Proven Strategies To Prevent Lower Extremity Amputation

From 2009 to 2012, amputation rates at our facility dropped 77.3 percent as a result of the staff employing basic strategies in both prevention and wound care. This occurred despite the consistent rates of new foot ulcers that arise each year in patients with diabetes. A study by Apelqvist and colleagues in 1994 demonstrated that treatment of diabetic foot ulcers costs significantly less than amputation, making reduced amputation rates a benefit to both patients and the healthcare system at large.1

   A combination of factors contributed to the aforementioned success at our facility, including early referral of high-risk patients to podiatry, improved access to care, a multidisciplinary approach to patient management and continuity of care by each wound care provider. Other preventive strategies included patient foot care education, shoe gear and orthotics or bracing, surgical correction of deformity in at-risk patients and regular, long-term follow-up.

   Early access to care for at-risk patients is of significant importance. Many patients receive referrals to the podiatry service for basic foot care education as well as routine foot care. We are lucky to have a health technician trained to perform nail and callus care who also educates patients on diabetic foot care. This routine care leads to early identification of problems. We can therefore refer patients immediately to a provider, which prevents many problems due to the frequent foot evaluations and repeated reminders of how patients should care for their feet. Several studies have demonstrated that foot care education is important in foot ulcer and amputation prevention.2-4

   When patients receive referrals for ulcer treatment, we attempt to see them for their initial visit within a week. Earlier intervention has led to better success with healing in our experience. We assign the patients to one provider who sees them weekly or sometimes more often, providing continuity of care.

A Closer Look At The Initial Care For Referred Patients

The initial exam routinely involves vascular and neurological assessment as well as evaluation of foot deformity possibly contributing to the ulceration and a detailed evaluation of the wound. If pedal pulses are not palpable, we order non-invasive arterial studies and obtain a vascular consult as appropriate based on the results. We take X-rays at the first visit to rule out any evidence of osteomyelitis and assess any deformity that might be contributing to the wound. The X-ray images also serve as a comparison if the ulcer becomes worse in the future.

   Wound management consists of cleansing, debridement and the use of a variety of local wound care products. We utilize antibiotics if indicated and of course manage serious infections with surgical debridement and hospitalization. If the wound probes to bone and X-rays are negative, additional imaging studies such as magnetic resonance imaging or bone scans can rule out bone infection. If infection is present, surgical or antibiotic management occurs depending on many factors beyond the scope of this article.

   If the patients’ vascular status is adequate, almost uniformly, we apply a Jones compression dressing to the affected extremity to control edema and provide some immobilization of the area.5 Offloading of the wound occurs with padding, surgical shoes, casts, crutches, walkers or wheelchairs. Most importantly, patients receive strict instructions limiting their walking to short distances (i.e. bathroom and back) with either partial weightbearing on the heel for forefoot ulcers or complete non-weightbearing. Research has shown non-removable offloading devices such as casts to be more effective than removable devices. This is likely due to forced adherence.6-7 Patients also get instructions to elevate the affected extremity consistently, limiting dependency on ambulation to 30 minutes at a time.

   The provider most often changes the dressings in the clinic each week, which has worked better than at home dressing changes in my patient population in almost every case. As a general rule, the wound care products one applies directly to the wound do not usually promote healing as much as strict offloading, elevation and compression when appropriate. We measure wound size and depth at each visit to determine if there is progress with the current wound care regimen. If not, we alter the treatment. One must question the patient at each visit about changes in activity, blood sugar and other factors to determine if other factors are preventing healing.

Pertinent Insights On Preventing Diabetic Ulcer Recurrence

After achieving healing, offloading with appropriate shoe gear, orthotics or bracing is imperative to help prevent recurrence. Several studies have shown some benefit in the prevention of re-ulceration with the use of therapeutic footwear.8 Researchers found this benefit was even more significant in those patients with severe foot deformity. I frequently utilize shoes with forefoot rockers to offload pre-ulcerative lesions plantar to the metatarsal heads. I also use orthotics with metatarsal pads and accommodation under the affected areas.

   Hastings and coworkers determined the ideal location for metatarsal pad placement to offload the forefoot at 6 to 11 mm proximal to the metatarsal head line.9 One can also sometimes add a 3 degree rearfoot varus or valgus wedge for additional offloading when a first or fifth metatarsal head pre-ulcerative lesion is present. I have found hallux interphalangeal joint pre-ulcerative lesions to be particularly difficult to offload. However, I have had some success preventing recurrence with a more distally placed rocker sole, starting at the base of the hallux in addition to an orthotic with a 3 degree rearfoot varus post. I will sometimes also use a forefoot varus post, a toe raise under the base of the hallux and accommodation under the pre-ulcerative area.

   In Charcot feet that do not have significant plantar prominence, I have used both Charcot restraint orthotic walkers and patellar tendon bearing braces successfully. In my experience, I have found that a patellar tendon bearing brace provides the best offloading for plantar heel pre-ulcerative lesions. The patients obviously have to wear the device at all times when on their feet to avoid recurrent ulceration.

   Patients with significant deformity and adequate vascular status may benefit from surgical correction to reduce pressure and avoid re-ulceration.10 Surgery ideally happens after the wound has healed but can sometimes occur to promote healing in situations in which local wound care has not been completely effective. For distal and dorsal toe ulcers in relatively flexible hammertoe deformity, percutaneous tenotomy (with a local anesthetic for the patient) works well to correct deformity.11 One can often perform the procedure safely and achieve good results, even in elderly patients with multiple comorbidities. Other standard or minimal incision procedures include bunionectomy, proximal interphalangeal joint arthroplasty or fusion, metatarsal osteotomy, midfoot or rearfoot fusion, and even Charcot reconstruction on a case-by-case basis.12

   One must critically evaluate the patient’s health status and ability to adhere with postoperative instructions in order to select the best procedure for the patient. Researchers have reported that tendo-Achilles lengthening and gastrocnemius recession reduce pressure on the ball of the foot and aid with ulcer healing and prevention.13 When performing a tendo-Achilles lengthening, take care to avoid over-lengthening in order to prevent plantar heel ulceration in the neuropathic foot.13-14

In Conclusion

Routine follow-up of patients with a history of ulceration has been critical in maintaining long-term healing.15 Some may develop calluses in the area of their previous ulcer that need periodic debridement to avoid re-ulceration, even with the use of appropriate footwear. Periodic replacement of therapeutic shoe gear, orthotics and bracing is important in order to maintain appropriate support and protection of the patient’s feet. Researchers have shown that patient adherence to wearing prescribed footwear at home is poor.16 We repeatedly give written as well as verbal foot care instructions to patients through our clinics in an attempt to improve adherence. Pamphlets are also available in the waiting rooms at our outside clinics for patient education.

   I will admit that wound care is extremely labor intensive with frequent, long visits required to provide appropriate care. Even with the significant emphasis on wound management at our facility, we are not always successful in healing wounds or maintaining healing without amputation. There is no magic involved in healing diabetic foot ulcers but most ulcers will respond to a standard protocol of basic wound care strategies in combination with comprehensive, multidisciplinary patient management.4,17-18

   Dr. Schweinberger completed a limb preservation fellowship at Madigan Army Medical Center in Tacoma, Wash. She currently works in the podiatry department at the VA Medical Center in Cheyenne, Wyo.

References
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2. Singh N, Armstrong DG, Lipsky BA. Preventing foot ulcers in patients with diabetes. JAMA. 2005;293(2):217-228.
3. Johnston MV, Pogach L, Rajan M, Mitchinson A, Krein S, Bonacker K, Reiber G. Personal and treatment factors associated with foot self-care among veterans with diabetes. JRRD. 2006;42(2):227-238.
4. Apelqvist J, Larsson J. What is the most effective way to reduce incidence of amputation in the diabetic foot? Diabetes Metab Res Rev. 2000;16 Suppl 1:S75-S83.
5. Andersen C, Roukis T. The Diabetic Foot. Surg Clin N Am. 2007;87(5):1149-1177.
6. Lewis J, Lipp A. Pressure-relieving interventions for treating diabetic foot ulcers. Cochrane Database Syst Rev. 2013;1.CD002302. doi: 10:1002/14651858.
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11. Laborde JM. Neuropathic toe ulcers treated with toe flexor tenotomies. Foot Ankle Int. 2007;28(11):1160-1164.
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15. Waaijman R, Keukenkamp R, de Haart M, Polomski WP, Nollet F, Bus SA. Adherence to wearing prescription custom-made footwear in patients with diabetes at high risk for plantar foot ulceration. Diabetes Care. 2013 Feb 19. [Epub ahead of print].
16. Apelqvist J, Larsson J, Agardh CD. Long-term prognosis for diabetic patients with foot ulcers. J Intern Med. 1993;233(6):485-491.
17. Weck M, Slesaczeck T, Paetzold H, Muench D, Nanning T, Gagem G, Brechow A, Dietrich U, Holfert M, Bornstein S, Barthel A, Thomas A, Hanefeld M, Koehler C. Structured health care for subjects with diabetic foot ulcers results in a major reduction of amputation rates. Cardiovasc Diabetol. 2013;13;12(1):45 [Epub ahead of print].
18. Vuorisalo S, Venermo M, Lepaentalo M. Treatment of diabetic foot ulcers. J Cardiovasc Surg (Torino). 2009;50(3):275-91.
19. Wrobel J, Charns M, Diehr P, Robbins J, Reiber G, Bonacker K, Haas L, Pogach L. The relationship between provider coordination and diabetes-related foot outcomes. Diabetes Care. 2003;26(11):3042-3047.

   For further reading, see “Preventing Amputation In Patients With Diabetes” in the March 2008 issue of Podiatry Today.