Horizontal cleavage tear of discoid medial meniscus diagnosed on MRI and treated with arthroscopic partial resection.

Purpose: To provided an evidence-based summarisation of the discoid medial meniscus in conjunction with a case report describing a novel management approach which includes MRI-assisted pre-operative planning and a limited meniscal resection.

Methods: Case report and structured literature review of Medline referenced articles from 1941 to 2011.

Results: Forty-one papers describing 61 patients and 82 discoid medial menisci were identified. Data extracted included patient demographics, diagnostic techniques, operative interventions, and associated pathological findings. These findings were compared with the index case report. A new technique involving MRI-assisted pre-operative planning and limited meniscal resection is described.

Conclusion: The discoid medial meniscus remains a rare abnormality with significant associated morbidity. It continues to provide physicians with both diagnostic and interventional challenges. MRI-assisted pre-operative planning can provide surgeons with the opportunity to plan for limited resection so as to maximally lessen the probability of early-onset osteoarthritis which may result from loss of meniscal tissue.