When Patients With Diabetes May Benefit From Below-Knee Amputation

Below-knee amputation. To see it in print conjures up images of failure. When we see it written in the OR schedule, we often ask ourselves, “What happened?” Was it a bypass that failed, a Charcot reconstruction that got infected or a heel ulcer in a patient with end-stage renal disease?

Numerous publications and thought leaders have described the continued challenge and struggle to reduce the amputation rate, citing global studies saying that we have failed to achieve this goal. The implication of all of these studies is that the incidence of limb loss due to diabetes should be zero.

The recent literature has signaled a change in perception. Surgeons are beginning to acknowledge that there is a small subset of patients who may actually benefit from early intervention such as a below-knee amputation. Certainly, much of the goals of diabetic limb salvage should be to avoid major amputation but should there also be a time when the patient and/or the doctor can choose to opt out of limb salvage and be better off for it?

A Closer Look At The Research On Diabetic Amputation

Lower extremity amputations are a serious process and do not come without risks. Aulivola and colleagues reported that the 30-day mortality rate following a major lower extremity amputation was 8.6 percent.¹ Specifically, the rate was 16.5 percent for above-knee amputations (AKAs) and 5.7 percent for below-knee amputations (BKAs). These same authors showed an overall survival rate after a major lower extremity amputation of 69.7 percent and 34.7 percent at one and five years respectively. One- and five-year survival rates were significantly worse for AKAs (50.6 percent and 22.5 percent) than BKAs (74.5 percent and 37.8 percent). Survival rates in patients with diabetes and end-stage renal disease were noticeably worse.

Ploeg and colleagues found a long-term survival rate of 62 percent at one year, 50 percent at two years and 29 percent at five years for patients with BKAs.²

Evans and colleagues pointed out the fact that limb salvage is “complex, controversial, costly and variable throughout the world.”³ Limb salvage aims at preventing debilitating situations from occurring by removing infected bone, closing difficult wounds and correcting underlying structural deformities. Their paper showed that one should consider aggressive efforts at limb salvage with proximal forefoot or midfoot amputations prior to higher-level amputations due to the morbidity and mortality that occur with the higher-level amputations.

Therein lies the underlying question: Is limb salvage at any cost or at all costs always justifiable?

Gil and coworkers looked at the cost comparison between limb salvage and amputation in diabetic patients with Charcot foot.⁴ While it is apparent that the Charcot foot complicated by osteomyelitis is a challenge, the best efforts of the surgeon may still result in continued osteomyelitis. If the patient develops continued osteomyelitis, one should not consider all to be hopeless.

Wukich and Pearson looked at self-reported outcomes of transtibial amputations for non-renconstructable Charcot neuroarthropathy in patients with diabetes.⁵ Their data showed that there might be a downward trend in major amputations in patients with diabetes although there is still a subset of patients who ultimately require major lower extremity amputations. While the outcomes were on the whole favorable, 12 of the 13 patients they surveyed were satisfied with the amputation and had no reservations.

In looking at amputation and ambulation in patients with diabetes, Attinger and Brown noted that limb salvage and BKA led to similar ambulatory rates but the two-year survival rate in the BKA group was markedly lower (52 percent versus 80 percent).⁶ Patients with more severe rearfoot ulcers and those with ulcers complicated by osteomyelitis had an ambulatory rate that declined according to the number of comorbidities patients had. Their conclusion was that function and quality of life are the outcomes of interest, and one may maximize them with either limb salvage or amputation.

Boutoille and coworkers compared the quality of life of patients with diabetes with chronic foot ulcerations to those undergoing a lower-limb amputation.⁷ They found that often it is patients with ulcers, not those with toe or transmetatarsal amputations, who have more physical limitations and pain. In a series of focus groups, Brod found that the quality of life for both the caregivers and partners of the patients are affected by the lack of mobility, stress and strain of everyday living.⁸  

Emphasizing The Importance Of Addressing Infection, Ischemia And The Inability To Offload

At our institution, when discussing limb salvage with patients, we often use the expression of the three I’s: infection, ischemia and inability to offload. If you are not successful in these concepts, a limb salvage attempt will fail more often than not. Patients often overlook the importance of function, albeit rightfully so. At our institution, many patients refuse to undergo an amputation regardless of what is in their best interest. It is our job as physicians to match the correct solution to the patients’ lifestyle in order to provide individuals with the best chance to achieve their desired level of activity as quickly as possible.

That is not to say patients do not warrant an attempt at limb salvage. There are many situations in which we offer a patient a major amputation and with a more aggressive approach to wound care, surgical reconstruction or revascularization, we can achieve the goal of limb salvage. One must outline the potential risks and benefits to the patient beforehand along with the real likelihood of success.

In summary, there are many instances in which patients can avoid major amputation. There are, however, circumstances in which limb salvage is neither probable nor practical. In those cases, rather than undertaking a treatment plan that is doomed to fail, not to speak of the added expense and physical toll it may take on the patient, the decision to undergo (or recommend) a major amputation sooner rather than later may be in the best interests of the patient as well as the healthcare provider.

Dr. Rosenblum is an Assistant Clinical Professor of Surgery at Harvard Medical School and the Associate Chief of the Division of Podiatric Surgery at Beth Israel Deaconess Medical Center in Boston.

Dr. Braunagel is a Clinical Fellow in Surgery at Harvard Medical School and a second-year podiatry resident at Beth Israel Deaconess Medical Center in Boston.

References
1. Aulivola B, Hile CN, Hamdan AD, et al. Major lower extremity amputation: outcome of a modern series. Arch Surg. 2004;139(4):395-399.
2. Ploeg AJ, Lardenoye JW, Vrancken Peeters MP, Breslau PJ. Contemporary series of morbidity and mortality after lower limb amputation. Eur J Vasc Endovasc Surg. 2005;29(6):633-7.
3. Evans KK, Attinger CE, Al-Attar A, et al. The importance of limb preservation in the diabetic population. J Diabetes Complications. 2011;25(4):227-31.
4. Gil J, Schiff AP, Pinzur MS. Cost comparison: limb salvage versus amputation in diabetic patients with charcot foot. Foot Ankle Int. 2013;34(8):1097-9.
5. Wukich DK, Pearson KT. Self-reported outcomes of trans-tibial amputations for non-reconstructable Charcot neuroarthropathy in patients with diabetes: a preliminary report. Diabet Med. 2013;30(3):e87-90.
6. Attinger CE, Brown BJ. Amputation and ambulation in diabetic patients: Function is the goal. Diabetes Metab Res Rev. 2012;28 (Suppl 1):93-6.
7. Boutoille D, Feraille A, Maulaz D, Krempf M. Quality of life with diabetes-associated foot complications: comparison between lower-limb amputation and chronic foot ulceration. Foot Ankle Int. 2008;29(11):1074-8.
8. Brod M. Quality of life issues in patients with diabetes and lower extremity ulcers: patients and their care givers. Qual Life Res. 1998;7(4):365-72.

Additional References
9. Pinzur MS, Gil J, Belmares J. Treatment of osteomyelitis in charcot foot with single-stage resection of infection, correction of deformity, and maintenance with ring fixation. Foot Ankle Int. 2012;33(12):1069-74.
10. Paola LD, Brocco E, Ceccacci T, et al. Limb salvage in Charcot foot and ankle osteomyelitis: combined use single stage/double stage of arthrodesis and external fixation. Foot Ankle Int. 2009;30(11):1065-70.
11. Wukich DK, Hobizal KB, Brooks MM. Severity of diabetic foot infection and rate of limb salvage. Foot Ankle Int. 2013;34(3):351-8.

Editor’s note: For further reading, see “Point-Counterpoint: Is An Initial TMA Better Than A Partial Ray Amputation in Patients With Diabetic Neuropathy?” in the June 2014 issue of Podiatry Today, “Understanding The Biomechanics Of The Transmetatarsal Amputation” in the March 2013 issue, “A Guide To Digital Amputations In Patients With Diabetes” in the September 2011 issue or the December 2011 online-exclusive case study “Closing A Chronic DFU At A TMA Site.”