The evolution of prosthetic legs and knees over 500 years, and the innovators behind them.

Prostheses were first invented to help the casualties of war, and today’s state-of-the-art prosthetics help enable sportsmen and women to do what they love. Often, it's the wearers themselves who drive new developments. The innovators below have all shown the desire to push technology ever further and defy the people who told them it couldn’t be done.

Ambroise Paré

© Josh Parkin French Army surgeon and physician to the royals Ambroise Paré – regarded by some as the founder of modern surgery – published one of the earliest references to prostheses in 1579. At a time when wearing a peg leg or no leg at all were the only options for amputees, Paré created functional mechanical limbs that attempted to work the way biological limbs did, including a bending knee that could be locked while standing. He also developed a mechanical hand that was worn into battle by a French Army captain, who said it was so effective it even allowed him to grip and release his reins.

Benjamin Palmer

© Josh Parkin “The artificial leg patented by Mr. Palmer, is, in its way, a most admirable, ingenious, and philanthropic contrivance.” So wrote The Times in 1851 when amputee Benjamin Palmer presented his so-called ‘American leg’ at the first World Fair in London. The leg used springs and metal tendons to imitate joint movement, and incorporated a heel spring.

Dubois L Parmelee

© Josh Parkin In 1863, New Yorker Dubois L Parmelee designed a new way to attach the artificial limb to the body socket using atmospheric pressure. In this way, as Parmelee noted in the patent, “the straps usually employed for this purpose can be dispensed with”.

The Salem leg

© Josh Parkin The American Civil War of 1861–65 saw around 60,000 amputations – possibly three-quarters of all operations performed during the war. The US government responded by initiating a programme to supply prosthetic devices to every amputee, allowing veterans to return to work and support their families. This encouraged the growth of a prostheses industry, and the ‘Salem leg’ achieved early prominence after being recommended by the government for the Army. War amputee Edward F O’Brien wrote to the manufacturer of the Salem leg in 1866 to tell him that he could ride a horse with almost as much ease as he could before losing his leg. “In fact,” he said, “it is so near perfect that very few people believe that I wear an artificial limb.”

The Hanger leg

© Josh Parkin James Edward Hanger, the first documented amputee of the Civil War, was a Confederate soldier who lost his leg after being shot by a cannonball. While recovering, Hanger worked on the standard-issue replacement leg he was given by the Army. He patented his improved version after the war ended: it had hinges at both the knee and the foot and was designed to work noiselessly. Hanger was commissioned by Virginia state government to develop prosthetic limbs for veteran soldiers, and the business he founded is now a major artificial limb producer.

The first microprocessor knee

© Josh Parkin Since the earliest prostheses, reproducing the complexities of the human knee has been a major challenge. The first knees that used a computer chip to control their swing were introduced in the 1990s; the microprocessor controls the speed and ease of the knee swing, as well as the stability of the knee joint when it’s stationary. Sensors provide input to the prosthetic knee so it can know which stage of the gait it’s in and adapt to different situations.

The Bartlett Tendon Universal Knee

© Josh Parkin The Bartlett Tendon Universal Knee was made for extreme sports, such as skiing and downhill mountain biking, and its rubber tendons give a natural-feeling resistance and tension to the user. The knee was invented by Brian Bartlett, a professional skier who lost his leg aged 24 after being hit by a car. Bartlett used the leg to compete in mountain biking circuits alongside able-bodied people – and frequently won.

The Flex Foot Cheetah

© Josh Parkin The Flex Foot Cheetah was invented by medical engineer Van Phillips, who lost his leg below the knee aged 21. It’s made from carbon fiber and works like a spring, storing the kinetic energy of the wearer’s steps. The Cheetahs are perhaps best known for being the prosthesis of choice for South African sprint runner Oscar Pistorius (leading to his nickname, ‘the Blade Runner’). Pistorius used them in the 2012 Summer Olympics, when he became the first double-amputee runner to compete at the Olympic Games, and his use of the legs opened up a debate about whether sprung prostheses can actually give their users an unfair advantage by allowing them to use less energy.

The Moto Knee

© Josh Parkin This competitor to the Bartlett Tendon Universal Knee is also designed for extreme sports, such as jet skiing and snowboarding. It was designed by motorcycle and snowmobile racer Mike Schultz, who lost his leg in a snowmobiling accident. Despite having no engineering experience, Schultz won a silver medal in the Moto X Racing Adaptive using his newly built prosthetic just seven months after losing his limb. Like most extreme sports prostheses, the Moto Knee isn’t suitable for everyday use. Rather than swinging like a normal leg, it mimics the action of the flexed quadriceps muscles (the four main muscles on the front of the thigh, which are used to straighten the knee).

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