Getting Under Foot
How Lower-Extremity Positioning Can Impact More Than Just Legs & Feet
- By Laurie Watanabe
- Aug 01, 2013
In discussions of seating & mobility, there is no shortage of talk about the pelvis, the head (“Proper position optimizes field of vision and opportunities for socializing!”) and the upper extremities (“We’re aiming for efficient self propulsion or ease of reaching driving controls!”).
In all the conversations of clinical efficacies and medical justifications, lower-extremity positioning may get short-changed. But there are multiple reasons to get feet and legs properly positioned — and a number of obstacles that can keep it from happening.
Visual Signs of Poor Positioning
Asked the goal of proper lower-extremity positioning, Chris Reidmiller, ATP, national sales manager of Therafin Corp., says, “A natural pelvic position. Everything is a stepping stone; everything has its place. One spot out of position can cause the rest of everything to be out of position. If the lower extremities are out of whack, they can pull the pelvis out of whack, which in turn can pull the spine, head position and so on.”
Stephanie Tanguay, OT, ATP, clinical education specialist at Motion Concepts, agrees.
“As long as our legs are attached to our pelvis, there is absolutely going to be an effect of not properly positioning the lower extremities,” she says. “Keeping our feet and legs in orientation, in the proper alignment, will help with stabilizing and maintaining seated posture.”
What, then, does poor lower-extremity positioning look like? What are some visual cues that indicate there might be a problem? “I always think of one where the knees are up in the air, essentially,” Reidmiller says. “The lower extremities aren’t positioned properly or aren’t at the right length. Or they could have a poor angle of the lower extremities, which is causing the pelvis to tilt, which is going to ultimately result in their head leaning forward, maybe more of a C curve of their spine, allowing their head to lean forward. You usually see that because the pelvis is being pulled out, which indicates the legs are way out of proportion also.”
Tanguay cites clients with “knees being up higher than their pelvis and being unsupported or unweighted. We tend to see somebody who has their femurs offloaded: Their legs tend to swing in the breeze a little bit, left and right.”
Consumers themselves tend to speak up when legs and feet aren’t positioned symmetrically, Tanguay adds. “I hear them mention symmetry.…I hear consumers and their caregivers a lot of the time saying, ‘They’re not the same.’”
Positioning Goals to Aim For
But ultimately, optimal positioning for feet and legs might not include picture-perfect symmetry.
“We’re not always guaranteed that both of our ankles have the same range of motion or the same leg length,” Tanguay points out. “There’s a lot of things that can contribute to having asymmetrical leg length — maybe rotation of the pelvis, a dislocated hip, a surgical revision of the head of the femur. You could have a history of lower-extremity fracture that can shorten seat depth as well.
“[Consumers] want the footplate angle to always be symmetrical. If we have an angle-adjustable knee position, like you might have with the Seating Dynamics multi-spline joint, there’s somebody who would be saying, ‘They’re not the same.’ I know that we tend to think of everything being symmetrical, and that’s what’s ‘right,’ but it’s not. It has to really be more of what the range of motion is and what the body presents.”
In other words, achieving the “right” foot and leg positioning can sometimes require meeting a consumer where they are. And overall, lower-extremity positioning needs to work well with the positioning needs of other parts of the body.
So how do you know when you’ve got the right combinations dialed in?
Greg Peek, owner of Seating Dynamics, says, “My experience in adjusting footrests and legrests taught me that when they’re properly adjusted, there should be minimal weight on the footplate, and the thighs should be supported at the edge of the cushion or along the entire surface contact between the thigh and the cushion. That’s where the weight should be supported primarily, and the footplate is there as a support. It’s not the primary support/weight-bearing surface.”
When the footplate bears too much weight, Peek explains, “It is going to have an impact on what the [seat] cushion is doing. If you’ve got an improperly adjusted footrest that is too short, it’s going to bear more weight, and it’s going to lift the thigh off the cushion and put more pressure on ischials.”
Tanguay says another problem occurs when the consumer is sitting more forward than they should be, or when they’ve slid down or forward on the seat cushion, causing some posterior pelvic rotation.
“Once the pelvis rotates posterior, it’s very easy to lose alignment of our femurs,” she says. “A lot of time how it manifests is our patient [sits] abducted, and at the lower extremities the outside aspect of the calf just below the knee can be sitting up against the hanger of the lower-extremity support.”
Tanguay says in those cases, consumers or family members will report seeing on the skin “an indentation; there’s always a little curved tubular mark. If it’s somebody who has mild edema, if you’re touching that hanger of the lower-extremity support, the soft tissue and the fluid will kind of move around it, so we have that indentation.”
Tanguay says manufacturers offer padded hanger wraps, or off set receivers so hangers can be set offboard and, the hope is, out of the way. Or: “If we can do something a little better with their posture to get them positioned back a little bit more, or maybe have a cushion that has a slightly higher contour on the front corners, on the edges of the product. That’s when we tend to use something that has an adductor — it would help keep the legs a little bit better in alignment and hopefully keep them from touching the hangers.”
Range of Motion & Other Restrictions
Loss of range of motion and similar mobility restrictions can be another lower-extremity positioning challenge.
For instance, windswept positions, Reidmiller says, can be difficult to accommodate: “They have fixed leg angles,” he says, but consumers with windswept positioning may have other issues as well.
“If you hold your head to the side long enough, your body is going to try to correct itself,” he explains. “So when you have a spinal rotation, your body is trying to correct itself over time. We all want our visual plane horizontal and that sort of thing, so our body will try to pull in different directions to keep our head the way it needs to be.
“So with the windswept position, it usually means their spine is rotated also to allow their head to get into that visual plane. Sometimes we’re not trying to get the pelvis in a neutral position, because the majority of those windswept positions are fixed types of positions where they have muscle shortenings; they’re really tight. So what we’ll do is give them the proper head position and to help support them, and let the legs fall where they need to go to give us that and support the rest of the body.”
Meanwhile, Tanguay says the more time a consumer is in a seated position — such as in a wheelchair — “there’s a higher prevalence of them having shortened calf muscles. A lot of our consumers end up losing some of the dorsi-fl exion of their ankle, meaning that they’re toe up and heel down. When the calf muscles get tight, that type of range of motion, we see a lot of consumers who lose that very rapidly. It gets tight, and they have to do stretches.”
There are many ways to intervene when optimal lower-extremity positioning isn’t easily achievable. In the past, solutions have included essentially strapping feet to their footrests — an intervention that could result, Reidmiller says, in consumers looking “like Frankenstein.” But today’s clinicians and ATPs have a wider array of choices.
And some of those choices involve tweaking a client’s positioning rather than opting for accessories.
“If we have a consumer that could actually sit in a chair with a tighter knee angle,” Tanguay says, “I’m thinking of a manual chair with an 85° front or an 80° front orientation, where somebody sits with their feet kind of tucked underneath them a little bit more, that person hopefully has a little bit more of that range. I actually angle footplates quite oft en in those types of chairs so they can have a little more of that stretch and be oriented in a little more dorsi-flexion. There are some people who might say they really like that because that dorsi-flexed angle of the footplate when they position their feet back on it, it has a little bit more contact and there’s a little bit more resistance. It actually gives them a little bit more stability. If they’re going over uneven surfaces, it’s less likely that their foot might migrate out of the footplate, drop off the front edge. They can maintain that position without having to have something like a strap around their lower leg.
“If somebody has the range, I would rather set that orientation up with a little bit of dorsi-flexion rather than having it too flat.”
Reidmiller has seen a number of clients with tone so strong that they break footplates and similar accessories. For these clients, dynamic accessories that move and flex with them may be the answer.
“The tone’s got to go somewhere,” he explains. “And if something’s solid or static, the tone’s going to go into that piece of equipment, and it tends to break. If we allow them to alleviate that tone, hopefully there’s less breakage.”
Peek has a long history of developing dynamic components, including dynamic rocker backrests and now, dynamic footrests.
“Being a mechanical designer, when somebody tells me a footrest broke — well, why did the footrest break?” Peek asks. “When you hear that over and over again, you know there’s a pattern causing it. And in a lot of cases, what I hear of is extensor tone.
[The rocker backrest and dynamic footrests] were conceived for the same basic need: to absorb energy and not transmit load into the wheelchair. Their original purpose was from a mechanical perspective, not a clinical perspective.”
But in working to create more durable positioning components, Peek also has tapped into the cause of at least some tone incidents.
“In some cases, it’s sensory seeking,” he says. “[Consumers] bang on the [backrest] to make sure they’re grounded with Mother Earth. I’ve heard numerous people comment that when they meet with firm resistance — and I think this can apply to the back, foot, whatever — that will trigger things, and they will work harder at getting that sensory feedback.”
But dynamic components — Peek has created telescoping varieties as well as those with dynamic plantar-dorsi and angle-adjustable features — can help to de-escalate those incidents of extensor tone instead of revving them up.
“By absorbing the energy, unless it reaches end of travel, we’re never going to see the load to the component or the wheelchair that we would if the component was not there,” he says. “It’s absorbed the energy and the travel, hopefully successfully, but at least to some degree.”
Doing the Most with the Least
While perhaps not getting the same amount of attention in seating discussions as the pelvis, properly positioned lower extremities can greatly enhance the mobility experience for consumers. And greater understanding of the hows and whys of seating give clinicians and ATPs the opportunity to achieve positioning success while possibly using fewer static accessories.
“We all want to live, we all want to move,” Reidmiller says. “That’s what our bodies are intended to. So, allow them to move, but find a compromise.”
This article originally appeared in the August 2013 issue of Mobility Management.