Generally speaking, underarm crutches and forearm crutches are interchangeable and it mostly depends on the preference of each user or the doctor's recommendation, as both designs have their pros and cons. The cuffs of forearm crutches help distribute body weight uniformly, while completely eliminating unpleasant armpit hard spots. This makes them more comfortable than their underarm counterparts but they cannot support as much weight, which is why bariatric crutches will only be available as underarm/axillary. Forearm crutches are lighter and give your hands the freedom to perform other tasks when just standing. They also offer more mobility and better posture than underarm crutches, as the user can stand upright. Unfortunately, they usually come with additional strain on arms, hands, and wrists, and they are not quite as stable, which makes them more difficult to use and poses a challenge for seniors.