An MPFL tear is a common knee injury that significantly impacts kneecap stability. It often leads to feelings of instability and can affect a person’s ability to move freely. Understanding its causes, symptoms, and treatments is important for those experiencing knee instability.
The Medial Patellofemoral Ligament Explained
The medial patellofemoral ligament (MPFL) is a band of tissue on the inner side of the knee. It connects the patella (kneecap) to the femur (thigh bone). The MPFL plays a significant role in stabilizing the patella, especially during the initial degrees of knee bending. Its main function is to prevent the kneecap from moving too far outwards from its natural groove. This ligament provides 50-80% of the resistance needed to keep the kneecap properly aligned.
How MPFL Tears Happen
MPFL tears typically occur from a traumatic event that forces the kneecap out of its normal position. A common cause is a patellar dislocation, where the kneecap shifts completely out of its groove. This often happens with sudden twisting motions of the knee, especially when the foot is planted, or from a direct blow.
Sports involving pivoting, quick changes in direction, or collisions are frequent scenarios for MPFL tears. When the kneecap dislocates, it stretches or tears the MPFL. Some individuals have underlying factors like looser ligaments or knee anatomy variations that increase their susceptibility.
Identifying the Symptoms
An MPFL tear often presents with immediate and noticeable symptoms. Patients typically experience sudden pain and may feel or hear a popping sensation at the time of injury. If the kneecap dislocates, a visible deformity of the knee may be present. Swelling around the knee usually develops quickly after the injury.
Beyond the initial trauma, symptoms include difficulty bearing weight on the affected leg and a feeling of instability, as if the knee might “give way.” The knee may also feel stiff, and its range of motion can become limited. A catching sensation or crackling sounds may occur when bending or straightening the leg.
Diagnosing and Treating an MPFL Tear
Diagnosis typically begins with a physical examination of the knee. A healthcare provider checks for tenderness, swelling, and assesses the knee’s range of motion and stability. Imaging tests are used to confirm the diagnosis and evaluate the injury’s extent.
X-rays rule out bone fractures or other bony abnormalities. Magnetic Resonance Imaging (MRI) provides detailed soft tissue images, allowing doctors to visualize the MPFL and assess tear location and severity. MRI can also identify other potential knee injuries, such as cartilage damage or bone bruising.
Treatment approaches vary depending on the tear’s severity and recurrence. Non-surgical treatment is often the initial approach for partial tears or first-time dislocations. This conservative management includes rest, ice, compression, and elevation. Pain medication may be prescribed for discomfort. Physical therapy strengthens surrounding muscles to improve stability and restore function.
Surgical intervention may be recommended for complete MPFL tears, recurrent kneecap dislocations, or when non-surgical treatments have failed. The most common surgical procedure is MPFL reconstruction, where a new ligament is created using a tendon graft. This procedure aims to restore kneecap stability by providing a strong restraint against outward movement. An MPFL repair, reattaching the torn ligament, may also be performed, though reconstruction is more common for complete tears.
Recovery and Rehabilitation
Recovery from an MPFL tear, whether treated non-surgically or surgically, centers on a structured rehabilitation program. Physical therapy plays a central role in regaining the knee’s strength, flexibility, and stability. Initially, the focus is on controlling pain and swelling, and gradually increasing range of motion. For surgical cases, the knee may be immobilized in a brace for several weeks, and crutches may be used to limit weight-bearing.
As healing progresses, physical therapy exercises strengthen the quadriceps, hamstrings, and gluteal muscles for knee support. Balance and proprioception exercises are also incorporated to improve overall knee stability. Recovery ranges from several weeks for non-surgical cases to 4-6 months for surgical reconstruction before returning to full activities. Athletes may require additional time for sport-specific training before returning to their previous activity levels. Adherence to the rehabilitation protocol is important for a successful outcome and to minimize re-injury risk.