Comparative evaluation of transcutaneous oxygen tension and ankle-brachial index as predictors of reoperation following below-knee amputation.

OBJECTIVE: Decision-making regarding level of lower extremity amputation is sometimes challenging. Selecting an appropriate anatomic level for major amputation requires consideration of tradeoffs between postoperative function and risk of wound complications that may require additional operations, including debridement and/or conversion to above-knee amputation (AKA). We evaluated the utility of common, non-invasive diagnostic tests used in clinical practice to predict the need for reoperations among patients undergoing primary, elective, below knee-amputations (BKAs) by vascular surgeons. METHODS: Patients undergoing elective BKA over a 5-year period were identified using Current Procedural Terminology codes. Medical records were reviewed to characterize demographics, pre-amputation testing transcutaneous oxygen tension (TcPO2), and ankle-brachial index (ABI). The need for ipsilateral post-BKA reoperation (including BKA revision and/or conversion to AKA) regardless of indication was the primary outcome. Associations were evaluated using univariable and multivariable logistic regression models. Cutpoints for TcPO2 values associated with amputation reoperation were evaluated using receiver operating characteristic curves. RESULTS: We identified 175 BKAs, of which 46 (26.3%) required ipsilateral reoperation (18.9% BKA revisions and 14.3% conversions to AKA). The mean age was 63.3 ± 14.8 years. Most patients were male (65.1%) and White (72.0%). Mean pre-amputation calf TcPO2 was 40.0 ± 20.5 mmHg, and mean ABI was 0.64 ± 0.45. In univariable models, post-BKA reoperation was associated with calf TcPO2 (odds ratio [OR], 0.97; 95% confidence interval [CI], 0.94-0.99; P = .013) but not ABI (OR, 0.53; 95% CI, 0.19-1.46; P = .217). Univariable associations with reoperation were also identified for age (OR, 0.97; 95% CI, 0.94-0.990; P = .003) and diabetes (OR, 0.43; 95% CI, 0.21-0.87; P = .019). No associations with amputation revision were identified for gender, race, end-stage renal disease, or preoperative antibiotics. Calf TcPO2 remained associated with post-BKA reoperation in a multivariable model (OR, 0.97; 95% CI, 0.94-0.99; P = .022) adjusted for age (OR, 0.98; 95% CI, 0.94-1.01; P = .222) and diabetes (OR, 0.98; 95% CI, 0.94-1.01; P = .559). Receiver operating characteristic analysis suggested a TcPO2 ≥38 mmHg as an appropriate cut-point for assessing risk for BKA revision (area under the curve = 0.682; negative predictive value, 0.91). CONCLUSIONS: Reoperation after BKA is common, and reoperation risk was associated with pre-amputation TcPO2. For patients undergoing elective BKA, higher risk of reoperation should be discussed with patients with an ipsilateral TcPO2 <38 mmHg.

The impact of diabetes on mortality rates after lower extremity amputation.

OBJECTIVE: To assess the impact of diabetes, amputation level, sex and age on mortality rates after lower extremity amputation (LEA) in Belgium, and to assess temporal trends in one-year survival rates from 2009 to 2018. METHODS: Nationwide data on individuals who underwent minor and major LEA from 2009 to 2018 were collected. Kaplan-Meier survival curves were constructed. A Cox regression model with time-varying coefficients was used to estimate the likelihood of mortality after LEA in individuals with or without diabetes. Matched amputation-free individuals with or without diabetes were used for comparison. Time trends were analysed. RESULTS: Amputations 41,304 were performed: 13,247 major and 28,057 minor. Five-year mortality rates in individuals with diabetes were 52% and 69% after minor and major LEA, respectively (individuals without diabetes: 45% and 63%, respectively). In the first six postoperative months, no differences in mortality rates were found between individuals with or without diabetes. Later, hazard ratios (HRs) for mortality in individuals with diabetes (compared with no diabetes) after minor LEA ranged from 1.38 to 1.52, and after major LEA from 1.35 to 1.46 (all p ≤ 0.005). Among individuals without LEA, HRs for mortality in diabetes (versus no diabetes) were systematically higher compared to the HRs for mortality in diabetes (versus no diabetes) after minor and major LEA. One-year survival rates did not change for individuals with diabetes. CONCLUSIONS: In the first six postoperative months, mortality rates after LEA were not different between individuals with or without diabetes; later, diabetes was significantly associated with increased mortality. However, as HRs for mortality were higher in amputation-free individuals, diabetes impacts mortality less in the minor and major amputation groups relative to the comparison group of individuals without LEA.

The incidence of lower extremity amputation and its associated risk factors in patients with diabetic foot ulcers: A meta-analysis.

This study analysed the incidence of lower extremity amputation and its associated risk factors in patients with diabetic foot ulcers. This study systematically searched both Chinese and English databases, including CNKI, Wanfang, VIP, PubMed, EMBASE and Web of Science, to identify cohort studies related to lower extremity amputation and associated risk factors in patients with diabetic foot ulcers up to October 2023. The patients were stratified based on whether they underwent lower extremity amputation, and relevant data, including basic information, patient characteristics, complications, comorbidities and pertinent laboratory test data, were extracted from the included studies. The literature quality assessment in this study utilized the Newcastle-Ottawa Scale to screen for high-quality literature, resulting in the inclusion of 16 cohort studies, all of which were of at least moderate quality. Meta-analysis of outcome indicators was conducted using the Stata 14.0 software. The results indicate that the overall amputation rate of lower extremities in patients with diabetic foot ulcers is 31% (0.25, 0.38). Among the 16 variables evaluated, gender (male), smoking history, body mass index (BMI), hypertension, cardiovascular disease, kidney disease, white blood cell count, haemoglobin and albumin levels were found to be correlated with the occurrence of lower extremity amputation in patients with diabetic foot ulcers. However, no significant correlation was observed between age, diabetes type, duration of diabetes, stroke, glycosylated haemoglobin, creatinine and total cholesterol levels and lower extremity amputation in patients with diabetic foot ulcers. This meta-analysis indicates that the overall amputation rate in patients with diabetic foot ulcers is 31%. Factors such as gender (male), smoking history, high BMI, hypertension, cardiovascular disease, kidney disease, white blood cell count, haemoglobin and albumin levels are identified as significant risk factors for lower extremity amputation in diabetic foot ulcer patients. These findings suggest that attention should be focused on these risk factors in patients with diabetic foot ulcers to reduce the risk of lower extremity amputation. Therefore, preventive and intervention measures targeting these risk factors are of significant importance in clinical practice. (Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/, identifier [CRD42024497538]).

A critical literature review highlighting the methodological differences within epidemiological studies: Pedal Amputations in England.

INTRODUCTION: There is an absence in the application of standardised epidemiological principles when calculating and reporting on lower extremity amputation (LEA) rates [1]. The rates of minor LEAs in the diabetic population range from 1.2-362.9 per 100,000 and in the population without diabetes 0.9-109.4 per 100,000. The reported rates of major lower limb amputations vary from 5.6-600 per 100,000 in the diabetic population and 3.6-58.7 per 100,000 in the total population [1]. The variation in methodology does not facilitate comparison across populations and time. All studies published using the population from England, UK, describing minor amputations were systematically reviewed and rates and methodologies compared. METHOD: A systematic search was carried out using (PRISMA) guidelines [2] to reveal primary data of minor lower extremity amputation rates in England between 1988-2018. This was carried out using electronic databases, grey literature and reference list searching. The search yielded eleven studies that were eligible for review. RESULTS: Significant variation in the reporting of minor lower extremity amputation rates across regional and gender groups in England was found. Rates in the diabetic and non-diabetic population varied from 1.2 to 362.9 per 100,000 and 0.9 to 109.4 per 100,000 respectively. This was predominately a result of poorly describing numerator and denominator populations and defining minor amputations differently. As a result, there was an inability to confidently establish regional, gender and time trends. CONCLUSION: The inconsistent nature of reporting minor amputations makes drawing conclusions on temporal and population change difficult. Future studies should describe and present basic numerator and denominator population characteristics e.g. number, age and sex and use the standard definition of minor amputation as one that is at or below the ankle.

The continued financial effect of COVID: Increasing costs for non-elective major lower extremity amputations.

Background: The COVID-19 pandemic necessitated changes in processes of care, which significantly impacted surgical care. This study evaluated the impact of these changes on patient outcomes and costs for non-elective major lower extremity amputations (LEA). Methods: The 2019-2021 Florida Agency for Health Care Administration database was queried for adult patients who underwent non-elective major LEA. Per-patient inflation-adjusted costs were collected. Patient cohorts were established based on Florida COVID-19 mortality rates: COVID-heavy (CH) included nine months with the highest mortality, COVID-light (CL) included nine months with the lowest mortality, and pre-COVID (PC) included nine months before COVID (2019). Outcomes included in-hospital patient outcomes and hospitalization cost. Results: 6132 patients were included (1957 PC, 2104 CH, and 2071 CL). Compared to PC, there was increased patient acuity at presentation, but morbidity (31%), mortality (4%), and length of stay (median 12 [8-17] days) were unchanged during CH and CL. Additionally, costs significantly increased during the pandemic; median total cost rose 9%, room costs increased by 16%, ICU costs rose by 15%, and operating room costs rose by 15%. When COVID-positive patients were excluded, cost of care was still significantly higher during CH and CL. Conclusions: Despite maintaining pre-pandemic standards, as evidenced by unchanged outcomes, the pandemic led to increased costs for patients undergoing non-elective major LEA. This was likely due to increased patient acuity, resource strain, and supply chain shortages during the pandemic. Key message: While patient outcomes for non-elective major lower extremity amputations remained consistent during the COVID-19 pandemic, healthcare costs significantly increased, likely due to increased patient acuity and heightened pressures on resources and supply chains. These findings underscore the need for informed policy changes to mitigate the financial impact on patients and healthcare systems for future public health emergencies.

Fatigue, fear of being mobilized and residual limb pain limit independent basic mobility and physiotherapy for patients early after major dysvascular lower extremity amputation: A prospective cohort study.

AIM: Early mobilization of patients with a major lower extremity amputation (LEA) is often a challenge because of lack of compliance. Therefore, we investigated factors limiting independent mobility and physiotherapy on the first day with physiotherapy (PTDay1) and the following 2 days after LEA. METHODS: A total of 60 consecutive patients, mean age 73.7 years (SD 12.1 years), undergoing LEA were included over a period of 7 months. The Basic Amputee Mobility Score was used to assess basic mobility. Predefined limitations for not achieving independent mobility or not completing physiotherapy were residual limb pain, pain elsewhere, fear of being mobilized, fatigue, nausea/vomiting, acute cognitive dysfunction or "other" factors reported on PTDay1 and the following 2 days after LEA. RESULTS: Fatigue and fear of being mobilized were the most frequent limitations for not achieving independent mobility on PTDay1 and the following 2 days after LEA. Patients (n = 55) who were not independent in the Basic Amputee Mobility Score activity transferring from bed to chair on PTDay1 were limited by fatigue (44%) and fear of being mobilized (33%). A total of 21 patients did not complete planned physiotherapy on PTDay1, and were limited by fatigue (38%), residual limb pain (24%) and "other" factors (24%). CONCLUSION: Fatigue and fear of being mobilized were the most frequent factors that limited independent mobility early after LEA. Fatigue, residual limb pain and "other" factors limited completion of physiotherapy. Geriatr Gerontol Int 2024; 24: 470-476.

The Risk of the Aggravation of Diabetic Foot According to Air Quality Factors in the Republic of Korea: A Nationwide Population-Based Study.

This study aims to examine the association between the occurrence of diabetic foot and air quality (SO2, CO, NO2, O3). Open data were collected to conduct a big data study. Patient information was gathered from the National Health Insurance Service, and the National Institute of Environmental Science's air quality data were used. A total study population of 347,543 cases were reviewed (case = 13,353, control = 334,190). The lag period from air quality changes to the actual amputation operation was calculated for each factor. The frequency of diabetic foot amputation in each region was identified and analyzed using a distributed lag non-linear model. Gangwon-do showed the highest relative risks (RRs) for SO2 and CO, while Chungcheongnam-do exhibited the highest RR for NO2. Jeju had the highest RR for O3. Regions like Incheon, Busan, and the capital region also showed significant risk increases. These findings emphasize the importance of tailored air quality management to address diabetic foot complications effectively.

Diabetic Foot Osteomyelitis Undergoing Amputation: Epidemiology and Prognostic Factors for Treatment Failure.

Background: When treating diabetic foot osteomyelitis (DFO), it remains difficult to determine the presence of residual infection and the optimal treatment after bone resection. In this study, we aimed to investigate the clinical characteristics of and prognostic factors in patients with DFO undergoing amputation. Methods: This retrospective study involved 101 patients with DFO who underwent amputation. Data on their demographics, clinical characteristics, tissue culture, and surgery type were collected. Patients were grouped according to primary closure status and clinical outcome postamputation. A good outcome was defined as a successful complete remission, characterized by the maintenance of complete wound healing with no sign of infection at 6 months postamputation. Multivariate logistic regression analysis was performed. Outcomes according to surgery type were also analyzed. Results: Staphylococcus aureus (17%) and Pseudomonas species (14%) were the most prevalent pathogens. Gram-negative bacteria were isolated from 62% of patients. In patients with primary closure, hemodialysis and ankle brachial index (ABI) <0.6 were associated with poor outcomes. In patients with DFO, ABI <0.6 was the only prognostic factor associated with treatment failure. Antimicrobial stewardship allows patients who underwent major amputation to reduce the duration of antibiotic therapy compared to those after minor amputation, although it did not contribute to reducing mortality. Conclusions: Peripheral artery disease and hemodialysis were associated with poor outcomes despite radical resection of the infected bone. Vigilant monitoring after amputation and antimicrobial stewardship implemented based on microbiological epidemiology, prognostic factors, and the type of surgery are important. A multidisciplinary team could assist in these activities to ensure treatment success.

Impact of diabetes on medical costs in the pre- and postoperative year of lower extremity amputations in Belgium.

AIMS: To compare the medical costs of individuals undergoing lower extremity amputation (LEA) in Belgium with those of amputation-free individuals. METHODS: Belgian citizens undergoing LEAs in 2014 were identified. The median costs per capita in euros for the 12 months preceding and following minor and major LEAs were compared with those of matched amputation-free individuals. RESULTS: A total of 3324 Belgian citizens underwent LEAs (2295 minor, 1029 major), 2130 of them had diabetes. The comparison group included 31,716 individuals. Amputation was associated with high medical costs (individuals with diabetes: major LEA €49,735, minor LEA €24,243, no LEA €2,877 in the year preceding amputation; €45,740, €21,445 and €2,284, respectively, in the post-amputation year). Significantly higher costs were observed in the individuals with (versus without) diabetes in all groups. This difference diminished with higher amputation levels. Individuals undergoing multiple LEAs generated higher costs (individuals with diabetes: €39,313-€89,563 when LEAs preceded index amputation; €46,629-€92,877 when LEAs followed index amputation). Individuals dying in the year after a major LEA generated remarkably lower costs. CONCLUSIONS: LEA-related medical costs were high. Diabetes significantly impacted costs, but differences in costs diminished with higher amputation levels. Individuals with multiple amputations generated the highest costs.

Evaluating the impact of an interdisciplinary integrated limb preservation service operating concurrently with a single-specialty service.

BACKGROUND: This study examined the efficacy of an interdisciplinary limb preservation service (LPS) in improving surgical outcomes for diabetic foot ulcer (DFU) patients compared to traditional care. METHODS: Data from January 1, 2017 to September 30, 2020 were retrospectively reviewed. An interdisciplinary LPS clinic began on August 1, 2018, coexisting with a preexisting single specialty service. Primary outcomes were major/minor amputation rates and ratios and hospital length of stay. Surgical endpoints pre- and post-LPS launch were compared. RESULTS: Among 976 procedures for 731 unique DFU patients, most were male (80.4%) and Hispanic (89.3%). Patient demographics were consistent before and after LPS initiation. Major amputation rates decreased by 45.5% (15.4%-8.4%, p = 0.001), with outpatient procedures increasing over 5-fold (3.3% pre-LPS to 18.7% post-LPS, p < 0.001). Hospital stay reduced from 10.1 to 8.5 days post-LPS (p < 0.001). The major to minor amputation ratio declined from 22.4% to 12.7%. CONCLUSIONS: The interdisciplinary LPS improved patient outcomes, marked by fewer major amputations and reduced hospital stays, suggesting the model's potential for broader application.

Risk Prediction of Diabetic Foot Amputation Using Machine Learning and Explainable Artificial Intelligence.

BACKGROUND: Diabetic foot ulcers (DFUs) are serious complications of diabetes which can lead to lower extremity amputations (LEAs). Risk prediction models can identify high-risk patients who can benefit from early intervention. Machine learning (ML) methods have shown promising utility in medical applications. Explainable modeling can help its integration and acceptance. This study aims to develop a risk prediction model using ML algorithms with explainability for LEA in DFU patients. METHODS: This study is a retrospective review of 2559 inpatient DFU episodes in a tertiary institution from 2012 to 2017. Fifty-one features including patient demographics, comorbidities, medication, wound characteristics, and laboratory results were reviewed. Outcome measures were the risk of major LEA, minor LEA and any LEA. Machine learning models were developed for each outcome, with model performance evaluated using receiver operating characteristic (ROC) curves, balanced-accuracy and F1-score. SHapley Additive exPlanations (SHAP) was applied to interpret the model for explainability. RESULTS: Model performance for prediction of major, minor, and any LEA event achieved ROC of 0.820, 0.637, and 0.756, respectively, with XGBoost, XGBoost, and Gradient Boosted Trees algorithms demonstrating best results for each model, respectively. Using SHAP, key features that contributed to the predictions were identified for explainability. Total white cell (TWC) count, comorbidity score and red blood cell count contributed highest weightage to major LEA event. Total white cell, eosinophils, and necrotic eschar in the wound contributed most to any LEA event. CONCLUSIONS: Machine learning algorithms performed well in predicting the risk of LEA in a patient with DFU. Explainability can help provide clinical insights and identify at-risk patients for early intervention.

Experiences of middle-aged individuals with lower extremity amputation caused by diabetic foot ulcer after disability in China: A qualitative study.

AIM: To understand the experiences of individuals who undergo LEA due to DFU after disability. DESIGN: A descriptive research design in qualitative research. METHODS: Semi-structured interviews were used in this qualitative descriptive study. Eleven middle-aged patients (45-59 years) who underwent LEA due to DFU were purposively selected and interviewed. Qualitative data were thematically analysed. RESULTS: Three themes and 10 subthemes were identified. The themes were (1) role function confusion, (2) self-concept stress and (3) unreasonable objective support. Subthemes included (1) weakened career role, (2) family role reversal, (3) social role restriction, (4) over-focusing on appearance, (5) immersion in patient experience, (6) living with faith, (7) polarization of independent consciousness, (8) low perceived benefits of peer support, (9) existence of treatment disruption and (10) poor participation in medical decision-making.

The Incidence and Outcomes of Major Limb Amputation in New Zealand from 2010 to 2021.

Background: Major limb amputation (MLA) can be a common outcome due to severe peripheral artery disease (PAD) and diabetic foot disease (DFD), and it carries a significant mortality burden. In New Zealand (NZ), there is little documentation of the incidence rate and mortality after MLA. The aim was to report the national crude and standardised rates and the mortality post MLA. Methods: This retrospective observational study included all MLAs that occurred within NZ from 1/1/2010 to 31/12/2021 due to DFD and/or PAD. Two national databases (National Minimum Dataset and the Australasian Vascular Audit) were utilised. The crude rates were calculated as cases per 100,000 in the NZ population per year including all ages (using the 2013 and 2018 NZ census figures). The age-standardised rates used the World Health Organization standard population. Post-operative mortality was calculated from the date of first hospitalisation for MLA. Results: From 2010 to 2021, there were 5293 MLA procedures in 4242 patients. On average, there were 8.5 MLAs per week and 441.1 MLAs annually. The overall crude rate was 9.44 per 100,000, and the standardised rate was 6.12 per 100,000. Over the 12 years, the crude rate decreased by 22% (p < 0.001), and the standardised rate decreased by 20.4% (p < 0.001). After MLA, the 30-day and 1-year mortality was 9.5% and 29.6%, respectively. From 2010 to 2021, the relative reduction in 30-day mortality was 45.1% (p < 0.001), and the reduction in 1-year mortality was 24.5% (p < 0.001). Increasing age, female sex and end-stage renal failure were predictors of 30-day and 1-year mortality. Conclusions: A considerable number of MLAs occur in NZ, with substantial perioperative mortality; however, the national incidence rates and mortality have improved over the last 12 years. This data might serve as benchmark to further reduce MLAs and improve patient outcomes.

Capture-recapture method to estimate lower extremity amputation rates in Rio de Janeiro, Brazil

Objective. To estimate rates of lower extremity amputations (LEAs) in persons with peripheral vascular disease, diabetes mellitus, trauma, neoplasm, osteomyelitis, or emphysematous gangrene. Methods. Regional amputee registries were used to estimate the rate of lower extremity amputations with the capture-recapture (CR) technique. Data were extracted from three amputee registries in Rio de Janeiro: source 1, with 1 191 cases from 23 hospitals; source 2, with 157 cases from a limb-fitting center; and source 3, with 34 cases from a rehabilitation center. Amputee death certificates from source 1 identified 257 deaths from 1992 to 1994. Three CR models were evaluated using sources 2 and 3. In order to avoid an overestimation of the rate of LEAs, two models were applied for the data analysis: in one case, deceased patients listed in source 1 were excluded from the model, and in the other case, deceased patients were included as well. Results. Excluding the 257 deaths, the estimated number of amputations in the municipality of Rio de Janeiro from 1992 to 1994 was 3 954, for a mean annual incidence rate of 13.9 per 100 000 inhabitants. Among persons with diabetes, the annual incidence rate of lower extremity amputations was substantially higher (180.6 per 100 000 persons per year), representing 13 times the risk of individuals without diabetes. The yearly rate of LEAs according to the routine surveillance system was estimated at 5.4 and 96.9 per 100 000 in the general population and in diabetics, respectively. If data from the three registries are added, 1 382 patients with LEAs were identified, with the reasons for the amputations distributed as follows: peripheral vascular disease = 804 (58.1%); diabetes mellitus = 379 (27.4%); trauma = 103 (7.4%); osteomyelitis = 44 (3.1%); gangrene = 36 (2.6%), and neoplasm = 16 (1.1%). Conclusions. These findings show a high incidence of LEAs in Brazil, when compared to countries such as Spain, that is attributable mainly to peripheral vascular disease and diabetes mellitus

Objetivos. Estimar las tasas de amputación del miembro inferior (AMI) en individuos con vasculopatías periféricas, diabetes sacarina, traumatismos, neoplasias, osteomielitis o gangrena enfisematosa. Métodos. Se utilizaron los registros regionales de amputados para estimar la tasa de AMI con el método de captura-recaptura (CR). Los datos se obtuvieron a partir de tres registros de amputados de Río de Janeiro: la fuente 1, con 1 191 casos de 23 hospitales; la fuente 2, con 157 casos de un centro de miembros artificiales, y la fuente 3, con 34 casos de un centro de rehabilitación. Los certificados de defunción de los amputados de la fuente 1 identificaron 257 muertes entre 1992 y 1994. Se investigaron dos modelos de CR utilizando las fuentes 2 y 3. Con el fin de evitar la sobreestimación de la tasa de AMI, en el análisis de los datos se aplicaron dos modelos: en uno se excluyeron los pacientes fallecidos que figuraban en la fuente 1, y en el otro se incluyeron. Resultados. Excluyendo las 257 muertes, el número estimado de amputaciones en el municipio de Río de Janeiro entre 1992 y 1994 fue de 3 954, lo cual representa una incidencia anual media de 13,9 por 100 000 habitantes. En los pacientes diabéticos, la incidencia anual de AMI fue considerablemente mayor (180,6 por 100 000), lo cual representa un riesgo 13 veces mayor que en individuos sin diabetes. De acuerdo con el sistema de vigilancia habitual, las correspondientes tasas anuales de AMI fueron de 5,4 y 96,9, respectivamente. Combinando los datos de los tres registros, se identificaron 1 382 pacientes con AMI, cuyas causas se distribuyeron del siguiente modo: vasculopatías periféricas, 804 (58,1%); diabetes sacarina, 379 (27,4%); traumatismos, 103 (7,4%); osteomielitis, 44 (3,1%); gangrena, 36 (2,6%), y neoplasias, 16 (1,1%). Conclusiones. En comparación con otros países, como España, estos resultados muestran una alta incidencia de AMI en Brasil, atribuible principalmente a las vasculopatías periféricas y a la diabetes sacarina