Volumetric assessment of extrusion in medial meniscus posterior root tears through semi-automatic segmentation on 3-tesla magnetic resonance images

Changwan Kim; Seong-Il Bin; Bum-Sik Lee; Won-Joon Cho; June-Goo Lee; Gi-Woon Yoon; Jong-Min Kim

doi:10.1016/j.otsr.2020.02.020

Volumetric assessment of extrusion in medial meniscus posterior root tears through semi-automatic segmentation on 3-tesla magnetic resonance images

Orthop Traumatol Surg Res. 2020 Sep;106(5):963-968. doi: 10.1016/j.otsr.2020.02.020. Epub 2020 Aug 8.

Authors

Changwan Kim¹, Seong-Il Bin¹, Bum-Sik Lee¹, Won-Joon Cho², June-Goo Lee³, Gi-Woon Yoon¹, Jong-Min Kim⁴

Affiliations

¹ Department of orthopaedic surgery, College of medicine, Asan medical center, University of Ulsan, Seoul, Democratic People's Republic of Korea.
² Department of orthopaedic surgery, Bonbridge hospital, Seoul, Democratic People's Republic of Korea.
³ College of medicine, Asan medical center, Biomedical engineering research center, Asan institute for life sciences, University of Ulsan, Seoul, Democratic People's Republic of Korea.
⁴ Department of orthopaedic surgery, College of medicine, Asan medical center, University of Ulsan, Seoul, Democratic People's Republic of Korea. Electronic address: jmkim@amc.seoul.kr.

PMID: 32782171
DOI: 10.1016/j.otsr.2020.02.020

Abstract

Background: Many reports have described the relationship between medial meniscus posterior root tears (MMPRTs) and meniscal extrusion on coronal magnetic resonance (MR) images. However, volumetric assessment of meniscal extrusion has not been performed, and the correlation between extrusion length and volume remains unclear.

Hypothesis: Extrusion in both length and volume would be greater in MMPRTs than that in the normal medial meniscus, and the extrusion length measured on coronal MR images would be correlated with the extrusion volume.

Patients and methods: A total of 20 knees who underwent isolated MMPRTs without trauma history were included in the MMPRT group, and another 20 knees with normal medial meniscus were selected as the control group. All 40 knees underwent 3-tesla MR imaging. The extrusion length of the medial meniscus was measured using coronal MR images only. Volumetric assessments of the meniscus were performed and analyzed via a semi-automatic segmentation. Group-wise comparisons of the extrusion length and volumetric values were conducted, and the correlation between the two measures in both groups was evaluated.

Results: The mean extrusion length of the medial meniscus in the MMPRT group was significantly longer (2.60 vs. 0.63mm; p<0.001) than that in the control group. The mean extrusion volume was also significantly higher in the MMPRT than that in the control group (770.93 vs. 193.80 mm³; p<0.001). The extrusion length was significantly and positively correlated with the extrusion volume in both groups (R=0.64; p=0.002 in MMPRT, R=0.73; p<0.001 in the control group).

Discussion: Semi-automatic segmentation was used to measure the volume of meniscal extrusion, which had previously only been estimated indirectly with the extrusion length on coronal MR images. MMPRTs significantly increased the extrusion in both measures. The extrusion length measured on coronal MR images was positively correlated with the extrusion volume in both groups.

Level of evidence: III, Case-control study.

Keywords: Extrusion; Medial meniscus posterior root tears; Meniscus; Segmentation.

MeSH terms

Case-Control Studies
Humans
Magnetic Resonance Imaging
Menisci, Tibial* / diagnostic imaging
Retrospective Studies
Tibial Meniscus Injuries* / diagnostic imaging