Two knee reconstruction procedures are used for a dislocating patella. The first is Tibial Tubercle Transfer (TTT) and the second is Medial Patellofemoral Ligament Reconstruction (MPFL). The knee cap or patella acts as a pulley at the front of the knee. It allows the large quadriceps muscles of your thigh to pull across the front of the knee acting on the patellar tendon to straighten the knee. The patellar sits in a groove at the front of the femur (thigh bone) called a trochlea groove. With a direct blow or a twisting injury, the patella can be dislocated out of its groove onto the outside of the knee joint.
How does the MPFL tear?
Here in Perth, playing netball would be one of the most frequent causes of a dislocated patella. When the patella is forced to the outside of the knee joint, everything that is attached to the inner half of the knee cap is torn or damaged. The muscle here is the VMO which is the inner quadriceps muscle.
The ligament attaching to the inner half of the knee cap is the medial patellofemoral ligament. It is one of the major structures which keeps the knee cap centralised in its groove. Patella dislocation tears the MPFL and sprains the VMO muscle.
What happens during the MPFL reconstruction?
To perform this reconstructive knee surgery, your orthopaedic surgeon will make a new ligament to replace the torn MPFL. He can use a graft tendon from your body such as a hamstring tendon or part of the quadriceps tendon, or an artificial ligament called the LARS graft. Holes are drilled in the femur, and the inner edge of the patella and the new ligament is secured in these holes with screws.
MPFL reconstruction is sometimes combined with Tibial Tubercle Transfer surgery (TTT).
Get in touch with us!
Dr David Colvin consults at:
Western Orthopaedic Clinic
Suite 213, 25 McCourt Street,
Subiaco WA 6008 (Perth)
- These rooms are part of St John of God Subiaco Hospital.
- Parking is available on site.
Dr David Colvin operates at: