Frequently Asked Questions

Common materials: sockets use resin, carbon fiber, and thermoplastic sheets; liners use silicone, gel, and polyurethane; connectors use titanium, aluminum alloy, and stainless steel; feet contain carbon-fiber energy-storing plates, foam, and elastomers; cosmetic covers use silicone, EVA, and more. Carbon fiber is strong, light, and elastic — good for weight bearing and active users; silicone and gel feel soft, protect skin, and suspend well; titanium is corrosion-resistant, light, and strong but pricey. Which is best depends on the area, use, and budget, usually combining materials — the best choice matches your needs rather than a single material.

Silicone liners are elastic, durable, high-friction, and suspend stably — good for active users who need reliable fixation, but they breathe less, are a bit heavier, and can cause sweating. Gel liners are softer, cushion better, and fit comfortably, and are friendlier for sensitive skin and volume changes, though less durable and tear-resistant. The choice depends on skin condition, sweating, activity level, and suspension type; some products use silicone-gel hybrid designs. Best to trial and compare under your prosthetist's advice and pick the one that fits your limb, rather than judging generically which is better.

Advantages: high strength and low weight, bearing heavy loads while reducing wear burden; good elasticity that stores and releases energy, making walking more efficient and springy with an energy-storing foot; good fatigue resistance and longer life; and a modern look. It's widely used in sockets, foot energy-storing plates, frames, and connectors. Drawbacks: higher cost, complex processing, and difficulty repairing on-site if damaged. Especially worth considering for active users needing lightweight, high-efficiency hardware. Check whether the specific components truly use carbon fiber and their craftsmanship — not just the name.

Common types: 1) Basic (SACH) foot — simple, stable, and cheap, good for low-activity or elderly users; 2) Single-axis foot — with ankle motion, suited to uneven ground; 3) Energy-storing foot (ESR) — with elastic elements that store and release energy, good for more active users needing efficiency and spring; 4) Microprocessor ankle-foot — self-adjusting, for complex terrain and high-demand users; plus sports-specific feet and adjustable-heel-height feet. Choose based on activity level, weight, terrain, and use case.

Main types: mechanical knees (single-axis, polycentric, mechanically controlled) — stable, durable, battery-free, good for low-activity or budget-limited users; pneumatic knees — air-controlled swing, more natural gait with adjustable speed; hydraulic knees — finer control, good for variable walking speeds; microprocessor knees — sensor- and computer-controlled in real time, high safety, fall prevention, and stair/slope adaptation, good for active users who value safety. Consider activity level (K-level), weight, residual limb length, terrain, and budget, and trial-compare if needed.

A hydraulic knee uses hydraulic damping to control resistance in swing and stance phases. Compared with mechanical and some pneumatic knees, it adjusts more smoothly to walking speed, giving a more natural gait and easier handling of slopes and speed changes — good for medium-to-high activity users with variable speeds or frequent slopes. Drawbacks: slightly heavier, pricier, and needs maintenance. Whether it's worth it depends on your activity level and terrain: big gains for active users on complex ground; low-activity, mostly indoor, flat-walking users may not need it, as a mechanical or pneumatic knee suffices.

Common types: 1) Liner with lock (pin or strap) — reliable fixation and easy donning, good for below-knee prostheses; 2) Vacuum suspension, including passive and active powered vacuum — great fit, high stability, and good limb volume control, but needs a seal sleeve and maintenance; 3) Suction suspension — sealed contact between limb and socket, simple but sensitive to volume change; 4) Belt or supracondylar strap — simple but with moderate comfort and suspension; 5) Silicone liner friction suspension. Choice depends on limb condition, length, activity level, and sweating.

Vacuum suspension holds the prosthesis firmly to the limb by creating and maintaining negative pressure between the limb and socket. There are passive types (maintaining vacuum via an expulsion valve as you walk) and active types (an electric pump continuously draws air for steadier vacuum). Pros: extremely reliable suspension, good socket fit, excellent limb volume control, more stable skin, and greater walking confidence; cons: needs a seal sleeve or sealing design, active vacuum needs charging and maintenance, and initial donning is a bit more involved. Good for active users needing stability and volume control.

A lock connects the liner and socket to prevent the prosthesis from coming off; common types include pin lock, strap lock, magnetic lock, and ratchet lock. The choice depends on residual limb length and shape (very short limbs may not suit pin locks), weight-bearing and skin condition, activity level, and habits. Pin locks are easy to don and strong but can pull on the limb end; strap locks are gentler; vacuum or suction suspension may not use a lock. The right lock improves stability and comfort; the wrong one causes pain or slipping — let your prosthetist assess and choose.

Clean liners, socks, and seal sleeves daily: hand-wash liners with warm water and mild soap or a dedicated cleaner, rinse, and dry without sun or high heat; change and wash socks daily; check seal sleeves for damage and replace on schedule; and avoid oil, sharp objects, and clear tape. Regularly check for aging, cracking, or thinning and replace promptly to protect suspension and skin health. Cleanliness also reduces odor and skin problems. Follow product and prosthetist guidance for specifics.