I agree with Strange that cardio is the only way to accelerate the caloric burn but few of us are capable (not talking about your young, strong and otherwise healthy ones...)
Way back when when I actually had functional knees/hips/ankles, my sport of choice was always climbing...Didn't matter what...stairs, hills, walls (just joking about the walls)...I love climbing and it is the best way to integrate intense exercise that is both calorie burning and strength building.
I was lucky enough to have a park with a spiral ramp/path up a hill about 6-8 stories high and a single flight of stairs (70steps) on the side...I was never a runner so this was ideal for me, it built cardio fitness, could be done in all sorts of weather (we rarely get that much snow here so winters were fine), required no supplementary equipment other than comfortable footwear with good support and weather adapted clothing plus I would add a couple of water bottles as barbells and drank my way through them.
I always started out slowly and worked my way up...even post-op (about 6-8 weeks), I would start by slowly walking around the park and then just climbing up and down a couple of steps.
As time went by I could climb the stairs 10-15xs and the ramp a couple time as a warm up and cool down.
When I was too sick to go out I would just climb the stairs in my house (very high ceiling so about 20 steps up) as many times as I could throughout the day and then do 1/2hr-1hr slowly climbing up and down.
It takes 0 skill, is doable for anyone with reasonable leg/knee health and actually helps to improve both knees and hips if done with a straight back and proper support.
And it burns a ton of calories.
I cannot jump rope to save my life (or my Achilles tendon) and should not be doing it with all of my hernias and dropping pouch problems but as soon as I get this ankle healed I will be back to climbing.
Maybe you could try it?
Sharon