Culture Concordance in Different Sections of the Metatarsal Head: Interpretations of Microbiological Results.

Microbiological cultures of per-wound bone biopsies have shown a lack of correlation and a high rate of false-negative results when compared with bone biopsy cultures in diabetic foot osteomyelitis. The selection of samples from the area of active osteomyelitis, which contains a complete census of the microorganisms responsible for the infection, is essential to properly guide antimicrobial treatment. We aimed to comparatively evaluate the quantitative and qualitative cultures taken from different areas, in metatarsal heads resected for osteomyelitis. For this purpose, we consecutively selected 13 metatarsal heads from 12 outpatients with plantar ulcers admitted to our diabetic foot unit. Metatarsal heads were divided transversally into 3 portions: plantar (A), central (B), and dorsal (C), and the 39 resulting samples were cultured. Qualitative and quantitative microbiological analysis was performed, and the isolated species and bacterial load, total and species specific, were compared between the 3 metatarsal bone segments. The primary outcome of the study was the bacterial diversity detected in the different bone sections. Cultures were positive in 12 of the 13 included metatarsal heads (92%). A total of 34 organisms were isolated from all specimens. Ten of the 12 cultures (83%) were polymicrobial. Ten of the 13 metatarsal heads (77%) had identical microbiological results in each of the 3 bone sections. The largest number of microorganisms was found in the central section. The overall concordance between sections was 91%. The predominant microorganisms were coagulase-negative staphylococci (41%). Statistical differences were not found in the bioburden between sections (range 3.25-3.41 log10 colony-forming unit/g for all sections; P = .511). The results of our study suggest that microorganisms exhibit a high tendency to spread along the metatarsal bone and that the degree of progression along the bone is species dependent. The central portions of metatarsal bones tend to accumulate a higher diversity of species. Thus, we recommend this area of bone for targeted biopsy in patients with suspected osteomyelitis.

Role of inflammatory markers in the healing time of diabetic foot osteomyelitis treated by surgery or antibiotics.

OBJECTIVE: To analyse the predictive role of inflammatory markers in the healing time of diabetic foot osteomyelitis treated by surgery or antibiotics. METHODS: An observational study of patients with diabetic foot ulcers (DFU) and clinically suspected osteomyelitis. The patients underwent surgical or antibiotic treatment for bone infection in a specialised diabetic foot unit. Blood samples were taken from each patient to analyse biomarkers. The main outcome was the number of weeks until healing occurred. RESULTS: A total of 116 patients took part in the study. The number of weeks until healing was similar for both groups (surgical n=96 and antiobiotic n=20, treatments). No association was observed among biomarkers as predictors of time-to-healing. CONCLUSION: There is not enough evidence to define the prognostic role of inflammatory markers in the healing time of DFUs complicated with diabetic foot osteomyelitis, regardless of the treatment administered.

Early Foot Structural Changes After Lateral Column Exostectomy in Patients With Charcot Foot.

Although exostectomy for chronic midfoot plantar ulcers in Charcot foot is apparently effective, with healing rates of nearly 75%, a subset of patients develop recurrent ulceration and show an unstable foot position, especially after undergoing exostectomy confined to the lateral column. The reasons for this failure have not been investigated. The main objective of this study was to evaluate the early changes in radiographic alignment after an exostectomy in patients with Charcot neuropathic osteoarthropathy (rocker bottom) and plantar ulcer located in the lateral column. The present study evaluated retrospectively changes in radiographic alignment after an exostectomy in 12 Charcot feet (rocker bottom) with plantar ulcer located in the lateral column. Indication for plantar exostectomy was the treatment of ulcer affected by osteomyelitis. We evaluated the early changes in the alignment of the foot on weight-bearing lateral radiographs 6 months after exostectomy. Paired sample Wilcoxon test was used to calculate the differences between preoperative and postoperative measurements. Furthermore, the relationship between revision surgery and early changes in radiographic angular measurements was determined by using the Mann-Whitney U test. After exostectomy, the inclination of the calcaneal bone decreased (P = .003; r = 0.849) and declination of talus bone increased (P = .041; r = 0.589). The change in calcaneal inclination was associated with revision surgery (P = .042; r = 0.586). The present case series demonstrates that exostectomy procedure for the lateral column in patients with Charcot foot results in radiological changes in the hindfoot over the sagittal plane. The inversion of the calcaneal pitch angle suggests the possibility of further adverse events and the need for revision surgery.