Below Knee vs Above Knee Prosthetics – Key Differences Explained

By Pro-Ortho Perfect India | Prosthetics & Orthotics Specialists, Thane & Pune

When a patient or family member is researching prosthetic options after an amputation, one of the most common questions is: what is the difference between a below knee and an above knee prosthetic? While both replace a lost limb, the two are fundamentally different devices — in design, complexity, rehabilitation requirements, cost, and functional outcomes.

This guide explains both types clearly, compares them side by side, and helps you understand what to expect at each level.

Understanding Amputation Levels First

The type of prosthetic a patient needs is determined by the level of amputation:

• Below knee (trans-tibial): Amputation through the shin bone, between the knee and ankle. The patient's natural knee joint is preserved.
• Above knee (trans-femoral): Amputation through the thigh bone, between the hip and knee. Both the knee and ankle-foot must be replaced by the prosthetic.

This single difference — whether the knee is preserved — has enormous implications for everything that follows.

Side-by-Side Comparison

Factor	Below Knee (Trans-Tibial)	Above Knee (Trans-Femoral)
Joints replaced	Ankle and foot only	Knee, ankle, and foot
Natural knee preserved?	✅ Yes	❌ No
Energy to walk	~25% more than able-bodied	~60–70% more than able-bodied
Rehabilitation time	3–6 months to independent walking	6–12 months to independent walking
Basic cost (India)	₹30,000 – ₹60,000	₹80,000 – ₹1,50,000
Advanced cost (India)	₹1,50,000 – ₹4,00,000	₹4,00,000 – ₹15,00,000+
Key component	Prosthetic foot	Prosthetic knee + foot
Socket type	Patellar tendon bearing / total contact	Ischial containment / CAT-CAM
Typical suspension	Pin-lock liner, vacuum, sleeve	Suction, vacuum, hip belt
Running possible?	Yes, with running blade	Yes, with specialised prosthetic
Stairs / uneven terrain	Good — natural knee controls it	Challenging — requires prosthetic knee control
Fall risk	Lower	Higher — especially without microprocessor knee

Below Knee Prosthetics — What Makes Them Simpler

The single biggest advantage of a below knee amputation is that the patient's own knee joint is intact. The knee is the most mechanically complex joint in the lower limb — having it means the patient retains natural propulsion, balance feedback, and the ability to change direction. The prosthetic only needs to provide a stable, energy-returning foot.

Below knee prosthetics consist of three main parts:

• The socket — the custom-fitted interface between the residual limb and the prosthetic. This is the most critical component regardless of level.
• The pylon — a structural tube connecting socket to foot, usually adjustable for alignment.
• The prosthetic foot — ranges from a basic SACH foot to a high-performance carbon fibre energy-return foot (ESAR).

Most below knee amputees achieve a near-normal gait with good rehabilitation. Many return to running, cycling, and sport.

Above Knee Prosthetics — The Added Complexity of the Knee

Above knee prosthetics must replace both the knee and the foot — and the prosthetic knee must be safe enough to prevent falls while allowing a natural-looking gait. This is a significant engineering challenge.

Above knee prosthetics have four main parts:

• The socket — typically an ischial containment design that captures the sitting bone for better suspension and control
• The prosthetic knee — ranges from a single-axis mechanical knee to a fluid-controlled polycentric knee to a fully computerised microprocessor knee (C-Leg, Genium, Rheo Knee)
• The pylon — connects knee to foot
• The prosthetic foot — same range as below knee, but must work in combination with the knee mechanism

Mechanical vs Microprocessor Knees

The knee mechanism choice is the single biggest decision in above knee prosthetics:

• Single-axis mechanical knee (₹80,000–₹1,50,000 for the knee alone) — simple, durable, good for low-activity patients. Requires careful weight shift to control stance stability.
• Polycentric / hydraulic knee (₹2,00,000–₹4,00,000) — better stability on slopes and at varying speeds. More natural swing phase.
• Microprocessor knee (₹8,00,000–₹15,00,000+) — sensors detect movement 50–100 times per second and adjust resistance accordingly. Dramatically reduces fall risk. Best for active community ambulators.

Rehabilitation: What to Expect at Each Level

Below knee: Prosthetic training typically begins 4–8 weeks post-surgery. Most patients walk independently within 3–6 months. Running, stairs, and sport are achievable goals for motivated patients.

Above knee: Prosthetic training is more intensive. Patients learn hip-driven gait patterns, how to control the prosthetic knee safely, and how to navigate varied terrain. Independent community walking typically takes 6–12 months. Consistent physiotherapy is essential.

Can You Preserve the Knee? Surgical Considerations

When amputation is medically necessary, surgeons always try to preserve as much limb length as possible — and particularly to preserve the knee joint if there is any viable tissue below it. Even a short below knee residual limb is functionally superior to an above knee amputation. Patients facing planned amputation should ask their surgeon explicitly: "Is a below knee amputation possible in my case?"

Frequently Asked Questions