Kneecap (Patellar) Instability: Ligament Reconstruction Using Soft Anchors and Screws Animation

Kneecap (Patellar) Instability: Ligament Reconstruction Using Soft Anchors and Screws Animation

This animation will demonstrate an M P F L reconstruction using a tendon graft, soft body anchors, and an absorbable screw. To review, the medial patellofemoral ligament, or mpfl, is a ligament located at the inner side of the knee. The MPFL connects the kneecap to the thigh bone, or femur, and helps to stabilize the kneecap.

A small incision will be made through the skin and soft tissue along the inner border of the kneecap and the bone will be prepared where the graft will attach. Then, a drill is inserted into a drill guide to create a socket into the inner border of the kneecap. The first anchor is inserted into the drill guide and tapped in place into the socket. This soft body anchor comes with sutures which will be released as the drill guide is removed. Each anchor has 2 types of suture tapes, black and blue. Tension is applied to the black suture tapes to ball up the anchor under the bone to hold it in place. The same steps are repeated for the second anchor.

Next, a tendon graft is positioned through the loops of the blue sutures. Tension is applied to the blue sutures to secure the graft along the border of the kneecap. A template is placed at the inner side of the thigh to help locate the attachment site for the MPFL on the bone. X-ray is also used during the procedure to find the exact location of the attachment site. Once correctly identified, a guide pin will be drilled into the thigh bone to create a small tunnel that exits out the other side of the thigh. A reamer will also be used to make a socket at the beginning of this tunnel at the inner side of the thigh.

A passing suture is then passed under the skin and secured to the ends of the graft to pull the graft toward the tunnel in the thigh bone. This passing suture is then connected to a guide wire which is used to pull the graft through the tunnel. Once the ideal alignment of the kneecap and graft is achieved, an absorbable screw will be inserted into the socket made in the thigh bone to secure the graft in place. After the procedure is complete, the black suture tapes will be used to close the soft tissue around the kneecap and additional sutures will be used to close the skin incisions.