MR images

Had two similar cases. Patients complained of symptoms similar to complete ACL tear, that is of feeling of unstable knee during walking on uneven terrain and going up and down the stairs, though there was no joint instability in physical examination. The cyst was removed during knee arthroscopy with good short-term result.

In our experience ACL cysts usually present blocking or swelling symptoms. None of them associated to instability. In our series we present those treated surgically, but there are many patients asymptomatic, or with very few symptoms. In that case, conservative treatment showd work fine.

When required, arthroscopic removal of the cyst has very good results.

If the MRI evidence a benign pattern of the cyst, no puncture is required. On the contrary, I believe puncture is a good alternative

Which portal do you use for its excision?

It's hard to say according to those MRI scans but cyst fenestration through anterior portal should be possible.

I feel that symptomatic ACL cysts are better treated with arthroscopy. The portals can be swapped intra operative if need be for better access.

But most of the time, one needs to make a postero medial portal as these are located post to ACL

You can try using anterior portals. If you cant reach it between ACL and PCL, you can use a posteromedial portal and an accesory posteromedial for watching an working in parallel. 

Yes I agree

Let me know how the surgery goes.

I could puncture the cyst from anterior portal and the derided the cyst going between acl and pcl

Here are my thoughts on the management of ACL cysts.

1. Small, asymptomatic ACL cysts (discovered on MRI) are usually left alone.

2, Large ACL cysts may present with loss of knee extension due to impingement against the roof of the intercondylar notch of the femur; these cyst can be treated by arthroscopic debridement. 

3. The status of the ACL should be checked at the time of arthroscopic surgery and treated on its own merit. 

I agree with Dipak