2025 ISAKOS Congress in Munich, Germany

2025 ISAKOS Biennial Congress Paper


Postoperative Meniscal Extrusion is due to Meniscal Fiber Disruption and Increased Volume With Increased Extrusion for a Transtibial Repair With and Without a Centralization Stitch for Type 2 Medial Meniscal Root Tears: A Prospective Level I 7T MRI Study

Luke V. Tollefson, BS, Edina, MN UNITED STATES
Christopher Michael LaPrade, MD, Chanhassen, MN UNITED STATES
Abdul Wahed Kajabi, PhD, Minneapolis, MN UNITED STATES
Karsten Knutsen, BS, Minneapolis, MN UNITED STATES
Collin Steinberger, None, Minneapolis, MN UNITED STATES
Jutta M Ellermann, MD, Minneapolis, Minnesota UNITED STATES
Robert F. LaPrade, MD, PhD, Edina, MN UNITED STATES

Twin Cities Orthopedics and University of Minnesota, Edina, MN, UNITED STATES

FDA Status Not Applicable

Summary

The use of a centralization stitch for medial meniscus transtibial root repairs (MMRR) did not significantly decrease postoperative medial meniscus extrusion due to degenerative intrameniscal biochemical changes.

Abstract

Background

Postoperative meniscal extrusion has been reported in >50% of knees with medial meniscus root repairs (MMRR). Meniscal extrusion is a risk factor for the progression of a more rapid onset of osteoarthritis. The etiology and treatment of meniscal extrusion has not been well defined.

Purpose

The purpose was to assess medial meniscal root architecture and structural integrity and determine if the addition of a centralization suture to a transtibial MMRR can decrease meniscal extrusion in the early postoperative timeframe via high field MRI.

Methods

This was an IRB approved and NIH-funded prospective Level I study performed for patients with an isolated type II medial meniscal root tear. Patients undergoing a MMRR were randomly selected to undergo a transtibial repair with or without a centralization stitch. A power analysis determined that 24 patients were necessary for the study. Preoperative and 6-month postoperative imaging were performed using an FDA approved 7T MRI scanner. For morphological evaluation, the MRI protocol included T1- and T2-weighted turbo-spin echo sequences, along with a T2-weighted 3D SPACE with and without fat suppression. For quantitative meniscal assessment, a 3D multi-echo gradient recalled echo sequence was acquired for T2* relaxation time mapping. Manual 3D segmentation was performed on T2*-weighted images to capture the medial meniscus 3D structure. Medial meniscus extrusion was measured pre- and postoperatively on coronal T2-weighted images using two vertical lines at the peripheral margins of the medial tibial plateau and the outermost edge of the meniscal body.

Results

Twenty-four patients, mean age: 52 years; age range: 34-62 years; mean body mass index: 27.8 kg/m2; 21 females) were included. All MMRRs were found to have healed on MRI. Comparing the volumes, the medial meniscus was significantly larger in post-MMRR patients. There was a strong correlation between quantitative MRI mapping and meniscal extrusion; extrusion measurements taken from post-MMRR patients were significantly correlated with quantitative MRI mapping values comparing pre-MMRR (r=0.826; p<0.001) to post-MMRR (r=0.732; p=0.002) patients.

Postoperative extrusion increased in 22/24 (91.7%) patients. The centralization group had an average increase of 0.7 mm (18% increase) of extrusion postoperatively (p=0.017). The no centralization group reported an average increase of 1.6 mm (48% increase) of extrusion postoperatively (p=0.002). Additionally, there was significantly less variance in extrusion in the centralization group compared to the no centralization group, 0.67 mm versus 2.11 mm, respectively (p=0.039).

Conclusion

Elevated quantitative MRI values in the posterior horn of the medial meniscus reflected a disrupted collagen fiber network due to increased tissue hydration, proteoglycan breakdown, and enlargement of the menisci in post-MMRR patients. The use of a centralization stitch did not significantly decrease postoperative medial meniscus extrusion. Increased extrusion after a MMRR was due to degenerative intrameniscal biochemical changes. The use of a centralization stitch can help in reducing this extrusion, but more research is required to determine the proper number, placement, and technique of centralization sutures to minimize postoperative medial meniscus extrusion.