Alan M. Reznik, M.D.
The patella or kneecap is the moveable bone on the front of the knee. The patella is wrapped inside a large tendon that connects the large muscles on the front of the thigh, the quadriceps, to the lower leg bone. The underside of the patella is covered with articular cartilage, the smooth covering of joint surfaces. This slippery surface helps the patella glide in a special groove of the thigh bone or femur. Together the patella and the groove in the femur are called the patello-femoral mechanism.
Problems commonly develop when the patella suffers wear and tear and underlying cartilage begins to degenerate.
Degeneration may occur as part of the aging process or because of the way the patella moves through the groove in the femur. Remember, the quadriceps muscle controls the movement of the patella and if this muscle becomes weak for any reason an imbalance can occur which causes the patella to pull to one side more than the other. This places more pressure on one side of the underlying cartilage and can cause damage over time.
The normal patella should track in the groove of the femur in a relatively straight manner, but sometimes the patella can slip out of place due to injury or congenital abnormalities in the shape of the knee. This slippage may be very minor, or you may actually see that the patella is in the wrong position. If it slips all the way out of position this is called dislocation. If it only partially slips this is called subluxation.
Sometimes the bands of tissue that hold your kneecap in place can become too tight on one side and pull the patella out of the groove in the femur. This causes pain on stairs, squatting, kneeling and getting out of a car. The pressure may cause softening of the knee cap surface (chondromalacia of the patella). If this occurs your physician may prescribe physical therapy exercises, orthotics and patella bracing or taping to correct the problem. If all of the conservative measures fail to help you, you may require surgery. The surgery is called Lateral Release and for the proper indications it can help reduce the pain dramatically. This procedure is done to allow the patella to shift back to a more normal position and relieve the pressure on the articular cartilage. In this operation, the tight ligaments on the outside of the patella are released to allow the patella to slide more towards the femoral groove. The arthroscopic procedure as routinely performed by Dr. Reznik can be seen on Dr Reznik’s YouTube channel at Youtube.com/DrAReznik.
By Michael DeChello, MS, PT
The patellofemoral complex is comprised of multiple structures that stabilize the patellofemoral joint, the joint between the patella and femur. The quadriceps act as active stabilizers, the ligaments and retinaculum acts as passive stabilizers and the joint surfaces act as static stabilizers. An imbalance between any of these structures causes the tracking of the patella on the femur to be abnormal causing excessive stress on one of the structures leading to pain and dysfunction. A carefully designed lower extremity strengthening and stretching program is very important. Correcting any malalignments in the foot and knee via an custom orthotic for the shoe is necessary. Hip abductor weakness has recently been found to be associated with patellofemoral pain and should be addressed. Core strengthening exercises are also recommended for stabilization of the spine which allows for more efficient movement of the extremities.
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