Current Concepts In Diabetic Foot Surgery

Author(s): 
By Jarrett D. Cain, DPM, and Vickie R. Driver, DPM, MS

      Patients with diabetes can be a quite an undertaking for any physician who manages them on a consistent basis. In the past, this has created reservations when it comes to managing these patients especially from a surgical standpoint. However, over the years, with greater understanding of the disease, improvements in surgical techniques and emerging research, the reservations have diminished and the role of surgical management is a viable option when it comes to successfully treating those with diabetic ulcerations, infections and other related complications that exist in the foot and ankle.       It is important to note that the prevalence of diabetes is steadily increasing. Wild et al., have projected that the diabetic population could reach 366 million by 2030.1 The multisystem disease has been associated with numerous complications and can have a critical impact in the lower extremity. The presence of ulceration in the lower extremity is a significant complication among patients with diabetes. In a United Kingdom study of 1,150 patients with diabetes with a defined age and sex structure, Walters, et. al., showed the prevalence of past or present foot ulcerations was 7.4 percent.2       Diabetes continues to be the most common underlying cause of nontraumatic lower extremity amputations in the United States and Europe.3 This creates a secondary byproduct of the disease of diabetes. Direct costs for diabetic lower extremity amputations in the U.S. range from $22,700 for a toe amputation to $51,300 for an above-the-knee amputation in 2001 dollars.4       Men with diabetes are 1.4 to 2.7 times more likely than women with diabetes to require an amputation.5 It is well known that after undergoing amputation, 30 percent of patients lose their contralateral limbs within three years and after the amputation of a leg, approximately two-thirds of patients die within five years.6

Emphasizing The Value Of A Multidisciplinary Approach

      These statistics paint a realistic view of the impact of diabetes on the patients’ quality of life. However, careful management with a multidisciplinary team can produce very good results. In a five-year retrospective study, Driver, et. al., showed that even though the number of patients with the diagnosis of diabetes increased 48 percent, the number of amputations decreased 82 percent.7 This provides hope to physicians and patients in this area of management.       The goal of surgical offloading for the diabetic foot is designed to prevent the development of more advanced and debilitating conditions, and provide a stable plantigrade foot.8 These objectives require a multidisciplinary team approach to get the maximum results for the patient. Due to these patients’ complex nature and numerous comorbidities, a multidisciplinary team approach to management is recommended.       An ideal foot care team should include the following: a podiatric surgeon; a vascular surgeon; an infectious disease specialist; an endocrinologist, family practice or internal medicine physician; an orthopedic surgeon; a certified wound care nurse; an orthotist; and a certified diabetes educator (CDE). Numerous references from U.S. and European literature document improvements in patient outcomes including a reduction of lower-extremity amputation rates as a result of implementing a multidisciplinary approach to diabetic foot care.9-13 However, healthcare providers frequently work in situations without this level and variety of expertise. Accordingly, when it comes to patients with diabetes who develop a foot problem, these providers often need to refer these patients to specialists.

Pertinent Pointers On Assessing The Patient’s Level Of Risk

      When it comes to assessing and treating diabetic complications in the lower extremity, the American College of Foot and Ankle Surgeons (ACFAS) has provided a comprehensive Clinical Practice Guideline (CPG) for Diabetic Foot Disorders.14 The user-friendly guideline provides a very detailed assessment for all physicians to follow along with various pathways depending on the complication(s) that exist.       The clinical exam has seven parts. One would note past or current diabetic complications and treatments. Proceed to record the patient’s current history, including walking difficulties, shoe problems, pain, smoking, use of alcohol, age, sex, weight, ethnicity and HbA1c level. In the foot evaluation, the clinician assesses protective sensation, musculoskeletal deformities, vascular status and the skin and nail condition. Testing for neurological status would include the Semmes-Weinstein 5.07 (10-g) monofilament test and the vibration sensation tuning fork test. Check pedal pulses and administer other noninvasive vascular tests if one suspects ischemia. Check the patient’s footwear. Before and after the clinical examination, evaluate the patient’s knowledge of general diabetes self-care and foot care. If the patient has a current foot ulcer, complete the history of present illness.14       One would then stratify each patient into one of three risk classifications based on the examination and history (see “How To Arrive At An Appropriate Management Plan” below). Although not yet validated by clinical trial evidence, this approach may provide advantages over a “high versus low” classification. Patients with a foot deformity but without neuropathy are assigned a higher risk category than patients without deformity. Neuropathy will develop in some patients at moderate risk. Therefore, early intervention with footwear modification, education and surgery may be beneficial. We believe that three level risk strata encourage more aggressive surveillance and intervention in this subset of patients.

Understanding The Impact Of Patient Education

      Clinicians should emphasize patient education. The benefit of education in reducing diabetic foot ulcers and lower extremity amputations is well documented.15,16 One should assess patient awareness of foot care principles and procedures before and after examinations. Patients with diabetes often underestimate their foot risk status.       In addition to discussing the management plan with the patient, clinicians should review general diabetes issues with patients, including the diabetic disease process, glycemic control, nutritional management and medications. Discuss with patients how they can avoid foot trauma, and discuss the importance of proper foot hygiene, proper shoe selection and daily foot inspection.

Keys To Evaluating The Surgical Candidacy Of Patients With Diabetes

      There are various risk factors associated with amputation. Peripheral arterial disease (PAD) can lead to gangrene and cause amputation. The presence of infection also plays a significant role in leading to amputation.17 It is also important to note that the best predictor of amputation is a history of previous amputation along with the cumulative risks of neuropathy, deformity, high plantar pressure, poor glucose control and male gender, which are all additional factors for pedal ulceration in patients with diabetes.18       When weighing any amputation in the lower extremity, podiatric surgeons must consider the whole patient, paying close attention to the metabolic state of the patient with diabetes. In regard to surgical intervention for the diabetic foot, Armstrong and Frykberg have offered the following classification:       Class I: Elective foot surgery (performed to treat a painful deformity in a patient without loss of protective sensation)       Class II: Prophylactic foot surgery (performed to reduce the risk of ulceration or re-ulceration in patients with a loss of protective sensation but without an open wound)       Class III: Curative foot surgery (performed to assist in healing an open wound)       Class IV: Emergent foot surgery (performed to arrest or limit the progression of acute infection).19

How To Determine The Appropriate Level Of Amputation

      When deciding whether to amputate, one needs to determine the level of amputation. In order to answer this question, the surgeon must carefully evaluate the following factors:       • the extent of infection;       • vascular status;       • quality of the tissue;       • immune status;       • nutritional status;       • and the patient’s quality of life.       After addressing those issues, one can direct attention to the affected extremity. Limb salvage or preservation in essence involves maintaining a functional limb while providing the patient with a quality of life. The energy a patient expends when walking with a residual limb is inversely proportional to the length of the remaining limb and number of preserved joints.18 The less of the limb that one removes during surgery, the more energy the patient preserves to perform daily activities.       The levels of amputation in the lower extremity include: digital, ray, transmetatarsal, Lisfranc, Chopart, Syme and transtibial.       Digital amputations can be defined as an amputation that takes place at the metatarsophalangeal joint or any level distal to this joint.20 When dealing with these amputations, it is important to ensure that the patient has intact vascular status. Otherwise, this can lead to further complications. Sixty-five percent of hallux amputations develop a new ulceration and 53 percent require further proximal amputation.20       A ray amputation includes a toe amputation and all or a portion of a metatarsal.18 Although the surgeon can do this with multiple metatarsals in a transmetatarsal fashion, one can perform this procedure on an isolated metatarsal with complete resection of the metatarsal or partial resection. Multiple ray resections can cause substantial narrowing of the forefoot, which can make postoperative shoe wear difficult.18       Transmetatarsal amputation (TMA) includes removal of all the metatarsals at different lengths of the metatarsal. This procedure can preserve residual limb length to maintain function and reduce energy expenditure for the patient.21 In regard to proper patient selection for this procedure, one must determine the level of amputation along the metatarsal shafts because it is important to preserve the metatarsal length as much as possible without compromising healing.22 It is also important to note that the revision TMA rate is 30 to 40 percent in patients with diabetes.23       Lisfranc amputations are indicated when there is extensive soft tissue loss of the forefoot, which prevents a successful transmetatarsal amputation.24 As the level of amputation extends more proximal, it becomes a Chopart amputation at the level of the talonavicular and calcaneocuboid joint.       In regard to the Syme amputation, originally described in 1843, the surgeon would perform the amputation at the level of the ankle joint and as the level moves proximal, it becomes a transtibial amputation.25 Researchers have shown that Syme amputations provide less short-term morbidity with greater long-term survival than a transtibial amputation.26 When performing a transtibial amputation, one should make the level of the tibial cut as distal as possible down to the middle and distal third of the tibia.18

Pertinent Insights On Post-Op Management

      After providing a salvageable limb designed to the patient’s needs, the goal is to prevent future amputations in the patient. As with managing the totality of the diabetic disease, the same principles would apply to help prevent future amputations.       Postoperatively, it is important to maintain toe-off and propulsion in the gait cycle, and reduce transfer pressures to adjacent metatarsals and digits.20 In a retrospective study, Matsen, et. al., found patient satisfaction to be correlated with the comfort and condition of the residual limb, the appearance and function of the prosthesis, and the ability to exercise.27       Larsson, et. al., prospectively studied 189 diabetic patients who had either a minor or major amputation. They found the mean healing time was 29 weeks for minor amputations and eight weeks for major amputations.28 They also found the mortality rates at one, three and five years after the primary amputation were 15 percent, 38 percent and 68 percent respectively. The rate of new amputations after major and minor primary amputations was equal.28

In Summary

      With proper evaluation and consideration of the patient’s risk factors and comorbidities, surgical offloading may provide a viable option in limb salvage for properly selected patients.       Dr. Cain practices at the National Center for Limb Preservation/Advocate Lutheran General Hospital in Park Ridge, Ill. He is an Assistant Professor in the Department of Surgery at the Dr. William M. Scholl College of Podiatric Medicine at the Rosalind Franklin University of Medicine in Chicago.       Dr. Driver is Chief of the National Center for Limb Preservation at the Advocate Lutheran General Hospital in Niles, Ill. She is the Director of Clinical Research at the Center for Lower Extremity Ambulatory Research at the Dr. William M. Scholl College of Podiatric Medicine at Rosalind Franklin University of Medicine in Chicago.
 

 

References:

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