I have a WHAT? ACL Cyst/ Inter-articular Ganglion Cyst

http://sumerdoc.blogspot.com/2011_06_01_archive.html

“Ouch, I can’t extend my knee.” Inter-articular Ganglion Cysts (IGC) of the cruciate ligaments are rarely reported.¹ Reasons being that IGCs don't usually occur.² IGCs are painful and can be misdiagnosed as an anterior cruciate or posterior cruciate ligament sprain. IGCs are jelly-like structures that form from the alar folds that cover the cruciate ligaments.¹  IGCs of the ACL can cause knee pain and limit knee extension.¹ If flexion is limited then a PCL IGC may be suspected.¹ Motion of the knee causes compression or traction on the cyst, which then alters the surrounding nerve endings.¹ IGC occurrences have been shown to appear after multiple injuries to the ligament in stressful situations.²

IGCs are diagnosed with an MRI (Magnetic Renounce Imaging).² There are 1.3% of patients who present with an IGC when referred to get a MRI.² About 0.6% of arthroscopic exams end up being diagnosed with IGC.² Some studies believe that IGCs cannot be removed.¹ While others state that they can be removed arthoscopically.² Removal via arthroscopy has been shown to have positive outcomes with reduction of pain and increased extension. The cysts can be drained and treated with aggressive ultrasound.¹ After the removal of an IGC, future tears or sprains of the ACL, have been shown to occur.²

¹ Huang, G.-S., Lee, C.-H., Chan, W. P., Taylor, J. A. M., Hsueh, C.-J., Juan, C.-J., Chen, C.-Y.   and Yu, J. S. (2002), Ganglion cysts of the cruciate ligaments. Acta Radiologica, 43:       419–424.doi:10.1034/j.1600-0455.2002.430414.x 

²http://actaorthopaedica.be/acta/download/2000-5/garcia-alvarez.pdf