Diabetic foot osteomyelitis is common and causes substantial morbidity, including major amputations, yet the optimal treatment approach is unclear. We evaluated an approach to limb salvage that combines early surgical debridement or limited amputation with antimicrobial therapy.
We conducted a retrospective cohort study of patients treated between May 1, 2005, and May 31, 2007. The primary end point was cure, defined as not requiring further treatment for osteomyelitis of the affected limb. The secondary end point was limb salvage, defined as not requiring a below-the-knee amputation or a more proximal amputation.
Fifty patients with diabetic foot osteomyelitis met the study criteria. Initial surgical management included local amputation in 43 patients (86%) and debridement without amputation in seven (14%). Most infections (n = 30; 60%) were polymicrobial, and Staphylococcus aureus was the most common pathogen (n = 23; 46%). Parenteral antibiotics were used in 45 patients (90%). Patients who had pathologic evidence of osteomyelitis at the surgical margin received therapy for a median of 43 days (interquartile range [IQR], 36–56 days), whereas those without evidence of residual osteomyelitis received therapy for a median of 19 days (IQR, 13–40 days). Overall, 32 patients (64%) were considered cured after a median follow-up of 26 months (IQR, 12–38 months). Fifteen of 18 patients (83%) who failed initial therapy were treated again with limb-sparing surgery. Limb salvage was achieved in 47 patients (94%), with only three patients (6%) requiring below-the-knee amputation.
In patients with diabetic foot osteomyelitis, surgical debridement or limited amputation plus antimicrobial therapy is effective at achieving clinical cure and limb salvage. (J Am Podiatr Med Assoc 102(4): 273–277, 2012)
We aimed to evaluate surrogate markers commonly used in the literature for diabetic foot osteomyelitis remission after initial treatment for diabetic foot infections (DFIs).
Thirty-five patients with DFIs were prospectively enrolled and followed for 12 months. Osteomyelitis was determined from bone culture and histologic analysis initially and for recurrence. Fisher exact and χ2 tests were used for dichotomous variables and Student t and Mann-Whitney U tests for continuous variables (α = .05).
Twenty-four patients were diagnosed as having osteomyelitis and 11 as having soft-tissue infections. Four patients (16.7%) with osteomyelitis had reinfection based on bone biopsy. The success of osteomyelitis treatment varied based on the surrogate marker used to define remission: osteomyelitis infection (16.7%), failed wound healing (8.3%), reulceration (20.8%), readmission (16.7%), amputation (12.5%). There was no difference in outcomes among patients who were initially diagnosed as having osteomyelitis versus soft-tissue infections. There were no differences in osteomyelitis reinfection (16.7% versus 45.5%; P = .07), wounds that failed to heal (8.3% versus 9.1%; P = .94), reulceration (20.8% versus 27.3%; P = .67), readmission for DFIs at the same site (16.7% versus 36.4%; P = .20), amputation at the same site after discharge (12.5% versus 36.4%; P = .10). Osteomyelitis at the index site based on bone biopsy indicated that failed therapy was 16.7%. Indirect markers demonstrated a failure rate of 8.3% to 20.8%.
Most osteomyelitis markers were similar to markers in soft-tissue infection. Commonly reported surrogate markers were not shown to be specific to identify patients who failed osteomyelitis treatment compared with patients with soft-tissue infections. Given this, these surrogate markers are not reliable for use in practice to identify osteomyelitis treatment failure.
BACKGROUND: Diabetic Foot Osteomyelitis (DFO) is a common infection where treatment involves multiple services including Infectious Disease (ID), Podiatry, and Pathology. Despite its ubiquity in the hospital, consensus on much of its management is lacking. METHODS: Representatives from ID, Podiatry, and Pathology interested in quality improvement (QI) developed multidisciplinary institutional recommendations culminating in an educational intervention describing optimal diagnostic and therapeutic approaches to DFO. Knowledge acquisition was assessed by pre- and post-intervention surveys. Inpatients with forefoot DFO were retrospectively reviewed pre- and post- intervention to assess frequency of recommended diagnostic and therapeutic maneuvers, including appropriate definition of surgical bone margins, definitive histopathology reports, and unnecessary intravenous antibiotics or prolonged antibiotic courses. RESULTS: A post-intervention survey revealed significant improvements in knowledge of antibiotic treatment duration and the role of oral antibiotics in managing DFO. There were 104 consecutive patients in the pre-intervention cohort (4/1/2018-4/1/2019) and 32 patients in the post-intervention cohort (11/5/2019-03/01/2020), the latter truncated by changes in hospital practice during the COVID-19 pandemic. Non-categorizable or equivocal pathology reports decreased from pre-intervention to post-intervention (27.0% vs 3.3%, respectively, P=0.006). We observed non-significant improvement in correct bone margin definition (74.0% vs 87.5%, p=0.11), unnecessary PICC line placement (18.3% vs 9.4%, p=0.23), and unnecessary prolonged antibiotics (21.9% vs 5.0%, p=0.10). Additionally, by working as an interdisciplinary group, many solvable misunderstandings were identified, and processes were adjusted to improve the quality of care provided to these patients. CONCLUSIONS: This QI initiative regarding management of DFO led to improved provider knowledge and collaborative competency between these three departments, improvements in definitive pathology reports, and non-significant improvement in several other clinical endpoints. Creating collaborative competency may be an effective local strategy to improve knowledge of diabetic foot infection and may generalize to other common multidisciplinary conditions.
Below-the-knee amputation (BKA) can be a detrimental outcome of diabetic foot osteomyelitis (DFO). Ideal treatment of DFO is controversial, but studies suggest minor amputation reduces the risk of BKA. We evaluated risk factors for BKA after minor amputation for DFO.
This is a retrospective cohort of patients discharged from Denver Health Medical Center from February 1, 2012, through December 31, 2014. Patients who underwent minor amputation for diagnosis of DFO were eligible for inclusion. The outcome evaluated was BKA in the 6 months after minor amputation.
Of 153 episodes with DFO that met the study criteria, 11 (7%) had BKA. Failure to heal surgical incision at 3 months (P < .001) and transmetatarsal amputation (P = .009) were associated with BKA in the 6 months after minor amputation. Peripheral vascular disease was associated with failure to heal but not with BKA (P = .009). Severe infection, bacteremia, hemoglobin A1c, and positive histopathologic margins of bone and soft tissue were not associated with BKA. The median antibiotic duration was 42 days for positive histopathologic bone resection margin (interquartile range, 32–47 days) and 16 days for negative margin (interquartile range, 8–29 days). Longer duration of antibiotics was not associated with lower risk of BKA.
Patients who fail to heal amputation sites in 3 months or who have transmetatarsal amputation are at increased risk for BKA. Future studies should evaluate the impact of aggressive wound care or whether failure to heal is a marker of another variable.
We investigated the validity of probe-to-bone testing in the diagnosis of osteomyelitis in a selected subgroup of patients clinically suspected of having diabetic foot osteomyelitis.
Between January 1, 2007, and December 31, 2008, inpatients and outpatients with a diabetic foot ulcer were prospectively evaluated, and those having a clinical diagnosis of foot infection and at least one of the osteomyelitis clinical suspicion criteria were consecutively included in this study.
Sixty-five patients met the inclusion criteria and were prospectively enrolled in the study. Forty-nine patients (75.4%) were hospitalized, and the remaining 16 (24.6%) were followed as outpatients. Osteomyelitis was diagnosed in 39 patients (60.0%). Probe-to-bone test results were positive in 30 patients (46.1%). The positive predictive value for the probe-to-bone test was fairly high (87%), but the negative predictive value was only 62%. The sensitivity and specificity of the test were 66% and 84%, respectively. White blood cell counts and mean C-reactive protein levels did not statistically significantly differ between groups. However, erythrocyte sedimentation rates greater than 70 mm/h reached statistical significance between groups. Wound area and depth were not found to be statistically significantly different between groups.
Positive probe-to-bone test results and erythrocyte sedimentation rates greater than 70 mm/h provide some support for the diagnosis of diabetic foot osteomyelitis, but it is not strong; magnetic resonance imaging or bone biopsy will probably be required in cases of doubt. (J Am Podiatr Med Assoc 102(5): 369–373, 2012)
Background: We sought to determine the similarity of pathogens isolated from soft tissue and bone in patients with diabetic foot infections. It is widely believed that soft-tissue cultures are adequate in the determination of causative bacteria in patients with diabetic foot osteomyelitis. The culture results of specimens taken concurrently from soft-tissue and bone infections show that the former does not predict the latter with sufficient reliability. We sought to determine the similarity of pathogens isolated from soft tissue and bone in patients with diabetic foot infections.
Methods: Forty-five patients with diabetic foot infections were enrolled in the study. Patients had to have clinically suspected foot lesions of grade 3 or higher on the Wagner classification system. In patients with clinically suspected osteomyelitis, magnetic resonance imaging, scintigraphy, or histopathologic examination were performed. Bone and deep soft tissue specimens were obtained from all patients by open surgical procedures under aseptic conditions during debridement or amputation. The specimens were compared only with the other specimens taken from the same patients.
Results: The results of bone and soft-tissue cultures were identical in 49% (n = 22) of cases. In 11% (n = 5) of cases there were no common pathogens. In 29% (n = 13) of cases there were more pathogens in the soft-tissue specimens; these microorganisms included microbes isolated from bone cultures. In four patients (9%) with culture-positive soft-tissue specimens, bone culture specimens remained sterile. In one patient (2%) with culture-positive bone specimen, soft-tissue specimen remained sterile.
Conclusion: Culture specimens should be obtained from both the bone and the overlying deep soft tissue in patients with suspected osteomyelitis whose clinical conditions are suitable. The decision to administer antibiotic therapy should depend on these results. (J Am Podiatr Med Assoc 98(4): 290–295, 2008)
A universally accepted histopathologic classification of diabetic foot osteomyelitis does not currently exist. We sought to evaluate the histopathologic characteristics of bone infection found in the feet of diabetic patients and to analyze the clinical variables related to each type of bone infection.
We conducted an observational prospective study of 165 diabetic patients with foot ulcers who underwent surgery for bone infection. Samples for microbiological and histopathologic analyses were collected in the operating room under sterile conditions.
We found four histopathologic types of osteomyelitis: acute osteomyelitis (n = 46; 27.9%), chronic osteomyelitis (n = 73; 44.2%), chronic acute osteomyelitis (n = 14; 8.5%), and fibrosis (n =32; 19.4%). The mean ± SD time between the initial detection of ulcer and surgery was 15.4 ± 23 weeks for acute osteomyelitis, 28.6 ± 22.4 weeks for chronic osteomyelitis, 35 ± 31.3 weeks for chronic acute osteomyelitis, and 27.5 ± 27.3 weeks for the fibrosis stage (analysis of variance: P = .03). Bacteria were isolated and identified in 40 of 46 patients (87.0%) with acute osteomyelitis, 61 of 73 (83.5%) with chronic osteomyelitis, 11 of 14 (78.6%) with chronic acute osteomyelitis, and 25 of 32 (78.1%) with fibrosis.
Histopathologic categorization of bone infections in the feet of diabetic patients should include four groups: acute, chronic, chronic acute, and fibrosis. We suggest that new studies should identify cases of fibrosis to allow comparison with the present results. (J Am Podiatr Med Assoc 103(1): 24–31, 2013)
INTRODUCTION AND OBJECTIVES: Corynebacterium striatum (C. striatum) is known to colonize the skin and mucous membranes of most normal human hosts. While it is frequently isolated in clinical laboratories, the clinical significance of C. striatum is often unknown with respect to diabetic foot infections with osteomyelitis. There have been very few studies published on this topic, and even fewer that report on treatment courses. To our knowledge, there has been no study published reporting diabetic foot osteomyelitis with isolation of C. striatum from bone culture.
METHODS: Four patients were known to have been treated at our facility for C. striatum diabetic foot osteomyelitis. The medical records for each patient were thoroughly reviewed with close attention directed towards the past medical history, wound duration, wound and bone cultures, antimicrobial therapy and clinical outcomes.
RESULTS: Bone cultures of all 4 patients were notable for C. striatum. Diphtheroids were also noted on wound cultures for 3 patients which were not speciated. All bone cultures were obtained during surgical treatment of the diabetic foot infection. All patients were type II diabetics but varied with respect to age and gender. All patients were treated with an extended course of antibiotics and/or surgical resection of osteomyelitis. Patients were followed until complete wound closure.
CONCLUSIONS: We report four cases of diabetic foot osteomyelitis in which C. striatum was noted and treated as a pathogen. Diphtheroids are often overlooked as a potential pathogen in diabetic foot infections and rarely treated as such. However, our findings suggest that clinicians should consider C. striatum as a possible cause of osteomyelitis, especially when patients fail to completely heal wounds in a timely manner that have previously and repeatedly displayed Diphtheroids from cultures.
Several nonbiodegradable and biodegradable antibiotic cement delivery systems are available for the delivery of antibiotics for adjunctive therapy in the management of osteomyelitis. A major nonbiodegradable delivery system is polymethylmethacrylate beads. Antibiotics that can be incorporated into this delivery system are limited to the heat-stable antibiotics vancomycin and aminoglycosides, tobramycin being the most popular. Calcium sulfate and hydroxyapatite (Cerament Bone Void Filler) is a unique biocompatible and biodegradable ceramic bone void filler that can successfully deliver heat-stable and heat-unstable antibiotics in musculoskeletal infections. The use of Cerament as antibiotic beads has not been previously reported. An off-label case of diabetic foot osteomyelitis successfully managed with surgical bone resection and vancomycin Cerament antibiotic beads is presented. Subsequent surgery for the bone infection and staged removal of the antibiotic beads was not necessary. (J Am Podiatr Med Assoc 101(3): 259–264, 2011)
The preferred primary treatment of toe osteomyelitis in diabetic patients is controversial. We compared the outcome of primary nonoperative antibiotic treatment versus digital amputation in patients with diabetes-related chronic digital osteomyelitis.
We conducted a retrospective medical record review of patients treated for digital osteomyelitis at a single center. Patients were divided into two groups according to initial treatment: 1) nonoperative treatment with intravenous antibiotics and 2) amputation of the involved toe or ray. Duration of hospitalization, number of rehospitalizations, and rate of below- or above-the-knee major amputations were evaluated.
The nonoperative group comprised 39 patients and the operative group included 21 patients. The mean ± SD total duration of hospitalization was 24.05 ± 15.43 and 20.67 ± 15.97 days, respectively (P = .43). The mean ± SD number of rehospitalizations after infection recurrence was 2.62 ± 1.63 and 1.67 ± 1.24, respectively (P = .02). During follow-up, the involved digit was eventually amputated in 13 of the 39 nonoperatively treated patients (33.3%). The rate of major amputation (above- or below-knee amputation was four of 39 (10.3%) and three of 21 (14.3%), respectively (P = .69).
Despite a higher rate of rehospitalizations and a high failure rate, in patients with mild and limited digital foot osteomyelitis in the absence of sepsis it may be reasonable to offer a primary nonoperative treatment for digital osteomyelitis of the foot.