Working out with an Unhappy Triad

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Anyone have ideas on what I can do to burn some calories and get a good workout in while dealing with an "unappy triad"?! Basically tore (at least partially) my ACL and sprained both my MCL and LCL while skiing about a month and a half ago... I'll likely have to get surgery to get stability back for the long run, but I'm wondering what my options are for the short term as I'm starting to get major "cabin fever" and actually missing the gym! :{