The Vastus Medialis Insertion Is More Proximal and Medial in Patients With Patellar Instability: A Magnetic Resonance Imaging Case-Control Study.
Orthopaedic Journal of Sports Medicine
Background: The anatomy and function of the quadriceps muscle play a role in patellofemoral stability. Few studies have evaluated anatomic differences in the vastus medialis between patients with and without patellar instability.
Purpose: To compare the anatomy of the vastus medialis using magnetic resonance imaging in patients with patellar instability to a control group.
Study Design: Cross-sectional study; Level of evidence, 3.
Methods: A group of patients with patellar instability were sex-matched with a control group with anterior cruciate ligament tears, meniscal injuries, or sprains; patients younger than 15 years were excluded. The anatomy of the vastus medialis was examined by the distance between the distal origin of the vastus medialis in the femur and the medial femoral condyle, the distance from the proximal pole of the patella to the most distal insertion of the muscle and its ratio to the length of the articular surface of the patella, and a qualitative description of the insertion position of the muscle fibers (directly in the patella or the medial retinaculum).
Results: Both groups comprised 78 knees (48 female; 61.5%). The mean age in the control and patellar instability groups was 30.2 ± 7.8 years and 25.6 ± 7.5 years, respectively (
Conclusion: The distal insertion of the vastus medialis differed in knees with patellar instability, with a more proximal insertion and less patellar coverage relative to controls, and was more frequently found in the retinaculum instead of directly in the patella.
Gobbi RG, Hinckel BB, Teixeira PRL, Giglio PN, Lucarini BR, Pécora JR, Camanho GL, Demange MK. The Vastus Medialis Insertion Is More Proximal and Medial in Patients With Patellar Instability: A Magnetic Resonance Imaging Case-Control Study. Orthop J Sports Med. 2019 Dec 4;7(12):2325967119880846. doi: 10.1177/2325967119880846. PMID: 31840028; PMCID: PMC6893936.