17

Sockets and Stumps

A HEADLEY PATIENT’S FIRST STAY usually lasted twenty-four days. When the physios and everyone in the team agreed, people from the prosthetics department arrived, and that was always a very good day. Prosthetics are the artificial substitutes for parts of the human body that are missing. Prosthetics can be permanently implanted (teeth, facial bones, hips, knee joints) or removable (hand, arm, leg). Like the rest of this book, this chapter focuses mostly on removable prosthetic legs, because it is prosthetic legs that represent the greatest challenge to both builder and wearer. Legs need to be load-bearing, to carry their wearer forward, to get them up and out of the chair for as long as possible. Other prosthetics do other things for their wearer, but none has quite the same impact, or quite the same level of technical difficulty, as getting them up and out of their wheelchair.

Prosthetics in one form or another have been around as long as human beings have had the wit to build them. For most of lost-limb history, they’ve been made of wood, carved to shape and lumped around, strapped around whatever is left of the body part they were meant to replace. The modern prosthetic leg, jointed and with metal and wood parts as we would recognise it today, evolved for the two largest amputee cohorts produced in war: 38,000 from the American Civil War and (in Britain) 41,000 from the First World War. War didn’t just produce amputees and legs for its casualties; it also produced prosthetic limb industries – workshops, research, design studios, manufacturing and fitting. And durable, limbs as well as organisations. Many of the companies that were successful in the nineteenth and twentieth centuries are still market leaders today in the twenty-first (more about one in particular later). Today most people know about the extraordinary gains in prosthetic technology from events such as the Paralympics, where materials and design technologies are brought together to produce performance limbs for superhumans.1

Prosthetic limbs, and in particular prosthetic legs, have come to represent everything we know about dealing with amputation. This isn’t quite right, because the limb that we can see is only the end, not the means whereby amputees are able to function. Also, because despite all the research and development and superhuman efforts, prosthetic limbs don’t work as well as we would like. A design historian summed this up elegantly (as design historians are wont to do): ‘of all machines [the artificial limb] has the closest proximity with the human body but the least chance of matching its performance.’² The primary reason for the generally sub-optimal performance of artificial limbs is not the artificial limb itself but the stump on to which it fits. It fits on to the stump by means of a socket, and it is this system that is at the heart of limb replacement. Which is why this chapter is called ‘Sockets and Stumps’ rather than ‘Prosthetic Legs’.

Meanwhile, back to the team meeting at Headley where the amputee first met the prosthetics department (a private company, Blatchfords, by the way, founded in 1890 and greatly expanded during the First World War, responsible for a model of leg prosthetic named ‘The Clapper’, because that was the sound it made when fully extended; at least the models are silent now). In the twenty-first century the prosthetist took the bandages off their patient’s stumps and looked really closely at them, handling the stumps in a different way from everyone before, as something to work with, with potential. If there was no infection, and they were healing normally, and the work in the gym was going to plan, then they came back with a load of kit, including a bucket full of plaster cast. Then they covered the stumps in cling film and took a plaster cast mould.

In the prosthetists’ workshop, where they do more of these for highly demanding, impatient humans than anywhere else in the country, they think that plaster cast moulds are still more efficient than a digital scan and 3D printed models. So far, even the best computer scanner isn’t a match for a really experienced prosthetist with an artist’s eye and a set of fine files to reshape carefully until the fit is as good as it can be. The kit associated with making plaster casts can make the prosthetic workshop look like a sculptor’s studio. There are five prosthetists at Headley, and they all have white plaster residue in their fingernail beds and knuckles, and they all make very slightly different-looking casts, so anyone who knows how they work can tell who built which model, like telling a Michelangelo from a Bernini.3

In the workshop they make a hard-plug solid replica of the stump. And from the solid replica they make a bucket-shaped object that slots over the stump: a socket. And everything that has gone in this book before comes down to this piece of machinery, a socket, carefully honed to fit a human, and to the moment when it is first handed over (and it’s heavier than it looks – as heavy as the original body part it is to replace because that’s what the central nervous system is used to). They are not handing over a leg. They are handing over the means to a leg. The dictionary says a socket is a natural or artificial hollow for something to fit into or stand firm, or that can be used to make a connection.

So this is the beginning of a long journey together, not just a handover and a fitting, and most of the journeys begun in 2009 are still going on. Their patients will learn to call them ‘my prosthetist’, and no one will ever look at them as carefully as they do, except the patients themselves. They say things like, ‘Oh you’ve got a lovely residual limb’, which means the plastic surgeon and the physios and the negative pressure dressings and the wraps have all delivered them a stump they can work with. It isn’t weird, it’s good, so the patients adjust to the prosthetist’s mindset and then communication begins. Good communication, thinking about every word that is said to them to explain how they are feeling, what they see in the mirror. They learn precision communication about precision movement, and they learn not to hold back anything, because it saves time and pain.4 The only thing prosthetists never want to see in their workshop is soldiers suffering in silence, keeping quiet and bleeding into their sockets. Not helpful, ever, in or out of the workshop.

Sockets aren’t just about something to clip a limb into. They restore evenness of length to limbs, because blast injury rarely gives them anything neat to work with. Stumps are of different volumes, different widths and different lengths. Sockets have inner linings that even things up and make things steady.⁵ An amputated thigh bone (femur) floats about in the soft tissue of the thigh itself, without muscles and ligaments to hold it effectively where it should be. So the socket has to fit closely over the stump and give shape, structure in such a way that the whole thing is made stable, with no more floating about, doing damage. The socket needs to be not too tight and not too loose: just right to hold the stump in a new place, firmly, all the time.

Part of this stability is about the weight of the rest of the body and how that comes down on to the stump. Bone that has been cut through can’t take weight, so the socket is designed to take the weight of the body and distribute it back to areas with soft and hard tissue intact. Generally, this means the weight is moved through the socket structure to areas that can carry it, such as the hips and pelvis. So each stump, even on the same patient, is different because no two stumps are ever the same, not after 2009. Depending on the bone, and how the blast has blown it away, the socket may go high up the leg, almost to the hip to provide the support to the soft tissue and leftover muscles. It’s really complicated stuff, and never exactly, precisely, permanently right.

So 80 per cent of the prosthetist’s time with the patient will be about getting the sockets as right as humanly possible. Sometimes what’s right in the morning is wrong by the evening, leaving a blister or a patch rubbed red and raw, or swelling in the repairs made so carefully by the plastic surgeon. When the socket is first fitted, it’s left on for a while and then taken off again. They stare down at it, and wait for any red marks left behind to fade away. If after ten minutes the marks are still visible, then the socket needs work, so back they go to the cast, and the set of tools, and they work looking back and forth from the stump to the socket, and then they try again. Most people got a new socket or major socket work done at least once a month after their original fitting. It’s like a new pair of shoes that pinch at the end of the first day you wear them, even though you really want to wear them because they are new. And the next day, blisters, so you have to wear an old pair or trainers because of the pain.

But with sockets, not being able to put them on because of a graze or a blister or swelling meant going back in the chair. Stumps changed after they’d come back from their week off away from the gym, gone home, got hungry, started eating again and so been fed from morning until night by families grateful to see their progress. Out with friends, pubs, beer. Even slight fluctuations in weight affected the volume of the stump, and suddenly, really annoyingly, the socket no longer fitted. Some people have different stump volumes every morning and every evening, no matter what they do or don’t do. Humans swell and shrink as they get hot or cold, and fluid shifts around their body, particularly a body that has been assaulted and battered at the molecular level by blast injury. Just the simple act of sweating – the means whereby a body regulates its own temperature – is problematic with stump and socket. The socket traps the sweat, heat builds up, sweat accumulates, dirt accumulates in the sweat, and then the carefully repaired tissue on the stump softens – ‘macerates’, to give it its technical name – and then damage is done.6

But, for all of that, it was a great moment when the pair of elasticated socks that act as a liner between stump and socket was handed over for the first time. The patient padded out the gaps in their own scarred flesh to make it even, and then rolled them over their stump, handling it like the expert that everyone at Headley had helped them become. Sprayed the socks with some liquid that made them fit, and then on with the socket. Fitted like a dream, stayed on with a vacuum seal. It felt tight, always, the first time, as the flesh was enclosed and pressure started to take the strain and move the weight around. Then they looked down, and they no longer saw battered, bulbous remnants but two neat stumps, dressed and ready for business. And beside them the prosthetist smiled – just a small one, because although so much more work would be needed, this was still special.

Next stop: standing. Sockets can’t be stood on, and something needs to be clipped on to their ends that is suitable for standing. But going straight to a long prosthetic is very demanding, not only in terms of balance and mobility but also in terms of the immense effort required metabolically. So the solution is to go gradually, starting with a foreshortened prosthetic – ‘stubbies’, as they are more commonly known. A stub at the end of a stump, not yet a length. Stubbies have a clip that goes on to the socket and then a couple of inches of connection length with a rounded flat disk on the bottom. When patients stand, stubbies are what they first stand on, and it feels like not much effort at all, because their centre of gravity is low, so balance and stability are easy, and although their steps are short, the effort required to make them is not too much – heart rate stays low, less sweating into the socket, all round a good thing. Stairs are difficult in stubbies, but generally they are the prosthetic version of bedroom slippers. Something comfortable that can be relied on, although not always, according to one of their manufacturers, ‘cosmetically appealing’ (stubbies, not slippers). Stubbies won’t make them as tall as their rifle again, but they are a significant move forward.

Scott Meenagh was up on his stumps and stubbies three days after arriving at Headley. Mark Ormrod was asked to stand still while the prosthetic people marked up his socket for some minor adjustments. No chance, he was never standing still again unless it was on a parade ground or at his wedding, so the prosthetists could work while he was moving his weight from thigh to thigh, almost walking.7 Getting better was exciting, the first real positive personal excitement they’d had for a while.⁸ But the team had to be very careful at this stage, because their patients could easily start to overdo it, really pushing themselves in the gym, as their stubbies allowed them to use weights, stand up, develop the core and abs and joints, everything that hadn’t been blown up or removed by a surgeon.

Stubbies make the next stage much easier. The next stop will be big legs, as they call them at Headley (soldiers rename everything: crutches are comfy sticks). Big legs are the same length and weight as the leg that has gone, so they are tall again, taller than their mum. They haven’t rushed on to big legs because there’s one important thing to remember about big legs (or any prosthetic limb), and that is: the longer it is, the more complicated, the more difficult to master and the more expensive. Below the knee (a flesh wound, as they like to call it at Headley), prosthetics are pretty straightforward. Through the knee is more difficult, but what’s left of the joint can be incorporated into a socket design and every little helps with the new movement range. Above the knee is hardest of all. Nothing to work with, movement forward will come from the rest of the body, hips and pelvis, very hard.

And pretty soon into 2009 the staff at Headley understood this better than anyone, so word went out all the way back to the surgeons at Bastion. Give us as much bone to work with as possible, amputate low and keep everything long. Whatever can be spared, physios and prosthetists can work with. And the surgeons took note and changed their practice – as much bone as they could save sent home, below the knee where possible, through the knee likewise (although it’s a much more complicated surgical technique), above the knee only where life hung in the balance. Robert Jones had, of course, said it all before:

One point which has impressed all who are seeing end results is the necessity that we should work in much closer association with surgeons [at the Front]. In this way we could approach problems from their point of view, and they would learn also of the later phases of their cases. It would strengthen judgement on both sides, and clarify and standardize treatment. Consultants on both sides of the Channel would find it a welcome relief to share each other’s burdens.9

Surgeons and physios who worked at Bastion and Headley are still sharing that lesson and so, hopefully, the burdens of their colleagues today. In July 2016 the first of what will be a regular course teaching the techniques of through-knee amputations was held by orthopaedic surgeons from Bastion for surgeons from Cambodia, the Philippines, Indonesia, Ethiopia, Kenya, Mexico, Lebanon and Sri Lanka who are dealing with the aftermath of legacy minefields, in numbers that greatly exceed that of the Afghan cohort.¹⁰

No matter where in the world, especially Headley, with all the mirrors, the first few steps taken on ‘big legs’ weren’t particularly dignified. The big leg prosthetic itself was locked on to the socket fixture, but initially to keep it on there was a kind of harness in neoprene and Velcro, wrapped around the patient by the physio. Getting up on to the socket with the legs on was too hard for them to do on their own at first. In the early days the solution was a kind of mini-crane, with the patient clipped on then hoisted up and into position between a set of parallel bars; this held them there while they grabbed on and let the weight slowly come down through the sockets on to the legs. By 2010 the crane was wheeled out of the gym and the physios lifted their patients up themselves, one between two, and gently down on to the sockets. And whichever way it happened, usually when they looked up from between the bars, their families were there crying and taking all the photos their phones could handle because they were tall again, and it suddenly didn’t matter about all the webbing and the straps and the crane. This was it.11

And then cracking on (as every soldier I have ever met always says). The terrain between those two parallel bars became everything in their life. They could probably map it: the dents in the reinforced plastic handles, every single ripple in the mat on the floor, the sounds as their feet dragged when they shouldn’t, their breathing, heavy and hard, effortful, but slowly getting more even. Back and forth, back and forth, turn round and back again. Strain, strength, sweat in their socket, maceration, pain, parallel bars, new life. In all the photographs of them they are wearing their pushing gloves – the ones they were first given at Birmingham, which they put on when they had to start learning how to use a wheelchair. Now they use them to protect their hands on the parallel bars – much better – they don’t mind having them on in the photographs at all.

Big legs were starter legs. Fairly basic, just for learning to get up and stay up and move. Everyone knew what came next, and it was the high point of a journey where previously they thought there had no high points. The next steps would be taken on those really expensive legs that were tailor-made in the prosthetics workshop for them from socket fix to foot section. It really is a workshop, nothing remotely medical about it – and if earlier I compared it to a sculptor’s studio, it might also be a garage for a Formula One vehicle, which, in a way, it is. The lightest materials, brilliant technicians and the kind of design that means patients can have their limbs any way they want, in the future, even knock up a couple of shin pads on a 3D printer at home to match their jacket and shorts (not quite there yet, but it’s not as far away as you might think).

The really expensive stuff is in the knee joint. There are sensors all over the legs measuring what’s going on, and they send signals to a microprocessor tucked into the knee bend, and the microprocessor directs hydraulics to control the knee joint. The microprocessor is going to replace the twenty-odd years of sensory feedback from body to brain and make something new that works for limbs that weren’t always there. The whole central nervous system has to get used to a unit on the back of the new leg. It won’t be easy, but the effect is transformative: without knees, things like stairs become mountains. To lift up each leg, with a prosthetic attached, to go up a stair and then another and another, the amputee can only call on muscle groups at their hips and lower back. The actual lift arc that can be achieved is no more than inches, so going upstairs means swinging the whole leg around and over the top of each stair, and then hauling the rest of the body up too.

There’s a technical term for it: hip-walking. It is doubly difficult for the double amputee, swinging back and forth, stump drifting in the socket, a high arc of movement. Friction, heat and pain. The normal, confident, paced walk along a straight line with no one really noticing they are on prosthetics is broken for the shift to going upstairs. Everyone has to slow down, gather up the muscles they need around their body; everyone tries not to look or be looked at; everyone has to remember always, every day. They have to ask questions whether there will be stairs, and how many of them, and then have the difficult, unwelcome conversation about lifts. So a knee with a microprocessor can be transforming. Sensory data is gathered up from all over their leg, the new one and the old one. Things like gait and speed and surface. It learns to recognise the impulses that say what muscles are used for movement and what it means when they activate them. It’s not ideal: microprocessors need to deliver control strategies for how the legs manage at speed, on a variety of surfaces and for the kind of complicated gaits that the amputation has left them with. This little computer, which is replacing so much of their central nervous system, needs to recognise when they’ve stopped. It needs to be able to put their legs in the kind of holding patterns (‘conscious standing function’) that are needed for standing still or sitting down, or leaning. Something that allows them to get going again without too much effort to hitch up and off. And preferably do it in a way that doesn’t drain the batteries, because these kinds of legs need charging, so every time battery technology gets better, so do legs. And going upstairs is one thing. How about being able to walk backwards? And manage all the transitions – sit to stand to walk, walk to run, step over step upstairs and down, with no other compensating movements. So the new long leg was complicated, and wouldn’t deliver everything its owners wanted, but for all that they felt better the first time they saw them at Headley. And sometimes the prosthetic people liked a bit of drama, so they didn’t always tell them theirs were ready – they just made a normal appointment for some socket-tweaking, and they walked in and there were the legs, in the middle of the workshop, spray laminate coating glittering in a spotlight, and the patients’ spirits soared.

Then they put them on for the first time, and it suddenly wasn’t quite so straightforward. The really expensive legs were difficult to get used to – the sensors and microprocessors learning their new owner as much as their new owner was learning them. It felt like a step back, not confident steps forward. It felt like many steps back or, worse, no steps at all. Like learning to ride a bicycle. We can all remember that. The moment your training wheels are off and the hands of your family are pulled back (most of the way hovering near your back, but you can’t see that because they are behind you), and you have to go forward on your own, on the thin wheels with only your own brain doing the complicated balancing thing. That long second when you can’t quite bring yourself to push forward, when your memory reminds you of grazes and bleeding and plasters, but there’s too much at stake and so somehow your brain makes contact with the right muscles and the pedals turn and you move and you don’t fall. You don’t go very far, but it’s far enough, and you never forget how to do that again. And behind you, your family cry a little bit and take a billion photographs. It’s exactly like that, except it’s a first step, and there are no pedals: just the patient and the new version of their central nervous system, acting in tandem.

The first time on long legs, walking, reminded them that they had really forgotten how to do something that they thought they had mastered as toddlers. Falling. And the more and the further they moved, the more likely they were to fall. The prosthetics manufacturers know this (which is why some of their R&D comes under the heading ‘optimised stumble recovery’). So learning to walk became learning not to be afraid of falling, not minding and getting up again. Physios teach humans who no longer have all their original joints to care for those that are left. Before, when they fell, they put their hands out, palms down, to break their fall. But now they may not have both hands. And even if they do have both, falling damages wrists, elbows and shoulders, none of which they can afford to have out of action as they learn their prosthetics. So they learned to fall like a stuntman, starting on crash mats piled up in the gym, automatically going into a roll, dispersing the impact of hitting the ground on to their trunk, the least worst place for it to go on their new body.

Although Headley is recognised as world-class in the NHS and beyond, on one metric they failed constantly. Falling. People aren’t supposed to fall in hospital, because mostly they are over sixty-five and falling makes everything worse. Only at Headley did every fall teach the patients something, get them up faster; there are limits to NHS statistics, so move on and don’t worry about it.