Preserving the Diabetic Foot

Armed with the latest research and their own intriguing case studies, these authors take a closer look at limb salvage procedures and assess whether they are viable
alternatives to amputation.

By Jonathan E. Moore, DPM, MS, Lawrence Harkless, DPM and George Liu, DPM

Over 50 years ago when Dr. Elliot Joslin asked Dr. Leland McKittrick to evaluate the surgical options for his diabetic patients, there were few alternatives. Dr. McKittrick later became one of the pioneers of the transmetatarsal amputation, which, at that time, was referred to as the “diabetic operation.”1 It would be another 25 years before the advent of the femoral to popliteal arterial bypass, and some of the other vascular limb salvage procedures that would decrease the incidence of lower extremity amputations in the diabetic population.
The team approach has changed our overall methodology of salvaging the diabetic foot as compared to methods that were used 50 years ago. The team of vascular surgeons, podiatrists, orthopedists, wound care nurses and plastic surgery professionals have raised the success rate in terms of managing the complicated diabetic foot. However, in spite of all of the new technologies and heightened awareness, the incidence of diabetic limb amputation has continued to rise precipitously.
Despite great strides by the Health and Human Services (Healthy People 2010) to reduce lower-extremity amputations by 40 percent by the year 2010, nationwide statistics indicate that the incidence and prevalence of amputations has actually increased.
Many variables complicate the task of diabetic limb salvage. Clearly, in the face of foot infection, eradicating the infection should be the first and foremost step in controlling morbidity and mortality in the diabetic patient. Furthermore, assessing vascular disease (macro, micro functional), determining the level of tissue viability and identifying the problem wound will ultimately determine the prognosis for healing.
With these considerations in mind, here are some essential pearls for preoperative planning.
Preoperative Planning Essentials
1. Where is the patient along the risk spectrum for vascular disease? A history of clinical co-morbidities may indicate the level of macro- and microvascular disease and microcirculatory dysfunction. These are ultimate indicators of whether the patient has adequate blood flow for healing. A history of coronary artery disease (CAD) and cerebral vascular accidents (CVA) may indicate the presence of macrovascular disease. Be aware that neuropathy, retinopathy and nephropathy may indicate the presence of microvascular disease. Your patient may have microcirculatory dysfunction if there’s a history of gastroparesis, impotence or orthostatic hypotension.
2. Where is the patient along the spectrum of diabetes? The terrible triad (diabetes mellitus, hypertension and hyperlipidemia) often occurs in concert with mid-stage diabetes and vascular disease. Early signs of type II diabetes may include obesity, glucose intolerance and insulin resistance.
3. Identifying a family history of diabetes may help predict potential outcomes of limb salvage, based upon the patient’s genetic predisposition to associated co-morbidities which often complicate healing.
4. You should do a prompt incision and drain the infection before you initiate any revascularization procedure. Keep in mind that morbidity and mortality are dramatically reduced when you eliminate the infection, even in the presence of ischemia.
5. In your clinical vascular exam, evaluate for the presence of arterial pulses from abdominal aorta to the dorsalis pedis, digital hair, temperature gradient and atrophic skin changes. If you see clinical signs of vascular insufficiency or ischemia, you should pursue non-invasive arterial exams (arterial dopplers, segmental pressures, pulse volume recordings, toe and ankle brachial indices) and transcutaneous oxymetery. An arteriogram is indicated if limb salvage necessitates planning for a bypass.
6. Keep in mind that paradoxical palpable pulses in the clinically ischemic foot are often the result of autonomic arterial vasodilatory dysregulation. This is not an accurate indicator of pulsatile blood flow.
7. Diabetic foot infections are often associated with polymicrobial organisms. You should institute broad spectrum antibiotic treatment until culture-specific organisms are available.
8. Consent for amputations should include levels beyond what is clinically suspected. Common delays in patient presentation allow the infection to grow worse, causing more tissue destruction.
9. It has been shown that educating the patient on diabetes and foot maintanence reduces the number of limb-threatening events.
10. Carefully evaluate the immune and nutritional status (i.e. serum albumin over 3.5 gm/dL, and a total lymphocyte count of less than 1,500 cells per cubic millimeter) of the patient before surgery.
11. When your patient has ischemia without infection, you should pursue angiographic studies before proceeding with surgical intervention. When you are dealing with ischemia with localized infection (i.e. local cellulitis with no drainage), treat the patient with intravenous antibiotics first. Then follow up with a vascular consult and subsequent surgical intervention.
Each clinical case is unique and requires individual assessment and treatment. The following case summaries identify key principles in diabetic limb salvage. Since diabetes affects many organ systems, the foot should not be evaluated in a vacuum. The current literature suggests that a multidisciplinary approach is important in successful care and overall management of the diabetic patient.
Case Study #1: Assessing The Roles Of HBO, Sub-Total Calcanectomy And Apligraf
A 75-year-old Hispanic male with a six-year history of diabetes presented with an infected ulceration on his right heel. The two-month old ulceration was caused by a thermal burn, sustained from the patient’s prolonged use of an electrical blanket to his neuropathic feet.

Since the initial ulceration, the patient had undergone local wound care with hyperbaric oxygen therapy (HBO). Despite this treatment, the patient’s ulcer had progressed in size with the development of a focal area of necrosis accompanied by erythema.
The patient’s past medical history was remarkable for hypertension, diabetes, peripheral vascular disease, neuropathy and prostate cancer. His medications included Insulin, Fosinopril, Lasix, Zocor and Reglan. He was allergic to penicillin. His family history was significant for diabetes, prostate cancer and hyperlipidemia. Both his mother and father had diabetes while his brother and sister underwent amputations.
Upon doing a clinical examination, we found palpable femoral and popliteal pulses bilaterally with non-palpable pedal pulses. The patient had a dry blackened eschar with surrounding cellulites at the posterior right heel. He had no protective threshold.
After resolving the cellulitis with intravenous antibiotic therapy, we ordered an arteriogram. It revealed that the patient had significant disease at the trifurcation with severe occlusion of the dorsalis pedis and the peroneal artery. We subsequently performed a popliteal to distal posterior tibial arterial bypass.
Following the bypass, we did a sub-total calcanectomy (including resection of the Achilles tendon) to help close the patient’s wound. (See “What Research Reveals About Sub-Total Calcanectomies.”) Post-operatively, the wound dehisced from the central aspect under the most tension.
Evaluating Post-Op Concerns
And The Eventual Results
The patient resumed HBO with local wound care for approximately 11 weeks before subsequently developing a granular base at the posterior plantar right heel. We applied Apligraf to help close the wound. After complete wound closure, we gave the patient an ankle foot orthosis (AFO) in order to prevent a potential equinus deformity from developing after the partial calcanectomy.
From a foot salvage perspective, there were concerns over whether the wound would close with an aggressive partial calcanectomy after an arterial bypass. This did prove to be a problem since the wound dehisced in the central aspect. We also wondered if the patient could maintain foot function with the loss of the Achilles tendon. Revascularizing the foot was clinically successful in supporting post-op healing. However, it was necessary for us to employ adjunctive modalities in order to facilitate final closure of the defect. The patient was able to maintain foot function with an AFO.
Although the benefits of Apligraf have been well described in the literature, little has been written about applying Apligraf in post-surgical wounds. In this case, the patient responded well with the combination of both Apligraf and HBO therapy.
Case Study #2: Treating Charcot Deformities
A 56-year-old Hispanic female who has a 25-year history of diabetes came in with a chief complaint of a painful left plantar prominence. She had a one-year history of Charcot neuroarthropathy deformity with a resulting rigid collapsed Lisfranc joint deformity.
She also had a history of a plantar cuboid ulceration, which we were able to heal with a total contact cast (TCC). The patient proceeded to wear prescription extra-depth shoes with custom-molded inlays. Seven months later, she developed sharp and throbbing pain to the midfoot and cuboid area, which limited her activity. She also complained of instability and used a wheelchair for mobility.
The patient’s past medical history was significant for Charcot osteoarthropathy in the left foot of two years’ duration, hypertension and hyperlipidemia. Her medications included Monopril, Synthroid, Insulin 70/30, Metformin and Pravachol.
Upon doing the clinical exam, we noted palpable dorsalis pedis and nonpalpable posterior tibial vessels bilaterally. Protective sensation was absent. We also noted a rocker-bottom type deformity left foot with pain, crepitus and instability with range of motion at the midtarsal joint.
When Surgical Complications Occur
We performed a Lisfranc’s arthrodesis to address the instability, deformity and pain. Postoperatively, the patient came into the emergency room with a painful hematoma dorsally over the incision sites. After evacuating the hematoma, we saw that a full thickness necrosis had developed over the dorsal foot. The dorsal wound had failed to heal, necessitating local wound care and adjunctive HBO therapy. Despite this treatment, the wound remained recalcitrant, exposing dorsal tendons and bone. We proceeded to perform an open TMA for foot salvage.
Postoperatively, the plantar flap became progressively cyanotic and dusky in appearance. We consulted vascular surgery and obtained an arteriogram, which revealed significant occlusion of the proximal posterior tibial artery with patent anterior tibial and peroneal arteries. An anterior tibial to peroneal arterial bypass was performed.
The plantar flap failed so surgeons performed subsequent debridement, leaving a large defect. We consulted plastic surgery for coverage. The decision was made to employ a split thickness skin graft (STSG) and it resulted in uneventful healing. In the
post-operative follow-up, we emphasized using extra depth shoes and an ankle foot orthosis (AFO).
One year later, the patient developed an equinovarus deformity of the TMA with an ulcer submetatarsal 4th and 5th, requiring us to release the anterior tibialis tendon by excising the 5th metatarsal base and performing an exostectomy of the 4th metatarsal. In addition, we performed a percutaneous tendoachilles lengthening to alleviate forefoot pressures. The patient’s ulceration healed and is now being successfully offloaded in a custom molded shoe with an accommodative insole.
What You Can Learn
From This Particular Case
Why did this procedure fail initially? The Charcot foot is often associated with warmth, swelling and the presence of a bounding pulse. Clinically, the foot appears to be well perfused. However, you shouldn’t consider paradoxical palpable pulses in the Charcot foot a measure of pulsatile blood flow. Patients who have long-standing diabetes and autonomic neuropathy may have palpable pulses and good capillary return, but as a result of microcirculatory dysfunction.
Longstanding diabetes, hypertension and hyperlipidemia have been linked with vascular disease. Performing a non-invasive arterial examination enables you to assess the quality of quanitative arterial flow required for healing. Although the patient fulfilled the criteria for surgical intervention (instability, pain, preulcerative bony prominences), recognizing the level of micro- and macrovascular disease would have helped to characterize the patient’s healing prognosis.
Arthrodesis Vs. Exostectomy:
Which Procedure Gives You Better Results?
In the early literature, researchers reported poor outcomes in using the arthrodesis procedure in the neuropathic foot. Ryerson et. al., cautioned against arthodeisis in this patient population, calling any such surgery a “folly.”5 However, recent studies have been more favorable.
Stone and Daniels performed three Lisfranc and seven hindfoot arthodesis procedures for Charcot arthropathy over a three-year period.6 They maintained postoperative correction after 12 to 37 months, achieving limb salvage in nine of the 10 patients. One failure was related to nonunion and progressive deformity and reulceration.
Bono et. al., reported a 91 percent success rate with 11 arthrodesis procedures in neuropathic patients.7 Papa et. al., reported a 66 percent fusion rate in 29 patients after performing arthrodesis procedures.8 They were able to achieve foot salvage 93 percent of the time.
Although many recent studies have demonstrated successful outcome measures in using the arthrodesis procedure to restore stability and function in deformed Charcot feet, other studies demonstrate that complication rates can be high.
Early and Hansen reviewed 18 patients (21 feet), who underwent surgical reconstruction for midfoot collapse due to Charcot.9 The surgeons had performed open reduction internal fixation and were able to achieve limb salvage in 18 of 21 feet three to nine months postoperatively. However, keep in mind that 50 percent of the patients who presented with an ulcer had postoperative problems.
Catanzariti and Mendicino reviewed 27 procedures in which physicians performed an exostectomy for chronic ulceration in the midfoot secondary to bony prominence from Charcot deformities.10 The physicians were able to achieve a 74 percent healing rate for 18 medial and nine lateral ulcerations. However, revisional surgery was required in five of the nine lateral ulcerations.
Overall, the authors reported that performing an ostectomy for medial column prominences was a viable option for foot salvage, but lateral column ostectomies were less predictable.
Brodsky and Rouse reviewed 12 patients that underwent exostectomy for midfoot collapse.11 Eleven of the 12 patients healed with no subsequent breakdown or new exostosis formation. Myerson reported successful outcomes in eight of 12 patients who underwent plantar midfoot ostectomy on a 23-month follow-up.12
Be Aware Of These Key Considerations
For Treating The Charcot Foot
When deciding between an exostectomy and an arthrodesis for the Charcot foot, keep these important points in mind.
• Reserve realignment arthrodesis for clinical situations when significant instability of the midfoot with associated ulceration fails conservative offloading modalities and any other exostectomy procedures.
• Arthrodesis of neuropathic joints are associated with a high rate of complication so reserve arthrodesis as your last option for treatment. Failed arthrodesis for a Charcot joint will likely result in amputation. The forces that caused the initial destruction of the normal bone and joint structures still exist to cause the breakdown of the surgical result.
• Consensus in the literature supports surgical intervention after the acute phase of Charcot. During the acute stage, osteopenic bone serves as a poor conduit for internal fixation. Furthermore, using external fixation has shown satisfactory results in restabilizing rearfoot Charcot, even in the edematous and demineralizing stages.
• The goal of the arthodesis procedure is to realign the foot on the leg, even if the stable fibrous ankylosis is the final result.
• With an open wound that probes to bone, you should rule out osteomyelitis via a biopsy or other diagnostic studies before considering exostectomy or arthrodesis procedures.
• When performing an exostectomy, make sure you perform adequate resection to prevent reoccurrence. However, don’t be too aggressive as this can cause instability.
• Make sure you give the patient the appropriate post-op accommodative shoe or offloading device in order to protect the surgical correction.
In a review of 114 patients that presented with acute Charot, Fabrin et. al., demonstrated that conservative care (i.e. TCCs, crutches, therapeutic protective shoes) is adequate in most cases.13 They found that major surgical correction was only required in less than 5 percent of the cases.
Final Notes
Without question, limb salvage in the diabetic patient can be quite a challenge. Diabetes is responsible for approximately 50 percent of all non-traumatic amputations in the United States. Researchers estimate that a second amputation will be required in more than 55 percent of these patients within five years.14 Thirty percent of patients will die within the first three years after an amputation while 60 percent will die within the first five years after amputation.15
In a recent article, Van Damme et. al., reported that diabetic patients with poor ambulatory recovery undergo a major amputation.16 In their study of 146 diabetic patients that received an amputation, only 63 percent achieved independent walking capability with their limb prosthesis.
There are clear indications for performing a lower extremity amputation. Many times, one definitive procedure is needed for a patient to achieve independent functionality. However, as physicians and specialists of the lower extremity, our ultimate goal should be to maximize the patient’s potential for limb salvage and achieve the optimal long-term functional outcome. n

Dr. Harkless is the Louis T. Bogy Professor of Podiatric Medicine and Surgery within the Department of Orthopaedics and Podiatry at the University of Texas Health Science Center in San Antonio, Texas. Dr. Moore is an Assistant Instructor and Diabetic Foot Fellow within the aforementioned department. Dr. Liu is the Chief Resident within the aforementioned department.

References:

References

1. Joslin E.P., The menance of diabetic gangrene. N Engl J Med. 211(16) 1934.

2. Crandall R.C., Wagner R.W. Jr., Partial and total calcanectomy; a review of thirty-one consecutive cases over a ten year period. J Bone Joint Surg. Am. 63 (152), 1981.

3. Smith J.W., Jacobs, R.L., Fuchs M.D., Salvage of the Diabetic foot with exposed Os Calcis- Clinical Orthopedics and related research 1993, 296, pg 71.

4. Baravarian B., Menendez M.M., Weinheimer D.J., Lowery C., Kosanovich R. Vidt L, Subtotal calcanectomy for the treatment of large heel ulceration and calcaneal osteomyelitis in the diabetic patient. J Foot Ankle Surg. 1999 May-Jun;38(3):194-202.

5. Ryerson E.W. et al, The classic. Arthrodesing operations on the feet: Edwin W. Ryerson M. D. Clin Orthop. 1977 Jan-Feb;(122):4-9.

6. Stone N.C., Daniels, T.R., Midfoot and hindfoot arthrodesis in diabetic charcot arthropathy, Canadian Journal of Surgery, 2000 Dec 43(6)449.

7. Bono, J.V., Roger, D.J., Jacobs, R.L. Surgical arthrodesis of the neuropathic foot. Clin. Orthop. 296: 14-20, 1993.

8. Papa J., Myerson M., Girard P., Salvage, with arthrodesis, in intractable diabetic neuropathic arthropathy of the foot and ankle. J Bone Joint Surg Am. 1993 Jul;75(7):1056-66.

9. Early J.S., Hansen, S.T., Surgical reconstruction of the diabetic foot: A salvage approach for midfoot collapse. Foot and Ankle International 1996 June 17(6) 325.

10. Catanzariti A.R., Mendicino R., Haverstock B., Ostectomy for Diabetic Neuroarthropathy Involving the Midfoot Journal of Foot and Ankle Surgery 2000, Sept/Oct 39(5) 291.

11. Brodsky J.W., Rouse A.M., Exostectomy for symptomatic bony prominences in diabetic charcot feet. Clin Orthop. 1993 Nov;(296):21-6.

12. Myerson M.S., Henderson M.R., Saxby T., Short, K.W., Management of Midfoot Diabetic Neuroarthropathy: Foot Ankle Int 1994 May;15(5):233-41.

13. Fabrin, Jesper MD; Larsen, Kirsten; Holstein, Per E. MD, DRMEDSC, Long-Term Follow-Up in Diabetic Charcot Feet With Spontaneous Onset. Diabetes Care June 2000 23(6) 796.

14. Banks A.S, McGlammary E.D. Charcot foot. JAPMA 1989 (79)213.

15. Duggar G.E., Deandrade J.R. Griggs, O., Time-line for the diabetic foot. Reconstructive Surgery of the Foot and Leg, Update 1988 ed. By E.D. McGlammary, Podiatry Institute Publishing Co. Tucker, GA 1988.

16. Van Damme H., Rorive M., Martens De Noorhout B.M., Quaniers J., Scheen A., Limet R., Amputations in diabetic patients: a plea for footsparing surgery. Acta Chir Belg 2001, May/June 101(3) 123.