Review Question - QID 5862

Figures A and B show the AP and lateral of a patient who underwent an uncomplicated total knee replacement 2 years ago. They have complained of persistent pain and recurrent effusions since the second post-operative month. Laboratory analysis was obtained, with an ESR of 20mm/hr (normal 0-12mm/hr) and a CRP of 6 mg/L (normal 1-3mg/L). She has had no fevers or chills. She states that she hears and feels a clunking sensation when ambulating. Physical exam shows moderate flexion instability and significant instability in 90 degrees of flexion. What is the next best step in management