Patellar Dislocation Treatment
A patellar dislocation occurs when the kneecap is forced out of the trochlear groove — the shallow channel on the front of the femur in which the patella normally tracks during bending and straightening of the leg. In nearly all cases, the kneecap shifts laterally (toward the outside of the knee), stretching or tearing the medial patellofemoral ligament (MPFL) — the primary soft tissue restraint that holds the patella in place — and potentially damaging the cartilage on the underside of the kneecap or the surface of the trochlear groove. Patellar dislocations most commonly result from a sudden change of direction, a pivoting movement with the foot planted, or a direct blow to the inner side of the kneecap during contact sports. The kneecap may spontaneously relocate when the leg is straightened, or it may need to be manually repositioned. Either way, the damage to the ligaments and tendons in the knee joint has already occurred — and without proper evaluation and treatment, the risk of recurrent dislocation and progressive cartilage damage increases significantly with each episode.
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 across the full spectrum — from first-time acute dislocations in adolescent athletes to chronic recurrent instability requiring surgical stabilization. His published research on patellar viability and the knee’s extensor mechanism gives him an evidence-based understanding of the anatomic and biomechanical factors that contribute to patellar dislocation, including trochlear groove depth, limb alignment, and MPFL integrity. As Chief Medical Officer for the New Jersey Devils and Philadelphia 76ers, he manages acute kneecap dislocations on the sideline and develops return-to-play plans that balance competitive demands with long-term joint health. Named a Castle Connolly Top Doctor every year since 2000, he evaluates and treats patellar dislocations with same-day imaging at his Upper East Side practice in New York City.
Dislocated Kneecap Surgery or Treatment
The tendons and ligaments attached to the patella can be damaged during a patellar dislocation. The patella can also be fractured or damaged during trauma to the knee. Patellar dislocation treatment depends on the extent of the damage and if it is a recurring injury. When minimal damage to the ligaments occurs, they can heal with rest, followed by rehabilitation to strengthen the knee. In more severe or recurrent patellar dislocations, surgery may be required to repair ligaments, fractures or to stabilize the kneecap.
A patellar dislocation can cause intense pain, swelling and instability in the knee. It is important to have a patellar dislocation injury examined by an orthopedic specialist to determine if there is any damage to the components of the knee. Our experts at Jonathan Glashow, MD, Orthopedic Surgery & Sports Medicine can provide diagnosis and treatment for kneecap dislocations at our facility in UES New York City. We offer same day appointments and treatments. Contact us to schedule an emergency exam if you or a family member suffers from a patellar dislocation or severe knee injury.
Frequently Asked Questions About Patellar Dislocation
What does a patellar dislocation feel like?
A patellar dislocation typically produces an immediate, intense pain at the front of the knee, often accompanied by a visible shift of the kneecap to the outside of the joint. Patients frequently describe a sensation of the knee “giving way” or “popping out.” Rapid swelling develops within the first few hours as blood and fluid accumulate in the joint. The knee may feel locked if the kneecap does not relocate on its own, and there is usually significant difficulty bending or straightening the leg. Even after the kneecap returns to its groove — whether spontaneously or with manual assistance — the knee typically remains painful, swollen, and unstable for days to weeks.
What is the difference between a patellar dislocation and a subluxation?
A patellar dislocation occurs when the kneecap shifts completely out of the trochlear groove and remains displaced until it is manually repositioned or spontaneously returns when the leg is straightened. A subluxation is a partial or transient dislocation — the kneecap shifts partially out of the groove and then snaps back into place on its own, often within a fraction of a second. Subluxations can cause similar symptoms including pain, swelling, and a sensation of the knee giving way, and they indicate the same underlying instability that puts the kneecap at risk for a full dislocation. Both conditions require evaluation to assess for MPFL damage and underlying anatomic risk factors.
What happens to the MPFL when the kneecap dislocates?
The medial patellofemoral ligament is almost always torn or significantly stretched during a patellar dislocation — it is the first structure to fail when the kneecap shifts laterally. The MPFL is the primary soft tissue restraint against lateral patellar displacement, and once it is damaged, the kneecap loses its primary checkrein. In many first-time dislocations, the MPFL can scar and heal with enough strength to prevent recurrence — particularly with bracing and physical therapy. However, when the MPFL does not heal adequately or when anatomic risk factors predispose the patient to recurrent instability, MPFL reconstruction may be recommended to restore the restraint surgically.
Can a patellar dislocation heal without surgery?
Many first-time patellar dislocations — particularly those without associated cartilage damage, loose bodies, or significant anatomic risk factors — can be treated successfully without surgery. Treatment typically involves a brief period of immobilization in a brace, followed by a structured physical therapy program focused on strengthening the quadriceps (especially the vastus medialis oblique), improving hip stability, and restoring normal patellar tracking. Dr. Glashow monitors each patient’s progress and uses imaging to assess whether the MPFL has healed adequately. Surgery is typically recommended if the kneecap dislocates a second time, if imaging reveals significant cartilage damage or loose bodies, or if anatomic factors such as a shallow trochlear groove make recurrence highly likely.
How likely is it that the kneecap will dislocate again?
The recurrence rate after a first-time patellar dislocation varies depending on the patient’s age, anatomy, and activity level. Studies show that approximately 15 to 45 percent of patients who experience a first-time dislocation will go on to have at least one recurrence — with younger patients and those with predisposing anatomic factors (such as a shallow trochlear groove, high-riding patella, or increased Q-angle) at the higher end of that range. Each additional dislocation further damages the cartilage and stretches the MPFL, making subsequent episodes more likely. This is why Dr. Glashow emphasizes comprehensive evaluation after a first dislocation to identify risk factors and determine whether surgery should be considered to prevent a cycle of recurrent instability.
When is MPFL reconstruction recommended for patellar dislocation?
MPFL reconstruction is typically recommended for patients who have experienced two or more patellar dislocations, patients with a single dislocation accompanied by significant anatomic risk factors that make recurrence highly likely, and patients whose imaging reveals cartilage damage or loose bodies within the joint that need to be addressed surgically. For detailed information about the MPFL reconstruction procedure, visit the MPFL Reconstruction page.
