Causes of knee pain evaluated by arthroscopy after knee arthroplasty: a case series

Background The origin of persistent pain and joint limitation after knee arthroplasty are controversial and difficult to diagnose. Knee arthroscopy is indicated when the results of routine evaluation tests are not clear. The purpose of this study was to determine through arthroscopy the cause of post-knee-arthroplasty pain symptoms in patients without a prior diagnosis of cause of pain. Methods This prospective case series study described the outcomes of 34 patients (35 knees) with pain and limited function in the arthroplastic joint, who underwent diagnostic and therapeutic arthroscopy. Patients were clinically evaluated using range-of-motion tests and the Lysholm, Hospital for Special Surgery (HSS) and Knee Society Score (KSS) scales. Results The procedure found cyclops in 17 knees, synovitis in 9 knees, arthrofibrosis in 6 knees, polyethylene wear with debris in two knees, and polyethylene bouncing in one knee with unicompartmental arthroplasty with a mobile polyethylene platform. It was effective for the relief of pain symptoms, with excellent or good outcomes in 80% of cases; there was a poor outcome in 11.43%, which maintained the presentation of pain and underwent revision arthroplasty, and, in 8.57%, did not undergo another surgery despite symptom persistence. Conclusions Post-arthroplasty knee arthroscopy seems beneficial in patients with pain and without a pre-established diagnosis and who had already undergone conservative treatment unsuccessfully.