Arthroscopic treatment of popliteal cyst: clinical and radiological results

Introduction: The popliteal cyst is a common knee condition. It results from distention of gastrocnemius-semimembranosus bursa through a one-way valve allowing synovial fluid influx only. Most of those cysts are asymptomatic, however, some of them exhibit manifestations including posterior knee pain, swelling and limited range of motion. The initial treatment modality is conservative treatment. For popliteal cysts with failed conservative protocol, arthroscopy has been widely used. In addition to the ability to address both the cysts and associated intraarticular pathologies, arthroscopy offer a minimally invasive modality with minimal soft tissue complications and significantly lower rates of recurrence compared to open approach. This study assesses the clinical and radiological outcome of arthroscopic management of popliteal cyst. Methods: This was a prospective case series in which arthroscopic approach was employed in 40 knees having popliteal cyst with failed conservative treatment. A preoperative assessment- both clinical based on Rauschning and Lindgren grading system and radiological based on MRI measurement of cyst dimensions – was conducted. Postoperatively, a similar clinical and radiological assessment was conducted. Postoperative results were compared to preoperative ones. Results: Postoperative clinical and radiological assessment showed statistically significant improvement compared to preoperative condition. Discussion: Arthroscopic intervention has been commonly used in management of popliteal cyst. Compared to open excision, literature showed that arthroscopy offers a minimally invasive technique with the advantage of directly addressing associated pathologies with subsequent reduction in the rate of recurrence. Conclusion: This study showed that arthroscopic decompression of popliteal cyst achieved significant clinical and radiological improvement.