As an athlete, knee pain can significantly disrupt your training and even your everyday life. Injury to the medial patellofemoral ligament, or MPFL, is a common cause of knee pain often seen in the field of sports medicine.
Part of an intricate network of soft tissues that gives your knee stability, the MPFL is one of four major ligaments in the knee. It connects your kneecap, called the patella, to your femur, also known as your thigh bone; it keeps your kneecap moving smoothly along the groove of your femur.
Sports injuries such as knee dislocations can cause patellar instability; if the MPFL is not able to keep the kneecap in place, pain and weakness are the result. MPFL injuries are most common in young female athletes: however, an MPFL injury can occur in all age groups. In this article, we detail the symptoms of and potential treatments for an MPFL injury.
What Causes MPFL Tears?
An injury to the medial patellofemoral ligament occurs when your kneecap dislocates or partially dislocates and tears the ligament located on the inside of your knee. In some cases, a weakened leg muscle or underlying knee abnormality causes a tear.
A torn MPFL, like other common knee injuries, typically happens while playing sports. The athlete’s knee may be slightly bent or straight as a tackle or force pushes the kneecap out of place. Forceful twisting, turning, or knee trauma damages the ligament.
What Are the Symptoms of an MPFL Injury?
Your MPFL keeps your kneecap moving smoothly inside the groove of your femur. During a patellar dislocation, your MPFL may get torn. The symptoms of an MPFL injury or torn ligament may consist of:
- A feeling that your knee is giving away or can’t support your weight
- Stiffness, pain, or swelling in the kneecap area
- Cracking or creaking sounds with knee movement
- A locking sensation that feels like your knee is stuck after sitting for a long time
- Movement of your kneecap to the side of the joint
- A loss of range of motion
- Exterior knee tenderness
What Are the Risk Factors for an MPFL Injury?
The main risk factors for an MPFL injury are age, birth sex, high levels of physical activity, and/or abnormal anatomy. A study published in Orthopaedics & Traumatology: Surgery & Research finds that “traumatic patellar dislocation is most often due to trauma sustained during physical or sports activity. Two-thirds of acute patellar dislocations occur in active young patients (less than 20 years old).”
Primary risk factors for experiencing a torn or injured MPFL include:
- Naturally loose ligaments, commonly found in girls and women
- Trochlear dysplasia, a deformity of the femoral trochlea
- Weak leg muscles or chronic weak knee muscles
- Presence of bony malalignments, such as valgus alignment, femoral anteversion, or tibial external rotation
- Involvement in any activities with a pivoting motion such as basketball, soccer, football, and tennis
- Previous knee dislocation or patellofemoral instability
- A connective tissue disorder, like Ehlers-Danlos syndrome hypermobility type
How Is an MPFL Injury Diagnosed?
Doctors diagnose damage to the MPFL by reviewing your medical history and asking you how you hurt your knee. They will ask about your symptoms, including the location of your pain and when it occurs.
The doctor examines your knee by testing it for strength, range of motion, and flexibility. During the exam, you may be asked to perform an activity that causes you pain while reviewing your kneecap mobility.
A doctor may request an x-ray or magnetic resonance imaging (MRI) scan to view your knee joint, assess ligament health, and confirm the diagnosis. Often, a primary care doctor will refer you to an orthopedic physician for further evaluation.
How Do You Prevent an MPFL Injury?
Exercises and protective gear can help you prevent injury to your MPFL. To reduce your risk and keep your ligaments healthy, consider:
- Strengthening your quadriceps by performing leg lifts and squats
- Building the muscles in your outer and inner thighs
- Wearing protective gear during athletic activities
- Doing hamstring curl exercises
- Stopping activity when you feel pain in your knee
- Wearing a knee brace if you’ve had a previous injury
Is MPFL Repair Better Than Reconstruction?
There are multiple options for treating an MPFL injury, including nonsurgical options, repairs, and reconstructions. Currently, reconstruction is advised for most patients; we’ll detail this more below. The most important thing is not to ignore it: once you damage your MPFL, you’re at an increased risk of repeated knee dislocations. Repeated dislocations in turn may lead to patellofemoral arthritis, which can occur after the cartilage surrounding your knee joint is damaged.
Treatment options vary based on the activity level of the patient, associated injuries, and the grade of the injury. Damage to the MPFL may be classified based on the location or type of injury, such as ruptures, sprains, avulsion fractures, and tears. Doctors may sub-classify injuries as osteochondral, ligamentous, or bony avulsion injuries.
Nonsurgical Alternatives to MPFL Reconstruction
For some patients, nonsurgical options may work best, particularly:
- Patients without pieces of soft tissue, cartilage, or bone floating around in the knee
- Patients with no cartilage damage
- Patients with a connective tissue disease.
Many first-time and uncomplicated injuries to the MPFL can be treated using a combination of nonsurgical treatments, such as:
- NSAIDs for inflammation, swelling, and pain
- Ice and heat for pain management
- Initial immobilization and activity modification
- Physical therapy to strengthen muscles surrounding the knee
- Functional rehabilitation and range of motion exercises
- Hip, gluteal muscle, and quadriceps strengthening exercises
- A knee brace, patella sleeve (called a J sleeve), or patellar taping
Your physical therapist will give you a list of activities to avoid and exercises to complete at home. It is essential to work with your doctor to determine when it’s the right time to return to regular activity.
Surgical Treatment
Doctors may recommend knee surgery for severe injuries, failure of nonsurgical methods, chronic instability, detached bone or cartilage, or recurring kneecap dislocation. Surgeons may choose to reconstruct the ligament or directly repair it. Possible options may include:
- MPFL Repair: Typically, only first-time acute injuries are considered for an MPFL repair. This method fixes the medial patellofemoral ligament and was once a method used immediately following surgery. However, in most cases, MPFL reconstruction is the better option.
- MPFL Reconstruction: A new medial patellofemoral ligament is created using a graft from another ligament, like a hamstring, either from the patient’s body or from a donor. This protects the joint from additional damage while stabilizing the knee.
- Lateral Release and Medial Imbrication: This procedure creates one or two incisions near the patella to tighten or loosen ligaments on either side of the kneecap in order to promote healthier movement of the kneecap. Medial imbrication may also tighten the tissues on the inner side of the knee by extending the quadriceps muscles on the kneecap.
- Bone Realignment: For abnormal anatomy, a bone realignment, such as the Fulkerson procedure, may be used. It repositions the tibial tubercle, the secondary part of the shinbone where bones form. This process makes dislocations less likely.
How Should I Prepare for MPFL Reconstruction Surgery?
Before surgery, the objective is to reduce knee swelling. Doctors may prescribe a knee brace and physical therapy, such as a pre-surgery rehabilitation program. The goals of MPFL reconstruction surgery are to recover full range of motion, return to normal activities, and regain knee stability.
Your surgeon will discuss what to do and not do before the surgery. Common instructions include:
- No food or drink after midnight before your surgery
- Recommendations about any prescribed medications
- The time you should arrive at the facility
- How to report an illness or infection before the surgery
Furthermore, your doctor or anesthetist will discuss your options for pain during the surgery, which may include general or spinal anesthetic. The Alexander Outpatient Advantage means that the surgery usually takes 1-2 hours, and patients can return home immediately to recover.
How Long Does It Take to Recover from MPFL Reconstruction?
Exact recovery times depend on the individual patient, but most people are cleared to resume activities like driving within 4-6 weeks, and many can return to their normal athletic activities within 6 months.
Directly after the MPFL reconstruction surgery, patients receive a brace to immobilize the knee and walk with a crutch. You may receive a continuous passive motion machine (CPM) for use at home. The CPM machine helps reduce stiffness and scar tissue by moving the patellofemoral joint without using the patient’s muscles. The brace may be worn for up to six weeks, or until the patient can walk without a limp.
Will I Need Physical Therapy after MPFL Reconstruction?
Physical therapy is an important part of the recovery process after surgery. It may include using tools or specific exercises to assist with mobility and range of motion in the joint (for instance, exercising on a stationary bike is often recommended). Three months after the surgery, you may do advanced exercises to improve your range of motion and gain endurance.
When Can I Return to Sports after MPFL Reconstruction?
Most patients are able to return to their sport within 6 months of the surgery. High-impact and pivoting sports (like basketball, soccer, or football) may take longer to return to than lower-impact activities (like swimming or cycling). You should always discuss the process with your physician and physical therapist to make sure you’re ready to resume more intense physical activity.
What Is the Success Rate of MPFL Reconstruction?
According to research published in Current Reviews in Musculoskeletal Medicine, “Modern MPFL reconstruction is a well-described operative intervention which is successful in the vast majority of chronic patellar instability patients. Excellent functional results have been reported as high as 95%, and numerous studies have documented [a] significant reduction in postoperative re-dislocation.”
Read more about how Alexander Orthopaedics has helped patients in their own words.
Find Out More About MPFL Reconstruction at Alexander Orthopaedics
Kneecap dislocations can have many different possible causes and treatments, so it’s important to discuss your options with an experienced surgeon and physical therapist. At Alexander Orthopaedics, our team assesses your MPFL injury diagnosis then works with you to create a plan for treatment and recovery. Our signature Outpatient Advantage model focuses on streamlining the recovery process by allowing you to recover in the comfort of your own home as opposed to a hospital room. Schedule an appointment to learn more about how we can help you return to the sports you love, pain-free.