Summary

Circumferential ring augmentation procedure of the meniscus reduces the degree of meniscus extrusion, and it also restores meniscal function by lowering tibiofemoral joint contact pressure.

Abstract

Introduction

The major meniscal functions are load bearing, load distribution, and shock absorption by increasing the tibiofemoral joint (TFJ) contact area and dissipating axial loads by conversion into circumferential hoop tension. On the other hand, meniscus radial tear (especially root tear) or degenerative change of the joint accompanies the loss of hoop tension and resultantly cause meniscus extrusion and knee osteoarthritis. Various surgical techniques and methods (pull-out or suture anchor) of meniscus repair has been introduced in the literature in order to restore hoop tension and prevent progression of degenerative arthritis. Unfortunately, recent studies report that previous repair techniques neither reduced meniscus extrusion nor prevented the progression of arthrosis completely. The authors previously analyzed the morphological and biomechanical characteristics of the “juxta-meniscal capsule” and reported its supportive role in maintaining the circumferential hoop tension of the meniscus. Thus, based on the assumption that augmenting this capsular structure may restore the functions of the meniscus, the authors devised the circumferential ring augmentation. Thus, the purpose of this study is to biomechanically analyze ring augmentation procedure to assess whether it can restore meniscal function.

Methods

A total of 28 rabbits were divided into four groups (A: normal, B: root tear, C: root tear + repair, D: root tear + ring augmentation). For ring augmentation, wire suture was passed circumferentially to the periphery of the meniscus, and each of the two suture ends were passed through the anterior and posterior insertional root and fixed by post-tie. At 4 weeks after surgery, the degree of meniscus extrusion was analyzed using micro-CT and tibiofemoral joint contract pressure was measured accordingly.

Results

Ring augmentation group resulted in significantly less meniscal extrusion compared to the root group and repair group. Tibiofemoral joint contact pressure was also significantly lower in the ring augmentation group.

Conclusion

Circumferential ring augmentation procedure of the meniscus reduces the degree of meniscus extrusion, and it also restores meniscal function by lowering tibiofemoral joint contact pressure, which may eventually contribute to the prevention of the progression of knee osteoarthritis.