Really you need the results of the Wikipedia reference-linkMRI to ascertain the extent of the damage. By the sounds of it thought a 90 degree lateral angle at the knee following dislocation means probably collateral ligament, Wikipedia reference-linkcruciate ligament and probable meniscal injuries. A fixed brace would be the normal first course of action.

On a brighter note, the Australian rugby team player, Tim Horan, did something similar about 15 years or so ago and he recovered and went on the play for the wallabies again at international level. So all is not lost but it will take a lot of work from both you and the physio. Chin up and let's wait and see what the scans show.