Arthroscopic treatment of symptomatic synovial plica of the knee. Long-term followup.

We studied all patients undergoing arthroscopic resection of symptomatic plica without other intraarticular abnormality at our institution from October 1981 to March 1987. To be considered abnormal, plicae had to be thickened and/or fibrotic when viewed arthroscopically. Seventy-six of nearly 2000 patients (4%) who underwent diagnostic arthroscopies met our inclusion criteria. Clinical response after arthroscopic resection was evaluated in 51 patients at an average of 47 months (range, 15 to 77). Excellent or good results were obtained in 57 (75%) of the patients. Eleven patients (14%) had an impingement lesion defined as a localized femoral condylar ridge or groove of the articular surface that impinged upon the plica with increasing flexion. All of these patients had an excellent or good result. Other factors associated with a favorable outcome included a specific preoperative diagnosis localizing symptoms to the medial compartment, onset of pain after a period of increased athletic activity or after a twisting injury, and younger age. Poor prognostic factors included associated chondromalacia and an unclear preoperative diagnosis.