A case report of an unusual location of pericruciate meniscal cyst with adjacent bony erosion

The prevalence and characteristics of osseous erosions associated with parameniscal cysts on knee MRI

OBJECTIVES

To determine the prevalence and characteristics of erosions associated with parameniscal cysts (PMCs) and to evaluate the profile of the associated meniscal tears MATERIALS AND METHODS: PACS database was reviewed for knee MRI scans performed over a 5-year period identifying those with PMCs in patients aged 18 years and above. The scans with PMCs were evaluated for the presence of associated osseous erosions. These erosions and PMCs were then analyzed.

RESULTS

The search revealed 6773 knee MRI examinations, of which 555 had confirmed PMCs. There were 7 PMC-associated erosions for a prevalence of 1.3% (95% CI 0.6, 2.6). All erosions involved the proximal tibia. Three of 7 erosions had underlying marrow edema, and 4 out of 7 had an overhanging margin. The mean dimension of all PMCs was 13 mm (SD = 11). The mean dimension of PMCs associated with erosions was 38 mm (SD = 22), while that of PMCs without erosions was 12 mm (SD = 10) (P < 0.001, Wilcoxon rank sum test). Ninety-three percent (95% CI 90.5, 94.8) of PMCs had associated meniscal tears, most commonly of the horizontal type (57%). All PMCs with underlying erosions were associated with meniscal tears, most commonly complex type tears (5/7).

CONCLUSION

Erosions can rarely be associated with contiguous parameniscal cysts (PMCs). These cysts are significantly larger compared with those without underlying erosions.

Medial meniscal cyst as a cause of painful erosion of the tibial plateau

Medial cysts are rarely encountered as a cause of bone erosion. It is thought meniscal cysts are present in up to 22 % of meniscal tear operations. MRI is the gold standard for visualisation of meniscal cysts. Decompression is often guided by careful study of the pre-operative MRI scans in multiple planes. This is the first case report demonstrating erosion of the medial tibial plateau due to an incarcerated meniscal cyst highlighting the potential for bone damage if left untreated. Level of evidence IV.

An intra-articular knee cyst in a 2-year-old associated with an aberrant anterior cruciate ligament

Intra-articular ganglia of the knee occur infrequently, with an overall incidence estimated to be from 0.2 to 1.9%. To date, the youngest patient reported with an intra-articular ganglion was an adolescent. In this paper, we describe a 2-year-old patient with a massive intra-articular knee cyst and an aberrant anterior cruciate ligament (ACL) origin. The cyst was successfully treated with arthroscopic debridement. Proposed pathology and treatment recommendations for intra-articular cysts are reviewed.

Pericruciate intra-articular lateral meniscal cyst without meniscal tear

A case of intra-articular pericruciate type of meniscal cyst from anterior horn of lateral meniscus without associated meniscal tear is reported with review of literature. To our knowledge such association has not been reported earlier.