The fate of Baker’s cyst after total knee arthroplasty

Aims and Objectives: Baker’s cysts are common in knees with degenerative changes. Common opinion is that most them vanish after treatment of the intraarticular knee disorder. The present study aimed to evaluate the fate of Baker’s cyst and its associated symptoms after TKA. Materials and Methods: In this prospective study, 105 patients with a MRI verified Baker’s cyst, primary OA and an appointment for TKA were included. Three patients were lost to follow-up (two died and one septic TKA removal). Mean age was 70.1 ± 7 years. Ultrasound was performed to evaluate the existing and the gross size of the cyst was performed before and one year (mean 12.3 ± 1.1 months) after TKA. Additionally, Baker’s cyst associated symptoms were recorded Results: After one year, Baker’s cysts were still detected in 85.3% of the patients (n = 87). There was a significant reduction in Baker’s cyst associated symptoms from before (70.6%) to after surgery (31.4%; p < 0.0001). No patients developed new Baker’s cyst associated symptoms. However, out of the 72 patients that reported preoperatively about Baker’s cyst associated symptoms, one year after surgery 44.4% (n = 32) of the patients still complained about Baker’s cyst associated symptoms. The size of Baker’s cysts decreased significantly from pre- (mean 1447 mm2) to postoperative (969 mm2) ultrasound assessment (p < 0.0001). Conclusion: Baker’s cysts vanished only in a small amount of patients (15%) one year after TKA. Nevertheless in this in general considered successful surgery, in close to half of the patients (44.4%) with preoperative Baker’s cyst associated symptoms, these symptoms did not vanish until one year after TKA. Thus, it might be worthwhile to evaluate its treatment options and include them in future treatment plans.