Can the Disoid Meniscus Remodel After Saucerization?

BACKGROUND/PURPOSE: The discoid meniscus is a congenital variant that is reported to be present in 3-5% of the United States population. Treatment involves partial meniscectomy and saucerization to obtain a more anatomic-appearing meniscus. The immediate post-operative cross-sectional morphology is often squared due to the inherent thickness of the discoid meniscus at the resection margin. The purpose of this study is to determine if the discoid meniscus can remodel and regain the triangular cross sectional configuration of a normal meniscus after surgical intervention. METHODS: A retrospective chart review was performed to identify all patients undergoing partial meniscectomy for symptomatic discoid meniscus within the past 3 years at our institution. Patients were included if they had a subsequent knee magnetic resonance imaging (MRI) study. Each MRI study was evaluated by two orthopaedic surgeons independently. The extent of remodeling was graded on the cross-sectional morphology of the saucerized discoid meniscus on coronal and sagittal T1-weighted images of the corresponding knee mri based on the following scheme: 1) complete for a triangular cross-section, 2) partial for a trapezoidal cross-section , and 3) none for a square cross-section. Descriptive means and statistical analysis for intraclass correlation coefficient (ICC) were performed using Microsoft Excel. RESULTS: A total of 11 patients and 14 knees were included in this study. Average age at time of surgery was 10.85. Average time to the follow-up MRI of the same knee was 540.50 +/- 341.84 days. 2 knees required additional surgical intervention following their index surgery. Complete remodeling was identified in 78.5% (11/14) knees. 1 knee had no remodeling and 2 knees had partial remodeling. Our ICC was 0.87 (95% CI: [0.66,0.96]). CONCLUSION: Our results indicate that the discoid meniscus has the potential to remodel into a “normal” triangular cross-sectional morphology after partial meniscectomy and saucerization. In our series, 21.4% (3/14) knees did not experience complete remodeling. This may have been due to over resection of the discoid meniscus at the index surgery owing to the extent of an existing tears. The remodeling all occurred within a two-year time frame though the exact time is unknown. This study indicates no additional intervention is required at the central resection margin to thin out the thick edge that often results from the meniscal biter.