Clinical, Radiographic, and Ultrasound Findings Between Simple and Complicated Baker's Cysts.

Purpose: The aim of the study was to compare the clinical, radiographic, and ultrasound findings between simple and complicated Baker's cysts.
Methods: Forty-seven knees with Baker's cysts in 45 patients with knee pain were identified from a chart review. Baker's cysts were classified as simple or complicated according to ultrasound findings. Clinical data, including duration of knee pain, visual analog scale score, Kellgren-Lawrence grade, ultrasound findings, including the size and sonomorphology of the BC, severity of osteophytosis, thickness of joint effusion, meniscal tear, and synovial proliferation of the two types of BC, were compared.
Results: There were 22 knees with a simple cyst and 25 knees with a complicated cyst. The thickness of the suprapatellar effusion in complicated Baker's cysts (5.7 ± 3.0 mm) was significantly greater than that in simple Baker's cysts (3.8 ± 3.2 mm), and the presence of synovial proliferation in the suprapatellar recess was significantly higher in complicated Baker's cysts (22 knees, 88.0%) than in the simple Baker's cysts (12 knees, 54.5%). However, there were no significant differences in demographic, radiographic, and other ultrasound parameters between the two types of BC.
Conclusions: Synovial proliferation with larger effusion in the suprapatellar recess was more associated with complicated BC than simple BC.