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Can A TMA Without A Plantar Flap Be A Viable Option For Limb Salvage?

Although a viable plantar flap is a mainstay of traditional transmetatarsal amputation (TMA), the authors of a new study suggest that a TMA without a plantar flap could be an alternative to below-knee amputation. 

In the retrospective study, recently published in the Annals of Vascular Surgery, researchers assessed 27 consecutive patients without an available plantar flap who had a guillotine TMA. Surgeons resected the metatarsals as flush as possible with the soft tissue and utilized negative pressure wound therapy (NPWT) to encourage granulation over exposed bone. Patients then either continued NPWT until secondary closure (11/27) or had split-thickness skin grafting (14/27). 

Over more than two years of follow-up, two of the 27 patients eventually had a below-knee amputation. In the skin grafting cohort, 12 patients (86 percent) healed at a median of 75 days. In the NPWT group, seven patients (64 percent) healed at a median of 165 days. The remaining patients, except for one lost to follow up, continued to have ambulatory wound care. 

“It is okay to think outside the box,” says Ashley Miller, DPM, an author of the study. “Although a percentage of patients required a significant time to heal their wound, we kept 95 percent of our patients in this study weightbearing with their own foot.” 

Anthony Tickner, DPM, says the study is helpful in that it stresses the benefit of trying and exhausting different avenues before rushing into a below-knee amputation. 

In regard to the durability of tissue at the amputation site, Dr. Miller acknowledges the challenge of not having a plantar flap. 

“We work very closely with a prosthetic team present in our weekly clinics,” explains Dr. Miller. “For each healed patient, we make a custom extra-depth diabetic shoe with a steel shank extension and soft plastazote toe filler. We believe this helped keep the distal ulceration rate down.” 

She also notes that for appropriate patients, they offer gastrocsoleus lengthening or recommend physical therapy to address equinus. Dr. Tickner agrees that addressing biomechanical issues and offloading should be part of a clear plan prior to surgery. 

“I would say that compared to even five or 10 years ago, we are doing a better job of limb salvage,” says Dr. Tickner, the Medical Director of the St. Vincent Hospital/Restorix Health Wound Healing Center in Worcester, Mass. “However, we should always look not only for ways to prevent amputation but also how to lessen the time to heal. In addition to NPWT and split-thickness skin grafting mentioned in the study, I like to add certain collagen matrices and other skin substitutes, including amniotic products, into my treatment protocols. I find this approach to be very beneficial in conjunction with NPWT and use these types of products to cover bone and deeper structures, thus bridging the gap and possibly speeding healing.” 

“To have success with (a TMA without a plantar flap), it takes a lot of dedication from both the physician and the patient,” maintains Dr. Miller, who is affiliated with the Department of Surgery at Harbor-UCLA Medical Center in Torrance, Calif. “In most cases, it takes many clinic visits, multiple surgical procedures for revisions, debridements or skin grafting, a significant amount of time with NPWT, and for those who underwent skin grafting, a possible hospital admission. The patient needs to know what this limb salvage technique entails and the physician has to be all in throughout the ups and downs.” 

A Closer Look At A Proposed Classification For Lapidus Modifications 

By Jennifer Spector, DPM, FACFAS, Senior Editor

In a recent Orthopaedic Forum article in the Journal of Bone and Joint Surgery (American), two orthopedic surgeons proposed a new set of terminology and a classification for the Lapidus procedure. Noting five primary descriptors of Lapidus modifications for hallux valgus correction, the authors suggest that surgeons can also use these classification descriptors when performing a first tarsometatarsal arthrodesis as part of a flatfoot or arch reconstruction. 

The classifications outlined in the article are as follows: 

• first tarsometatarsal arthrodesis (first metatarsal base to medial cuneiform without intermediate cuneiform or second metatarsal fixation); 

• first tarsometatarsal arthrodesis with three-corner fixation (with intermediate cuneiform or second metatarsal fixation but without preparation for additional fusion); 

• three-corner tarsometatarsal arthrodesis (adding fusion of either intermediate cuneiform or second metatarsal); 

• first tarsometatarsal arthrodesis with four-corner fixation (intermediate cuneiform and second metatarsal fixation without preparation for additional fusion); and 

• four-corner tarsometatarsal arthrodesis (fusion of all joints between the bases of the first and second metatarsals, and the medial and intermediate cuneiforms). 

Panagiotis D. Symeonidis, MD, PhD, the lead author of the article, notes challenges with the current Lapidus terminology. 

“Currently, there are endless modifications of the arthrodesis of the first tarsometatarsal joint that are loosely referred to as ‘modified Lapidus,’” maintains Dr. Symeonidis, an orthopaedic surgeon at St. Luke’s Private Hospital in Thessaloniki, Greece. “The relevant research, including comparative studies and meta-analyses, is hindered by the lack of standardization in the relevant terminology. 

“In this new Lapidus classification, we introduce the concepts of three- and four-corner fixation and arthrodesis respectively. This simple concept incorporates the existing techniques in a simple yet precise manner. This results in four main types of the procedure. The addition of a capital S denotes the concomitant distal soft tissue release.” 

Dr. Symeonidis points out that in the future, the classification could also add variants such as the use of grafting and derotation techniques. 

The new terminology does not support a specific technique or fixation method, stresses Dr. Symeonidis. 

“This classification can serve as a tool for research, proper CPT coding and an overall better documentation and communication with regard to this popular procedure,” explains Dr. Symeonidis. “Beyond hallux valgus correction, one may be able to apply this to reconstruction surgery and even certain trauma cases.” 

What Is The Best Initial Test For Onychomycosis? 

By Jennifer Spector, DPM, FACFAS, Senior Editor 

A new study in the Journal of the American Podiatric Medical Association suggests periodic acid- Schiff (PAS) testing is the most appropriate initial test for onychomycosis although the addition of multiplex polymerase chain reaction (PCR) may be beneficial. 

Due to the ability of PCR to return quicker species identification than fungal culture, the study authors compared the use of multiplex PCR to PAS testing in 203 patients with clinically-diagnosed onychomycosis. 

Splitting representative nail samples between PAS and multiplex PCR tests, the researchers found that PAS revealed positive results in 109 (53.7 percent) of the samples while 77 (37.9 percent) were positive with PCR. Of those testing positive with PAS, 41 had a negative PCR result and of those testing positive on PCR, nine showed a negative PAS result. 

Warren S. Joseph, DPM, FIDSA, is encouraged by the rapid and sensitive features of molecular techniques. He shares that clinical diagnosis alone along with other current testing options have their pitfalls, leading to some level of misdiagnosis. 

“This study shows PCR was not the ideal test we would hope it to be,” says Dr. Joseph. “Probably the most interesting finding was that PAS detected fungus in 41 cases in which the PCR was negative. Given that PCR is, theoretically, significantly more sensitive than PAS, this finding is surprising. Certainly, PCR has the advantage of being able to actually identify the fungus itself.” 

Dr. Joseph notes that although the authors feel PCR could play a role in “guiding” therapy, he wonders how important that guidance is since dermatophytes predominantly cause onychomycosis. Dr. Joseph additionally shares the need for further study of cost-effectiveness of molecular techniques in various clinical scenarios. A number of different techniques for molecular diagnosis continue to emerge and could change the landscape of diagnosing onychomycosis in the future, according to Dr. Joseph. 

“Although I firmly believe that molecular testing is the future of diagnosis, I wonder if it is yet ‘ready for prime time.’ There are many unanswered questions on how to interpret results and how … they compare to established tried and true modalities,” says Dr. Joseph, an Adjunct Clinical Professor at the Arizona College of Podiatric Medicine at Midwestern University in Glendale, Ariz. “Is there really a clinical advantage and, even if so, is that advantage worth what is bound to be the increased cost? I am hopeful but these are questions I have yet to see answered.” 

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By Jennifer Spector, DPM, FACFAS, Senior Editor
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