Can any of my brothers here who are expert lifters offer advice to a guy who is incapable of some lifts due to an injury?

Five years ago I was a Fisheries Officer on Canada's west coast when I suffered an injury at sea while boarding a foreign fishing trawler. My left knee, left shoulder, left elbow and several ribs were crushed between two boats.

As a result I no longer have a full range of movement or flexibility on my left side, specifically I can't twist my leg or put my left arm behind my back without a serious dislocation. This makes lifts such as squats impossible, which is a key element of stronglifts.

I'm looking for some alternatives that can give the same or nearly the same benefits.

Thanks in advance for any and all replies!