Bipartite patella is a congenital condition (present at birth) that occurs when the patella (kneecap) is made of two bones (instead of a single bone). Normally, the two bones would fuse together as you grow. But in patella bipartite, they remain as two separate bones.
Most of the time, this condition is silent. The person doesn’t even know he or she has it. But direct trauma to the kneecap or repetitive injury (overuse) can trigger painful symptoms. The usual advice given to athletes with this condition is to rest and stop playing until the symptoms go away.
It’s understandable that if you are trying to get on the tennis team, this isn’t very helpful advice. You may benefit from antiinflammatory medications and a four-to-six week course of physical therapy. The therapist will help you find ways to modify your activity. Exercises to balance function of the quadriceps muscle may help.
In cases where the pain is severe enough to limit daily activities (or for athletes with an upcoming season), surgery may be indicated. There are several approaches available to the surgeon. The exact procedure used depends on the size and condition of the bone fragment.
If the fragment is small enough, it could be just removed. Large fragments can be taken out, too, but there is a chance that arthritis will develop later. The surgeon may also release the vastus lateralis. These are the tendon slips from the quadriceps muscle that attach along the outside edge of the patella. Too much pull too often from this tendon can cause pain. Symptoms may be relieved by releasing the tendon from the fragment and/or from the entire patella.