Even with the best prosthetic care and rehabilitation efforts, a positive prosthetic outcome often hinges on the identification and resolution of a skin problem that in other circumstances might be considered insignificant. When such a problem occurs—particularly on the portion of a residual lower limb that, during weight bearing, is exposed to shear, friction, and other contact pressures and stresses inside the prosthetic socket—its impact can be life-changing.
A 2010 study, "Skin Problems of the Stump in Lower Limb Amputees: 1. A Clinical Study," (Acta Dermato-Venereologica 91(2): 173–7) by Henk E. J. Meulenbelt, Jan H. B. Geertzen, Marcel F. Jonkman, and Pieter U. Dijkstra, Department of Rehabilitation Medicine, University Medical Center Groningen, University of Groningen, Netherlands, collected and examined data concerning the prevalence of residual-limb skin problems on 124 individuals with lower-limb amputations. The investigators evaluated the impact of these problems, and the differences between clinically observed skin problems and those reported by the study participants.
Interestingly, they found that significantly more skin problems were reported than observed, with cold skin and excessive perspiration in particular being more often reported than observed. The prevalence of skin problems on the residual limb was estimated as 36 percent and often resulted in a reduction in walking distance without a break, as well as a reduction in prosthesis use overall.
Joan Sanders, PhD, professor in the Department of Bioengineering, University of Washington, Seattle, points out that sometimes amputees inadvertently contribute to their skin problems by using prosthetic liners that negatively affect their skin tissues.
Sanders is currently participating in a National Institutes of Health (NIH)-funded project to characterize and compare eight qualities of skin interface materials currently on the market: compressive cushioning, shear cushioning, suspension, adherence, volume accommodation, breathability, thermal conductivity, and durability.
The results of the project should be posted to the University of Washington website by the end of the year. Sanders has been measuring pressures and shear stresses on skin in the prosthetic interface for a number of years; however, her research often identifies residual-limb volume as a major factor influencing those pressures and stresses. "The limb is very dynamic and commonly changes size throughout the day. At present, prosthetic sockets do not have the ability to change shape with the limb. This mismatch between a changing limb and a fixed socket has the potential to create interface pressures and shear stresses that are detrimental to the skin and other limb tissues."
Practitioners may advise patients to manage their changing limb volume by adding or removing socks—and this is where things break down, Sanders notes. When asked, some patients assured researchers that they change socks—but measurements suggested otherwise. Not changing socks to match limb volume can be a major source of skin problems, Sanders says.
She explains that while healthy people typically experience only small residual-limb volume changes throughout the day, "people with co-morbidities can experience very unpredictable volume changes. They may know that in the morning their limb is going to shrink a lot in the first hour they use their prosthesis. They recognize that after that point, they will then have to stop and put on a sock. Since they have to take their pants off to add or remove socks, that's a real pain—particularly during the winter months in the northern part of the country. Some subjects come in when it is snowing outside, and they're wearing shorts! It makes it easier for them to access their prosthetic socket, and they reason that 'only one leg is cold!'"
Sanders believes that oftentimes, patients' response to residual-limb volume changes is subconscious. "They may believe they just 'don't feel like walking right now' without recognizing that their limb has shrunk and their prosthesis doesn't fit right. Making that association sometimes doesn't happen, and they don't know this is the source of the problem and can lead to skin problems."
New Technologies Address Volume Management
New materials, including smart liners, adjustable sockets, and vacuum-assist systems may be helpful, but Sanders urges caution. While vacuum-assist approaches to volume management appear to enhance healing in some patients, they may not be appropriate for patients who have excessive fluid buildup due to edema. She also foresees danger in adjustable sockets that shrink to fit a limb that has reduced in volume. "The limb is going to reactively reduce its volume further—and now the socket shrinks even more. Dehydrating the limb in that manner eventually is going to be a real threat to the limb."
Kevin Carroll, MS, CP, FAAOP, director of prosthetics for Hanger Clinic, Austin, Texas, says that while many adjustable sockets have been on the market for 15 years or more, the concept "hasn't really taken off, possibly because it puts a lot of responsibility on the patient," he says. "With this type of socket, the patient has to adjust the volume of the socket themselves. There have also been some difficulties in materials currently used in adjustable sockets."
Many of the adjustable sockets rely on pneumatics, he notes—tightening the sockets in strategic areas by pumping air into them. "It has not been well received, generally speaking. As better technologies come along, the adjustable socket may become a more viable solution," he says.
Carroll adds, "Socket materials and technology have come a long way in recent years, and the liners have greatly improved. There are numerous liner choices available—liners that quickly take the shape of the patient's limb, exceptionally stiff gel liners, and those that are very soft and gentle and appropriate for older adults with very delicate skin, for example. It's important to be selective in choosing a liner," he cautions. "No one liner is right for everybody."
Optimizing Residual-Limb Health
When it comes to residual-limb health, perspiration is one of the biggest issues that needs to be managed, Carroll says, since perspiration buildup inside the liner acts almost like an acid, creating irritants that cause folliculitis and skin breakdown. "A liner that may once have been perfectly fitted to the patient may now, as the result of limb-volume changes and other factors, fit loosely enough to allow perspiration buildup," he explains. "This can cause breakdown of the hair follicles, and oftentimes major rashes appear—almost like ringworm-type marks on the skin. It's very noticeable in lower-limb prosthetic users, particularly where bridging occurs between the tibia and fibula and the liner, allowing sweat to collect.
"Prosthetists may benefit from involving a dermatologist in the care of such cases, to evaluate the person's skin and recommend the most appropriate antiperspirant to use, applying it at bedtime," he suggests.
Scott D. Cummings, PT, CPO, FAAOP, immediate past president of the American Academy of Orthotists and Prosthetists (the Academy), and clinician at Next Step Orthotics & Prosthetics, headquartered in Manchester, New Hampshire, says that the increased use of gel liners has resulted in "an uptick in skin problems within the last ten years or so…. The environment that they create is a perfect breeding ground for those bugs that cause bacterial and fungal infections, so basically patients are wearing petri dishes—dark, warm, moist environments. The liners, on the one hand, satisfy a number of needs in terms of pressure distribution and reduction of shear forces and friction, but the tradeoff is an environment that's easy for infections to thrive in."
Some manufacturers are working to address this issue, Cummings says, but as a whole, "the roll-on material in either cushion or locking liner types provides an environment that's ideal for cultivating skin problems."
Like Sanders and Carroll, he suggests adding socks of varying thickness to provide an additional layer of protection, breaking the contact between the liner and the skin. However, he says, the key to residual-limb skin health is educating patients about hygiene, and he offers a checklist for prosthetists to provide to their patients—preferably in written form.
"So much information is provided at once, it's easy to later confuse it or forget portions of it," he says. "Written instructions are very helpful in stressing the importance of performing each aspect of maintenance and hygiene correctly."
Instructions should not only outline general practices to which all prosthetic patients should adhere, but they should also be tailored to the specific needs of each patient and his or her prosthesis design. Cummings starts with the following fundamental residual-limb care checklist:
- Keep the residual limb dry. A patient may need to remove his or her prosthesis once or twice a day and dab it dry, change socks, or switch the liner.
- Clean the limb and interface every day with soap and water, whether it's a hard socket, a sock, a liner, or the suction sleeve for a transtibial prosthesis. Use a mild, unscented soap. Cummings says Next Step has had good luck with Hibiclens. "We don't go to the antibacterial soaps until we're sure there is a bacterial issue," he says. It's important to rinse out all of the soap residue because it can become a breeding ground for fungus or bacteria.
- Don't scrub the liner with anything. Rub the hard socket with a cloth, put the socks through the laundry, but don't abrade the liner surface. "We get people who think a deep clean with a cloth or brush will do the trick," Cummings says. "It may do it that day, but they're creating a rougher surface that breeds future problems. Instead, introduce the soap or the rubbing alcohol with the liner right side in, then rub the liner surfaces together, polishing the inside against itself. Then just rinse it and air-dry it."
- Avoid using scented soaps, lotions, creams, or perfumes to mask an odor. These can create even more problems.
- Spray the liner twice a week with a rubbing alcohol spray. This won't just clean the liner, it will also kill bacteria. Don't use rubbing alcohol spray too often because it dries out the liner material and abrades the surface of the liner making it easier to harbor unfriendly growths.
- Know the warning signs of various types of dermatitis, and watch for them.
- Act quickly if you suspect a problem. It's important to catch skin issues in the early stages before they become too big.
"We can make a dramatic improvement in the comfort and condition of the residual limb if the patients are really on the ball with their self care," Cummings concludes. "That's saying a lot, but it's absolutely true."
M. Britt Spears, CPO, FAAOP, president, Spears Prosthetics & Orthotics/Rehab Services, Memphis, Tennessee, says that management to prevent residual-limb skin-care issues should begin immediately following amputation. "When you start with a new patient, you try to get them to a point to where their tissue is able to take all the rigors that an internal socket environment is going to expose them to," he says.
Spears explains that applying rigid dressings after surgery not only promotes healing in a sterile environment and protects the limb from outside trauma, but doing so also prevents flexion contractures and edema resulting from the surgery. The process better prepares the skin for healthier transitioning into a preparatory prosthesis—shortening the time normally required for the transition by about one-third.
Vigilance and addressing problems early on is advantageous for many skin-health issues. Adherence scars, for example, which occur when the suture line sticks to the cut end of the tibia or femur, require prompt attention. "Patients should be advised to mobilize the scar tissue and usually get good results, but if more than a year passes, it's going to be extremely difficult to achieve mobilization," Spears warns. "Sometimes a patient's suture line opens up and begins filling in with granulated tissue and adhering to the tibia, especially, and really requires regular mobilization."
Spears also asks physicians to leave the patient's sutures in place for at least 24 days, so tissues mend thoroughly— especially trouble areas such as skin graft sites. "We start new amputees early on massaging and patting the residual limb hard and sharply, which tends to shock the nerves and cut down on pain, and also builds healthier tissue that's more resistant to skin problems. A good-fitting socket and careful hygiene are essential, in addition to a regimen of stretching and massaging the skin that should continue for a lifetime. It's like taking a bath—you never outgrow the need."
Identifying Common Residual-Limb Skin Problems
Enumerating and defining the full array of potential residual-limb skin-health problems might seem overwhelming to clinicians and patients alike. However, M. Jason Highsmith, PT, DPT, CP, FAAOP, assistant professor in the School of Physical Therapy & Rehabilitation Sciences, University of South Florida (USF), Tampa, made waves at a recent Academy meeting with a presentation that cut the list down to size. Highsmith identified the most commonly seen skin-health problems prosthetists were likely to encounter while fitting lower-limb prosthesis users and explained how to recognize them and what to do about them (Table 1 below). The presentation evolved from findings of a paper titled, "Common Skin Pathology in LE Prosthetic Users," in which Highsmith partnered with his brother, dermatologist James T. Highsmith, MD. The paper was published in the November 1, 2007, issue of the Journal of the American Academy of Physician Assistants.
"We both learned a lot about each other's fields at that time," Highsmith says. "I think that has really been the catalyst in creating such high interest within the prosthetic area."
The opportunity allowed the brothers to freely explore and address questions from both professional perspectives and present a more comprehensive picture—and consequently to move forward with their findings and create two dermatology modules for interface and skin problems that will appear later this year on the USF Prosthetics & Orthotics Demonstration Project website (http://oandp.health.usf.edu).
The Highsmith and Highsmith joint presentation to the Academy—and others like it to follow soon—addressed the pathophysiology, evolution, and management or treatment of the most common dermatological problems, including pressure sores, infection, irritant contact dermatitis, negative pressure hyperemia, intertrigo, xerosis (dry, flaking skin), eczema, folliculitis, volume issues, dicubitus ulcers, and scars, as well as tumors and growths.
James Highsmith says that one of the most common problems he sees in prosthetic patients is hot spots, also known as pressure sores. "It seems to be an issue of good fit and interface contact," he says, "but hygiene also remains an essential element."
Highlights of his observations include the following:
- Elderly amputees have thinner, drier skin, due to loss of collagen as they age. "Over age 65, about 70 percent of people in one study had xerosis with no other health problems at all. Dry skin is itchy and can lead to other problems—scratching or rubbing it can actually lead to lichenification, or thickening of the skin."
- The unnatural interface between the residual limb and the socket or device is difficult to cool; as it gets hotter and more sweat forms, it can change the body's pH and create a lot more skin problems. A recent study shows that neurotoxin injections into the residual limb have delivered good results over long periods, and this area is being explored further.
- What's good for your skin should be good enough for your device. Use the same kind of soap or cleaner on both to avoid increasing your risk of getting another contact or irritant dermatitis.
He advises amputee patients to talk to their prosthetists about skin problems without delay, and stresses the value of collaboration, such as the one he has enjoyed with his brother.
"Speaking as a dermatologist, we would love to work with more prosthetists—a lot can be gained, and it could make a huge difference for our patients."
Judith Philipps Otto is a freelance writer who has assisted with marketing and public relations for various clients in the O&P profession. She has been a newspaper writer and editor and has won national and international awards as a broadcast writer-producer.