Luxating patella is a condition in which the patella, or kneecap,<unk>  or moves out of its normal location.  The luxation is usually medial, but can be lateral.
Dislocated patella
Retrocalcaneal bursitis
Olecranon bursitis
Chondromalacia patellae
Prepatellar bursitis
Humerus fracture
Iliotibial band syndrome
Calcific tendinitis