Medial Patella-Femoral Ligament (MPFL) Reconstruction
The medial patellofemoral ligament — or MPFL — is the primary soft tissue restraint that prevents the kneecap from sliding laterally out of the trochlear groove during knee flexion and extension. When a traumatic patellar dislocation occurs, the MPFL is almost always torn — and once damaged, the ligament rarely heals with enough strength to prevent the kneecap from dislocating again. Patients with recurrent patellar instability experience episodes of the kneecap slipping out of place during sports, daily activities, or even simple movements like twisting or turning — producing pain, swelling, a sensation of the knee giving way, and progressive cartilage damage on the underside of the kneecap each time a dislocation occurs. MPFL reconstruction is a surgical procedure that replaces the damaged ligament with a tendon graft, restoring the anatomic restraint that holds the kneecap in its groove and preventing further dislocation.
Dr. Jonathan Glashow is a board-certified orthopedic surgeon and Clinical Associate Professor of Orthopedic Surgery at NYU Grossman School of Medicine, with over 30 years of experience treating patellar instability and patellofemoral disorders across all age groups — from adolescent athletes experiencing their first dislocation to adult patients with chronic recurrent instability. His published research on patellar viability and the knee’s extensor mechanism directly informs his understanding of the anatomic factors that contribute to patellar instability and the surgical precision required for successful MPFL reconstruction. As Chief Medical Officer for the New Jersey Devils and Philadelphia 76ers, he manages acute and chronic patellar injuries in professional athletes where restoring full kneecap stability is essential for return to competition. Named a Castle Connolly Top Doctor every year since 2000, Dr. Glashow performs MPFL reconstruction at his Upper East Side practice in New York City.
Symptoms, Diagnosis, and Surgical Treatment
Symptoms of a dislocated kneecap include:
- Pain in the kneecap when engaged in physical activity
- Feeling of your kneecap slipping with twisting or turning movements
- In some cases a near patella dislocation (subluxation) when the knee is close to being straight (the patient can actually feel and see it move)
An MPFL injury happens when the knee is fully straight (extended) and the leg is either rotated or a force is applied to the inside of the kneecap (patella) causing the knee cap to move from its normal position to the outside of the knee. When this occurs the ligament MPFL that normally holds the knee cap in place is torn. Other injuries such as cartilage damage can occur during the traumatic dislocation as well.
An X-ray of your knee will be necessary to get a clear picture of your bone structure. A CAT scan or MRI may also be recommended so the orthopedic surgeon can get a better three-dimensional picture of the bones, ligaments, or cartilage.
After proper evaluation of a first dislocation and if no other injuries are present, sometimes non operative treatment will be the treatment of choice. If the other injuries are present of if there have been multiple dislocation of the patella arthroscopic surgery can correct this condition. Medial patella-femoral ligament (MPFL) reconstruction surgery involves using a ligament taken from somewhere else in one’s body or a synthetic replacement. The NYC orthopedic surgeon reconstructs the MPFL to keep the kneecap in place: in the “trochlear groove”, preventing further dislocation.
Medial Patella Femoral ligament (MPFL) reconstruction is a method of rebuilding the ligament on the inside of the patella that is torn during dislocation. This is similar to other ligament reconstructions about the knee. A portion of the hamstring tendon is often used to rebuild the MPFL.
Contact a Top Knee Surgeon in NYC
If you are experiencing recurrent kneecap dislocation, persistent patellar instability, or have been told you need MPFL surgery and want an evaluation from one of New York City’s most experienced knee surgeons, Dr. Glashow can provide a comprehensive assessment with same-day imaging at his Upper East Side practice. Contact our office to schedule your consultation.
Frequently Asked Questions About MPFL Reconstruction
What is the MPFL and what does it do?
The medial patellofemoral ligament is a band of tissue that runs from the inner edge of the kneecap to the medial (inner) side of the femur. Its primary function is to prevent the kneecap from shifting outward — laterally — as the knee bends and straightens. When the MPFL is intact, it acts as a checkrein that holds the patella centered in the trochlear groove of the femur. When it is torn during a patellar dislocation, the kneecap loses its primary restraint and becomes susceptible to repeated dislocations.
How do I know if I need MPFL reconstruction?
MPFL reconstruction is typically recommended for patients who have experienced two or more patellar dislocations, patients with persistent patellar instability or subluxation after a single dislocation, and patients whose imaging shows a torn MPFL along with anatomic risk factors — such as a shallow trochlear groove or elevated tibial tuberosity — that make recurrent dislocation likely without surgical intervention. After a first-time dislocation with no associated injuries, Dr. Glashow often recommends a trial of bracing, physical therapy, and strengthening. If instability persists or a second dislocation occurs, reconstruction becomes the standard recommendation.
What does MPFL reconstruction surgery involve?
During MPFL reconstruction, Dr. Glashow replaces the damaged ligament with a tendon graft — typically a portion of the hamstring tendon harvested from the same knee. The graft is threaded along the anatomic path of the MPFL, attached to the inner border of the kneecap, and fixed to the femur at the precise anatomic attachment point using small anchors or interference screws. The goal is to restore the natural checkrein that prevents lateral patellar translation while maintaining the knee’s full range of motion and normal kneecap tracking.
Is MPFL reconstruction the same as patellar realignment surgery?
Not exactly. MPFL reconstruction specifically addresses the torn ligament that is the primary restraint against lateral patellar dislocation. Patellar realignment is a broader category that may include MPFL reconstruction along with additional procedures — such as tibial tubercle osteotomy (moving the attachment point of the patellar tendon) or lateral release — to correct the underlying anatomic factors contributing to instability. Dr. Glashow evaluates each patient’s anatomy with X-rays, CT scans, and MRI to determine whether MPFL reconstruction alone is sufficient or whether additional realignment procedures are needed for a durable result.
How long does recovery take after MPFL reconstruction?
Most patients wear a brace and use crutches for the first four to six weeks after surgery to protect the graft while it incorporates. Range-of-motion exercises begin within the first week and progress gradually, with strengthening introduced over the following months. Return to low-impact activities typically occurs around three months, and clearance for sports involving pivoting, jumping, and contact generally takes six to nine months — depending on the patient’s individual healing and the demands of their sport. Dr. Glashow coordinates rehabilitation closely with physical therapists to ensure the reconstructed MPFL heals with proper tension and the kneecap tracks normally before returning to activity.
Can patellar dislocation happen again after MPFL reconstruction?
MPFL reconstruction has a high success rate for preventing recurrent patellar dislocation, with published studies showing re-dislocation rates of less than 5 to 10 percent in appropriately selected patients. The likelihood of recurrence depends on several factors including the accuracy of graft placement, whether underlying anatomic risk factors were also addressed during surgery, and the patient’s compliance with the rehabilitation program. Dr. Glashow’s experience with patellar anatomy — informed by his published research on patellar viability and the extensor mechanism — helps ensure that each reconstruction addresses the full spectrum of contributing factors.
