Chopart Amputation, a Viable Alternative for Non-Ambulatory Patients

This content was created in partnership with the American Society of Podiatric Surgeons.

Diabetes is a global pandemic, and the sequela of this disease can lead to life-threatening wounds requiring amputation. With increasing age and comorbidities comes an increase in likelihood of developing such wounds. The United States has millions of patients with diabetes (up to 10% of the population), and 25% of these individuals are over the age of 65. Anywhere from 5–7% of this population will develop a diabetic foot ulceration that will eventually lead to amputation. Combined with peripheral vascular disease (PVD), these amputations can lead to death.¹

Traditionally, the level of amputation ranges from distal to proximal, with many proximal amputations progressing from the transmetatarsal level to a below-knee amputation (BKA) once the foot is deemed unsalvageable. The Chopart amputation is an option often overlooked largely due to the associated complications that can ensue. This includes equinovarus contractures and difficulties with accommodating shoe gear leading to breakdown of the amputation site. Francois Chopart first described this level of amputation in 1792, as a solution for extensive forefoot infections or crush injuries. Sir James Symes best described it as “the most valuable of all partial foot amputations [removing the largest portion of foot required] to remove disease or injury, [but also] preserves a support for the patient.”²

With proper fitting of a prosthesis, regular wound care, and close follow up, this level of amputation can be a viable alternative to the more aggressive BKA. With more proximal amputations, there is increased energy expenditure, increased cardiac demand, and overall increased mortality rate.³

We present a case study involving an individual with significant past medical history of dementia, diabetes, heart failure, hypertension and more, presenting with significant infection to his left foot. With the patient's medical history, clinical presentation, and non-ambulatory status, a Chopart amputation was the best choice of amputation to preserve limb length. This level of amputation is often overlooked, leading to more proximal below-knee or above-knee amputations. These more proximal amputations have been shown to be detrimental to patient mortality. We believe the Chopart amputation is a viable alternative, especially in non-ambulatory patients with lower extremity infections.

What You Should Know About Patient Presentation and Treatment

A 74-year-old male presented to the emergency room with wet gangrene of his left foot. The patient had an extensive past medical history including frontotemporal dementia, congestive heart failure, hypertension, hyperlipidemia, diabetes, chronic kidney disease, chronic atrial fibrillation, severe pulmonary hypertension, and poor compliance with his medications and care. He was seen initially by his primary care physician (PCP), who had prescribed intravenous vancomycin and ceftriaxone. The patient's PCP was the primary source of past medical history due to the patient’s mental status (awake, alert and oriented score of 1).

Clinically, the patient was febrile to a temperature of 100.5ºF, with tachycardia to 103, and tachypnea to 24. On physical exam the patient had palpable dorsalis pedis and posterior tibial pulses to his left lower extremity, but had diffuse edema to his foot and ankle. There were diffuse wet gangrenous changes to the foot, with dishwater drainage from the dorsolateral aspect. The second digit was necrotic, with cyanotic changes to the first, third, and fourth digits and a white fifth digit. The foot was malodorous with positive probe to bone, as well as tunneling towards the cuboid and tunneling towards the plantar aspect of the foot from the dorsum (Figure 1A and Figure 1B). On complete blood count, his white blood cell count was elevated to 22, with neutrophils at 89.6% indicating a positive left shift. This provided a clinical picture positive for meeting sepsis criteria. On radiographic imaging, there was evidence of soft tissue emphysema present on the AP view extending proximally towards the metatarsal bases, as well as plantar proximally to the level of the midfoot on the lateral view (Figure 2A and Figure 2B).

At this point, a vascular consultation was initiated. Due to the intact vascular supply to the foot, no immediate vascular intervention was deemed necessary. The vascular team continued to monitor the outcomes in the eventual possibility of patient requiring a below-knee amputation or vascular intervention following podiatric intervention.

After thorough discussion of treatment options with the patient’s son (the health care proxy), a Chopart amputation was deemed a viable option to salvage the left lower extremity. The patient was taken to the operating room where a full-thickness circumferential incision was made using a scalpel at the level of the Chopart joint. The tarsal bones were disarticulated, leaving the majority of the navicular bone intact as it was hard, viable bone. During the procedure, a plantar tract tunneling towards the posterior calcaneus was appreciated, with 30–40 cc of dishwater purulence draining from the foot. A rongeur was utilized to remove devitalized tissue, tendon, and bone. A sagittal saw was then used to plane the navicular bone to a level that could allow granulation and soft tissue coverage in the future. The surgical site was copiously irrigated using pulse lavage with 3 L of normal saline. Dirty and clean cultures, with bone margins, taken during the procedure for culture and pathology. The plantar tract was packed with ¼-inch iodoform packing strips and surgical site was kept open due to lack of adequate soft tissue coverage and active infection (Figure 3).

The patient was continued on intravenous antibiotics of vancomycin and piperacillin-tazobactam (Zosyn, Pfizer) while the OR cultures speciated. Negative-pressure wound therapy was placed at surgical site postoperatively to allow for granulation and drainage of infection via negative pressure wound therapy (NPWT). Postoperative radiographs revealed no further soft tissue gas at that time (Figure 4).

Bone biopsy intraoperatively yielded Morganella morganii, and deep wound culture swabs grew Morganella morganii, Enterococcus raffinosus, Streptoccocus anginosus, and mixed anaerobic flora. Our infectious disease team recommended a 7-day course of vancomycin and metronidazole (Flagyl, Pfizer) for the soft tissue infection, and a 6-week course of cefepime for the osteomyelitis. At post operative day 4, the wound base showed signs of fibronecrotic tissue at the remaining plantar tissue, but the surgical site was primarily granular in nature (Figure 5). The negative pressure canister continued to reveal mixed purulent and sanguineous drainage from the site.

The Advantages of a Chopart Amputation

With the increasing rate of diabetes and diabetes-related wound care complications in the country, selecting the appropriate level of amputation based on patient activity level is critical. In a non-ambulatory patient with extensive infection to the foot, a Chopart amputation can make an enormous difference in patient longevity versus performing a BKA. After carefully considering all factors, preserving limb length should always be the primary goal in limb salvage procedures.

While a BKA is a more definitive procedure and can be a good option in active patients with no other comorbidities, it can be detrimental in the elderly diabetic population. After a significant amputation such as a BKA or an above-knee amputation (AKA) in this population, the 5-year mortality rate (5MR) significantly increases. Thorud and colleagues conducted a 2016 systematic review on mortality rate following major amputation in patients with diabetes and PVD.¹ The authors note lower extremity amputation, combined with PVD and other comorbidities can precipitate death within 5 years. The 5MR can range anywhere from 53–100%. Following a BKA, this range is 42–80%, while an AKA can result in a 5MR of 40–90%. Some of the most significant risk factors for increasing 5MR include diabetes, PVD, renal disease, proximal amputation level, and patient age. Age was the most significant of all comorbidities leading to an increase mortality rate, along with level of amputation. It is important to note that aside from the immediate effects of a proximal amputation, there are devastating effects on patient overall health and patient psychology. These factors are not to be taken lightly when planning the surgical approach to lower extremity infections.

A systematic review performed by Schade and colleagues on the factors associated with successful Chopart amputation in the patient with diabetes noted the viability of this level of amputation upwards of 12 months in ambulatory patients.⁴ The Chopart amputation provides the largest foot amputation possible that still allows support to the lower extremity that is no less efficacious than an amputation preserving the tarsal bones. This level of amputation has become unpopular in recent years secondary to complications such as an equinovarus contracture and lack of proper accommodative foot gear. However, the authors note with close follow-up, regular wound care, and supportive bracing, it can be a good alternative to the more proximal BKA or AKA. When combined with proper prosthesis for ambulation, patients were ambulatory upwards of 12 months postoperatively. This also allowed for decrease energy expenditure, cardiac demand, and mortality rate.

Oftentimes with diabetic wounds, there is a component of PVD. Yanagiuchi and colleagues explored simultaneous endovascular treatment (EVT) in 79 limbs among 73 patients along with foot amputation in patients with ischemic wounds with bacterial infection.³ Previous studies showed the one-year healing rate ranging anywhere from 54–86% at a range of 95–146 days. In the study, there was a wound healing rate of 82% at 6 months with a mean healing time of 76 days. They attribute the improved healing to proactive wound management, amputation to remove necrotic infected tissue, and appropriate intravenous antibiotic course. When planning for limb salvage procedures, the peripheral vascular disease component needs to be addressed. The timing of the EVT is controversial and further research needs to be done regarding performing therapy prior, during, or after amputation. However, there is significant evidence advocating for joined vascular and podiatric approach when planning for limb salvage.

A recent 10-year case study published by Yoho and colleagues in 2022 further supports the viability of the Chopart amputation, even in ambulatory patients.⁵ The authors followed a patient with a history of diabetes and PVD who presented with osteomyelitis to the midfoot. The patient had a previous first ray partial amputation as well as partial second ray amputation, and was referred to vascular surgery to evaluate their femoral-tibial bypass graft. A large bulla to the lateral midfoot was appreciated during the procedure, and fluoroscopy showed destructive changes to the distal calcaneus, the cuboid, lateral metatarsal bases, as well as the medial cuneiform. The patient promptly underwent a Chopart amputation with primary closure. At the 8-week follow-up mark, the patient's antibiotic regiment was finished, and at 4 months the patient was fitted for a lower extremity prosthesis. The patient continued to follow up showing marked improvement. While they did have a wound at the central distal aspect of the amputation site at the 6-year mark, with regular wound care and offloading, the patient returned to normal function. At the 10-year mark, the patient was fully ambulatory on the Chopart amputation with the surgical site fully healed.

In Conclusion

As foot and ankle surgeons, the primary focus of diabetic infection control should always be limb length salvage. The Chopart amputation is often overlooked as a good alternative, in both ambulatory and non-ambulatory individuals. With a combined approach to address any PVD and biomechanical deforming factors, we believe this can be a procedure that not only preserves limb length, but preserves patient’s mortality and mental wellness. The alternative of a more proximal amputation (BKA or AKA) places increased cardiovascular burden on patients, further reducing their 5MR. We believe this case study provides another viable option for the fast-growing population of diabetic individuals with infected lower extremity wounds.

Dr. Brummer is a board certified foot surgeon by the American Board of Podiatric Surgery and is a Fellow of the American College of Foot and Ankle Surgeons and a member in good standing with the American Podiatric Medical Association. He has also been an active member of the New York State Podiatric Medical Association; where he is the past President of the New York Division of the New York State Podiatric Medical Association.

Dr. Guduru practices in New York City.

References
1.    Thorud JC, Plemmons B, Buckley CJ, Shibuya N, Jupiter DC. Mortality after nontraumatic major amputation among patients with diabetes and peripheral vascular disease: a systematic review. J Foot Ankle Surg. 2016 May-Jun;55(3):591-9. doi: 10.1053/j.jfas.2016.01.012. Epub 2016 Feb 19. PMID: 26898398.
2.    Gomez A, et al. “François Chopart.” Life in the Fast Lane • LITFL, 27 Mar. 2021, https://litfl.com/francois-chopart/.
3.    Yanagiuchi T, Kato T, Hirano K, Toki H, Imura H, Matsubara K, Ushimaru S, Yokoi H, Zen K, Matoba S. Predictors of delayed wound healing after simultaneous endovascular treatment and minor forefoot amputation for chronic limb-threatening ischemia with wound infection. Vascular. 2022 Feb 1:17085381211067601. doi: 10.1177/17085381211067601. Epub ahead of print. PMID: 35105193.
4.    Schade VL, Roukis TS, Yan JL. Factors associated with successful Chopart amputation in patients with diabetes: a systematic review. Foot Ankle Spec. 2010 Oct;3(5):278-84. doi: 10.1177/1938640010379635. PMID: 20966454.
5.    Yoho RM, Wilson PK, Gerres JA, Freschi S. Chopart's amputation: a 10-year case study. J Foot Ankle Surg. 2008 Jul-Aug;47(4):326-31. doi: 10.1053/j.jfas.2008.04.007. PMID: 18590897.