developmental anatomy of the meniscus in the … · the meniscus and tibialplateau in pediatric...

DEVELOPMENTAL ANATOMY OF THE MENISCUS IN THE SKELETALLY IMMATURE

OBJECTIVES and BACKGROUND• Although the morphologic anatomy of the meniscus is well-studied,

meniscal development in the skeletally immature remains unclear.• In adults, the lateral and medial meniscus is thought to have

proportionally less coverage over the tibial plateau in comparison to pediatric subjects.

The purpose of this study is to investigate the anatomic relationship of the meniscus and tibial plateau in pediatric cadaveric specimens and

how meniscus coverage of the tibial plateau changes with age.

METHODS• Twenty-nine cadaveric pediatric knees ranging from 1 month to 36

months of age underwent gross dissection to expose the medial and lateral menisci.

• Axial view photographs of the tibial plateau with attached menisci were taken.

• Then, both lateral and medial menisci were removed.• Subsequent photos were taken of the tibial plateau with menisci

removed. See Figures 1 and 2.– A ruler was placed in the field at the level of the plateau in each

image to aid in quantitation of meniscus and plateau area.• A quantitative image-analyzer was used to calculate the area of the

medial and lateral meniscus as well as the medial and lateral tibialplateaus.

RESULTS• An independent samples t-test demonstrated a difference between the

medial and lateral compartments. In Table 1 and Table 2, the difference in percent coverage between the medial (x = 52.66%) and lateral (x = 64.71%) meniscus is statistically significant (p<0.001**).

• ANOVA indicated that medial and lateral meniscus percent coverage does not significantly vary by tibial plateau length (p > .05)

DISCUSSION• Previously collected data by Bloecker et al. reported that in adults, the lateral meniscus

covers approximately 59% of the lateral tibial plateau, while the medial covers about 50%of the medial tibial plateau.

• This study indicated that the pediatric meniscus covered proportionally more area than the adult menisci.

CONCLUSIONS• Understanding age-related meniscal anatomy may provide a better understanding of

meniscus development.• Percent coverage of both the lateral and medial meniscus over tibial plateau length

appears to decrease with age in pediatric cadaveric specimens. This decreasing trend is more apparent in specimens of 24 months to 36 months in age and may be further substantiated by data from older specimens.Acknowledgements: Allosource, Centennial, CO

Correspondence: Kevin Shea : kevingshea@gmail.com

1George Washington University, Washington, DC. 2Georgetown University School of Medicine, Washington, DC. 3St. Luke’s Hospital System, Boise, ID. 4University of Minnesota, St. Paul, MN. 5Texas Scottish Rite Hospital for Children, Dallas, TX. 6The Ohio State University, Columbus, OH.

TIBIAL PLATEAU LENGTH nMEDIAL

MENISCUS % COVERAGE

LATERAL MENISCUS% COVERAGE

2.25—2.75 cm (group 1) 8 53.66% 62.99%

2.75—3.25 cm (group 2) 7 54.79% 63.92%

3.25—3.75 cm (group 3) 6 56.01% 61.84%

3.75—4.5 cm (group 4) 6 52.87% 63.62%Mean 27 52.66%** 64.71%**

Age n Medial meniscus area/ Medial plateau area

Lateral meniscus area/ Lateral plateau area

1 month 5 55.46% 67.84%3 months 5 54.58% 65.91%4 months 6 55.85% 60.44%5 months 2 55.78% 67.62%10 months 2 50.02% 64.37%12 months 4 47.79% 64.81%24 months 4 40.89% 69.17%36 months 1 51.88% 54.19%

FIGURE 2. Axial view of tibial plateau with the menisci removed.

FIGURE 1

REFERENCES: Bloecker K, Wirth W, Hudelmaier M, Burgkart R, Frobell R, Eckstein F. Morphometric Differences between the Medial and Lateral Meniscus in Healthy Men - A Three-Dimensional Analysis Using Magnetic Resonance Imaging. Cells Tissues Organs [serial online]. March 2012;195(4):353-364. Available from: Academic Search Complete, Ipswich, MA.

Nicolas G. Anchustegui1, Jessica F. Burlile, BA, BS2, Connor G. Richmond, BS3, Marc Tompkins, MD4, Henry B. Ellis, MD4, Philip L. Wilson, MD5, Laura C. Boucher, PhD, ATC6, Kevin G. Shea, MD3

MEDIAL

LATERAL

FIGURE 2

TABLE 2. Percent meniscus coverage of the tibial plateau delineated by age.

FIGURE 3. The percent coverage of the menisci and the area of the medial and lateral meniscus plotted against age and tibial plateau length.

FIGURE 1. Axial view of dissected 3 month old male knee with the lateral and medial meniscus intact.

MEDIAL

LATERAL

TABLE 1. Percent meniscus coverage of the tibial plateau delineated by tibial plateau length.