Limb Salvage or Amputation of the Diabetic Foot?

The decision often hinges on how a given inter­vention will affect the patient’s quality of life. How, then, to define optimal QoL for your patient, and to agree on the means to achieve it?

By Cary Groner

As clinicians well know, diabetes puts patients at risk of foot ulcers that can lead to poor outcomes, evidenced by the 40% 5-year mortality in patients with newly diagnosed diabetic foot ulcers (DFUs).¹ As many as 25% of patients with diabetes will develop a diabetic foot ulcer, of which at least one quarter do not heal, putting patients at risk of amputation.²

Amputation necessitated by nonhealing ulcers from diabetic neuropathy or peripheral vascular disease has typically involved the loss of part of the foot or part of the leg; in recent years, however, clinicians have developed options that, in the best of cases, minimize the loss of structural parts. Surgeons may attempt to salvage as much of the limb as possible, and can choose such amputation levels as toe, transmetatarsal, or a more proximal partial-foot amputation such as the Chopart’s or Syme’s amputation. Severe infection often requires transtibial amputation (TTA).

Since 2000, the number of TTAs has declined as partial foot amputations (PFAs) have increased.³ The apparent advantages of PFA, compared with TTA, include improved mobility and quality of life (QoL) as well as lower mortality—although the higher mortality reported in patients with TTA may be associated with underlying disease rather than the procedure itself.^4,5

Increasingly, however, disadvantages associated with PFAs have come in to focus for clinicians, including a significant rate of failure due to complications such as dehiscence and re-ulceration, as well as the resulting secondary (and more proximal) surgeries these problems necessitate. Even a first-ray amputation affects gait and QoL,⁶ and studies have reported that approximately one third of patients with a PFA require revision surgery, compared with 10% of those who underwent TTA.^7,8 An ipsilateral reamputation rate as high as 60% 5 years from the original surgery has been reported in patients with PFA.⁹

In light of these findings, clinicians face a complex array of variables to consider when choosing between limb salvage and a more proximal amputation such as TTA, including patient preference, which might not align with the practitioner’s clinical judgment. Illustrating this point is a 2017 report that 94% of patients who underwent a series of PFAs would prefer those salvage procedures again rather than undergo TTA.¹⁰ The decision often hinges on how a given intervention will affect the patient’s QoL. The questions about how to proceed then shift to: How does the patient define optimal QoL? And how can physician and patient agree on the means to achieve that goal?

Function, function, function

“Mobility is what counts,” said Jonathan Labovitz, DPM, medical director of the Foot & Ankle Center at Western University of Health Sciences, Pomona, California (see page 9). When deciding on a below-knee amputation and attempting limb salvage, he looks for middle ground that is defined by how functional the patient is likely to be. It might be acceptable in some situations for the patient to undergo multiple limb-salvage procedures, noted Labovitz, “but you have to think about not just getting the limb closed, but getting it closed and functional.”

Function has not only physical but psychosocial implications. Patients who lose ambulatory capability can become more dependent on friends and family. “They feel like a burden, and no one wants that,” he said. “In deciding whether to amputate or salvage, it always comes back to function, so that [the patient is] as independent as possible. If you can’t give them that independence with limb salvage, then you may need to take more off, because they’ll do better with a higher-level amputation and a prosthesis. We know they have a shortened lifespan, so let’s give them the best life we can.”

Of course, the level of amputation affects function. For example, loss of metatarsophalangeal joints, as in a transmetatarsal or higher procedure, profoundly affects gait.¹¹ These patients give up significant plantar flexor power at the ankle and also lose plantar weight-bearing surface, pronation and supination during gait, and active push-off.

Michael Pinzur, MD, professor of orthopedic surgery and rehabilitation at Loyola University Medical Center, Maywood, Illinois, added that decisions about limb salvage should include the answers to 4 essential questions—

1. Will limb salvage outperform amputation and a prosthetic limb?
2. What is a realistic expectation regarding results for each option?
3. What are the costs to the patient, financially and otherwise, of multiple procedures and time away from work?
4. What are the risks?

The goal of treatment, Pinzur noted, is not limb retention but optimization of the patient’s ability to function. And because QoL is subjective, a patient may consider his own QoL to be greater than does a patient with the same or even better function, simply because he can still perform the activities that are important to his happiness and independence.

Hard choices

Dane Wukich, MD, the Dr. Charles F. Gregory Distinguished Chair in Orthopaedic Surgery at the University of Texas Southwestern Medical Center in Dallas, told LER that several variables influence his decision to abandon attempts at limb salvage–

• Presence of severe life-threatening infection
• Presence of a deformity that cannot be reconstructed
• Inability to restore good circulation to the limb

Wukich is mindful of his own research that found that patients with foot ulcers fear major lower-extremity amputation more than they fear death.¹² “If a patient is frightened of losing their leg, and they spend 18 months trying to save it, amputation is a big, big decision for them,” he said. “One way we can help with that is to have them meet preoperatively with the physical medicine and rehabilitation doctors so they can talk about what it’s going to be like afterward.”

To better understand their situation, patients may also meet with a physical therapist or occupational therapist, a prosthetist, and even other patients who have undergone the same procedure.

Wukich noted that patients who have delayed amputation often admit months later that they would have done it sooner had they known what it would be like. “I look at an amputation as the first step in rehabilitation, rather than as a treatment failure,” he said.

Wukich agrees with Labovitz and Pinzur: Mobility and function strongly influence patient perceptions of their QoL. “The key is to get patients up and moving,” said Wukich. Those who ambulate are more likely to improve their QoL, even using a prosthesis.

How best to assess QoL in patients?

Wukich primarily uses the Short Form Health Survey 36 (SF-36) and the streamlined SF-12. “Those are validated instruments across many, many areas of health,” Wukich said. “They’re generic, so we also use the Foot and Ankle Ability Measure, which gives us further information about how patients are doing in terms of physical and mental quality of life.”

In March this year, Wukich and co-author Katherine Raspovic, DPM, examined a number of QoL measures in patients with diabetic foot disease, through patient-reported outcomes.¹³ No single measure is currently considered a gold standard but, taken together, they provide important—if often complex—information about aspects of diabetic foot disease and its effects on health-related QoL.

For example, it appears that foot disease can affect diabetes patients’ physical QoL more so than mental QoL, particularly in Charcot neuroarthropathy.^14,15 Wukich and Raspovic also cite research demonstrating that:

• mental QoL is higher in patients with healing foot ulcers compared with patients who had nonhealing DFUs¹⁶
• patients with unhealed ulcers reported more pain and physical limitations than those with minor amputations¹⁷
• 2-year survival was greater in patients with amputation preserving the ankle compared with patients who had undergone TTA (80% and 48%, respectively).¹⁸

Additional studies reported improved physical and mental QoL following TTA, including lower-extremity function and mobility, particularly among those who ambulated.¹³

Overall, the authors concluded that in select patients—generally those with better cardiovascular status—amputation can improve self-reported QoL when it leads to better physical function.

Wukich and Raspovic also addressed the apparently lower impact on mental QoL, which has perplexed many researchers and clinicians. It might be that foot ulcers cause less-than-expected emotional distress because the associated neuropathy can diminish the sensation of pain. It may also be that SF-36 fails to adequately capture emotional distress in these patients.

Importantly, research has consistently shown that patients with diabetes have roughly double the risk of both clinical depression and elevated depressive symptoms compared with the general population.¹⁹ Furthermore, diabetic neuropathy has been shown to impair both physical and emotional function,²⁰ and research has begun to delineate important connections between neuropathy and psychosocial outcomes, including depression, anxiety, and how well patients manage their risk of DFU.²¹

When the best choice is not obvious

Because diabetes, neuropathy, peripheral vascular disease, and their sequelae affect so many aspects of a patient’s life, clinicians have developed team treatment approaches that strive to address, under 1 roof, most patient challenges. A recent systematic review of papers looking at multidisciplinary limb salvage teams reported that amputation severity was reduced, mortality in the postsurgical period was lower, and length of hospital stay was shorter when patients received multidisciplinary team care²²; another study found that multidisciplinary limb salvage teams effectively healed wounds, maintained ambulatory status in patients with limb-threatening wounds, and helped minimize readmission.²³

David Armstrong, MD, PhD, DPM, director of the Southwestern Academic Limb Salvage Alliance (SALSA) at the Keck School of Medicine at the University of Southern California, told LER that the team’s preference is for limb salvage to the greatest extent possible. The approach, summarized as “toe and flow,” involves clinicians from both podiatry and vascular surgery.

“We think that, in most patients, less is more; that is, a more distal amputation is preferable to a more proximal one,” Armstrong told LER. “That said, there are times when function may be better with a more proximal procedure such as a below-knee amputation. That tends to be true in younger patients with significant tissue loss and a lot of reconstructive surgery ahead of them,” in which 1 good-quality amputation could result in a higher QoL.

Older patients with other problems, such as cardiovascular or cerebrovascular complications, who may have reduced potential for rehabilitation, may benefit more from limb-sparing procedures. Armstrong indicated that, in such patients, a good-quality midfoot amputation can yield a higher QoL. Although he acknowledged that some clinicians prefer to proceed to a higher-level amputation such as a TTA rather than subject a patient to repeated procedures in an attempt to save the limb, Armstrong doesn’t always agree.

“The best choice for a given patient isn’t always obvious,” he said. “The longer I work as a surgeon, the more I realize that thinking I can really fix anyone is the height of hubris. What I can do is help folks move through their world a little better. Sometimes that means performing multiple procedures, but most of the time it doesn’t. So, while I respect the argument that you don’t want to just keep operating on these patients, if you really extend that logic out, it means eliminating most vascular surgeries and most orthopedic surgeries, because the longer you follow these patients, the more certain you become that what you’ve done will fail.”

Armstrong agrees with his colleagues that function is a valuable measure of success, and that mobility is the key to QoL: that is, how well they can do what they care about doing.

“Ultimately, it’s the job of the team to figure out what that is,” said Armstrong, “and help the patient get back to doing it.”

The team approach to optimizing QoL

At the University of California–San Francisco Center for Limb Preservation, co-director Alexander Reyzelman, DPM, works with the medical center’s chief of vascular and endovascular surgery, Michael S. Conte, MD, to achieve optimal limb-salvage outcomes. “You can’t save the leg with vascular, or orthopedics, or podiatry alone,” Reyzelman said. “It has to be a team approach, so we see the patients together and assess whether they need revascularization, or a foot procedure, or both—and if they need both, which should come first.” Time is tissue, he said.

Reyzelman and his team use the Wound, Ischemia, and Foot Infection (WIfI) Scale²⁴ to assess the status of diabetic foot wounds. Though not a QoL measure, the classification system was developed by the Society for Vascular Surgery. It has been shown to predict several outcomes including length of hospital stay and freedom from amputation.^25-27 The classification system assesses the risk of losing the leg. “If the risk is high, that doesn’t mean we won’t try to save the leg; it just may mean multiple procedures over many months, and the patient needs to know that, because it will significantly affect their quality of life,” he said.

Reyzelman’s concept of QoL includes considerations of the patient’s age, cultural background, support from family and friends, and personal goals. “It’s important to discuss those goals, concerns, and desires,” he said, noting that a patient in the 7th or 8th decade of life who is less active and has comorbidities may have trouble rehabilitating a below-knee amputation, whereas a patient in the 5th or 6th decade of life who is functioning well might feel that a below-knee amputation is more appropriate. Some patients, regardless of age or function, want to save their foot at all cost. “It’s a complicated decision process and a difficult discussion for doctors to have with their patients because it’s like life and death—except it’s limb death,” he said.

Reyzelman does his best to meet with the patient and family members to help them understand that they are part of the process, and can continue the deliberations outside the doctor’s office.

“We have an honest discussion about the pros and cons of partial foot amputation versus below-the-knee,” Reyzelman continued. A PFA may require more than 1 procedure, long-term antibiotics, and rehabilitation at a skilled nursing facility, requiring patient and family understanding that the process will take months, not weeks. They also need to understand that below-the-knee amputation is not the end of the world, because advances in rehabilitation and prosthetics have improved the process of returning to function.

Jonathan Labovitz said that, for such reasons, he considers it important to include either a psychologist or a psychiatrist on the treatment team when possible, to address those factors of getting at what the patient wants.

Key to the conversation

Australian and US researchers are collaborating to develop resources for such shared decision-making. The researchers note several important facets of any such decision, including psychosocial implications and conversations about mortality.²⁸ Michael Dillon, PhD, BPO (Hons), associate professor at the National Centre for Prosthetics and Orthotics at La Trobe University, Melbourne, Australia, told LER that including the 5-year risk of death in the conversation often affects the patient’s decision.

“If you have a significant risk of dying within 5 years, how do you want to spend that time?” he asked. “Shared decision-making provides an opportunity to support patients in the complexities of the choices they have to make. I’m OK with whatever they decide, as long as they have the information to make that choice.”

Cary Groner is a freelance writer in the San Francisco, California, Bay Area.