Crutches, walking sticks, wheel chairs, and the like. I just watched a LP where a colonist lost a leg and realized that there is no way of dealing with it. Its one of those problems humans have been solving for millions of years, and is really painful when it isn't an option. Maybe a generic prosthetic item that can be crafted, perhaps in different levels. A crafting bench can make wood prosthetics, a research table might be able to make metal prosthetics, which could partially restore limbs. A prosthetic leg combined with a walking stick or cane might restore 75-80% mobility. You could buy hi-tech prosthetics from traders, or fashion them from dead mechanoids that could restore a damaged body part to full function, such as a lost eye being replaced by a cybernetic one. The generic prosthetic could be used similarly to med-kit, which can only be applied to destroyed body parts.