What is an MPFL reconstruction?
In a normal knee, the patella (knee cap) sits in a groove on the end of the femur (thigh bone). The groove itself helps to hold the patella in place but one of the main stabilising structures is the Medial Patellofemoral Ligament (MPFL), which is a ligament which is attached to the inner side of the patella and the inner side of the femur. If the patella starts to shift sideways, the ligament pulls taut and holds it in.
If your patella dislocates, the MPFL is invariably torn or stretched. Even though it can heal, it is often not as strong as it was before. This makes it more likely for the patella to dislocate again in future.
An MPFL reconstruction uses a tendon to create a new ligament between the patella and femur, which stabilises the patella.
How is an MPFL reconstruction performed?
When you are asleep under an anaesthetic, first, an arthroscopy is performed to examine the rest of the knee to check that there are no other injuries. Any damage to the patella can be treated and any loose bodies can be removed. The position and movement of the patella is also assessed as the knee moves through a full range of movement.
Next, a 2-3cm incision is made over the front of the knee and one of the hamstring tendons is harvested from the back of the thigh. This is doubled over and sutured to create the MPFL graft. Two more 2cm incisions are made over the inner side of the knee cap and the inner side of the thigh bone. Tunnels are then drilled into the patella and femur. The graft is pulled into these tunnels to recreate the MPFL on the inner side of the knee. It is then fixed in position with a metal button and screw. It is very uncommon for these to need to be removed later.
What is the recovery like after surgery?
After an MPFL reconstruction, you will stay in hospital for one night. A physiotherapist will show you how to use crutches but I am happy for you to out your full weight through the leg. You will also be given some knee exercises to do to start your rehabilitation. You will not need a brace.
Once you have been discharged, you should see your physiotherapist within a couple of weeks. If you don’t have one, I can organise for you to see one of my highly experienced physios. The knee is sore and swollen for several weeks but this is usually easily manageable with the painkillers that you will be given when you are discharged. You will need to take 2-3 weeks off work. You won’t be able to drive until you can walk without crutches and without strong painkillers. This usually takes 2-3 weeks.
Your knee rehabilitation will take about 6-9 months in total but you will be walking comfortably within a couple of weeks. You should notice that your patella is stable almost immediately after surgery.
How successful is MPFL reconstruction?
MPFL reconstruction is a very reliable operation for stabilising the patella. Over 90% of patients are satisfied or very satisfied. The chance of having another dislocation is very low (less than 5%) and is usually only happens with significant trauma. Sometimes there can be some ongoing tenderness over the inner side of the knee but it is very uncommon for this to be severe.