I think it is significant that you have sustained an injury. Ancient law codes that forbid, for instance, usury or rentseeking, often permit the physically disabled to draw a living this way.
Also, you do, as you say, own the means of production. You're not a capitalist, you're a business owner, and there's a difference there. You're not speculating and driving up the price of equipment to make it unattainable and then trapping your workforce in a debt trap, you're paying above market wages for work you'd do yourself if you weren't injured.
So I think as long as you are paying them a good wage that affords them the cost of living and lets you eat too, I don't think you need to fret too hard about the ethics of it. Do make sure you're covered and they're covered by unemployment and workers comp insurance.