Offloading devices are the first line of defense in healing and preventing diabetic foot ulcers. But when ulceration-prone areas of the foot are associated with anatomical deformities or biomechanical impairments, surgery may be a more effective option.
by Cary Groner
Patients with recalcitrant or repeated diabetic foot ulcers present special challenges if the ulcers are caused by anatomical deformities or biomechanical impairments. Solutions run the gamut from long periods of offloading in total contact casts (TCCs) to corrective surgery, and if necessary, to amputation. Few outcomes studies have compared surgery to nonoperative approaches, so practitioners rely largely on patient preferences and their own clinical experience to make treatment decisions.
“For many years, this aspect of care has been ill-defined,” said David Armstrong, DPM, MD, PhD, professor of surgery and director of the Southern Arizona Limb Salvage Alliance (SALSA) at the University of Arizona College of Medicine in Tucson. “People just say, ‘Well, I think I’m going to do surgery on this person.’ Often there are good intentions and good reasons, but there hasn’t been an overarching philosophy.”
Increasingly, however, better research and communication between practitioners are elucidating which procedures appear to be most helpful for certain conditions and patient types.
Deformities and their implications
Nonsurgical approaches such as therapeutic shoes, custom-molded insoles, and total contact casting were long considered the gold standard for conservative management of diabetic foot ulcers. The picture changes when ulceration-prone areas of the foot are associated with deformities, however. These include bony prominences on the plantar aspect of the metatarsophalangeal joints and the hallux.1 When the degree or location of the deformity makes extrinsic solutions untenable, surgery may be required to correct the deformities in order to minimize the shear and pressure forces they create.2
Research has found associations between certain deformities and ulcer locations. One study looked at three conditions—Charcot neuroarthropathy, compensated forefoot varus, and uncompensated forefoot varus or valgus—and reported that these were associated with certain pressure patterns and callus formation. Charcot led to midfoot ulceration; compensated forefoot varus was associated about half the time with ulcerations at the second, third, or fourth metatarsal heads; and about a third of patients with uncompensated varus or valgus got ulcers at the first or fifth metatarsals.3 Other research has found a relationship between foot type, deformity, and ulcer locations, as well.4
Even when extrinsic approaches heal ulcers for a while, underlying deformities increase the likelihood that ulcers will return when the cast or other offloading device is removed and the patient returns to more typical load bearing.
“Full-contact casting or orthoses are very good options for nonsurgical treatment,” said Martinus Richter, MD, PhD, a surgeon in the Department of Trauma, Orthopedics, and Foot Surgery at Coburg Clinical Center in Coburg, Germany. “With unloading, almost any ulcer can be healed. The problem is that eventually patients want to walk again, because if they don’t, their diabetes gets worse. So then the ulcer comes back, and if it is being caused by a deformity, it must be corrected with surgery.”
There is research to support this position. In a 2007 paper in Foot & Ankle International, for example, Swiss clinicians reported that total contact casting was associated with an ulcer recurrence rate of 57%, even with optimal instructions, follow-up, and unloading shoes. They performed operative corrections on patients with recurrent ulcers and underlying deformities, and concluded that because those patients stayed ulcer-free thereafter, “…foot deformities should be operatively corrected immediately after primary healing.”5
“When you first see a patient, you have to determine what’s causing the ulcer,” said Michael Pinzur, MD, professor of orthopedic surgery and rehabilitation at Loyola University Medical Center in Maywood, IL. “Is it related to a deformity? Is it neuropathic or ischemic? No amount of accommodative treatment will heal an ischemic ulcer, so you have to get a vascular surgeon involved in those cases.”
Even when adequate blood flow is present, however, patients sometimes have other problems, such as motor imbalances resulting from peripheral neuropathy, that may limit the efficacy of nonsurgical solutions, Pinzur explained.
“In those cases, you may want to do an Achilles tendon lengthening or a gastrocnemius lengthening to create muscle balance,” he said. “It’s a relatively low-risk procedure with a high probability for healing.”
Limited ankle dorsiflexion leading to forefoot plantar ulceration also benefits from Achilles lengthening, studies show. Armstrong and colleagues first described the mechanism of action in a 1999 paper in the Journal of Bone and Joint Surgery; the procedure was associated with increased ankle dorsiflexion and significantly reduced peak plantar forefoot pressures, from 86 N/cm2 to 63 N/cm2.6
In 2003, researchers at Washington University in St. Louis reported in JBJS that after two-year follow-up, 81% of patients in a TCC treatment group had ulcer recurrence, versus 38% of subjects who had Achilles tendon lengthening.7 Subsequently, a 2004 Danish study reported the surgery led to ulcer healing at 12 months in 91% of 75 feet, but noted that the procedure was not appropriate for patients with complete anesthesia of the heel pad, due to the increased risk of heel ulceration.8
Research also supports the notion that problems such as claw toes and hammertoes benefit from flexor tenotomy, which addresses the deformities and relieves the ulcer-causing pressure associated with them.9,10
Forefeet and arthroplasty
Surgery is proving effective in other forefoot conditions, as well. Armstrong and colleagues reported in 2005 that in diabetes patients with chronic ulcers, fifth metatarsal head resection led to faster healing (5.8 vs. 8.7 weeks) and lower reulceration rates (4.5% vs. 27.8%) than conservative treatment (dressing changes, offloading, and weekly debridement).1 In a similar study in Diabetes Care, Armstrong reported that in wounds of the plantar hallux, resectional arthroplasty led to significantly faster healing (24 vs. 61 days) and fewer ulcer recurrences (4.8% vs. 35%) than standard therapy.2
Caution is in order, however, before picking up the scalpel to remove bone.
“There are three types of causes I think about when I see forefoot ulcers,” said Jeffrey Johnson, MD, associate professor of orthopedic surgery and chief of the foot and ankle service at Barnes-Jewish Hospital at Washington University Medical Center in St. Louis. “Ulcers can result from an Achilles tendon contracture in an otherwise normal foot, a lesser toe deformity such as a claw toe, or a bony deformity, often from Charcot. In a claw-toe deformity, the toe dorsiflexes, which puts more pressure under the metatarsal head.”
Johnson prefers nonsurgical management initially—or, in the case of a claw toe with a toe tip ulcer, correction of the claw toe with a percutaneous FDL (flexor digitorum longus) tenotomy, performed in the office. The problem with removing a single metatarsal head, he said, is that forefoot pressure is subsequently distributed over a smaller area.
“If only four metatarsal heads are on the ground, there’s much less surface area under the ball of the foot to distribute the weight-bearing stresses, and that’s another cause of ulcers,” he said.
For Sheldon Lin, MD, associate professor in the department of orthopedics at the University of Medicine and Dentistry of New Jersey, a combination approach may bring the best outcomes in some cases. Lin published a paper describing Keller arthroplasty combined with total contact casting for ulcers under the interphalangeal joint of the great toe.11 The method was effective; all ulcers healed within 24 days.
Lin explained that the approach is appropriate for two distinct situations.
“If I have a patient whose ulcer won’t heal, but there’s no underlying bone infection, what do I do? If there’s limited range of motion, I would do the Keller arthroplasty with a total contact cast,” he said. “In the second case, he’s healed; but if he still has limited range of motion, he’s at high risk for ulcer recurrence. In that case you can do a prophylactic procedure to reduce that risk.”
Charcot deformities loom large in any discussion of surgical approaches to healing.
“Our thinking about this is evolving,” said Johnson. “Ten or fifteen years ago, nonoperative management was the gold standard for Charcot, but there are better indications and better tools now. There are several stages of Charcot, and when we’re talking about surgery we mean doing it once things have settled down, when a fracture deformity has healed and we’re dealing with a permanent fixed deformity.”
Johnson noted that certain Charcot-related problems may lend themselves to earlier intervention, including unstable ankle deformities that involve dislocation of the bones.
“We’re picking certain deformities in the early stages and saying we can do something about this now that may prevent a prolonged nonoperative course followed by deformity correction surgery later,” he said.
Bracing still has an important role, however. For one thing, it may give the patient a chance to heal before anything else is decided.
“That way, you can do your surgery through a closed, clean skin envelope, which lowers the risk of infection,” Johnson said.
In certain cases, surgery may be delayed or avoided altogether.
“If they’re not having pain, and are relatively ulcer-free, then I think that’s a successful, functional outcome,” he explained.
According to Dane Wukich, MD, associate professor of orthopedic surgery at the University of Pittsburgh School of Medicine, clinicians are reconsidering their approach to Charcot deformities as a result of other factors, too.
“I think the pendulum is swinging toward operative intervention for a number of reasons,” he said. “We’re getting more experience and better methods of fixation. We have internal fixation methods such as locking plates, and external circular fixation, and we’re addressing comorbidities such as vitamin D deficiency, which is much more likely in people with Charcot and diabetes. The bottom line is that as surgeons, we’re less willing to accept these deformities than we were in the past.”
Sheldon Lin described specific circumstances in which he favors surgery.
“If you look at the lateral view, and the cuboid subluxes 40 or 50 percent plantar in relationship to the calcaneus, or there’s a large bony exostosis there, these are patients who will benefit from a reconstructive osteotomy,” he said.
Researchers have focused a relatively high level of attention on Charcot-related problems, and as a result there’s more information available to inform practitioners’ treatment decisions.
For example, as early as 2000, clinicians reported success with arthrodesis of the tarsal-metatarsal area for Charcot arthropathy in diabetes patients, seeing no postoperative ulcerations after a mean of 41 months follow up.12 Michael Pinzur has recently described success with postsurgical neutral ring fixation, with 24 of 26 patients ulcer-free after a minimum of one year post-surgery.13,14 A 2009 paper reported treatment success using intramedullary screws for correcting midfoot collapse; three of 22 patients had recurrence of plantar ulcers at the metatarsophalangeal joint an average of 52 months after surgery.15 And in a 2010 article from Germany, researchers found that primary surgical reconstruction and reorientation arthrodesis led to healing of all eight ulcers studied (100%), without recurrence.16
“In 1993, when I wrote my first paper on the Charcot foot,17 I thought that most cases should be treated nonsurgically,” Pinzur told LER. “This year, I will probably operate on 90 to 95 percent of the Charcot patients I see.”
Part of this change, Pinzur acknowledged, has to do with selection bias; because he’s now one of the country’s authorities, he tends to see cases that others have been unable to heal. But beyond that, clinical experience and demographics play a role.
“I put a 350-pound person into a CROW [Charcot Restraint Orthotic Walker] that costs them hundreds of dollars, and then they come back and tell me they won’t wear it,” Pinzur said. “The concept of non–weightbearing doesn’t make sense to me in such patients because they’ll do that for several months and heal, but as soon as they start walking the skin breaks down again, and you’ve wasted all that time. The quality of life for these people is miserable, and it doesn’t get better with successful treatment. So how do you define success? You can salvage the limb by making the patient non–weightbearing, but then they lose their job. I always want to understand the root cause of the disorder, and then arrive at options for the individual patient.”
Frustration and preparation
Pinzur’s frustration is shared by others, but it’s clear that surgery isn’t a panacea.
“I can’t tell you how many patients have been referred to me because someone attempted a realignment procedure—with all the best intentions—that was a disaster,” said Jeff Johnson. “The alignment was not corrected, they still didn’t have a stable foot and ankle, and they may have had chronic osteomyelitis.”
That doesn’t make surgery a bad thing; it just makes bad surgery a bad thing.
“We know that patients with severe coronal plane malalignment, or with severe midfoot rocker bottom, are going to do poorly without surgery,” Johnson continued. “In those cases, nonoperative treatment may be used initially to help the patients get ready for surgery; there are also new techniques that employ early surgery, such as small wire external fixation for the ankle and hindfoot, and intramedullary metatarsal screw fixation for midfoot deformities.”
As a result of such considerations, clinicians have developed a variety of protocols to help direct treatment.
“Unfortunately, the most unhealthy people often need surgery the most,” said Dane Wukich. “I go over the risks and benefits, try to get their blood sugar and Vitamin D levels controlled. I think if you get them to optimal status, it’s much better.”
The German health system allows Martinus Richter luxuries usually unavailable to American practitioners.
“I admit them to the hospital for a couple of weeks, get their diabetes under control, then I operate,” he said. “We send them home afterward, to unload for six weeks.”
For Michael Pinzur, it’s a matter of addressing the needs of individual patients.
“I may see three patients in a row with the same diagnosis, and offer three different treatments,” he said. “You can’t treat a 22-year-old type 1 diabetic the same as you would a 60-year-old type 2 patient. It depends on what they need.”
In 2003, David Armstrong and his colleagues published a classification system to facilitate decisions about foot surgery in diabetes patients with adequate blood flow.18 Class 1 is elective surgery, performed for the relief of pain in the absence of significant neuropathy. Class 2, prophylactic surgery, is to reduce risk of ulceration or reulceration in patients who have lost protective sensation but don’t have an open wound. Class 3, curative surgery, is similar to Class 2, but is performed on those with open wounds. Class 4, emergency surgery, is done to limit the progression of acute infection.
“We devised this to facilitate a logical thought process and communication with other physicians, the patient, and the patient’s family,” Armstrong explained. “The type of procedure could be the same in each category; it could be a bunion, an arthroplasty, a tendon lengthening, and so forth. What changes is the patient’s risk profile and the purpose of the procedure.”
Armstrong views such care decisions on a continuum rather than as strictly surgical vs. nonsurgical.
“How do we reduce pressure and shear on the skin?” he asked. “You can do it externally through casts, shoes, insoles, braces, and orthotics. You can do it internally through physical therapy or surgery. It’s a spectrum. We do surgery if we’ve had trouble with external pressure modification, or if someone has such a significant deformity that we can’t effectively accommodate it. We’re also more apt to operate on an active person than on someone who just wants to get out of bed and do a few basic activities. Very often, it’s a combination of surgical and nonsurgical approaches.”
As these and other techniques continue to evolve, practitioners and their patients can look forward to better ways to make clinical decisions about this complex and vexing challenge.
Cary Groner is a freelance writer based in the San Francisco bay area.
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