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Patellar Realignment /Patellar Stabilization (MPFL Reconstruction)

What is Medial Patellofemoral Ligament Reconstruction?

Medial patellofemoral ligament reconstruction is a surgical procedure indicated in patients with patellar instability (multiple kneecap dislocations). Medial patellofemoral ligament is a band of tissue that extends from the medial femoral epicondyle to the superior aspect of the patella. The medial patellofemoral ligament is the major ligament which stabilizes the patella and helps in preventing patellar subluxation (partial dislocation) or dislocation. This ligament can rupture or get damaged when there is patellar dislocation. Dislocation can be caused by a direct blow to the knee, twisting injury to the lower leg, strong muscle contraction, or because of a congenital abnormality such as shallow or malformed joint surfaces.

Medial patellofemoral ligament reconstruction using autogenous tissue grafts is done by following the basic principles of ligament reconstruction such as:

  • Graft Selection: Strong and stiff graft should be selected. The superficial slip of the central quadriceps tendon is my preferred graft.
  • Location: The graft should be located isometrically
  • Correct tension: The tension set in the graft should be appropriate, usually with the knee at 60'.
  • Secure Fixation: Stable fixation of the graft should be achieved with an interference screw
  • Avoid condylar rubbing or impingement: The graft should not rub against condyle or cause impingement

Medial Patellofemoral Ligament Reconstruction Procedure

The surgical procedure of medial patellofemoral ligament reconstruction involves the following steps:

Graft Selection and Harvest: After performing any surgery inside of the knee that is indicated, your surgeon will make an 8-10 cm skin incision over your knee. The underlying subcutaneous fat and fascia are dissected. The central 8-10mm of the quadriceps tendon are then identified and released from the rest of the quadriceps tendon. The distal attachment on the top of the patella is left in place, but the tendon is released at the top.

Location of the Femoral Isometric Point: Using an x-ray machine during surgery, the point on the femur for insertion is identified. A small incision is made over the side of the knee and a guidewire is placed into the femur. This is then overdrilled to enlarge the size of the hole. The above harvested tendon is then tunneled under soft tissue to the inner side of the knee (medial)

Correct Tension: The tension is set in the graft with your knee flexed at roughly 60° and the tension should be appropriate enough to control lateral excursion.

Secure Fixation: The bone is fixed into the thigh bone (femur) with a screw to hold the tendon in place. Since it was left attached to the top of the kneecap, no fixation is required on the kneecap.

Avoid Condylar Rubbing and Impingement: After graft fixation, the range of motion is checked to make sure there are no restrictions in patellar or knee movements.

Postoperative Care after Medial Patellofemoral Ligament Reconstruction

A knee brace is used during walking in the first 6 weeks after surgery. You will not be allowed to put weight on the leg for 4 weeks then progressive weight bearing is allowed. Range of motion will progress as tolerated with physical therapy. Full recover usually takes 4-6 months and ideally allows for full return to activities.

At times, a bone cutting operation is required to move the attachment of the kneecap tendon (patellar tendon) to better align the position of the kneecap relative to the groove in which it rides. If necessary, two screws are used to hold this new position in place and the patient must wait usually 6 weeks until this is healed to start walking.

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