Should the meniscal height be considered for preoperative sizing in meniscal transplantation?

Abstract

Purpose and hypothesis: In preoperative sizing for meniscal transplantation, most authors take into consideration the length and width of the original meniscus, but not its height. This study aimed at evaluating (1) whether the meniscal height is associated with the meniscal length and width, (2) whether the heights of the meniscal segments are associated with the individual's anthropometric data, (3) whether the heights of the meniscal segments are associated with each other in the same meniscus, and (4) the degree of symmetry of the meniscal dimensions between the right and left knees.

Methods: In this cross-sectional, observational study, two independent radiologists measured the meniscal length, width and height in knee magnetic resonance imaging scans obtained from 25 patients with patello-femoral pain syndrome. Reproducibility of measurements was calculated with intraclass correlation coefficients. Associations between the anthropometric data and the meniscal measurements, the meniscal length and width versus height, and the heights of the meniscal segments in the same meniscus were examined with Pearson's correlation.

Results: Inter-observer reliability was excellent (>0.8) for length and height and good (0.6-0.8) for width measurements. There was also excellent agreement (>0.8) for the length and width of the menisci in the right and left knees. The heights of the horns of the lateral meniscus showed good agreement (0.6-0.8), while the heights of the other meniscal segments had excellent agreement between the sides (>0.8). There were significant associations with generally low (r < 0.5) correlation between the heights of the meniscal segments and the lengths and widths of the menisci, between the meniscal height and anthropometric data, and between the heights of the meniscal segments in the same meniscus. Correlations between anthropometric data and meniscal length and width were generally high (r > 0.7).

Conclusions: There was excellent agreement between the meniscal dimensions of the right and left knees, and a weak association between the meniscal height with the meniscal width and length, between the height of the menisci with anthropometric data and between the heights of the segments in the same meniscus. The height of the meniscal segments may be a new variable in preoperative meniscal measurement.

Keywords: Accuracy; Dimensional measurement; Graft; Imaging; Inter-observer variation; Joint; Knee; MRI scans; Magnetic resonance; Medial; Meniscus; Meniscus lateral; Tibial menisci; Transplantation.

Fig. 1

Proton-density-weighted sequences, acquired in the axial plane to demonstrate in a single image both menisci, the tibial insertion sites and the periphery of the menisci’ anterior horn, body and posterior horn

Fig. 2

Measurement of the meniscal width and length in an axial slice. For the meniscal length, we identified the most anterior point of the anterior horn and the most posterior point of the posterior horn of the meniscus. A line traced between these points measured the meniscal length. In the picture below, the meniscal length is 30.6 mm (green A line). For the meniscal width, we traced a line between the most central points of the insertion sites of the anterior and posterior horns of the meniscus. In the midpoint of this line, we drew a perpendicular line up to the periphery of the outer contour of the body of the meniscus that was used to measure the meniscal width. In the picture below, the width is 21.9 mm (yellow B line)

Fig. 3

Height of the medial meniscal body, defined as the largest dimension in the longitudinal axis of the medial meniscus obtained in a coronal slice, at the same level in which the width of the medial meniscus was measured in an axial slice

Fig. 4

Height of the anterior horn of the lateral meniscus, defined as the largest dimension in the longitudinal axis of the anterior horn of the lateral meniscus obtained in a sagittal slice, at the same level in which the length of the lateral meniscus was measured in an axial view

Fig. 5

Anterior horn of the medial meniscus extending beyond the limits of the anterior tibial plateau margin (arrow)