Michael S. Pinzur

2012 Infectious Diseases Society of America Clinical Practice Guideline for the Diagnosis and Treatment of Diabetic Foot Infections a

Foot infections are a common and serious problem in persons with diabetes. Diabetic foot infections (DFIs) typically begin in a wound, most often a neuropathic ulceration. While all wounds are colonized with microorganisms, the presence of infection is defined by ≥2 classic findings of inflammation or purulence. Infections are then classified into mild (superficial and limited in size and depth), moderate (deeper or more extensive), or severe (accompanied by systemic signs or metabolic perturbations). This classification system, along with a vascular assessment, helps determine which patients should be hospitalized, which may require special imaging procedures or surgical interventions, and which will require amputation. Most DFIs are polymicrobial, with aerobic gram-positive cocci (GPC), and especially staphylococci, the most common causative organisms. Aerobic gram-negative bacilli are frequently copathogens in infections that are chronic or follow antibiotic treatment, and obligate anaerobes may be copathogens in ischemic or necrotic wounds. Wounds without evidence of soft tissue or bone infection do not require antibiotic therapy. For infected wounds, obtain a post-debridement specimen (preferably of tissue) for aerobic and anaerobic culture. Empiric antibiotic therapy can be narrowly targeted at GPC in many acutely infected patients, but those at risk for infection with antibiotic-resistant organisms or with chronic, previously treated, or severe infections usually require broader spectrum regimens. Imaging is helpful in most DFIs; plain radiographs may be sufficient, but magnetic resonance imaging is far more sensitive and specific. Osteomyelitis occurs in many diabetic patients with a foot wound and can be difficult to diagnose (optimally defined by bone culture and histology) and treat (often requiring surgical debridement or resection, and/or prolonged antibiotic therapy). Most DFIs require some surgical intervention, ranging from minor (debridement) to major (resection, amputation). Wounds must also be properly dressed and off-loaded of pressure, and patients need regular follow-up. An ischemic foot may require revascularization, and some nonresponding patients may benefit from selected adjunctive measures. Employing multidisciplinary foot teams improves outcomes. Clinicians and healthcare organizations should attempt to monitor, and thereby improve, their outcomes and processes in caring for DFIs.

The Charcot Foot in Diabetes

The diabetic Charcot foot syndrome is a serious and potentially limb-threatening lower-extremity complication of diabetes. First described in 1883, this enigmatic condition continues to challenge even the most experienced practitioners. Now considered an inflammatory syndrome, the diabetic Charcot foot is characterized by varying degrees of bone and joint disorganization secondary to underlying neuropathy, trauma, and perturbations of bone metabolism. An international task force of experts was convened by the American Diabetes Association and the American Podiatric Medical Association in January 2011 to summarize available evidence on the pathophysiology, natural history, presentations, and treatment recommendations for this entity.

Energy demands for walking in dysvascular amputees as related to the level of amputation.

Cardiac function and oxygen consumption were measured in 25 patients who underwent amputation for peripheral vascular disease (PVD), and in five similarly aged control patients with PVD. Five patients at each of the midfoot, Symes, below-, through-, and above-knee amputation levels and the five controls were measured at rest, normal walking speed, and maximum walking speed on a treadmill. At normal walking speed, all of the patients functioned at approximately 80% of their cardiac capacity. Normal walking speed and cadence decreased and oxygen consumption per meter walked increased with more proximal amputation. The ratio of cardiac function and oxygen consumption at normal walking speed as compared with at rest increased with more proximal amputation, and the capacity to increase walking speed and oxygen consumption lessened. Our results suggest that peripheral vascular insufficiency amputees function at a level approaching their maximum functional capacity. At more proximal amputation levels, the capacity to walk short or long distances is greatly impaired.

Charcot Ankle Fusion with a Retrograde Locked Intramedullary Nail

Twenty patients with severe neuropathic (Charcot) ankle deformities underwent 21 attempted ankle fusions with a retrograde locked intramedullary nail as an alternative to amputation. All had insensate heel pads and had failed at nonoperative methods of accommodative ambulatory bracing. In 11, the talus was either absent, or the deformity was of sufficient magnitude to require talectomy to align the calcaneus under the tibia for plantigrade weightbearing. Ages ranged from 28 to −68 (average 56.3) years. Nineteen were diabetic, 12 being insulin-dependent. Their average body weight was 102 kg, with 11 greater than 90 kg at the time of surgery. Eight had chronic large full thickness ulcers overlying, but not involving bone of the medial malleolus, medial midfoot, or proximal fifth metatarsal, at the time of surgery. At a follow-up of 12 to 31 months, 19 achieved bony fusion. In the 10 patients where talectomy was not required, fusion was achieved at an average of 5.3 months without complications. In the patients who required talectomy, six of the patients required eight additional operations to achieve fusion. Three achieved fusion following removal of the nail and prolonged bracing. One opted for ankle disarticulation for chronic persistent infection, rather than attempt reoperation. One died of unrelated causes during the early postoperative period. Retrograde locked intramedullary ankle fusion is a reasonable alternative to amputation in the neuropathic (Charcot) ankle that cannot be controlled with standard bracing techniques. The potential for morbidity requiring reoperation is greatly increased when the deformity is of sufficient magnitude to require talectomy to achieve alignment of the calcaneus in a plantigrade weight-bearing position under the tibia or when there are large open ulcers.

Surgical Versus Accommodative Treatment for Charcot Arthropathy of the Midfoot

Background: The treatment of Charcot foot arthropathy is one of the most controversial issues facing orthopaedic foot and ankle surgeons. Although current orthopaedic textbooks are in almost universal agreement that treatment should be nonoperative, accommodating the deformity with orthotic methods, most peer-reviewed clinical studies recommend early surgical correction of the deformity. In a university health system orthopaedic foot and ankle clinic with a special interest in diabetic foot disorders, a moderate approach evolved for management of this difficult patient population. Methods: Patients with Charcot arthropathy and plantigrade feet were treated with accommodative orthotic methods. Those with nonplantigrade feet were treated with surgical correction of the deformity, followed by long-term management with commercial therapeutic footwear. The desired outcome for both groups was long-term management with standard, commercially available, therapeutic depth-inlay shoes and custom-fabricated accommodative foot orthoses. During a 6-year period, 198 patients (201 feet) were treated for diabetes-associated Charcot foot arthropathy. The location of the deformity was in the midfoot in 147 feet, in the ankle in 50, and in the forefoot in four. Results: At a minimum 1-year follow-up, 87 of the 147 feet with midfoot disease (59.2%) achieved the desired endpoint without surgical intervention. Sixty (40.8%) required surgery. Corrective osteotomy with or without arthrodesis was attempted in 42, while debridement or simple exostectomy was attempted in 18 feet. Three patients had initial amputation (one partial foot amputation, one Syme ankle disarticulation, and one transtibial amputation), and five had amputation (two Syme ankle disarticulations and three transtibial amputations) after attempted salvage failed. Conclusion: Using a simple treatment protocol with the desired endpoint being long-term management with commercially available, therapeutic footwear and custom foot orthoses, more than half of patients with Charcot arthropathy at the midfoot level can be successfully managed without surgery.

Current Topics Review: Charcot Neuroarthropathy of the Foot and Ankle:

Charcot arthropathy is a destructive process, most commonly affecting joints of the foot and ankle in diabetics with peripheral neuropathy. Affected individuals present with swelling, warmth, and erythema, often without history of trauma. Bony fragmentation, fracture, and dislocation progress to foot deformity, bony prominence, and instability. This often causes ulceration and deep infection that may necessitate amputation. Instability or deformity may limit the ability to use standard footwear. Treatment is focused on providing a stable and plantigrade foot for functional ambulation with accommodative footwear and orthoses. Historically, treatment had included nonweightbearing immobilization for the acute phase, and surgery had been reserved only for infection, unresolved skin ulceration, or deformity that precluded the use of therapeutic footwear. Current controversies include weightbearing in the acute or reparative phases and early surgical stabilization. Foot-specific patient education and continued periodic monitoring may reduce the morbidity and associated expense of treating the complications of this disorder and may improve the quality of life in this complex patient population.

Neutral ring fixation for high-risk nonplantigrade charcot midfoot deformity

Background: Charcot foot arthropathy negatively impacts the health-related quality of life (HRQL) of affected individuals. The disease process often is responsible for the development of significant deformity and disability, often progressing to lower extremity amputation. Many patients are morbidly obese, immunocompromised, and have complex wounds with underlying bony infection or poor bone quality, making operative correction and internal fixation problematic. Methods: Using a prospective clinical algorithm, 26 consecutive diabetic adults with multiple diabetic co-morbidities, including morbid obesity, had operative correction of nonplantigrade Charcot midfoot deformity at the midfoot level. Correction was maintained with a neutrally applied three-level ring external fixator. Average body mass index was 38.31 ± 12.51. Nineteen patients used insulin. Fourteen had open wounds with underlying osteomyelitis. The altered relationship between the forefoot and hindfoot was measured as 14.04 ± 31.09 degrees in the anteroposterior axis, and 16.70 ± 17.47 degrees in the lateral axis before surgery. Surgery included Achilles tendon lengthening, excision of infected bone, correction of the multiplanar deformity, and culture-specific parenteral antibiotic therapy. Results: At a minimum 1-year followup, 24 of 26 patients were ulcer and infection free and able to ambulate with commercially-available depth-inlay shoes and custom accommodative foot orthoses. One patient died of unrelated causes, and one had transtibial amputation for persistent infection. Four developed recurrent plantar ulcers, which resolved with excision of underlying bony prominences. There were two stress fractures through olive wire pin sites, one requiring intramedullary nailing. The radiographic anteroposterior axis was corrected to 3.12 ± 9.42 degrees, and lateral to 10.42 ± 11.86 degrees after surgery. Conclusions: Morbidly obese diabetic individuals with multiple co-morbidities complicating severe Charcot foot deformity can achieve correction of midfoot deformity after operative correction of the deformity and maintenance of that correction with a neutrally applied ring external fixator.

Lower-Extremity Amputation Risk After Charcot Arthropathy and Diabetic Foot Ulcer

OBJECTIVE To compare risks of lower-extremity amputation between patients with Charcot arthropathy and those with diabetic foot ulcers. RESEARCH DESIGN AND METHODS A retrospective cohort of patients with incident Charcot arthropathy or diabetic foot ulcers in 2003 was followed for 5 years for any major and minor amputations in the lower extremities. RESULTS After a mean follow-up of 37 ± 20 and 43 ± 18 months, the Charcot and ulcer groups had 4.1 and 4.7 amputations per 100 person-years, respectively. Among patients <65 years old at the end of follow-up, amputation risk relative to patients with Charcot alone was 7 times higher for patients with ulcer alone and 12 times higher for patients with Charcot and ulcer. CONCLUSIONS Charcot arthropathy by itself does not pose a serious amputation risk, but ulcer complication multiplicatively increases the risk. Early surgical intervention for Charcot patients in the absence of deformity or ulceration may not be advisable.

Functional outcome following anatomic restoration of tarsal-metatarsal fracture dislocation.

Anatomic restoration of displaced fracture-dislocation of the tarsometatarsal junction of the foot is essential, as even “minor” disruptions of this joint complex leads to poor clinical results. In order to determine a “key” element associated with good or poor functional outcomes, 11 patients with excellent radiographic results following surgical treatment of unilateral closed Lisfranc fracture-dislocation of the tarsometatarsal joint of the foot were evaluated at an average of 41.2 (range, 14 to 53) months following their injury and surgery. Their average age was 40.6 (range, 21 to 58) years. AOFAS midfoot scores averaged 71.0 (range, 30 to 95). Radiographic analysis at follow-up revealed anatomic reduction in 10 of 11. Eight of 11 had evidence of arthritis of the tarsometatarsal joints. Clinical alignment was normal in all subjects, with nine of 11 clinically exhibiting decreased relative range of motion. Gait analysis was performed with the F-Scan (Tekscan, Boston, MA) in-shoe pressure-monitoring system. Vertical ground reaction force was recorded under the hallux, first metatarsal head, lateral metatarsals, and heel. Stance phase duration, rate of loading, rate of unloading, peak loading, and total loading were recorded at each of the named regions. There was no statistical difference in the parameters measured between the injured and normal control feet. The results of this study reveal that when anatomic reduction is accomplished in tarsometatarsal fracture dislocation of the foot, objective measures of gait analysis are returned to normal. In spite of excellent radiographic results and return to normal dynamic walking patterns, subjective patient outcomes were less than satisfactory. It is presently well accepted that fracture-dislocations of the tarsometatarsal junction of the foot are best treated with anatomic restoration by closed, percutaneous or open methods. Many individuals achieve poor functional results. It is well accepted that patients are likely to develop late joint deformity at the tarsometatarsal junction, joint separation, and radiographic and clinical evidence of post-traumatic arthritis when anatomic reduction is not obtained. 1–7 The goal of this study was to determine if clinical results and subjective patient outcomes are assured with anatomic reduction. It appears that the major function of the tarsometatarsal joint complex is the regulation and redirecting of loading forces during weightbearing. There is very limited motion of the tarsometatarsal joint during walking. 8 This knowledge has prompted support for anatomic restoration following injury. Even with seemingly anatomic restoration of normal alignment, many patients fare poorly. The goal of this study was to objectively analyze the components of vertical ground reaction force during walking in patients who had evidence of excellent surgical reduction measured on follow-up weightbearing radiographs following isolated injury to the tarsometatarsal joint complex. We hoped to detect some key element of gait altered by the injury, and responsible for why patients fare poorly following this injury. By dissecting out the components of mechanical loading and unloading of the foot during walking, we wished to determine if there was a “key” factor associated with either favorable or unfavorable subjective clinical outcomes.

Complications of Ankle Fracture in Patients With Diabetes

Abstract Ankle fractures in patients with diabetes mellitus have long been recognized as a challenge to practicing clinicians. Complications of impaired wound healing, infection, malunion, delayed union, nonunion, and Charcot arthropathy are prevalent in this patient population. Controversy exists as to whether diabetic ankle fractures are best treated noninvasively or by open reduction and internal fixation. Patients with diabetes are at significant risk for soft‐tissue complications. In addition, diabetic ankle fractures heal, but significant delays in bone healing exist. Also, Charcot ankle arthropathy occurs more commonly in patients who were initially undiagnosed and had a delay in immobilization and in patients treated nonsurgically for displaced ankle fractures. Several techniques have been described to minimize complications associated with diabetic ankle fractures (eg, rigid external fixation, use of Kirschner wires or Steinmann pins to increase rigidity). Regardless of the specifics of treatment, adherence to the basic principles of preoperative planning, meticulous soft‐tissue management, and attention to stable, rigid fixation with prolonged, protected immobilization are paramount in minimizing problems and yielding good functional outcomes.