Dislocation of patella, closed

This code signifies a complete displacement of the kneecap (patella) from its normal position within the trochlear groove of the femur, without an open wound communicating with the dislocated joint. It represents an acute injury to the knee joint.

Apply this code for documented cases of patellar dislocation where the skin remains intact over the injury site. This typically occurs due to direct trauma or sudden twisting movements of the knee. Documentation should clearly state "dislocation of patella" and specify "closed."

• Differentiate from patellar subluxation, which is a partial displacement.
• Ensure the documentation specifies "closed" to avoid confusion with open dislocations.
• Consider an external cause code (E-code) to describe the circumstances of the injury.