Skin that comes in contact with the socket of the prosthesis must be cared for and monitored meticulously to prevent skin breakdown and skin infection. Pain is the first indication of a problem, and the patient should remove the prosthesis and inspect residual-limb skin when an unpleasant sensation is initially felt.
Skin problems can be serious and should be evaluated and treated as necessary by the patient’s health care professional in consultation with the prosthetist. As patients become familiar with recurrent problems, they may be able to identify which problems are minor and manage them on their own. However, anything unusual, persistent, painful, or worrisome should be evaluated by the professional.
(See also Overview of Limb Prosthetics.)
Risk factors for skin problems
Disorders that decrease circulation to the lower extremities (eg, peripheral arterial disease, diabetes) and put patients at risk of amputation also increase the risk of skin breakdown and infection after amputation.
Disorders that impair sensation (eg, diabetic neuropathy, other neurologic disorders) can delay diagnosis by preventing patients from feeling discomfort or pain from skin breakdown or infection. Patients with a sensory disorder should remove their prosthesis several times a day to check the skin for redness and other signs of breakdown or infection. Other patients should check for these signs at least once daily.
Skin problems and difficulty fitting the prosthesis are more likely when the residual limb has certain features, including excessive distal tissue beyond bone termination, loose skin, thick scars, skin and tissue invaginations, skin and tissue adherences, and terminal bone exostoses. These outcomes should be avoided as much as possible during surgery, although this is not always possible in traumatic cases.
If the prosthetic socket fits optimally, skin problems are minimal. But even with good fit, normal morphologic changes such as muscle atrophy and fluid volume fluctuation can alter the residual limb-to-socket relationship and increase risk of problems. Proximal constriction of the socket leads to vascular and/or lymphatic congestion and distal edema, with increased pressure over the distal residual limb.
Skin breakdown
Skin breakdown occurs at sites of pressure and where lateral (shear) forces are applied to the skin, particularly when moisture is present. Common pressure and shear injury locations include bony prominences, the margin of the prosthetic socket, and the distal residual limb.
The first sign of skin breakdown is erythema, which may be followed by pain, swelling, blisters, and ulcers. Continuing to wear the prosthesis causes more serious skin damage and can lead to skin infection.
Although it is not possible to prevent all skin breakdown, several measures can help prevent or delay its development:
Residual-limb hygiene (morning and evening): Wash with a mild soap and rinse thoroughly 2 times a day (more often for patients who sweat more than normal); the prosthetist can provide antiperspirant products specifically designed for people with an amputation.
Maintaining interface and socket fit
Maintaining a stable body weight: This is the best way to make sure the prosthesis continues to fit; even small changes in weight can affect the fit.
Eating a healthy diet and drinking water throughout the day: This helps control body weight and maintain healthy skin.
For patients with diabetes: Monitor and control blood sugar.
For patients with a lower-limb prosthesis: Ensure that the prosthesis is aligned optimally.
When patients see signs of skin breakdown, they should promptly see their prosthetist to rule out prosthesis fitting as the cause and if necessary have the prosthesis adjusted. When possible, patients should avoid wearing the prosthesis until it can be adjusted. If the prosthesis is not the cause, or if fitting adjustments do not correct the problem, medical evaluation should be done.
Skin infection
In normal, healthy skin, bacteria and fungi are kept in balance by dry, intact epidermis. However, the residual limb is contained within an interface, some form of viscoelastic gel layer or plastic, that creates a warm, moist environment that encourages growth of bacteria and fungi and development of infection. Damp skin also tends to breakdown, giving bacteria easy entry into the body. As a result, infection may spread.
Signs of infection include tenderness, skin erythema, pustules, ulcers or necrotic areas, and purulent discharge. A bad odor may indicate infection or poor hygiene. Minor bacterial infection may progress to cellulitis or produce an abscess; in such cases, patients may have fever and general malaise.
Any sign of infection should be evaluated promptly. Patients should be advised to seek immediate evaluation for the following symptoms:
The residual limb feels cold (indicating decreased circulation).
The affected area is red and/or tender.
The affected area gives off a bad odor.
Lymph nodes in the groin or armpits proximal to the residual limb enlarge.
Pus or a discharge is present.
The skin becomes gray and soft or black (either may indicate gangrene).
Treatment of bacterial infection typically involves local cleaning and topical antibiotics. Sometimes debridement, oral antibiotics, or both are needed. Typically, the prosthesis should not be worn until the skin infection is resolved. Erythema can indicate serious medical issues, which must be diagnosed and treated by a physician.
Measures described above to prevent skin breakdown also help prevent infections.
Fungal infection can be treated with an over-the-counter antifungal cream.
Other skin problems
Ingrown hairs and folliculitis, although not dangerous, can cause substantial pain and discomfort. Not shaving the hair on the residual limb can help prevent these problems.
Verrucous hyperplasia is a rare, serious skin condition of the distal tissues of below- and above-knee residual limbs consisting of rough, erythematous papules that coalesce to form plaques and warty bumps. It is caused by a combination of an ill-fitting prosthesis socket that compresses veins and lymph vessels, the loss of the normal venous and lymphatic return due to muscle contraction, and dependent edema of the distal residual limb. Verrucous hyperplasia is rare today because of improved socket design that incorporates distal/terminal compression of tissues to provide a back pressure. If the disorder does develop, patients should remove the prosthesis for a week and have socket fit adjusted, which typically corrects the problem within 2 to 4 weeks. However, this disorder can lead to serious infection if untreated. If bumps resembling warts appear, patients should immediately consult the prosthetist to have the socket adjusted.
