Comparison of simple and complicated Baker’s cysts: MRI findings

Complicated Baker’s cysts are significantly associated with increased synovial proliferation and other intra-articular pathologies compared to simple BCs, guiding better treatment.

Baker’s cysts (BCs) are commonly associated with intra-articular knee pathologies. MRI is the gold standard for evaluating BCs. This study compared MRI findings between simple and complicated BCs, to find out their association with each other and other knee pathologies.

Seventy patients undergoing knee MRI for symptomatic knees were included. MRI images assessed BC type (simple or complicated), BC morphology and volume, suprapatellar recess thickness and synovial proliferation, knee joint effusion grade, meniscal tear if present, and meniscal extrusion extent. Patients were categorized into simple BC and complicated BC groups for comparative analysis.

Fifty-two patients were included: 15 in the simple BC group and 37 in the complicated BC group. Complicated BCs showed significantly larger volumes, greater suprapatellar recess thickness, and more synovial proliferation in the suprapatellar recess (91.9% in the complicated BC and 46.7% in the simple BC) along with greater suprapatellar recess than the simple BC. Also, higher medial meniscal extrusion was observed in the case of complicated BCs.

Complicated Baker’s cysts on knee MRI demonstrate greater intra-articular pathologies compared to simple BCs. Particularly noteworthy was the significant association of synovial proliferation with complicated BCs, emphasizing its importance as a distinguishing factor in these cases.