Emerging Evidence Sheds Light On Charcot Reconstruction Outcomes

Is it possible for surgeons to identify patients most at risk for amputation or mortality after Charcot reconstruction? 

In a retrospective observational study recently published in the Journal of Foot and Ankle Surgery, researchers looked at success rates as well as amputation rates and mortality rates at 30 days, one year and three years after Charcot reconstruction. In the study involving 151 patients, the study authors also took associated risk factors, rates of infection, re-ulceration and return to ambulation into account. 

Luke J. McCann, DPM, MSPT, AACFAS, the lead author on the study, shares that their results highlight four primary characteristics that put these patients at risk for adverse outcomes postoperatively. These characteristics included end-stage renal disease, peripheral vascular disease, reconstruction during active Charcot and reconstruction at the ankle or subtalar joint, all of which contributed to poor outcomes. 

At three years post-op, 22 (14.6 percent) patients died and 23 (15.2 percent) patients underwent limb amputation. Specifically, mortality risk was 2.5 times higher if a patient had end-stage renal disease and 3.4 times higher among patients with peripheral vascular disease. According to the study, patients who needed reconstruction at the ankle or subtalar joint were 70 percent less likely to return to walking in comparison to those who had medial column reconstruction. 

“Having this information is helpful when it comes to counseling patients about the benefits and risks of a Charcot reconstruction,” adds Dr. McCann, an attending physician at Kaiser South San Francisco Medical Center in San Francisco. 

Dr. McCann says reconstruction during an active Charcot process had a 3.2 times higher risk of progressing to amputation. Additionally, he notes that patients with ankle and/or subtalar joint Charcot reconstruction were 3.3 times more likely to have an amputation in comparison to those who had midfoot reconstruction. 

Joseph D. Dickinson, DPM, FACFAS, principal investigator on the study, points out that when looking at the rates of mortality and amputation, 86 percent of patients were alive at three years post-op. 

“Out of those who survived, 85 percent kept their limbs,” explains Dr. Dickinson, an Attending Physician with the Kaiser San Francisco Bay Foot and Ankle Residency Program at Kaiser Foundation Hospital in Oakland, Calif. “So despite increased risk in these populations, we still feel the percentage of limbs salvaged was good.” 

Dr. McCann notes some surprising findings from the study. He says whether a patient had an adjunctive Achilles or gastrocnemius procedure had “no statistical impact on outcomes.” Dr. McCann also notes the choice of fixation (internal versus external fixation or a combination of both) did not have any impact on outcomes. 

In regard to the risks associated with acute phase Charcot reconstruction, the study authors recognize that there can still be benefit in this approach but note that their data could help surgeons provide realistic expectations for patients regarding possible outcomes. 

“We understand there will be instances in which Charcot reconstruction in the acute phase is indicated, given impending ulceration or a non-braceable deformity. However, it is important to note there would be a higher risk in that situation,” says Dr. Dickinson. 

Both authors stressed that some additional data found in the study could assist providers in assessing risk in this patient population. Re-ulceration at the site of reconstruction occurred in 31 percent of patients. Eleven percent of patients experienced a major infection requiring surgery while 29 percent of patients had a minor infection requiring antibiotics and wound care, according to the study. 

How Effective Is Vitamin B12 In Treating Diabetic Neuropathy? 

By Jennifer Spector, DPM, FACFAS, Senior Editor

One milligram of oral vitamin B12 (methylcobalamin) daily for 12 months improved multiple measures related to diabetic neuropathy, according to a recent study in Nutrients. 

In the randomized study, researchers assessed 90 patients with type 2 diabetes, peripheral and autonomic neuropathy, all of whom had baseline vitamin B serum levels less than 400 pmol/L. 

Comparing the active treatment (44 patients) and placebo groups (46 patients), the study authors assessed sural nerve conduction velocity and amplitude, vibration perception threshold, cardiovascular autonomic reflex tests and sudomotor function as well as quality of life questionnaires, pain scores and the Michigan Neuropathy Screening Instrument questionnaire and examination. The researchers found that the aforementioned vitamin B12 regimen improved all the parameters except for the cardiovascular autonomic reflex tests and screening instrument examination. 

Jonathan Labovitz, DPM, FACFAS, CHCQM views this study as critical in the treatment of diabetic neuropathy going forward. 

“We have worked hard to treat this problem for years but neglected some of the simple principles of nutrition like supplementation,” explains Dr. Labovitz, Associate Dean of Clinical Education and Graduate Placement for the Western University of Health Sciences College of Podiatric Medicine in Pomona, Calif. “Higher doses and prolonged use of metformin are known to reduce vitamin B12 levels over time. This study reinforces the need to monitor and treat patients with neuropathy by addressing all causes, not just allowing tunnel vision focusing on diabetes when B12 deficiency may contribute to the problem.” 

Assessing for and optimizing vitamin levels can be part of medical practice, and has the chance to significantly benefit patients, notes David G. Armstrong, DPM, MD, PhD, the Director of the Southwestern Academic Limb Salvage Alliance (SALSA). 

Dr. Armstrong says adding a certified nutritionist to his limb preservation unit over the past year has proven to be extremely beneficial for patients. 

“We have her meet with all of our patients, particularly ones that are pre- and postoperative, to optimize their current diet. This may also include supplementation for neuropathy,” adds Dr. Armstrong. 

When one considers the pathophysiology at a cellular level, treating neuropathy with vitamins, minerals and antioxidants likely plays a bigger role than the evidence currently shows, opines Dr. Labovitz. 

Palpation Versus Reality: A Closer Look At Identifying A Vital Surgical Structure For Medial Column Procedures 

By Jennifer Spector, DPM, FACFAS, Senior Editor 

How accurate is palpation in identifying the medial branch of the medial dorsal cutaneous nerve prior to medial column surgery? 

In a recent prospective study published in the Journal of Foot and Ankle Surgery, researchers evaluated 100 consecutive patients undergoing an elective Lapidus arthrodesis. By correlating visually identified intraoperative nerve location relative to the cuneiform and first tarsometatarsal joint with palpation-based localization, the study authors assessed the accuracy of the nerve palpation technique. 

They found a correlation between preoperative palpation of the nerve and intraoperative visualization in 99 out of 100 cases. In the remaining case, the palpated nerve was not visualized as it was proximal to the area of dissection. In 95 out of 100 cases, the medial branch of the medial dorsal cutaneous nerve crossed the dorsal Lapidus incision at the medial cuneiform or first metatarsal base, according to the study. In two cases, this medial branch crossed at the mid-metatarsal level and in three cases, it crossed proximal to the medial cuneiform. 

“The medial branch of the medial dorsal cutaneous nerve is at risk with almost any medial column procedure. One can easily and accurately palpate this nerve branch to assist with the incision planning process,” explains Troy J. Boffeli, DPM, FACFAS, the lead author for the study. 

Sharing that one cannot entirely avoid this nerve during surgical exposure, he stresses that palpating and marking the nerve preoperatively raises awareness for more careful dissection to mobilize the nerve. 

“Palpating the nerve in the pre-op area while the patient actively dorsiflexes the first toe against resistance helps provide a firm substance over which one can optimize palpation,” maintains Dr. Boffeli, the Director of the Foot and Ankle Surgery Residency Program at the Regions Hospital/HealthPartners Institute for Education and Research in St. Paul, Minn. 

Dr. Boffeli says surgeons can apply this technique with all medial column procedures including the Cotton osteotomy, naviculocuneiform fusion, talonavicular fusion and base wedge osteotomy. Lisfranc and hardware removal procedures are also at risk, notes Dr. Boffeli. 

“The incision for total ankle replacement also extends down the medial column lateral to the tibialis anterior,” points out Dr. Boffeli. “Knowing where the nerve is located might help surgeons make nerve-friendly incisions and deep dissection.”