Musculoskeletal Ultrasonography of Baker's Cyst in Primary Osteoarthritis of Knee: An Observational study

Background Knee pain and limitation of joint movement are common compliant in pain clinic due to knee osteoarthritis and often associated with Baker's cyst. These are usually asymptomatic during the initial phase and might be missed during clinical examination and later may present in complicated form. Musculoskeletal ultrasonography might be helpful in detecting asymptomatic Baker's cyst during the early course of the disease. Objective To observe the incidence of Baker's cyst in patient with primary osteoarthritis of knee with the help of routine musculoskeletal ultrasonography of knee during clinical evaluation of patient. Method A total of 114 patients with unilateral or bilateral knee pain diagnosed as primary osteoarthritis of knee were included in this study. Musculoskeletal ultrasonography was performed on all patients to look for the presence of Baker's cyst. The incidence of Baker's cyst was the primary outcome of this study. Depending upon the presence/ absence of Baker's cyst, two groups were formed, and variables were compared between these groups to find the factors associated with Baker's cyst. Statistical analysis was done using student t-test, ANOVA test and Chi-square test. Result The incidence of Baker's cyst in this study was 21.1% of the patients and 89.28% were asymptomatic. Baker's cysts were strongly associated with joint effusion and synovial hypertrophy. Conclusion Baker's cyst was a common finding in the patient with knee osteoarthritis. Musculoskeletal ultrasound would be a valuable tool to detect such asymptomatic cysts early.