Whether it’s for a Paralympic sprint or a simple stroll to the shops, a prosthetic limb is as individual as the person who wears it. Shanti Mathias visits the Auckland workshop where they’re created, customised and fitted.
Eighteen thousand kilometres away from Paris, Kent Perkins is trying to balance the excitement of the Paralympics with his anxiety. “You’re always kind of scared something is going to go wrong,” he says. “I shouldn’t say that, these limbs are strong, but it’s on the world stage!” Four of his patients at Peke Waihanga in Auckland are currently part of team New Zealand, competing at the Paralympic Games; legs he made in this workshop in Eden Terrace walked through the streets of Paris at the opening ceremony last week, and now bouncy running blades have raced on the athletic track and lunged on the badminton court, and jointed knees have walked to the edge of the pool.
Prosthetic limbs are a fascinating part of the Paralympics for those watching at home: seeing advanced pieces of technology totally integrated with the human body in a way that, for example, the phone that feels glued to your hand could never be. For those wearing them, they’re simply part of everyday life.
“My running leg feels so completely part of my body,” says Kate Horan, calling me (on speaker phone) while she drives along Wellington’s Transmission Gully. “I loved it, it had so much bounce.” Horan and her legs have appeared at multiple Paralympics; she competed in short-distance sprint events in the 2004 Athens games and the 2008 Beijing games, where she won silver in the women’s 200m T44.
Her blade had athletic spikes attached, perfectly ready for the field; its rigid zigzag structure mimicking the energy of muscles and ligaments more than her standard, straight prosthetic.
“My normal leg doesn’t have a lot of energy, doesn’t have a lot of propulsion – the blade was awesome for running, it had return.”
After repeated injuries from athletics became increasingly frustrating, Horan switched sports – to cycling. The prosthetic leg she used was completely different, cleated into the bike. “I always had to get onto my bike from the right side, and when I fell off the bike, my leg stayed attached – it took a lot to get used to that,” she says. There were other differences: because the femur on her amputated leg is shortened, her knees were in different places, so she had to work on the alignment of her hips. But after lots and lots of training, it became more natural, and she reached the finals of the pursuit, time trial and 500m competitions at the Rio Games in 2016.
Of course, most people with prosthetic limbs aren’t athletes competing on the world stage; instead, caring for the prosthetic and their stump is just part of their everyday lives. Today, Horan has a foot she uses to go running around Wellington – a different blade model, with a footshell that makes it easy to get up hills, as well as a day-to-day foot that is shaped more like a standard human leg.
How to make a new leg
To a prosthetist like Perkins, working with other people’s limbs is a question of customisation, again and again. His Paralympic patients are stress testing his work on the international stage, but for everyone he sees, he needs to figure out how they want to use their prosthetics, and how to make sure it fits perfectly.
“This is our casting room,” he says, walking me into a clean space with different machines. Two water-pressure casters make a model of a stump by applying pressure to a bladder, but plaster of paris or silicone might be used as well. He has multiple appointments with new amputees after an amputation; it can take a while for stumps to heal fully, and initial swelling has to reduce and skin to regrow before a prosthetic can be fitted. Patients with diabetes or vascular issues, who are often older and less fit, will have different needs than a younger person who has had a limb removed due to cancer, for example. Perkins and patients get feedback from their surgeons, physios and occupational therapists to settle on the type of limb they need.
The options available to prosthetists have changed dramatically in the last few decades – changes that Perkins has witnessed lots of in more than a quarter century of work. When he was training as an apprentice, “one of the guys who trained me was chopping down trees at Western Springs to make sockets, and prosthetic feet out of leather.” Aluminium came next, a much lighter and stronger material, and then composite materials like carbon fibre. Today, Perkins says, lots of the “bread and butter” sockets Peke Waihanga makes – usually “transtibial” or below-knee models – can be modelled on a computer and manufactured with 3D printers, meaning prosthetists can spend time working on more complex sockets like hips and femurs.
As Perkins and I walk towards the back of the Peke Waihanga clinic, it transitions from looking like a medical, clinical setting with a clean waiting room and walls with colourful decals, to a workshop space. Doors are labelled “do not come in without protective eyewear” and a sound of grinding mixed with the radio echoes from another corner. Boxes of spare feet in different colours sit on a shelf, while further along the corridor are boxes of allen keys and screwdrivers.
After measuring the volume of a stump to create a strong, stable socket, the question of what kind of limb is attached is very much dependent on physics, Perkins says. Most people aren’t thinking much about the force of gravity compared to the energy in their muscles, ligaments and tendons, but it’s a major consideration when those bones and muscles don’t exist. “When you lose muscle, it takes a lot more energy to walk – so a through-hip amputee [ie missing their entire leg] will need a lot more energy to walk a certain distance than a below-knee amputee,” Perkins says.
The weight of the patient is a major consideration, to ensure the prosthetic can endure the sorts of forces that will be put through it: an exuberant, playful child won’t be very heavy but might need to endure lots of twisting and jumping, while a leg for a taller, older adult working in an office might need to be sturdier, but not as bouncy.
In a little storeroom with in-progress prosthetics, he shows me some examples: a prosthetic with a springy ankle joint shaped like a small running blade. “It’s the same technology as running blades, but it looks a bit more like a foot – you can fit a shoe over it, which you can’t do with a blade.”
A longer stiff foam leg is poking out of the next shelf. It’s made to be durable and able to get wet, with the socket adjusted for someone whose knee is twisted outwards. A different clear socket is made to be ultra adjustable for a good fit before the final version: the transparent plastic makes it easy for Perkins to see if there are any gaps or pressure points that need to be tightened or stretched with a heat gun. Perkins rummages in the shelves again and pulls out a sleeve made of a stretchy, neoprene-like material. “Ah yeah, this is cool,” he says, demonstrating how a pin embedded in the fabric can screw into the leg with a little dial, for a stable fit that is easy to remove.
Lifestyle is a major consideration: for someone who wants to be out and about lots, maybe running, maybe skiing, Perkins will want to make a stronger, heavier limb, while for someone who has diabetes, a lighter leg that makes it easy to move around, mostly on smooth surfaces inside, is better.
Advanced technology comes at a cost
New limbs can be expensive: a reality that can highlight the difference between patients whose prosthetic is covered by the Ministry of Health (people who were born with congenital limb differences or have amputations due to diseases like diabetes and cancer) and those whose prosthetics are paid for by ACC (if a limb has been lost in an accident). “If we get an ACC patient, we do a full assessment of the cost, send it away to ACC so they can approve that and we can go ahead,” Perkins says. “But when it comes to the Ministry of Health, we’re bulk funded, so you have to kind of split the money up between people. And some people are going to be more active than others in the budget, or will need components that are more expensive.” Children need lots of limb adjustments and replacements, for example, as they’re always growing: usually, Perkins can adjust their limb after six months, but a full replacement will be needed after a year.
While sockets are made by the specialised prosthetists at Peke Waihanga, most of the parts are imported; one major manufacturer is German company Ottobock. A scroll through New Zealand’s import data offers a glimpse of how much that costs: millions of dollars of artificial limbs and joints (which includes hip and knee replacements) are imported each month, most of which the public system is paying for. “The cost of some stuff, like carbon-fibre feet, has come down a lot, but some of the newer technologies are still up there. In five years’ time that’ll reduce, they might be half the price,” Perkins says.
We go back into the workroom, where most of the prosthetists have their own bench set up with in-progress limbs. He shows me an electronic arm, very similar in shape to a biological arm, all dark black with several controller buttons so the fingers can move. I hold it, carefully: this is going to be part of someone’s body. It’s much heavier than the aluminium and carbon-fibre models we were looking at earlier. “It’s got a motor, and a battery on board as well – the downside is that it’s not necessarily easy to wear for a long period of time,” Perkins says.
Having an electronic device that weighs the better part of 10kg strapped to you at an odd angle for hours is pretty tiring, especially when it doesn’t have its own muscles to hold itself up. Electronic arms are among the most expensive prosthetics Peke Waihanga makes – a model can cost as much as $250,000, while more complex legs, like those with knee joints and computer chips, could be as much as $120,000, although they also come with a six-year warranty. Part of the cost is the specification – medical-grade materials are a lot higher standard and more expensive – as well as the relatively small market, meaning parts are often made to order.
While the prosthetists will try to match artificial feet with people’s natural skin tone, Perkins has found there’s increasingly a movement to decorate prosthetics and put them on display. “It’s gone towards not making things look like your other leg – it’s gone quite space age,” he says. He shows me a few examples: a sample leg with a dial to tighten around the socket is printed with animal illustrations. He passes me another leg with bright, tattoo-style illustrations of roses, then shows me a socket that has been dyed blue, which I hold gently. Perkins grins. “I’m not going to, but I could whack that socket around and it’s not going to crack or smash.” Having seen the workshop where fibreglass sockets are made with layers of resin, potential air bubbles sucked out by vacuums, I believe him.
Advances in technology have increased the possibilities, but that doesn’t mean everyone always wants the most advanced limb. “Oh no, it’s no different!” laughs Sarah Rigg, the clinical services manager at Peke Waihanga, when I ask her if the hook she has attached to her right arm is any different now to the ones she had as a child in the 70s.
Her hook is silver and double pronged, so it can grab onto things when she flexes her shoulder. The arm and a cable attach to a harness, making the prosthetic much lighter than heavy electronic models: she can use it for most of the day. Without needing batteries, a motor or lots of metal, she can do almost everything she needs with a hook, and a few other things besides. “I only need to wear one oven mitt when I’m getting something out of the oven, I’m never worried about cutting myself by accident,” she says. As a more self-conscious teenager, she had a more realistic prosthetic hand for a while, but she realised that the covering easily got “manky”; now she’s happy with her plain, but functional, aluminium hook.
Unlike the lower limb prosthetics, her arm can last much longer, as she isn’t putting as much force through it. “I think my last one lasted eight years, replacing the parts one-by-one – a new elbow, a new cable, sometimes you have to replace the straps,” Rigg says. Working at the limb service (she initially trained in architectural draughting) has opened her mind to how different the experience of other amputees and people with limb differences are. “I used to be able to drop my limb off at reception, say ‘I need this repaired’ and still carry on, pick it up after work. While if you have a faulty leg, you’re out of action, your mobility is taken away from you.”
Prosthetics are normal
Peke Waihanga estimates that in New Zealand around one person in 1,000 has lost a limb – around 4,400 total, with several hundred new amputations coming in each year. Rigg emphasises that everyone has an individual amputation journey. “It’s about your acceptance, but also the acceptance and tolerance of the world as well,” she says. Her prosthetic felt pretty unusual when she was younger; now she feels that there’s more acceptance, but also an undercurrent of vocal hostility towards difference, which she’s always aware patients might be carrying with them into the clinic.
For Kate Horan, the Paralympian who has competed in both sprinting and cycling, one of the greatest gifts has been learning from amputees. She has a vivid memory of trying to go skiing as a kid, but not being able to put a ski boot into her foot that didn’t bend at the ankle. Several decades later, now with kids of her own, she tried again, with other amputees around and encouraging her. “It’s possible with brute force to get that boot on!” she says. (Perkins also mentions that Peke Waihanga has ski-specific feet that people can try with their prosthetic.) “That was such a benefit of meeting other amputees, to ask questions,” she says.
Rigg would like not to be followed around by people assuming she needs help, like in changing rooms in clothes shops. “I’ve gotten dressed every day of my life, I do know how to do it,” she says. “I need to ask for help if I need it – but people also need to stop offering help if it’s not wanted.” For her, the prosthetic is useful, but unremarkable. “I recognise it as who I am – and I can always recognise my own shadow.”
