263029007 UMLS:C1135812 HP:0002999 Dislocated patellae