Superior dislocation of the patella with interlocking osteophytes.

Superior dislocation of the patella with interlocking osteophytes was only once found roentgenologically documented. Such a dislocation occurs without tendon rupture, and can occur with a hyperextension force. Reduction is easily accomplished by manipulation of the patella without anesthesia. Full active motion is present post-reduction. This entity should not be confused with vertical dislocations of the patella.