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Medial patellofemoral ligament

The medial patellofemoral ligament (MPFL) is the primary soft tissue stabilizer of the patella, preventing excessive lateral displacement. It is a band-like ligament of the knee that connects the medial border of the patella to the femur near the medial epicondyle. It plays a critical role in maintaining patellar stability, especially during early knee flexion (0–30°).

It is frequently injured in cases of lateral patellar dislocation, making it highly relevant in orthopedic, surgical, and radiological practice.

Synonyms

  • MPFL

  • Medial patellar stabilizing ligament

  • Patellofemoral ligament (medial)

Origin and Insertion

  • Origin: Superomedial border of the patella and quadriceps tendon junction

  • Course: Fibers run medially and posteriorly in a fan-shaped manner, forming part of the medial patellar retinaculum

  • Insertion: Medial femoral epicondyle region, just distal to the adductor tubercle and proximal to the medial collateral ligament (MCL) origin

Nerve Supply

  • Small articular branches from the femoral nerve and saphenous nerve provide sensory innervation

Arterial Supply

  • Medial superior genicular artery

  • Descending genicular artery

  • Contributions from branches of the femoral artery

Venous Drainage

  • Drains into the genicular venous plexus → popliteal vein → femoral vein

Function

  • Provides ~50–60% of medial restraint against lateral patellar displacement

  • Stabilizes patella during the initial 0–30° of knee flexion

  • Prevents recurrent patellar dislocation

  • Works synergistically with quadriceps and medial retinaculum

Clinical Significance

  • Most commonly injured ligament in acute lateral patellar dislocation

  • Chronic insufficiency leads to patellar instability and recurrent dislocation

  • Reconstructed surgically in cases of severe or recurrent instability

  • MPFL reconstruction is a common procedure in young athletes

MRI Appearance

T1-weighted images:

  • MPFL appears as a thin, low-signal band extending from medial patella to femur

  • Surrounded by bright fat planes aiding visualization

T2-weighted images:

  • Normal ligament remains low signal

  • Acute tears show discontinuity with hyperintense edema/hemorrhage adjacent to patella or femoral attachment

STIR (Short Tau Inversion Recovery):

  • Ligament remains dark if intact

  • Injury shows bright hyperintense edema or hemorrhage at origin or insertion

Proton Density Fat-Saturated (PD FS):

  • Normal MPFL appears low signal

  • Partial or complete tear shows bright hyperintense disruption within or around the ligament

T1 Fat-Sat Post-Contrast:

  • Normal ligament shows minimal enhancement

  • Injured or inflamed ligament shows focal enhancement

  • Postoperative reconstruction grafts show variable enhancement during healing

CT Appearance

Non-Contrast CT:

  • MPFL itself is not directly visualized due to low soft tissue contrast

  • Secondary signs (patellar maltracking, avulsion fragments at patella or femoral epicondyle) may be seen

Post-Contrast CT:

  • Limited role for ligament visualization

  • Enhancement may highlight associated soft tissue swelling, hematoma, or adjacent inflammatory changes

MRI images

Medial Patellofemoral Ligament (MPFL) axial cross sectional anatomy 3T MRI AI enhanced radiology anatomy image-img-00000-00000

MRI images

Medial Patellofemoral Ligament (MPFL) coronal cross sectional anatomy 3T MRI AI enhanced radiology anatomy image-img-00000-00000_00001

MRI image

Medial Patellofemoral Ligament (MPFL) ct axial