Morphological changes of the preserved discoid lateral meniscus on serial magnetic resonance imaging following partial meniscectomy and repair: A comparison between immediate and 2-year postoperative findings.

BACKGROUND

The purpose of this study was to analyze serial magnetic resonance imaging (MRI) changes in discoid lateral meniscus (DLM) from the immediate postoperative period to 2 years after partial meniscectomy and meniscus repair.

METHODS

From November 2015 to November 2023, 32 patients with MRI-confirmed torn DLM who underwent arthroscopic partial meniscectomy and meniscus repair were analyzed. MRI scans were performed immediately postoperatively and 2 years after surgery. Meniscal dimensions, including width, height, and mid-height, were measured on coronal and sagittal MRI to observe morphological changes.

RESULTS

The width of the anterior and posterior horns significantly increased in the follow up MRI (anterior: from 9.0 mm to 11.55 mm (P < 0.001); posterior: from 8.29 mm to 9.81 mm (P < 0.001)) compared with the immediate postoperative MRI. While there were no significant differences in the heights of the anterior horn, midbody, and posterior horn, mid-heights were reduced in all three parts (anterior horn: from 3.47 mm to 2.84 mm (P < 0.001), midbody: from 2.73 mm to 2.31 mm (P = 0.003), and posterior horn: from 3.09 mm to 2.74 mm (P = 0.008)).

CONCLUSION

The meniscal width of the anterior and posterior horns of DLM in the sagittal plane increased from the immediate postoperative state through to 2 years following partial meniscectomy and meniscus repair. Although the height of the anterior horn, midbody, and posterior horns remained consistent, the mid-height of these structures decreased at the 2-year follow up compared with the immediate postoperative status.