Presentation
12 months post right ACL reconstruction with knee pain.
Patient Data
Intact ACL graft, which is appropriately aligned.
Tibial tunnel cyst communicating with the knee joint at the medial aspect of the graft and extending into the pretibial space.
Small flap tear of the posterior horn of the medial meniscus.
Case Discussion
Tibial tunnel cysts may be a complication of ACL reconstruction surgery. The communicating type maintain a connection with the knee joint space, as we see in this case. This is presumed to be caused be either incomplete attachment of the graft to the bony tunnel or graft microtrauma.
It is important to differentiate non-communicating from communicating tibial tunnel cysts and convey this in radiology reports, as the conditions are managed differently. Please see related article for further details.