Three-dimensional meniscus allograft sizing—a study of 280 healthy menisci

Abstract

Background: Inaccurate meniscus allograft size is still an important problem of the currently used sizing methods. The purpose of this study was to evaluate a new three-dimensional (3D) meniscus-sizing method to increase the accuracy of the selected allografts. Methods: 3D triangular surface models were generated from 280 menisci based on 50 bilateral and 40 unilateral knee joint magnetic resonance imaging (MRI) scans. These models served as an imaginary meniscus allograft tissue bank. Meniscus sizing and allograft selection was simulated for all 50 bilateral knee joints by (1) the closest mean surface distance (MeSD) (3D-MRI sizing with contralateral meniscus), (2) the smallest meniscal width/length difference in MRI (2D-MRI sizing with contralateral meniscus), and (3) conventional radiography as proposed by Pollard (2D-radiograph (RX) sizing with ipsilateral tibia plateau). 3D shape and meniscal width, length, and height were compared between the original meniscus and the selected meniscus using the three sizing methods. Results: Allograft selection by MeSD (3D MRI) was superior for all measurement parameters. In particular, the 3D shape was significantly improved (p < 0.001), while the mean differences in meniscal width, length, and height were only slightly better than the allograft selected by the other methods. Outliers were reduced by up to 55% (vs. 2D MRI) and 83% (vs. 2D RX) for the medial meniscus and 39% (vs. 2D MRI) and 56% (vs. 2D RX) for the lateral meniscus. Conclusion: 3D-MRI sizing by MeSD using the contralateral meniscus as a reconstruction template can significantly improve meniscus allograft selection. Sizing using conventional radiography should probably not be recommended. Trial registration: Kantonale Ethikkommission Zürich had given the approval for the study (BASEC-No. 2018-00856).

Meniscus sizing using three-dimensional models of the ipsilateral tibia plateau based on CT scans – an experimental study of a new sizing approach

“…Although good average sizing values are reported in literature, inaccuracy of sizing is still a relevant problem and has to be improved. The ignored 3D shape of the meniscus might lead to an inaccurate meniscus size selection, regrettably corresponding with clinical experience and confirmed by recently published data [1, 6, 9, 13, 14, 17, 22, 23].…”

“…Finally, the best fifty selected menisci of each method were compared according to the MeSD, MaSD and the differences of width/length/height. Further, outliers were analyzed as a mismatch between the "original" and "selected meniscus" of > 5 mm in width, > 5 mm in length, > 4 mm in height or > 5 mm MaSD [1].…”

Pediatric meniscus morphology varies with age: a cadaveric study

“…With regard to meniscus transplantation, meniscus anatomy is important for selecting correctly sized allografts, and studies have analyzed best approaches for allograft selection [2]. Historically, MRI has been considered the gold standard [6], but Kaleka et al [11] evaluated both anthropometric (based on sex, height, and weight) and plain radiographic methods of predicting meniscal dimensions.…”

Editorial Commentary: Long-Term Survivorship of Knee Meniscal Transplant Surgery—The Importance of Patient-Reported Outcomes With Magnetic Resonance Imaging Demonstration of Retained Meniscal Transplant Function

“…At present, the sizing criteria for MAT remain rudimentary, and newer techniques including 3-dimensional MRI of available implants and the match to patients require further exploration. 4,5 The long-term effects of MAT in symptomatic younger patients after meniscectomy are reported by Brown and Carter 6 in "Meniscal Allograft Survivorship and Outcomes 20 Years After Implantation," and the authors are to be commended for following the results of the senior surgeon for over 20 years. One has to ask, How many surgeons have published their 20-year results of a surgical procedure?…”