Objectives: To evaluate the effect of various medial patellofemoral ligament (MPFL) fixation techniques on patellar pressure compared with the native knee.
Methods: A finite element model of the patellofemoral joint consisting of approximately 30,700 nodes and 22,200 elements was created from computed tomography scans of 24 knees with chronic lateral patellar instability. Patellar contact pressures and maximum MPFL graft stress at five positions of flexion (0°, 30°, 60°, 90°, and 120°) were analyzed in three types of MPFL reconstruction (MPFLr): (1) static/anatomic, (2) dynamic, using the adductor magnus tendon (AMT) as the femoral fixation, and (3) dynamic, using the quadriceps tendon as the attachment (medial quadriceps tendon-femoral ligament (MQTFL) reconstruction).
Results: In the static/anatomic technique, the patellar contact pressures at 0° and 30° were greater than in the native knee. As in a native knee, the contact pressures at 60°, 90°, and 120° were very low. The maximum MPFL graft stress at 0° and 30° was greater than in a native knee. However, the MPFL graft was loose at 60°, 90°, and 120°, meaning it had no tension. In the dynamic MPFLr using the AMT as a pulley, the patellar contact pressures were like those of a native knee throughout the entire range of motion. However, the maximum stress of the MPFL graft at 0° was less than that of a native ligament. Yet, the maximum MPFL graft stress was greater at 30° than in a native ligament. After 30° of flexion, the MPFL graft loosened, similarly to a native knee. In the dynamic MQTFL reconstruction, the maximum patellar contact pressure was slightly greater than in a normal knee. The maximum stress of the MPFL graft was much greater at 0° and 30° than that of a native MPFL. After 30° of flexion, the MQPFL graft loosened just as in the native knee.
Conclusions: The patellar contact pressures after the dynamic MPFLr were like those of the native knee, whereas a static reconstruction resulted in greater pressures, potentially increasing the risk of patellofemoral osteoarthritis in the long term. Therefore, the dynamic MPFLr might be a safer option than a static reconstruction from a biomechanical perspective.
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http://dx.doi.org/10.3390/jcm8122093 | DOI Listing |
J Clin Orthop Trauma
January 2025
St. George's University Hospitals NHS Foundation Trust, London, SW17 0QT, UK.
Introduction: medial patellofemoral ligament reconstruction (MPFLr) is a common surgical procedure for treating patellar instability. Grafts can be fixed to the femur using a bone-tunnel technique with an interference screw. However, this may lead to femoral tunnel enlargement (FTE) post-operatively.
View Article and Find Full Text PDFArthrosc Tech
November 2024
Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Patellar dislocation is a common knee injury, with concomitant pathoanatomical risk factors that synergistically interact and predispose to patellofemoral instability. Medial patellofemoral ligament (MPFL) reconstruction has demonstrated significant potential in the re-establishment of MPFL anatomic and biological function, with low patellar redislocation rates. Although many techniques for MPFL reconstruction have been developed, challenges such as patella fractures and high costs persist.
View Article and Find Full Text PDFArthroscopy
December 2024
University of Virginia Health System, Department of Orthopaedic Surgery.
Purpose: To describe the clinical and radiographic outcomes of patients undergoing a lateral opening distal femur osteotomy (DFO) to address valgus alignment and restore patellar stability.
Methods: A retrospective review of patients who underwent lateral opening DFO for recurrent patellar instability in the setting of valgus leg alignment at a single academic institution between January 2016 to December 2021 was performed. Patients without a minimum 24-month postoperative follow-up were excluded.
Orthop J Sports Med
December 2024
Department of Orthopaedics, University of Utah Health, Salt Lake City, Utah, USA.
Background: Improved patient outcomes and decreased patellar instability have been reported after medial patellofemoral ligament (MPFL) reconstruction for recurrent lateral patellar dislocation; however, there is a lack of comparative evidence on functional outcomes associated with different femoral attachment sites for the MPFL graft.
Purpose: To identify differences in MPFL reconstruction graft isometry with femoral tunnel malpositioning, specifically evaluating isometric differences as the femoral position is moved anterior, posterior, proximal, and distal relative to the Schöttle point, the femoral radiographic landmark of the MPFL.
Study Design: Descriptive laboratory study.
Ann Med Surg (Lond)
December 2024
Third Department of Orthopedic Surgery, National and Kapodistrian, University of Athens, KAT General Hospital, Athens, Greece.
Lateral patellar dislocation is irrefutably one of the most common knee injuries, while subsequent medial patellofemoral ligament (MPFL) damage requires proper orthopedic care. Treatment of these injuries is regularly associated with the need for MPFL reconstruction surgery. This operation, often in combination with other procedures, can result very fruitful in restoring knee kinematics.
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