Summary

Experimental model of medial meniscus posterior root tear increases the severity of cartilage damage in rabbits

Abstract

Background

Magnetic resonance imaging (MRI) is ideally suited for the investigation of joint diseases by virtue of its excellent soft tissue contrast, high spatial resolution, multiplanar capability, ability to allow direct visualization, and to quantify cartilage thickness and volume distribution under normal and pathologic conditions.

Objective

The main purpose of this study was to identify and evaluate early osteoarthritic changes using high-resolution magnetic resonance imaging after surgical release of the medial meniscus posterior root in rabbit knees.

Methods

Knee osteoarthritis (OA) was experimentally induced by medial meniscus posterior root (MMPR) transaction in the right knees of 12 male New Zealand White rabbits. Contralateral knees were used as healthy controls. High-resolution 4.7 Tesla MRI was performed at baseline, at 2-, and 4 months of post-surgery. Within-animal and between-knee comparisons were conducted to determine changes in cartilage thickness, water content on T2 weighted sequences, and meniscal extrusion.

Results

Progressive cartilage thinning, meniscal extrusion, and subchondral bone edema were evident in all knees after 4-months of follow-up. A significantly decreased cartilage thickness (0.53mm± 0.05) was observed at the final follow-up (p<0.001). Meniscal extrusion was evident after 2 months of post-surgery that gradually increased in all experimental knees. Moreover, knees with early cartilage swelling at 2 months of follow-up presented increased severity of cartilage damage.

Conclusions

Degenerative changes worsened at a rapid rate in knees with MMPR injury. Early cartilage swelling, persistent subchondral edema, and progressive meniscal extrusion predicted more severe progression to knee OA. These changes can be a promising therapeutic target, which promotes the interest of this model.