Characteristics of non-diabetic foot ulcers in Western Sydney, Australia

Effect of Sensory Neuropathy on the Predictive Value of Inflammatory Biomarkers for Osteomyelitis in Diabetic and Nondiabetic Patients with Foot Infections

OBJECTIVE

To investigate the predictive value of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) in persons with and without diabetes with osteomyelitis (OM).

METHODS

We evaluated 455 patients in a retrospective cohort study of patients admitted to the hospital with diabetic foot OM (n = 177), diabetic foot soft-tissue infections (STIs) (n = 176), nondiabetic OM (n = 51), and nondiabetic STIs (n = 51). Infection diagnosis was determined through bone culture, histopathologic examination for OM, and/or imaging (magnetic resonance imaging/single-photon emission computed tomography) for STI. The optimal cutoff values of ESR and CRP in predicting OM were determined by receiver operating characteristic curve analysis. Sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios were determined through contingency tables.

RESULTS

In persons without diabetes with STI or OM, the mean ESR and CRP differences were 10.0 mm/h and 2.6 mg/dL, respectively. In contrast, persons with diabetes had higher levels of each: 24.8 mm/h and 6.8 mg/dL, respectively. As a result, ESR and CRP predicted OM better in patients with diabetes. However, when patients were stratified by neuropathy status, ESR remained predictive of OM in diabetic patients with neuropathy (75% sensitivity, 58% specificity) but not in diabetic patients without neuropathy (50% sensitivity, 44% specificity). Also, CRP remained predictive irrespective of neuropathy status. A similar trend was observed in patients without diabetes.

CONCLUSIONS

Previous studies have reported that ESR and CRP are predictive of OM. However, this study suggests that neuropathy influences the predictive value of inflammatory biomarkers. The underlying mechanisms require further study.

Factors influencing lower extremity amputation outcomes in people with active foot ulceration in regional Australia: A retrospective cohort study

Australia has the second highest rate of non-traumatic lower extremity amputation (LEA) globally. Australia's large geographical size is one of the biggest challenges facing limb preservation services and may be contributing to LEA. The aim of this study was to determine what factors contribute to the likelihood of LEA in people with active foot ulceration in regional Australia. This retrospective cohort study audited patients with active foot ulceration in a multidisciplinary high risk foot service (HRFS) in regional Australia. Neurological, vascular and wound characteristics were systematically extracted, along with demographic information. Participants were followed for at least 12 months until healing or LEA occurred. Correlations between LEA and clinical and demographic characteristics were assessed using the Pearson's product moment correlation coefficient and chi squared test for independence. Significant variables (p < 0.05) were included in the model. Direct logistic regression assessed the independent contribution of significantly correlated variables on the likelihood of LEA. Of note, 1876 records were hand screened with 476 participants (25%) meeting the inclusion criteria. Geographical distance from the HRFS, toe systolic pressure (TSP), diabetes and infection were all significantly correlated with LEA and included in the logistic regression model. TSP decrease of 1 mmHg (OR 1.02, 95% CI 1.01-1.03), increased geographical distance (1 km) from HRFS (OR 1.006, 95% CI 1.001-1.01) infection (OR 2.08, 95% CI 1.06-4.07) and presence of diabetes (OR 3.77, 95% CI 1.12-12.65) were all significantly associated with increased likelihood of LEA. HRFS should account for the disparity in outcomes between patients living in close proximity to their service, compared to those in rural areas. Optimal management of diabetes, vascular perfusion and control of infection may also contribute to preventing LEA in people with active foot ulceration.

Clinical Outcomes of Foot Infections in Patients Without Diabetes

The aim of this study was to report clinical outcomes of moderate and severe foot infections in patients without diabetes. Medical records of 88 nondiabetic patients with foot infections treated at a safety net hospital were retrospectively reviewed. Patients were grouped by the presence of soft-tissue infection (STI) or osteomyelitis (OM). The diagnosis of OM was determined by positive bone culture or histopathology. STIs were defined by negative bone biopsy or negative imaging with magnetic resonance imaging or computed tomography/dual-modality radiolabeled white blood cell single-photon emission computed tomography. Patient outcomes were recorded ≤1 year after admission. Eighty-eight nondiabetic patients admitted to our institution for moderate or severe foot infections were included, 45 OM and 43 STI. No differences were noted in patient characteristics except that OM patients had a higher prevalence of neuropathy (66.7% versus 39.5%, p = .02). OM patients required surgery more often (97.8% versus 67.4%, p < .01), a greater number of surgeries (2.0 ± 1.2 versus 1.4 ± 1.3, p = .02), and more amputations (75.6% versus 11.6%, p < .01) than STI patients. OM patients had a higher proportion of wounds that healed (82.2% versus 62.8%, p = .04). There were no significant differences in reinfection (35.6% versus 25.6%, p = .36), foot-related readmission to hospital (35.6% versus 23.3%, p = .25), or total duration of antibiotics (13.9 ± 10.2 versus 13.5 ± 12.9, p = .87) between OM and STI patients. In conclusion, OM patients required more surgeries and amputations than patients with STIs; however, they had similar rates of reinfection and readmission within a year after the index hospitalization.

Long-term results after internal partial forefoot amputation (resection): a retrospective analysis

INTRODUCTION

Internal partial forefoot amputation (IPFA) is a treatment option for osteomyelitis and refractory and recurrent chronic ulcers of the forefoot. The aim of our study was to assess the healing rate of chronic ulcers, risk of ulcer recurrence at the same area or re-ulceration at a different area and revision rate in patients treated with IPFA.

MATERIALS AND METHODS

All patients who underwent IPFA of a phalanx and/or metatarsal head and/or sesamoids at our institution because of chronic ulceration of the forefoot and/or osteomyelitis from 2004 to 2014 were included. Information about patient characteristics, ulcer healing, new ulcer occurrence, and revision surgery were collected. Kaplan-Meier survival curves were plotted for new ulcer occurrence and revision surgery.

RESULTS

A total of 102 patients were included (108 operated feet). 55.6% of our patients had diabetes. In 44 cases, an IPFA of a phalanx was performed, in 60 cases a metatarsal head resection and in 4 cases an isolated resection of sesamoids. The mean follow-up was 40.9 months. 91.2% of ulcers healed after a mean period of 1.3 months. In 56 feet (51.9%), a new ulcer occurred: 11 feet (10.2%) had an ulcer in the same area as initially (= ulcer recurrence), in 45 feet (41.7%) the ulcer was localized elsewhere (= re-ulceration). Revision surgery was necessary in 39 feet (36.1%). Only one major amputation and five complete transmetatarsal forefoot amputations were necessary during the follow-up period. Thus, the major amputation rate was 0.9%, and the minor amputation rate on the same ray was 13.9%.

CONCLUSIONS

IPFA is a valuable treatment of chronic ulcers of the forefoot. However, new ulceration is a frequent event following this type of surgery. Our results are consistent with the reported re-ulceration rate after conservative treatment of diabetic foot ulcers. The number of major amputations is low after IPFA.

LEVEL OF EVIDENCE

Retrospective Case Series Study (Level IV).

Tibial cortex transverse transport facilitating healing in patients with recalcitrant non-diabetic leg ulcers

OBJECTIVE

The treatment of recalcitrant not-diabetic leg ulcers remains challenging. Distraction osteogenesis is accompanying by angiogenesis and neovascularization in the surrounding tissues. We previously applied tibial cortex transverse transport (TTT) to patients with recalcitrant diabetic foot ulcers and found neovascularization and increased perfusion in the foot and consequently enhanced healing and limb salvage and reduced recurrence. However, the effects of TTT on recalcitrant non-diabetic leg ulcer remains largely unknown.

METHODS

Consecutive patients (n ​= ​85) with recalcitrant non-diabetic leg ulcers (University of Texas Grade 2-B to 3-D, ie, wound penetrating to the tendon, capsule, bone, or joint with infection and/or ischemia) were recruited and divided into TTT (n ​= ​42) and control (n ​= ​43) groups based on the treatment they received. There were 36 (85.7%) arterial ulcers, 4 (9.5%) venous ulcers and 2 (4.8%) mixed ulcers in the TTT group and 32 (74.4%) arterial ulcers, 7 (16.7%) venous ulcers and 4 (9.3%) mixed ulcers in the control group (p ​> ​0.05). The two groups were matched on demographic and clinical characteristics. Patients in the TTT group underwent tibial corticotomy followed by 4 weeks of distraction medially then laterally, while those in the control group received conventional surgeries (debridements, revascularization, reconstruction with flaps, or skin grafts or equivalents). Ulcer healing and healing time, limb salvage, recurrence, and patient death were evaluated at a 1-year follow-up. Changes in leg small vessels were assessed in the TTT group using computed tomography angiography (CTA).

RESULTS

TTT group had higher healing rates at 1-year follow-up than the control group (78.6% [33/42] vs. 58.1% [25/43], OR 2.64 [95% CI 1.10 to 6.85], p ​= ​0.04). The healing time of the TTT group was shorter than the control group (4.5 vs. 6.1 months, mean difference -1.60 [95% CI -2.93 to -0.26], p ​= ​0.02). There were no significant differences in rates of major amputation, reulceration, or mortality between the groups (p ​> ​0.05). TTT group displayed more small vessels 4 weeks postoperatively at the wound area, the foot, and the calf of the ipsilateral side in CTA. All patients in the TTT group achieved good union at the osteotomy site and had no skin or soft tissue necrosis or infection around the incision area.

CONCLUSION

The findings showed that TTT facilitated the healing of recalcitrant non-diabetic leg ulcers and reduced the healing time compared with conventional surgeries. They suggest that TTT is an effective procedure to treat recalcitrant non-diabetic foot ulcers compared with standard surgical therapy. The procedure of TTT is relatively simple. Randomized controlled trials are required to confirm these findings.

THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE

TTT can be used as an effective treatment for recalcitrant non-diabetic leg ulcers in patients. The mechanism may be associated with the neovascularization in the ulcerated foot induced by TTT and consequently increased perfusion. Together with previous findings from recalcitrant diabetic leg ulcers, the findings suggest TTT as an effective procedure to treat recalcitrant chronic leg ulcers.

Diagnostic Utility of Erythrocyte Sedimentation Rate and C-Reactive Protein in Osteomyelitis of the Foot in Persons Without Diabetes

The aim of the study was to assess the diagnostic value of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels in differentiating foot osteomyelitis (OM) from soft tissue infection (STI) in persons without diabetes. We evaluated 102 patients in a retrospective cohort study of nondiabetic patients admitted to our institution with OM (n = 51) and with STI (n = 51). Patient diagnosis was determined through bone culture and/or histopathology for OM and magnetic resonance scan and/or single-photon emission computed tomography for STI. Cutoffs for ESR and CRP to predict OM as identified by receiver operating characteristic were 45.5 mm/h and 3.45 mg/dL, respectively. The ESR cutoff demonstrated a sensitivity and specificity of 49% and 79%, while the values for CRP were 45% and 71%, respectively. The combined sensitivity and specificity for ESR and CRP were 33% and 84%. The positive and negative predictive values were 68% and 60% for ESR and 61% and 56% for CRP, respectively. In conclusion, ESR and CRP demonstrate poor sensitivity and specificity for detecting OM in the nondiabetic foot. These markers have little diagnostic utility in the nondiabetic foot.