Below is some helpful information from our friends at Ottobock
Each suspension system has strengths and weaknesses. Here are some of the factors to think about, and how the systems compare:
Activity level. Shuttle-lock systems, best suited for older amputees and patients with reduced mobility, are mainly for amputees with a mobility or activity level of 1 or 2. Suction can be used for all activity levels. Vacuum is appropriate for activity levels 2 to 4, including the most active amputees.
Comfort. Vacuum and suction both require a total-surface-bearing socket, which distributes even pressure on your residual limb throughout every square inch of the socket’s surface area. That pressure relief alone makes these suspension systems more comfortable. The superior connection with vacuum, allowing minimal movement of the limb in the socket, makes it the most comfortable. Suction ranks second in linkage. Shuttle-lock systems offer the least control of forces and allow the most movement and rubbing in the socket, the cause of calluses, blisters and sores.
Performance. Vacuum offers the highest performance for maximum confidence and prosthetic control, which promotes a smoother, more symmetrical gait that uses less energy. Shuttle-lock systems fulfill the needs of users with a low activity level, but users with a high activity level probably would notice a lack of control and security.
Proprioception. Because a pump can generate five times the air-pressure differential of suction, vacuum scores highest here. Some patients say the sense of control is almost like having their leg back. Shuttle-lock systems have the lowest level of proprioception.
Limb health. Vacuum excels at limb health. Vacuum actually increases hydration and blood flow, so open wounds can heal even while you continue wearing the prosthesis. In addition, vacuum helps regulate volume changes in your leg as tissues shrink or expand during the day. As a result, your limb retains its size and shape all day, which helps to maintain a consistent fit.
In contrast, other suspension systems constrict blood vessels, causing leg volume to drop an average of 10 to 14 percent as fluids are squeezed out of your leg throughout the day. A prosthesis that fits tightly in the morning will loosen as the day progresses. Too much movement within a socket can cause pain, blistering and sores. Movement in and out of the socket can lead to repetitive impact forces as the socket slides during while you’re lifting your leg to take a step and pounds it back onto your limb when you put weight on your foot again.
Convenience. Shuttle-lock systems are the easiest to put on and take off. However, users of these systems may need to add or remove prosthetic socks up to three or four times a day to compensate for changes in leg volume.
With vacuum and suction, your daily routine includes rolling on a liner and shorter prosthetic sock; sliding into the socket; rubbing lotion on your leg at the top of the liner to prevent dragging on the skin; and rolling up the sleeve attached to the socket’s perimeter to create a seal with the liner.
Because there’s no need to modify the fit throughout the day, active vacuum may save on total time. Either way, most users say the morning regimen is worth it to enjoy the all-day benefits.