Medial patellar retinaculum
Retinaculum mediale patellae
Definition
The medial and lateral portions of the tendon of the Quadriceps pass down on either side of the patella, to be inserted into the upper extremity of the tibia on either side of the tuberosity; these portions merge into the capsule, as stated above, forming the medial and lateral patellar retinacula.
The medial patellar retinaculum is considered as a complex structure that includes several components contributing to the stability of the patella. It comprises the medial patellofemoral ligament (MPFL), medial patellotibial ligament (MPTL), medial patellomeniscal ligament (MPML), and fibrous expansions from the vastus medialis obliquus (VMO) muscle.[1-3]
The medial patellofemoral ligament is the primary stabilizer against lateral patellar displacement and originates from the medial femoral condyle, extending to the medial edge of the patella. It has two origins: a transverse origin from the bony groove between the medial epicondyle and the adductor tubercle, and an oblique origin from the proximal edge of the superficial medial collateral ligament.[4] The medial patellofemoral ligament fibers also interdigitate with the VMO tendon.[4-5]
The medial patellotibial ligament and medial patellomeniscal ligament are secondary stabilizers. The MPTL attaches to a bony ridge on the medial proximal tibia, while the MPML attaches to the meniscus and shares a common patellar insertion with the MPTL.[1][3] These ligaments function primarily in greater degrees of knee flexion.[6]
The medial patellar retinaculum also includes the deep capsular layer, which contains substantial retinacular fibers associated with the MPML.[7] This complex structure ensures the medial stability of the patella, preventing lateral displacement and contributing to the overall function of the knee joint.
References
1.Quantitative and Qualitative Analysis of the Medial Patellar Ligaments: An Anatomic and Radiographic Study.Kruckeberg BM, Chahla J, Moatshe G, et al.The American Journal of Sports Medicine. 2018;46(1):153-162. doi:10.1177/0363546517729818
2.Descriptive and Dynamic Study of the Medial Patellofemoral Ligament (MPFL).Decante C, Geffroy L, Salaud C, et al.Surgical and Radiologic Anatomy : SRA. 2019;41(7):763-774. doi:10.1007/s00276-019-02234-7.
3.Cadaveric Study of the Secondary Medial Patellar Restraints: Patellotibial and Patellomeniscal Ligaments.Kaleka CC, Aihara LJ, Rodrigues A, et al.Knee Surgery, Sports Traumatology, Arthroscopy : Official Journal of the ESSKA. 2017;25(1):144-151. doi:10.1007/s00167-016-4322-8.
4.The Anatomy of the Medial Patellofemoral Ligament.Baldwin JL.The American Journal of Sports Medicine. 2009;37(12):2355-61. doi:10.1177/0363546509339909.
5.Anatomic Study of the Attachment of the Medial Patellofemoral Ligament and Its Characteristic Relationships to the Vastus Intermedius.Mochizuki T, Nimura A, Tateishi T, et al.Knee Surgery, Sports Traumatology, Arthroscopy : Official Journal of the ESSKA. 2013;21(2):305-10. doi:10.1007/s00167-012-1993-7.
6.Recognition of Evolving Medial Patellofemoral Anatomy Provides Insight for Reconstruction.Tanaka MJ, Chahla J, Farr J, et al.Knee Surgery, Sports Traumatology, Arthroscopy : Official Journal of the ESSKA. 2019;27(8):2537-2550. doi:10.1007/s00167-018-5266-y.
7.Evaluation of the Medial Soft-Tissue Restraints of the Extensor Mechanism of the Knee.Conlan T, Garth WP, Lemons JE.The Journal of Bone and Joint Surgery. American Volume. 1993;75(5):682-93. doi:10.2106/00004623-199305000-00007.
8. This definition incorporates text from a public domain edition of Gray's Anatomy (20th U.S. edition of Gray's Anatomy of the Human Body, published in 1918 – from http://www.bartleby.com/107/).
