Can you tell me what happens if you dislocate your kneecap? I did this two years ago and so far I seem fine. But every now and then, I get painful twinges in that knee, and I wonder if I’m getting arthritis or something. Does that happen very often?

You are asking about the natural history of patellar (kneecap) dislocations. In other words, what happens over time with these injuries? That’s a good question and one that others have tried to investigate. At least one large study (100 patients) with a primary (first-time) patellar dislocation showed that a significant number of patients had arthritic changes. About one-third of the group had degenerative changes of the affected bone and joint within a dozen years of the injury.

There are many factors that can play into this. For example, patients with patellar dislocation and soft tissue damage (torn or ruptured ligaments) are more likely to develop alignment problems. Uneven loading of the joint can lead to arthritic changes from uneven wear and tear.

There may be some differences in what happens depending on what kind of treatment is given. Early surgery to repair the damaged soft tissues and stabilize the knee may be advised in active, healthy adults. This can reduce the risk of reinjury and/or redislocations. A second or third patellar dislocation increases your risk for arthritic changes.

But there could be a different reason for the twinges you are having in the knee. The leg is a single link in a long chain of biomechanical structures from head to toe. For example, muscle weakness or flexibility imbalances in the hip or ankle can affect the knee. It’s always a good idea to get help sooner than later for musculoskeletal problems. With a history of patellar dislocation and now these new symptoms, you would be a good candidate for a re-evaluation. An orthopedic surgeon or physical therapist can perform a detailed exam and perhaps identify what’s going on and what can be done about it.