While researching tibia tubercle tuberosity osteotomy, MPFL reconstruction was another surgery I also learned is commonly done for patella instability.
The MPFL ligament often becomes injured when the kneecap is dislocated. Patients with an underlying abnormality of the knee, or those with ligament laxity or weak leg muscles are at an increased risk for patella dislocations, as are individuals involved in sports or other activities that involve pivoting.
The MPFL plays an important role in keeping the patella on track and in place. It acts as a leash that restrains the movement of the patella. When patella dislocation occurs, the patella jumps the track and then comes forcibly back into place on its return. The patella bone always dislocates laterally, towards the outside part of the leg. When the patella returns into place it pulls down hard on the medial patellofemoral ligament causing ligament tearing, injury and cartilage damage.
This procedure involves ligaments and it helps to understand what they do to get a deeper understanding of this procedure. Ligaments connect bones to other bones to form joints. They are made of soft connective tissue and have a very low blood supply compared to muscles, making them very slow to heal and recover from injury.
The medial patellofemoral ligament is a ligament that connects the patella to the femur and allows the knee to pivot and shift. It is considered an extra-articular ligament, meaning it’s on the outer aspect of the knee joint. There is another extra-articular ligament, the lateral patellofemoral ligament but I have yet to see this ligament repaired with reconstruction like I do for the mpfl. For your cpt selection you will need to select extra-articular or intra-articular, that is the key difference for the ligament reconstruction codes cpt 27427 (extra-articular) cpt 27428 (intra-articular open) and cpt 27429 (both, intra-articular and extra-articular).
Intra-articular ligaments are the anterior cruciate and posterior cruciate ligament. The medial collateral ligament and the lateral collateral ligament are also intra-articular, but they are less frequently injured and rarely require surgical reconstruction or augmentation.
Diagnostic arthroscopy is usually done to inspect the cartilage and to see if there are any other injuries or disease processes that can be addressed during surgery.
Once the arthroscopic inspection is done, the ports are removed and the open portion of the surgery begins. The physician makes an incision over the injured ligament. The torn end may be reattached to the bone using anchors, staples, screws or washers. If reattachment on its own is not possible, the ligament is reattachment with a tendon autograft ( graft from self- think autograph) or allograft (same species, different person-cadaver ).
Websites to learn more
Here are some good websites and a YouTube video to learn more about the procedure.
YouTube video on this procedure
Until next week,
Michelle McKinney, CPC, CCS