The Role of Internal Offloading and Rotational Flap Closure of Charcot Arthropathy-Related Midfoot Ulcers

The patient with Charcot foot is seldom studied for their body’s ability to heal an open diabetic foot ulcer. These patients are usually excluded from all prospective randomized trials. Over a 5-year period, patients with Charcot arthropathy (CA) have been shown to have a 63% chance of developing a CA foot ulcer (CAFU), and those with a foot ulcer have a 37% mortality within the same timeframe.¹ To the authors’ knowledge, a correlation between healing a CAFU and mortality reduction has not been indicated. It is well-known that healing such ulcers improves quality of life and reduces the chance of hospitalization. The primary modality to heal such an ulcer is maintaining or creating a plantar grade foot.¹ In a retrospective study of 106 patients with CAFU, Schmidt and Holmes² reported that 44% of the patients’ ulcers had healed, 11% had received a minor amputation, and only 9% had undergone major amputation (approximately 6% had surgical reconstruction) at 18 months. In addition, the mortality rate was noted to only be 4%. It should be noted that this study involved a very comprehensive multidisciplinary limb salvage team²; however, this study did not review recurrence.² Up to 40% of patients with CAFU will have a recurrence at 1 year.³

At the authors’ institution, likelihood of recurrence appears to be dependent upon appropriate creation of a plantar grade foot, which is defined as walking with the toes and metatarsals flat on the ground. The plantar subluxation of the Charcot or LisFranc joint places abnormal pressure on the plantar fat pad and plantar skin, which can lead to ulceration due to lack of sensation. In the acute phase, casting to ensure immobilization is the first line of therapy. However, as seen in most cases at the authors’ institution and at others, these patients present in the outpatient setting, with chronic CAFUs.² Although continued casting and tissue grafting can close these ulcers, the recurrence rate after such closure is significantly high. In general, there are 3 patterns of midfoot CA: rocker bottom and forefoot abduction, dorsal subluxation/dislocation, and forefoot adduction. The most common of these 3 is the rocker bottom deformity. The ulcers in these cases tend to develop medially due to the extruded medial cuneiform, or laterally secondary to the displaced cuboid.

Although a full reconstruction including stabilization of the foot is a topic of conversation and is appropriate in some patients, this option is often not available.⁴ In the authors’ experience, internal hardware has a very high rate of infection in patients who have open ulcerations at the time of the procedure. For many of these patients with infected hardware, the present authors provide the hardware removal and wound closure services. In general, the advanced orthopedic reconstruction team prefers to defer these patients until wound closure has occurred. In fact, if hardware needs to be placed, the preference is for the external fixation technique.

With these limitations in mind, the case of an internal offloading procedure accompanied by local rotational flap closure—depending upon the location of the ulceration—is presented. The operation is based upon the concept of removing the pressure point from the soft tissue while closing the chronic wound with a rotational flap.

These procedures are performed under tourniquet exsanguination; in addition, the authors’ group always uses an oscillating bone saw and appropriate blade to provide a smooth bone surface. The 2-table approach, first with a dirty table and then moved to the clean table, was used. The incision is based upon the location of the ulceration (Figure 1). The first step is to surgically excise the ulcer from the plantar portion of the foot, then excise the soft tissue edges through the glabrous plantar skin, also debriding any other portion of non-boney base of the wound. Next, the foot is re-prepared; changing gloves and gowns, the surgeons then proceeded to make the primary surgical incision. Fundamentally, the incision is made on the medial or lateral foot at a point that allows maximal development of thick, soft tissue flaps (Figure 1). The periosteum is dissected using a periosteal elevator.

If the medial cuneiform bone is the culprit, the tibialis anterior tendon, the peroneus longus tendon, and the tibialis posterior tendon all need to be dissected off the bone prior to utilizing the oscillating bone saw to remove the offending bony prominence. If it is a subluxed navicular bone, the tibialis posterior tendon and potentially a portion of the plantar calcaneal navicular ligament will need to be removed prior to cutting away the exposed bone. If the target is the displaced cuboid bone, the peroneus longus tendon and peroneus brevis tendon will need to be mobilized appropriately. The authors like to use intraoperative fluoroscopy to be sure that the bony prominence has been removed and the foot has been brought to a flatter construct. Once the bone has been appropriately reduced from prominence (Figure 2, Figure 3), the tourniquet is deflated and hemostasis established.

At this point, the soft tissue flap is rotated, including appropriate muscular closure if available. At times, the abductor hallucis muscle can be mobilized medially to help close the wound defect when the wound is based under the cuneiform bone; in the case of the cuboid-related ulcer, the abductor digiti minimi muscle can be mobilized. Following this, the soft tissue defect in the foot is debrided and subsequently closed with deep stitches of 3-0 polyglactin. The dermal portion of the myocutaneous flap is fixed over the wound with 3-0 polypropylene suture, making sure to use a cutting needle. One edge of this myocutaneous flap is the primary incision. This incision does not close, but it is covered with an application of xenograft, which is sutured in place with 3-0 polypropylene or staples (Figure 4). In most cases, a percutaneous Achilles tendon lengthening completes the procedure. Closed-incisional negative pressure wound therapy is applied, and the patient is placed in a posterior rigid splint.

The postoperative care of these patients includes a 4-day hospitalization. On day 4, the closed-incisional negative pressure wound therapy is removed, and the patient is placed in a softer bivalved non-weightbearing splint. These patients are then instructed with physical therapy on how to use a rolling walker and plan for complete non-weightbearing for 4 weeks. At week 4, partial weightbearing is initiated with a total contact cast. The patient is seen in the outpatient office on a weekly basis through at least week 6 (Figure 5).

There are several interesting approaches to this problem. In the authors’ experiences, internal foot hardware has had significant difficulty stabilizing the poor bone integrity that is a hallmark of Charcot foot; in addition, very few foot and ankle surgeons are likely to put hardware into a foot that has an open wound. External fixation with a walking external frame has been described, which the authors occasionally use. In the treating center’s experience, few patients choose external fixation. In part, this is due to it requiring a 3-month time commitment of having the frame in place. Anecdotally, the results are very good for complete offloading with a frame and rotational flap creation. However, this is a greater commitment that most ambulatory patients are willing to agree to. Therefore, the authors presented the option of internal offloading and soft tissue coverage, ideally with rotational flap or adjacent myocutaneous flap as a feasible and well-accepted alternative.

Authors: Keval Ray, MD¹; and John C Lantis II, MD²

Affiliations: ¹Third-year surgical resident, Department of Surgery, Mount Sinai Health System, Icahn School of Medicine, New York, NY; ²Site Chief and Professor of Surgery, Mount Sinai West Hospital, Icahn School of Medicine, New York, NY

Disclosure: The authors disclose no financial or other conflicts of interest.

Correspondence: John C Lantis II, MD, FACS, Chief and Professor of Surgery, Mount Sinai West and Icahn School of Medicine, 425 West 59th Street, New York, NY, 10019; john.lantis@mountsinai.org

Recommended Citation: Ray K, Lantis JC II. The role of internal offloading and rotational flap closure of Charcot arthropathy-related midfoot ulcers. Wounds. 2022;34(1):17-19. doi:10.25270/wnds/2022.1719