From the Guidelines
The medial patellar retinaculum is a structure that plays a crucial role in maintaining the stability of the patella, and injuries to this area can be treated with MRI evaluation to assess the integrity of the medial patellofemoral ligament and medial patellar retinaculum, as well as to define the extent of cartilage injury and identify loose bodies 1.
Medial Patellar Retinaculum Injuries
- Medial patellar retinaculum injuries can occur due to patellar dislocation or chronic knee pain, and MRI is useful in evaluating the extent of the injury and guiding treatment.
- MRI without IV contrast may be indicated when radiographs demonstrate a small osseous fragment along the medial patellar margin or if there is a clinical concern for prior or chronic patellar dislocation-relocation 1.
- The treatment of medial patellar retinaculum injuries may involve conservative management or surgical intervention, depending on the severity of the injury and the presence of associated conditions such as cartilage lesions or loose bodies.
Diagnosis and Treatment
- MRI is a valuable tool in diagnosing medial patellar retinaculum injuries, as it can assess the integrity of the medial patellofemoral ligament and medial patellar retinaculum, define the extent of cartilage injury, and identify loose bodies 1.
- In some cases, contrast-enhanced MRI may be useful in diagnosing other causes of chronic knee pain, such as Hoffa’s disease, deep infrapatellar bursitis, patellofemoral friction syndrome, and adhesive capsulitis 2.
From the Research
Medial Patellar Retinaculum
- The medial patellar retinaculum is a complex structure that includes four components: the fascia, fibrous expansions of the vastus muscles, the medial patellofemoral ligament (MPFL), and the medial patellomeniscal ligament 3
- The MPFL is considered the primary stabilizer of the patella between full extension and 30° flexion, and its reconstruction is a common treatment for patellofemoral instability 4
Medial Patellar Retinaculum Injuries
- Medial patellar retinaculum injuries can occur due to traumatic patellar dislocation, which can result in osteochondral avulsion at the inferomedial patella 5
- These injuries can be treated with various surgical techniques, including MPFL reconstruction and lateral retinacular lengthening 6
Treatment Options
- MPFL reconstruction techniques differ in the graft used and the fixation method, and can be performed using a lateral parapatellar approach 6
- A new minimally invasive surgical technique for medial retinaculum repair has been introduced, which achieves reinforced reattachment of the torn region of the medial retinaculum without the use of grafts 5
- Rehabilitation after MPFL reconstruction is crucial, and typically involves a phased approach with gradual progression to full weight-bearing and return to activities 7
Surgical Techniques
- MPFL reconstruction can be performed using a gracilis allograft and adjustable loop cortical femoral fixation, which allows for reliable retensioning of the medial and lateral patellar soft tissues 6
- The technical challenges, advantages, and disadvantages of different MPFL reconstruction techniques are reviewed in detail, along with the postoperative rehabilitation protocol 4