Lisfranc/mid Foot Damage - Ligament - Misdiagnosed - Fusion?

Two years ago I fell onto my big toe, and heard a loud SNAP. The arch of my foot had collapsed immediately. There was a bruise on the top and bottom of my foot over the lisfranc joint. I couldn't bear weight for 1-2 weeks, can't remember exactly.

I had x-rays that showed nothing. I still don't know exactly what I did. The arch has collapsed and my foot aches all the time. I was told to have physiotherapy and wear an orthotic.

I fear I either tore slightly or completely the lisfranc ligament. Hopefully I didn't fracture anything. Recently I had a weight-bearing x-ray that showed loss of arch height and exaggerated space in the joint complex, but this was brushed off - I think, because the injury is so old. 

I was told I couldn't have suffered a lisfranc or I'd still be in terrible pain; however, I have read online similar misdiagnosed subtle injuries like mine that only become painful YEARS later, by then, with more damage done.

This is how it is: I can move the cuneiform (?) quite easily with my fingers, whereas I can't with the other foot. It feels loose, but not painful when I do this. It's slightly painful if I go on the tip of my toes, just feels strained. It's also much more prominent than my other foot. The arch sags from this point, as it did when I first heard the snap.

Has anyone else had an old ligament tear, gotten by with orthotics, and had no significant problems? 

I worry about arthritis setting in. Should I pursue and find out EXACTLY what I did? Or should I get by with the orthotic and if/when arthritis sets in, then have a fusion? Ignorance being bliss?

I know whatever I did, at this stage, the only thing left is fusion. I'm not sure whether this is something I should be doing sooner rather than later.

Could someone shed light on fusion? Especially if they had it young (I'm 20) and how it holds up long term etc.