The patella (more commonly known as the "kneecap") moves up and down in front of the knee joint along a built-in track called the patellofemoral groove. It is held in place by several ligaments on either side and by the patellar tendon (attached to the quadriceps muscle). The quadriceps muscle is the large, four-part muscle along the front of the thigh.
Although you can take your hands and passively move the kneecap from side to side, this is not an active movement you can make your patella do without assistance. We call that side-to-side (medial-to-lateral) movement accessory motion. The up-and-down and side-to-side accessory motions are referred to as patellar glide.
As part of the patellar tendon, there are slips of ligamentous fibers that help hold the patella in place and keep it from moving too far to one side or the other. On the inside of the kneecap is the medial patellofemoral ligament. On the outside is the lateral patellofemoral ligament.
Without the medial patellofemoral ligament, the kneecap dislocates laterally (in a direction sideways away from the other knee). Because the medial patellofemoral ligament is connected with other ligamentous structures, complete rupture will likely damage other areas as well. The medial patellofemoral ligament attaches above to the femur (thigh bone) and below to the tibia (lower leg bone).
Most ruptures occur at the femoral attachment. But the ligament can tear away from the tibial attachment or even in the middle (not at either bone attachment). This type of tear is called an intrasubstance tear.
A medial patellofemoral ligament injury can be treated conservatively without surgery. The knee may have to be immobilized in a splint for a number of weeks to allow for healing. Physical therapy, taping, and a home program of exercises prescribed by the therapist begin after the period of immobilization. The rehab program must be given the good old college try: in other words, for more than a few days or weeks. It can take months to rehab this injury.
But if nonoperative care fails and the patella dislocates again, then surgery to repair or reconstruct the ligament may be the next step. The surgical approach that works best depends on the underlying damage and specific patient factors.
The surgeon will use an arthroscope to look inside the joint and assess the damage before performing the actual repair. In this study, there was an equal number of patients with medial patellofemoral tears at the femoral, tibial, and intrasubstance locations.
Results were viewed in terms of final outcome (patellar stability or instability with another dislocation) but also included clinical data. Range of motion for the hip and knee was measured.
X-rays were taken to look at the position and angle of the patella over the femur. Knee function and disability were also measured.
Nearly three-fourths (72 per cent) of the patients had a stable patella with no episodes of redislo...