The front part of the knee is known as the patella or knee cap. The bending of the knee causes the patella to move in the groove of the femur known as the trochlear groove. The job of this groove is to make the patella move smoothly in a straight line. The pull of the quadriceps muscle and near-about ligaments helps in holding the patella in its groove. The patellofemoral instability occurs due to the slipping of the patella from its groove.
Individuals suffering from PFI may have a flat trochlear groove as well as a patella resulting in slipped patella from the groove. Occasionally, the patella shifts to a higher position than the trochlear making it difficult to enter the groove. Other factor includes weakening of quadriceps muscle, knocked knees, etc.
The medial patellofemoral ligament (MPFL) is one of the components that helps in stabilizing the patella according to recent research. It is a ligament thin in structure running down the lower part of the quadriceps muscle. Starting at the inner or medial end of the patella it runs through to the inner part of the femur just 2 cm above the knee joint. Damage to this ligament occurs when the patella is dislocated.
Anesthetic is administered to the patient via veins. In the medial patellofemoral ligament construction, a new ligament is made to replace the damaged part. One of the hamstring tendons is taken out via a small cut at the front inner part of the tibia. A 20cm length of tendon is taken out and blended with a new ligament. Many other small cuts are made at the front of the
knee to rebuild the ligament from the inner verge of the patella to the inner verge of the femur. For holding the MPFL into position plastic screws are put by making small drill holes.
The surgical procedure is done by making three small cuts measuring 2cm to 4 cm long.
but one large incision can be used too for the purpose. The surgery needs about 60-90 minutes to be completed.
After the surgery, a physiotherapist will guide you on how to use the crutches allowing you to put full pressure on your leg. Crutches are usually used for 3 to 5 days after the surgery to safeguard the knee from getting crumpled.
The early treatment includes decreasing the inflammation, giving compression to the knee, raising your leg, and controlling muscle wasting by tightening the muscle gently.
The physiotherapy at the early stages aims to restore a bit of movement of the joint of the knee, lessen the inflammation, and balance the strength of the muscle.
The main aims of physiotherapy in the early period are to restore some motion of the knee joint, reduce swelling and maintain muscle strength.
At the tome of the healing of ligaments, a brace to stabilize the patellofemoral is needed post MPFL procedure. The brace is used for the period of 6 to 12 weeks post-surgery.
What should I expect after my operation?
Usually, there is some amount of pain after the procedure but they are kept in check via painkillers and anti-inflammatory medicines for the next 5 days. The pain is not very harsh just after the surgery because of the administration of general anesthesia during the process to lessen the pain after the process is over.
To lessen the pain and swelling after the procedure, it is significant to apply ice on your knee on regular basis, after every 20 minutes.
There may be some stiffness in the knee following the surgery, so one should try to softly bend the knee to get over this feeling.
Because of many cuts near the knee, it is usual to feel some numbness in those areas. This sensation of numbness generally vanishes with time.
Following the surgery, there will be atrophy of the knee. This means that the quadriceps muscle will reduce at the front of the knee. This happens with every candidate and gets better with proper exercise and rehabilitation regime.
Candidates often need about 1-2 weeks to relieve themselves from work if working in an office setting and 3-5 weeks if working as manual labor.
The resultant fact is that most candidates go back to the normal daily chores, sports activity too with 2 to 4% chances of any more dislocations.
Sometimes a very small number of patients need further surgeries in addition to MPFL for stabilizing the patella.
Tibial tubercle osteotomy –
The procedure is generally needed by some people when the tibial tubercle and its patellar ligament attachment are in too far a position making the patella to come forward.
Additionally, the patella may be placed too high in relation to the femur bone.
An MRI scan and x-ray are usually done to make sure of the position of the tibial tubercle. And if the position is not proper and tibial tubercle osteotomy is needed then it is performed along MPFL and a lateral release.
In this process, the very stiff structure on the lateral side of the patella is cut. This is needed in patients having very stiff tissues pushing the patella to come out, forcing instability of knee or degeneration of cartilage.
Very few patients need this procedure, in relation to MPFL reconstructive surgery. This process is done either via the same cut of MPFL reconstruction or a much larger cut near the knee.