The kneecap (patella) is a triangular bone at the front of the knee. Several tendons and ligaments connect to the kneecap, including ones attached to the upper leg (femur) and lower leg (tibia) bones.

Though the kneecap is not needed for walking or bending your leg, it makes your muscles more efficient and absorbs much of the stress between the upper and lower portions of the leg. Climbing stairs and squatting can put up to seven times your normal body weight on the kneecap and the joint behind it.

The kneecap can fracture in many ways: partially or completely or into only a few or into many pieces. Sometimes when the kneecap is fractured, the ligaments or tendons attached to it can be sprained or torn.

Two types of surgery may be done to repair a fractured kneecap:

• Open reduction-internal fixation (ORIF) surgery. The surgeon opens the skin puts the broken bones back together metal wires, pins or screws. Broken pieces that are too small to be fixed are removed. If part or all of the kneecap is so severely fractured that it cannot be repaired, it may be partially or totally removed. After the bones have been rejoined, the opening is closed, a sterile dressing is put over the area and the knee is immobilized with a cast or other device so it cannot move while healing takes place. Sometimes, especially in patients who are thin, the wires, pins or screws can be irritating. If this is so, the devices will be removed after your kneecap has fully healed.
• Full or partial patellectomy. This procedure removes all or part of the kneecap. This surgery lasts about two hours. If after making an incision over your kneecap and examining the bones, your surgeon finds that the break is too severe to repair, he or she will remove the damaged pieces of bone. The surgery preserves the quadriceps tendon above the kneecap, the patellar tendon below and the other soft tissues around the kneecap. After this surgery, you will be able to extend your knee, but the strength of the extension will be weaker.

Once your kneecap has healed, making the muscles around your knee stronger can help avoid further injury. Playing contact sports or doing other activities that put stress on your knee can increase the risk of having another injury to the kneecap. You should avoid these activities or use a kneepad to cushion the blow when playing contact sports.

Physical therapy, learning ways to spare your knee stress and strengthening and conditioning your leg muscles on an on-going basis can help prevent more injuries to the knee. Your best exercise options are low-impact and non-weight-bearing, like stationary bikes and certain weightlifting programs, so that the knees do not have to absorb shock.