Can The Ostectomy Facilitate Optimal Outcomes With The Charcot Foot?

Author(s): 
Alan Catanzariti, DPM, FACFAS, and Robert Mendicino, DPM, FACFAS

When conservative care fails for the Charcot foot, the ostectomy can be a viable surgical alternative. Accordingly, these authors offer a closer look at factors to consider before proceeding with an ostectomy, pertinent insights on the procedure and keys to minimizing the risk of post-op complications.

Diabetes mellitus is the most common cause of neuroarthropathy involving the foot and ankle. The literature estimates that Charcot neuroarthropathy affects between 0.1 percent and 2.5 percent of the 16 million patients with diabetes mellitus in the United States.1 However, more recent studies report the incidence of Charcot neuroarthropathy is in the range of 0.1 percent to 29 percent.2

   Lavery and colleagues, in a population-based assessment of diabetic Charcot neuroarthropathy, reported an incidence of 8.5 per 1,000 people with diabetes per year.3 Although prevalence of this complex clinical entity is often reported to be less than 1 percent of the overall diabetes population, there is a trend for higher incidence of Charcot neuroarthropathy in patients with peripheral neuropathy and in those patients who present to specialty clinics. Armstrong and Peters reported a prevalence of 0.16 percent in a general population of patients with diabetes and 13 percent prevalence in high-risk patients with diabetes presenting to a specialty foot clinic.4

   Unfortunately, the ideal protocol for managing Charcot neuroarthropathy remains nebulous. Non-surgical treatment remains the standard of care for most patients who have developed diabetic Charcot neuroarthropathy although some literature has questioned this approach.5 Since Charcot neuroarthropathy is a progressive process, many patients who fail non-operative therapy may ultimately develop a severe rocker bottom deformity. This ultimately leads to plantar ulceration secondary to the increased pressures in an insensate foot and places these patients at risk for limb loss.

   One of the major problems with Charcot neuroarthropathy has been the lack of evidence-based standards. These patients are often high-risk surgical candidates because of morbid obesity, localized osteopenia, deficiency of endogenous growth factors and an impaired immune system. Treatment is often dictated by the patient’s unique set of circumstances and the goals for surgical outcome often vary from patient to patient.

   The ultimate question is “What constitutes a successful outcome?” This question is often answered by very strong opinions within the medical community by those treating Charcot neuroarthropathy. Unfortunately, these opinions are often based on inferences rather than evidence-based medicine.

Determining Why Non-Operative Therapy Fails

Charcot neuroarthropathy most commonly affects the midfoot. The primary indications for ostectomy include a midfoot deformity with secondary ulceration, which has failed to heal despite an extensive course of non-operative care. The other indication is for wounds that have healed but have broken down afterward in spite of appropriate shoe therapy, bracing, etc.

   One should consider an ostectomy for diabetic Charcot neuroarthropathy when non-operative therapy fails. However, before proceeding with any type of surgical intervention, one should ascertain why non-operative therapy has failed. Typical reasons for failure of non-operative therapy include:
• a lack of patience to allow the temporal Charcot neuroarthropathy process to resolve fully;
• inappropriate bracing;
• a lack of follow-up to evaluate the effectiveness of bracing;
• a lack of finances to purchase these devices; and/or
• an unwillingness of many patients to accept offloading devices.

   Many of the reasons for failed non-operative care will also adversely affect the outcome in patients undergoing surgical management.

Emphasizing Proper Staging Of Charcot Neuroarthropathy

There are various types of surgeries that have been recommended for midfoot Charcot neuroarthropathy. Basically, we divide these into simple ostectomy procedures and complex reconstructive procedures that involve osteotomy and arthrodesis. Various factors come into play when contemplating ostectomy versus reconstruction.

   One must consider the stage of the Charcot neuroarthropathy. We typically utilize a modified Eichenholz staging classification.6

   Stage 0 of Charcot neuroarthropathy has clinical manifestations without any type of radiographic changes. The stage 0 foot is typically an edematous, warm and erythematous foot without radiographic evidence of fragmentation, etc.7

   Stage 1 is the stage of development in which debris, fragmentation, disruption and dislocation are typically visible on radiographs.

   Stage 2 or the stage of coalescence demonstrates radiographic evidence of sclerosis, absorption of fine debris and fusion of large fragments.

   Stage 3 or late-stage Charcot neuroarthropathy typically demonstrates less sclerosis of the major fragments and some attempt at reformation of joint architecture. We consider ostectomy only in stage 3 Charcot neuroarthropathy.

Other Pertinent Factors In Determining Whether To Perform An Ostectomy

Instability is another important factor. Patients who have gross instability at the midfoot are poor candidates for ostectomy. Extensive soft tissue dissection in combination with an aggressive removal of bone may ultimately result in further midfoot instability. This type of deformity can be rather challenging to salvage even with complex reconstructive procedures.

   The degree of deformity is another factor that one should consider when contemplating ostectomy versus reconstruction. In the case of a rather large deformity, it is often better to address this with a reconstructive procedure rather than an ostectomy even when there is good stability about the midfoot. Unfortunately, the amount of bone required to remove the osseous prominence with a large deformity can result in instability.

   One should thoroughly assess the ulcer location to determine the exact apex of the deformity. This will provide information that might assist in choosing a surgical approach. Obviously, if there is an open wound with acute infection or osteomyelitis, the surgeon should address these issues prior to any type of definitive surgical procedure. Other things we typically consider are previous surgery and what we refer to as perimeter issues. Perimeter issues include lack of family support, tobacco use, inability to adhere to the postoperative regimen, etc.

   Prior to surgery, it is important to ensure appropriate surgical workup and preparation. It is critical to optimize all medical comorbidities including diabetes control and cardiac function. We typically obtain non-invasive arterial studies.

   There are several contraindications to the ostectomy. Lower extremity arterial disease that is not amenable to endovascular or bypass procedures is an obvious contraindication. Infection is also a contraindication. The infection should be completely resolved before proceeding with a definitive surgical procedure. Instability is an absolute contraindication to ostectomy.

   Lastly, an ostectomy is reserved for those patients in the late stage Charcot neuroarthropathy (i.e. stage 3). It is prudent to wait until there has been complete coalescence and the Charcot neuroarthropathy process has completed its course. We typically measure temperature and edema to ascertain the patient’s progress throughout the Charcot neuroarthropathy process.

Key Pearls For Performing The Ostectomy

There are various considerations one must take into account when proceeding with an ostectomy. Consider whether you want to take a direct or indirect approach to the underlying bone.8 A direct approach accesses the underlying bone through the apex of the deformity. We typically consider this if there is an existing wound, especially if the wound is deep. This approach involves excising the wound down to the level of the bone and then proceeding with an ostectomy. We consider an indirect approach — an incision placed either lateral or medial — when there is a closed soft tissue envelope or a superficial wound.

   Regardless of the surgical approach, surgeons should perform these procedures with full thickness flaps. The dissection is subperiosteal to maintain good perfusion to the flaps. We typically remove bone with large osteotomes, rongeurs or sagittal saws. A small sagittal saw works out well with medial and lateral approaches, and the osteotomes typically work better for direct approach ostectomies.

   Dissection should provide adequate exposure to the underlying bone. However, it is important to avoid unnecessary dissection of stabilizing soft tissues that might result in progression of the deformity. One must remove enough bone such that the underlying osseous prominence has been completely resected. One must balance this requirement against over-aggressive resection, which will lead to instability following surgery. In those patients with a closed soft tissue envelope, we often consider closed suction drains because the exposed cancellous surfaces can result in quite a bit of bleeding. We usually maintain the drain for one day.

   There are different types of closure options available. One may consider delayed primary closure in those cases in which there has been soft tissue infection or osteomyelitis. Obviously, one should wait until the infection has resolved and culture results have returned. In patients with osteomyelitis, we sometimes consider primary closure over antibiotic-loaded bone cement as an adjunctive therapy to long-term IV antibiotics.

   Consider plastic surgery consultation when there has been significant soft tissue loss or inadequate soft tissue to close the overlying bone. In these cases, surgeons can often perform a local soft tissue rearrangement. One can perform this during the time of the ostectomy or at a later date. However, in the majority of patients with adequate arterial perfusion, we will typically allow these wounds to heal by secondary intention. We employ standard techniques for local wound care. A large number of these patients receive vacuum-assisted closure and offloading.

   It is important to assess equinus in these patients. The vast majority of these patients have a component of equinus and we often consider either tendo-Achilles lengthening or gastrocnemius recession. This provides some offloading and is an excellent adjunct to an ostectomy. A recent study by Laborde has shown that midfoot ulcers treated with an isolated gastrocnemius soleus recession resulted in 10 out of 11 ulcers healed.9 The follow-up time was 39 months. There was only one failure out of the 11 patients and this patient ultimately had a midfoot arthrodesis. Additionally, there were no transfer ulcers in any patients in the study.

Addressing Post-Op Concerns And Potential Complications

The postoperative course following an ostectomy will vary from patient to patient. We usually place patients into the offloading device they had been using prior to surgery. This may be a fracture brace, Charcot restraint orthotic walker (CROW), total contact cast or some other device. It depends on the patient’s unique circumstances and special situation. We allow some of these patients partial weightbearing with the use of a walker. Some patients are required to be non-weightbearing for an extended period of time.

   Various complications are not uncommon following ostectomy. The most common complication is failure of the ulcer to heal. In some patients, the ulcer will not heal or a transfer ulcer will occur. We have noted this to be more common in lateral column wounds. A recurrent ulcer is another complication. Recurrence can develop with inadequate bone removal or increased instability resulting in greater deformity. Increased instability is a complication we have already discussed. Overzealous dissection of soft tissues or resection of bone can result in instability.

   Lastly, infection is always a potential complication and one should monitor these patients rather closely after surgery. A failed ostectomy can be a rather challenging situation to salvage. These patients are often at risk for limb loss and may require some type of complex osseous reconstruction with internal and/or external fixation. Additionally, if there has been significant soft tissue loss, a free tissue transfer may be necessary. Unfortunately, some of these failed cases result in limb loss.

   The majority of literature dealing with ostectomy in Charcot neuroarthropathy is evidence-based medicine level 3 or level 4. These studies have shown that patients do relatively well. Medial wounds have a good prognosis following ostectomy whereas lateral wounds have a higher failure rate. Ostectomy patients have a better prognosis when there is adjunct primary closure regardless of the technique and patients who have posterior group lengthening typically have better long-term results. Lastly, non-weightbearing is not always essential for healing.8,10-13

In Summary

An ostectomy is a good option for those diabetic patients with midfoot Charcot neuroarthropathy who have failed non-operative care. Surgeons should take some of the aforementioned considerations into account before proceeding to ensure that patients have good outcomes.

   Dr. Catanzariti is the Director of Residency Training in the Division of Foot and Ankle Surgery at Western Pennsylvania Hospital in Pittsburgh. He is a Fellow of the American College of Foot and Ankle Surgeons.

   Dr. Mendicino is the Chairman of the Division of Foot and Ankle Surgery at Western Pennsylvania Hospital in Pittsburgh. He is a Fellow and Past President of the American College of Foot and Ankle Surgeons.

References

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10. Brodsky JW, Rouse AM. Exostectomy for symptomatic bony prominences in diabetic Charcot feet. Clin Orthop Relat Res. 1993; 296:21-26.
11. Leventen EO. Charcot foot – a technique for treatment of chronic plantar ulcer by saucerization and primary closure. Foot Ankle. 1986; 6(6):295-299.
12. Rosenblum BI, Giurini JM, Miller LB, et al. Neuropathic ulcerations plantar to the lateral column in patients with Charcot foot deformity: a flexible approach to limb salvage. J Foot Ankle Surg 1997; 36(5):360-363.
13. Laurinaviciene R, Kirketerp-Moeller K, Holstein PE. Exostectomy for chronic midfoot plantar ulcer in Charcot deformity. J Wound Care 2008; 17(2):53-58.

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