Evolution of knowledge on meniscal biomechanics: a 40 year perspective

Abstract

Background: Knowledge regarding the biomechanics of the meniscus has grown exponentially throughout the last four decades. Numerous studies have helped develop this knowledge, but these studies have varied widely in their approach to analyzing the meniscus. As one of the subcategories of mechanical phenomena Medical Subject Headings (MeSH) terms, mechanical stress was introduced in 1973. This study aims to provide an up-to-date chronological overview and highlights the evolutionary comprehension and understanding of meniscus biomechanics over the past forty years.

Methods: A literature review was conducted in April 2021 through PubMed. As a result, fifty-seven papers were chosen for this narrative review and divided into categories; Cadaveric, Finite element (FE) modeling, and Kinematic studies.

Results: Investigations in the 1970s and 1980s focused primarily on cadaveric biomechanics. These studies have generated the fundamental knowledge basis for the emergence of FE model studies in the 1990s. As FE model studies started to show comparable results to the gold standard cadaveric models in the 2000s, the need for understanding changes in tissue stress during various movements triggered the start of cadaveric and FE model studies on kinematics.

Conclusion: This study focuses on a chronological examination of studies on meniscus biomechanics in order to introduce concepts, theories, methods, and developments achieved over the past 40 years and also to identify the likely direction for future research. The biomechanics of intact meniscus and various types of meniscal tears has been broadly studied. Nevertheless, the biomechanics of meniscal tears, meniscectomy, or repairs in the knee with other concurrent problems such as torn cruciate ligaments or genu-valgum or genu-varum have not been extensively studied.

Keywords: Biomechanics; Mechanical stress; Meniscus; Osteoarthritis; Systematic review.

Fig. 1

Significant events in cadaveric studies of the meniscus

Fig. 2

Clinical stress machine for evaluating the role of the intact meniscus and its influence on tibiofemoral stability. From “Medial and anterior instability of the knee. An anatomical and clinical study using stress machines” by Kennedy JC, Fowler PJ, 1971, The Journal of bone and joint surgery American volume. 1971;53(7):1257–70 [13]. With permission of Wolters Kluwer. Promotional and commercial use of the material in print, digital or mobile device format is prohibited without the permission from the publisher Wolters Kluwer. Please contact healthpermissions@wolterskluwer.com for further information

Fig. 3

Medial meniscus displacement during passive motion. A Schematic view of the insertion device and procedure of insertion of the beads into the meniscus. Beads were placed in the insertion needle, and the needle was again placed into a device that secured an insertion depth of 10 mm in the meniscal stroma through the knee joint capsule. Then, three beads of 0.8 mm diameter were inserted under arthroscopic control. B Knee-joint loading apparatus. On the left side, the femur (f), which is rigidly fixated in the semi-lunar device. Different knee-joint flexion angles are realized rotating the semi-lunar device thereby changing the angle of the femur relative to the tibia, as indicated in (a). The axial load (b) is applied to the femur. On the right side, the tibia (t). On this side of the apparatus, freedom of movements are internal and external rotation, varus–valgus rotation, ML translation and AP translation. Internal and external torques (d) were applied through a pair of sheaves (c). C Positioning of the loading apparatus, the Roentgen tubes, and the film cassette. Two separate X-rays were taken with two tubes on the same Roentgen film. Note the reference points on the film cassette and the positioning of the knee joint in the coordinate system: the X-direction represents ML displacements on the tibial plateau and the Z-direction represents the AP displacement on the tibial plateau. From “Displacement of the medial meniscus within the passive motion characteristics of the human knee joint: an RSA study in human cadaver knees.” by Tienen TG et al., 2004, Knee Surg Sports Traumatol Arthrosc. 2005;13(4):287-92 [17]. With permission of Springer

Fig. 4

Distribution of pressure on medial tibial plateau total and partial meniscectomy. A total meniscectomy increased peak local contact stresses more than two times and decreased in contact area by 75%, while partial meniscectomy only increased peak local contact stresses and decreased contact areas by 65 and 10%, respectively. From “Meniscal tears: the effect of meniscectomy and of repair on intraarticular contact areas and stress in the human knee. A preliminary report.” by Baratz ME, Fu FH, Mengato R., 1986, Am J Sports Med. 1986;14(4):270–5 [27]. Copyright © 1986 by American Journal of Sports Medicine. Reprinted by Permission of SAGE Publications, Inc

Fig. 5

Milestones in finite element modeling of the meniscus

Fig. 6

The distribution of shear stresses in the articular cartilage. A Influence of the Young’s modulus of the artificial meniscus, dented by EAM, on the maximum shear stresses at the interfaces of cartilage–cartilage, cartilage–bone, and cartilage–meniscus. A range for the stiffness of physiological meniscus in the circumferential direction of the knee is also shown. B Shear stress distribution in the auricular cartilages with artificial meniscus with EAM = 110 MPa. The Poisson ratio of the artificial meniscus is equal to 0.45 in this set of calculations. From “Influence of meniscectomy and meniscus replacement on the stress distribution in human knee joint.”, by Vaziri A et al., 2008, Ann Biomed Eng. 2008;36(8):1335–44 [45]. With permission of Springer

Fig. 7

A Three-dimensional geometry of the left knee, which includes femur, tibia, fibula, articular cartilage and lateral and medial menisci with the dotted line representing the trans epicondylar axis and the location where the loading was applied. B A typical mesh of the knee geometry. From “The combined effect of frontal plane tibiofemoral knee angle and meniscectomy on the cartilage contact stresses and strains.”, by Yang N et al., 2009, Ann Biomed Eng. 2009;37(11):2360–72 [46]. With permission of Springer

Fig. 8

Significant events in kinematic studies of the meniscus

Fig. 9

Kinematic study of radial tears of the lateral meniscus and its repair. The contact mechanics of large radial lateral meniscus tears were similar to those of partial lateral meniscectomy but contact pressure was significantly reduced with inside-out repair. A Stanmore Knee Simulator, B Sensor Placement, C The Force Profile. From “Dynamic contact mechanics of radial tears of the lateral meniscus: implications for treatment.”, by Bedi A et al., 2012, Arthroscopy. 2012;28(3):372–81 [58]. Copyright (2012), with permission from Elsevier