Risk factors for unplanned readmission and stump complications after major lower extremity amputation

Moderate and Severe Chronic Kidney Disease Predict Greater 5-Year Mortality following Major Lower-Extremity Amputation

BACKGROUND

Severe chronic kidney disease (CKD) predicts greater mortality after major lower-extremity amputation (LEA), but it remains poorly understood whether patients with earlier stages of CKD share similar risk.

METHODS

We assessed long-term postoperative outcomes for patients with CKD in a retrospective chart review of 565 patients who underwent atraumatic major LEA at a large tertiary referral center from 2015 to 2021. We stratified patients by renal function and compared outcomes including survival.

RESULTS

Preoperative CKD diagnosis was related to many patient characteristics, co-occurred with many comorbidities, and was associated with less follow-up and survival. Kaplan-Meier and Cox Regression analyses showed significantly worse 5-year survival for major LEA patients with mild, moderate, or severe CKD compared to major LEA patients with no history of CKD at the time of amputation (P < 0.001). Severe CKD independently predicted worse mortality at 1-year (odds ratio [OR] 2.91; P = 0.003) and 5-years (OR 3.08; P < 0.001). Moderate CKD independently predicted worse 5-year mortality (OR 2.66; P = 0.029).

CONCLUSIONS

This study demonstrates that moderate and severe CKD predict greater long-term mortality following major LEA when controlling for numerous potential confounders. This finding raises questions about the underlying mechanism if causal and highlights an opportunity to improve outcomes with earlier recognition and optimization CKD preoperatively.

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.

2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease" provides recommendations to guide clinicians in the treatment of patients with lower extremity peripheral artery disease across its multiple clinical presentation subsets (ie, asymptomatic, chronic symptomatic, chronic limb-threatening ischemia, and acute limb ischemia).

METHODS

A comprehensive literature search was conducted from October 2020 to June 2022, encompassing studies, reviews, and other evidence conducted on human subjects that was published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through May 2023 during the peer review process, were also considered by the writing committee and added to the evidence tables where appropriate.

STRUCTURE

Recommendations from the "2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with peripheral artery disease have been developed.

2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2024 ACC/AHA/AACVPR/APMA/ABC/SCAI/SVM/SVN/SVS/SIR/VESS Guideline for the Management of Lower Extremity Peripheral Artery Disease" provides recommendations to guide clinicians in the treatment of patients with lower extremity peripheral artery disease across its multiple clinical presentation subsets (ie, asymptomatic, chronic symptomatic, chronic limb-threatening ischemia, and acute limb ischemia).

METHODS

A comprehensive literature search was conducted from October 2020 to June 2022, encompassing studies, reviews, and other evidence conducted on human subjects that was published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through May 2023 during the peer review process, were also considered by the writing committee and added to the evidence tables where appropriate.

STRUCTURE

Recommendations from the "2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease" have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with peripheral artery disease have been developed.

Internal Iliac Artery Patency as a Predictor of Above-Knee Amputation Stump Healing

BACKGROUND

The primary aim of this study was to assess the role of internal iliac patency in predicting outcomes of above-knee amputation (AKA) stump healing. The secondary objectives were to assess the accuracy of Wound, Ischemia, and Foot Infection (WIfI) classification system in predicting AKA stump healing and its association with delayed mortality.

METHODS

This is a retrospective study performed in a vascular surgery unit in a tertiary hospital on patients who underwent AKAs over 1 year, from July 2021 until June 2022. Patient demographic data, WIfI scoring, outcome of AKAs, and patency of profunda femoris and internal iliac artery (IIA) were collected. To minimize confounding, a single vascular surgeon performed all computed tomography imaging reviews and arterial measurements. Approval for this study was obtained from the National Research Registry, NMRR ID-23-01865-KQ4 (investigator initiated research).

RESULTS

Ninety patients underwent AKA over 1 year, from July 2021 until June 2022. Occluded IIA in the presence of patent profunda femoris did not affect the wound healing of the AKA stump. There was significant association between WIfI scoring and mortality. Patients with a WIfI scoring of 3 to 4 were observed to have a higher mortality rate compared with patients with normal healing: 47 (72.0%) vs. 4 (80.0%); P = 0.021.

CONCLUSIONS

In this study, the IIA patency shows no statistically significant effect on AKA stump healing; however, the small number of patients is a drawback of the study. This study also demonstrates that the WIfI score can be a prognostic factor for mortality in patients undergoing AKA.

A qualitative study evaluating the discharge process for vascular surgery patients to identify significant themes for organizational improvement

OBJECTIVE

Transition from the hospital to an outpatient setting is a multifaceted process requiring coordination among a variety of services and providers to ensure a high-quality discharge. Vascular surgery patients comprise a complex population that experiences high unplanned readmission rates. We performed a qualitative study to identify themes for process improvement for vascular surgery patients. A validated discharge process, RED (Re-Engineered Discharge), was used to identify additional actionable themes to create a more efficient discharge process tailored specifically to the vascular surgery population.

METHODS

A prospective, qualitative analysis at a tertiary center using a semi-structured focus group interview guide was performed to evaluate the current discharge process and identify opportunities for improvement. Focus groups were Zoom recorded, transcribed into electronic text files, and were loaded into Dedoose qualitative software for analysis using a directed content analysis approach. Two researchers independently thematically coded each transcript, starting with accepted discharge components to identify new thematic categories. Prior to analysis, all redundancy of codes was resolved, and all team members agreed on text categorization and coding.

RESULTS

Eight focus groups with a total of 38 participants were conducted. Participants included physicians (n = 13), nursing/ancillary staff (n = 14), advanced nurse practitioners (n = 2), social worker/dietitian/pharmacist (n = 3), and patients (n = 6). Transcript analyses revealed facilitators and barriers to the discharge process. In addition to traditional RED components, unique concepts pertinent to vascular surgery patients included patient complexity, social determinants of health, technology literacy, complexity of ancillary services, discharge appropriateness, and use of advanced nurse practitioners for continuity.

CONCLUSIONS

Specific themes were identified to target and enhance the future vRED (vascular Re-Engineered Discharge) bundle. Thematic targets for improvement include increased planning, organization, and communication prior to discharge to address vascular surgery patients' multiple comorbidities, extensive medication lists, and need for complex ancillary services at the time of discharge. Other thematic barriers discovered to improve include provider awareness of patient health literacy, patient understanding of complex discharge instructions, patient technology barriers, and intrinsic social determinants of health in this population. To address these discovered barriers, organizational targets to improve include enhanced social support, the use of advanced nurse practitioners for education reinforcement, and increased coordination. These results provide a framework for future quality improvement targeting the vascular surgery discharge process.

Healing rates and outcomes following closed transmetatarsal amputations: A systematic review and random effects meta-analysis of proportions

Transmetatarsal amputation (TMA) is a common surgical procedure for addressing severe forefoot pathologies, such as peripheral vascular disease and diabetic foot infections. Variability in research methodologies and findings within the existing literature has hindered a comprehensive understanding of healing rates and complications following TMA. This meta-analysis and systematic review aims to consolidate available evidence, synthesising data from multiple studies to assess healing rates and complications associated with closed TMA procedures. Following Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, a systematic search of Medline, Embase, and Cochrane databases was conducted for articles published from January 1st, 1988, to June 1st, 2023. Inclusion criteria comprised studies reporting healing rates in non-traumatic transmetatarsal amputation patients with more than 10 participants, excluding open TMAs. Two independent reviewers selected relevant studies, with disagreements resolved through discussion. Data extracted from eligible studies included patient demographics, healing rates, complications, and study quality. Among 22 studies encompassing 1569 transmetatarsal amputations, the pooled healing rate was 67.3%. Major amputation rates ranged from 0% to 55.6%, with a random-effects pooled rate of 23.9%. Revision rates varied from 0% to 36.4%, resulting in a pooled rate of 14.8%. 30-day mortality ranged from 0% to 9%, with a fixed-effects pooled rate of 2.6%. Post-operative infection rates ranged from 3.0% to 30.7%, yielding a random-effects pooled rate of 16.7%. Dehiscence rates ranged from 1.7% to 60.0%, resulting in a random-effects pooled rate of 28.8%. Future studies should aim for standardised reporting and assess the physiological and treatment factors influencing healing and complications.

Risk factors for readmission of patients with amputation to acute care from inpatient rehabilitation: A retrospective cohort study

INTRODUCTION

Amputation is a major condition that requires inpatient rehabilitation. Some research has been conducted to explore the risk factors for readmission of patients from inpatient rehabilitation facilities to acute care hospitals. However, few studies have included patients with amputation in the study population.

OBJECTIVE

To identify the risk factors for readmission of patients with amputation to acute care hospitals from an inpatient rehabilitation facility.

DESIGN

Retrospective cohort study.

SETTING

An acute rehabilitation hospital associated with a community-based tertiary medical center.

PATIENTS

A retrospective review of 156 independent admissions of 145 patients from June 2019 to July 2022.

MAIN OUTCOME MEASURE

The study outcome measure was readmission to acute care from an acute rehabilitation unit.

RESULTS

Of the 156 independent admissions, the readmission rate was 19% (29/156). The most common cause of transfer was incision-site complications (9/29, 31%), including wound infection and wound dehiscence. Patients with amputation readmitted to acute care are more likely to be receiving dialysis (p < .001), have a longer length of stay in acute care before admission to the rehabilitation facility (p = .039), and have a lower Section GG score on admission (p < .001). Age, sex, ethnicity, amputation level, and history of diabetes mellitus were not associated with acute care hospital readmission. The logistic regression model revealed that patients being on dialysis was the only significant risk factor predictive of readmission to acute care (odds ratio [OR] 4.82, p = .006).

CONCLUSIONS

This study showed that incision-site complications were the most common cause of disruption in inpatient rehabilitation via acute hospital readmission in patients with amputation. Being on dialysis was associated with a higher risk of readmission to acute care hospitals. Based on the results of this study, specific rehabilitation plans might be required for patients with amputation who carry certain risk factors to reduce rehospitalization to the acute care unit.

Major lower extremity amputations - risk of re-amputation, time to re-amputation, and risk factors: a nationwide cohort study from Denmark

BACKGROUND AND PURPOSE

Re-amputation after lower extremity amputation is frequent. The primary aim of our study was to investigate cumulative re-amputation risk after transtibial amputation (TTA), knee disarticulation (KD), and transfemoral amputation (TFA) and secondarily to investigate time to re-amputation, and risk factors.

METHODS

This observational cohort study was based on data from the Danish Nationwide Health registers. The population included first-time major lower extremity amputations (MLEA) performed in patients ≥ 50 years between 2010 and 2021. Both left and right sided MLEA from the same patient were included as index procedures.

RESULTS

11,743 index MLEAs on 10,052 patients were included. The overall cumulative risks for re-amputation were 29% (95% confidence interval [CI] 27-30), 30% (CI 26-35), and 11% (CI 10-12) for TTA, KD, and TFA, respectively. 58% of re-amputations were performed within 30 days after index MLEA. Risk factors for re-amputation within 30 days were dyslipidemia (hazard ratio [HR] 1.2, CI 1.0-1.3), renal insufficiency (HR 1.2, CI 1.1-1.4), and prior vascular surgery (HR 1.3, CI 1.2-1.5).

CONCLUSION

The risk of re-amputation was more than twice as high after TTA (29%) and KD (30%) compared with TFA (11%). Most re-amputations were conducted within 30 days of the index MLEA. Dyslipidemia, renal insufficiency, and prior vascular surgery were associated with higher risk of re-amputation.

Phantom Limb Pain and Painful Neuroma After Dysvascular Lower-Extremity Amputation: A Systematic Review and Meta-Analysis

BACKGROUND

Phantom limb pain (PLP) and symptomatic neuroma can be debilitating and significantly impact the quality of life of amputees. However, the prevalence of PLP and symptomatic neuromas in patients following dysvascular lower limb amputation (LLA) has not been reliably established. This systematic review and meta-analysis evaluates the prevalence and incidence of phantom limb pain and symptomatic neuroma after dysvascular LLA.

METHODS

Four databases (Embase, MEDLINE, Cochrane Central, and Web of Science) were searched on October 5th, 2022. Prospective or retrospective observational cohort studies or cross-sectional studies reporting either the prevalence or incidence of phantom limb pain and/or symptomatic neuroma following dysvascular LLA were identified. Two reviewers independently conducted the screening, data extraction, and the risk of bias assessment according to the PRISMA guidelines. To estimate the prevalence of phantom limb pain, a meta-analysis using a random effects model was performed.

RESULTS

Twelve articles were included in the quantitative analysis, including 1924 amputees. A meta-analysis demonstrated that 69% of patients after dysvascular LLA experience phantom limb pain (95% CI 53-86%). The reported pain intensity on a scale from 0-10 in LLA patients ranged between 2.3 ± 1.4 and 5.5 ± .7. A single study reported an incidence of symptomatic neuroma following dysvascular LLA of 5%.

CONCLUSIONS

This meta-analysis demonstrates the high prevalence of phantom limb pain after dysvascular LLA. Given the often prolonged and disabling nature of neuropathic pain and the difficulties managing it, more consideration needs to be given to strategies to prevent it at the time of amputation.

Walking Exercise Sustainability Through Telehealth for Veterans With Lower-Limb Amputation: A Study Protocol

OBJECTIVE

This randomized controlled superiority trial will determine if an 18-month telehealth walking exercise self-management program produces clinically meaningful changes in walking exercise sustainability compared to attention-control education for veterans living with lower-limb amputation.

METHODS

Seventy-eight participants with lower-limb amputation (traumatic or nontraumatic) aged 50 to 89 years will be enrolled. Two groups will complete 6 one-on-one intervention sessions, and 6 group sessions over an 18-month intervention period. The experimental arm will receive a self-management program focusing on increasing walking exercise and the control group will receive attention-control education specific to healthy aging. Daily walking step count (primary outcome) will be continuously monitored using an accelerometer over the 18-month study period. Secondary outcomes are designed to assess potential translation of the walking exercise intervention into conventional amputation care across the Veteran Affairs Amputation System of Care. These secondary outcomes include measures of intervention reach, efficacy, likelihood of clinical adoption, potential for clinical implementation, and ability of participants to maintain long-term exercise behavior.

IMPACT

The unique rehabilitation paradigm used in this study addresses the problem of chronic sedentary lifestyles following lower-limb amputation through a telehealth home-based walking exercise self-management model. The approach includes 18 months of exercise support from clinicians and peers. Trial results will provide rehabilitation knowledge necessary for implementing clinical translation of self-management interventions to sustain walking exercise for veterans living with lower-limb amputation, resulting in a healthier lifestyle.

A Novel Strategy to Manage Below-Knee-Amputation (BKA) Stump Complications for Early Wound Healing and BKA Salvage

INTRODUCTION

The optimal management of major stump complications (operative infection or dehiscence) following below-knee-amputation (BKA) is unknown. We evaluated a novel operative strategy to aggressively treat major stump complications hypothesizing it would improve our rate of BKA salvage.

METHODS

Retrospective review of patients requiring operative intervention for BKA stump complications between 2015 and 2021. A novel strategy employing staged operative debridement for source control, negative pressure wound therapy, and reformalization was compared to standard care (less structured operative source control or above knee amputation).

RESULTS

32 patients were studied, 29 of which were male (90.6%) with an average age of 56.1 ± 9.6 y. 30 (93.8%) had diabetes and 11 (34.4%) peripheral arterial disease (PAD). The novel strategy was used in 13 patients and 19 had standard care. Novel strategy patients had higher BKA salvage rates, 100% vs 73.7% (P = .064), and postoperative ambulatory status, 84.6% vs 57.9% (P = .141). Importantly, none of the patients undergoing the novel therapy had PAD, while all progressing to above-knee amputation (AKA) did. To better assess the efficacy of the novel technique, patients progressing to AKA were excluded. Patients undergoing novel therapy who had their BKA level salvaged (n = 13) were compared to usual care (n = 14). The novel therapy's time to prosthetic referral was 72.8 ± 53.7 days vs 247 ± 121.6 days (P < .001), but they did undergo more operations (4.3 ± 2.0 vs 1.9 ± 1.1, P < .001).

CONCLUSION

Utilization of a novel operative strategy for BKA stump complications is effective in salvaging BKAs, particularly for patients without PAD.

Analysis of systemic risk factors between diabetic/vascular patients having primary lower limb amputations and re-amputations

Background: Patients with diabetes mellitus (DM) are known to be predisposed to many complications in the lower extremities such as neuropathy, peripheral artery disease (PAD) and infection. Diabetic foot ulcers are complications of diabetes that can lead to lower extremity amputations, re-amputations and high mortality rates.Purpose: The aim of this study is to evaluate the risk factors associated with higher re-amputation rates in diabetic foot disease.Research Design: This is a mono-centric retrospective comparative study.Study Sample: the study included 136 patients, with a total of 193 procedures (111 primary amputations and 82 re-amputations) between 2011 and 2021.Data Analysis: The t-student test and Spearman correlation were used to look for mean differences and any relevant association, respectively. Multivariate logistic regression analysis was computed to look for independent variables.Results: Twenty-two (27%) and 60 (50%) of those who had major and minor amputations, respectively, had a re-amputation (p = 0.006). Besides diabetes (89%), the commonest risk factor associated with amputation was hypertension (86.7%), be it for primary amputation or re-amputation, followed by peripheral (PAD) and coronary artery diseases. Only three risk factors showed independent correlation with re-amputation; chronic kidney disease (r = 15%, p = 0.03), smoking (r = 15%, p = 0.03), and simultaneous presence of DM + PAD (r = 13.7%, p = 0.05).Conclusions: Factors that were significantly correlated with increased re-amputation rates have a clear pathologic pathway that affects vascularity and wound healing. Further studies should be aimed at developing a clear scoring system that can be used to stratify patient for re-amputation risk, and to better predict the results according to the severity of diabetes.

Tourniquet use for people with peripheral arterial disease undergoing major lower limb amputations

BACKGROUND

At least 7000 major lower limb amputations (MLLAs) are performed in the UK each year, 80% of which are due to peripheral arterial disease (PAD). Intraoperative blood loss can have a deleterious effect on patient outcomes, and its replacement with transfused blood is not without risk. Tourniquets can be used in lower limb surgical procedures to provide a bloodless surgical field, minimise intraoperative blood loss, and reduce perioperative blood transfusion requirements. Although their safety has been demonstrated in certain orthopaedic operations, their use among people with PAD undergoing MLLA remains controversial. Many clinicians are concerned about tourniquets potentially compromising perfusion of the stump and thereby impacting wound healing through direct tissue injury, damage to the arterial supply of the wound, or both.

OBJECTIVES

To assess the safety and effectiveness of tourniquet use in people undergoing MLLA for complications of PAD, specifically with regard to intraoperative blood loss, change in haemoglobin levels, transfusion rates, wound healing, need for revision surgery, and postoperative complications including mortality.

SEARCH METHODS

We searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers from inception to 17 May 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing tourniquet use to no tourniquet use among people with PAD undergoing MLLA.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Primary outcomes were intraoperative blood loss, fall in haemoglobin levels, and perioperative blood transfusion requirement. Secondary outcomes were primary wound-healing rates, stump revision rates, other postoperative complications defined as per Clavien-Dindo classification, and postoperative mortality at 30 days and at maximal follow-up. We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

One RCT met our inclusion criteria, which was a prospective randomised blinded controlled trial conducted in Sheffield, UK in 2006. In total 64 participants undergoing transtibial amputation for non-reconstructable PAD were randomised to either tourniquet or no tourniquet to assess for intraoperative blood loss, fall in haemoglobin, transfusion requirement, wound healing, stump breakdown and revision. Ten participants were excluded postrandomisation (five from the tourniquet group and five from the no tourniquet group). The reported median volume of intraoperative blood loss was significantly less in the tourniquet group (255 mL (interquartile range (IQR) 150 to 572.5 mL))) compared to the control group (550 mL (IQR 255 to 1050 mL)) (P = 0.014). There was a significantly lower median drop in haemoglobin concentration in the tourniquet group (1.0 g/dL (IQR 0.6 to 2.4 g/dL)) compared to the control group (1.8 g/dL (IRQ 0 to 1.2 g/dL)) (P = 0.035). There was a significantly lower perioperative blood transfusion requirement in the tourniquet group (8 participants, 32%) compared to the control group (14 participants, 48%) (P = 0.047). There were no clear differences in wound breakdown, stump revision, primary wound healing at six weeks, postoperative complications (myocardial infarction, cardiac arrhythmias, pulmonary oedema), and death between groups. We assessed the one included study as at low risk of bias for sequence generation and blinding of outcome assessors; high risk of bias for incomplete outcome data and selective outcome reporting; and unclear risk of bias for allocation concealment, blinding of participants and personnel, and other sources of bias. We assessed the certainty of the evidence as low or very low due to risk of bias, small sample size, and the study being insufficiently powered for most outcomes.

AUTHORS' CONCLUSIONS

This review identified only one small historical RCT evaluating tourniquet use in MLLA. Tourniquets appeared to reduce intraoperative blood loss, drop in haemoglobin, and blood transfusion requirements following transtibial amputations for people with PAD. However, it is unclear whether tourniquets affect wound healing, stump revision rates, postoperative complications, or mortality. High-certainty evidence is required to inform clinical decision-making for the use of tourniquets in these patients.

From hospital to home following a lower limb amputation: A focus group study of healthcare professionals' views and experiences with transitioning

INTRODUCTION

Patients undergoing major lower limb amputation often have multiple comorbidities, requiring care from numerous healthcare professionals (HCPs). Furthermore, they may experience physical, medical and practical challenges post-amputation. Patients with complex needs are particularly vulnerable during care transitions and may benefit from integrated care models.

AIM

This study aimed to explore HCPs' views and experiences regarding the transition process after implementing an integrated care model for patients with lower limb amputation.

METHODS

We conducted two focus groups with 13 HCPs from a Danish hospital and three surrounding districts; all working in the Safe Journey programme. The interviews were analysed using thematic analysis.

RESULTS

Three themes were created: 1) becoming a team across sectors, 2) continuity of care as a driver for patient safety and 3) challenges in achieving safe transitions. The Safe Journey programme facilitated the construction of an interdisciplinary team, cross-sectoral communication and professional relations, increasing HCPs' sense of improved patient safety and care continuity. However, HCPs experienced an increased workload, including coordination and at-home patient visits.

CONCLUSIONS

HCPs found the Safe Journey programme to be valuable for patients undergoing major lower limb amputation and promotive of cross-sectoral professional relations, communication, continuity and patient safety. However, the programme was time- and resource-consuming compared to conventional models.

Mortality and Conversion to Transfemoral Amputation After Transtibial Amputation in the Veterans Affairs Health System

INTRODUCTION

Transtibial below-knee amputation (BKA) is associated with considerable morbidity, particularly in the vasculopathic population. The purpose of this study was to determine the cumulative probability of undergoing transfemoral above-knee amputation (AKA) conversion within 5 years of BKA and associated risk factors while accounting for the competing risk of death.

METHODS

This is a retrospective, national database study with structured query of the Veterans Affairs (VA) database for patients who underwent BKA from 1999 to 2020, identified by Current Procedural Terminology codes. Above-knee amputation conversion was identified using Current Procedural Terminology codes in combination with natural language processing to match procedure laterality. After internally validating our patient identification method, risk factors were collected. Competing risk analysis estimated the cumulative incidence rate of AKA conversion and associated risk factors with death as a competing risk.

RESULTS

Our query yielded 19,875 patients (19,640 men, 98.8%) who underwent BKA with a median age of 66 years (interquartile range, 60 to 73). The median follow-up was 951 days (interquartile range, 275 to 2,026). The crude cumulative probabilities of AKA conversion and death at 5 years were 15.4% (95% confidence interval [CI], 14.9% to 16.0%) and 47.7% (95% CI, 46.9% to 48.4%), respectively. In the Fine and Gray subdistribution hazard model, peripheral vascular disease had the highest AKA conversion risk (hazard ratio [HR] 2.66; 95% CI, 2.22 to 3.20; P < 0.001). Other factors independently associated with AKA conversion included urgent operation (HR 1.32; 95% CI, 1.23 to 1.42), cerebrovascular disease (HR 1.19; 95% CI, 1.11 to 1.28), chronic obstructive pulmonary disease (HR 1.15; 95% CI, 1.07 to 1.24), and previous myocardial infarction (HR 1.10; 95% CI, 1.02 to 1.19) (All P < 0.02).

DISCUSSION

Within this predominantly male, VA population, BKA carries a high risk of conversion to AKA within 5 years, without reaching a steady risk of AKA conversion within 5 years. Peripheral vascular disease, chronic obstructive pulmonary disease, cerebrovascular disease, previous myocardial infarction, and urgent BKA increase the risk of AKA conversion.

LEVEL OF EVIDENCE

Level III.

Analysis of Early Lower Extremity Re-amputation

BACKGROUND

Data is scarce regarding the need for early re-amputation to a higher anatomic level. This study seeks to define outcomes and risk factors for re-amputation.

METHODS

Patients undergoing primary major lower extremity amputation were identified within the 2012-2016 ACS-NSQIP database. Demographics, outcomes, and peri-operative characteristics were compared, and multivariable logistic regression model was used to determine association with early re-amputation.

RESULTS

Over a four-year period, 8306 below knee amputations and 6367 above knee amputations were identified. Thirty-day re-amputation occurred in 262 patients (1.8%) and was associated with increased length of stay (12.9 vs. 7.3 days, p<0.001), higher rates of readmission (64.9% vs. 13.6%, p<0.001), and overall complications (69.5% vs. 39.3%, p<0.01). On multivariable analysis, advanced age (OR 1.02, CI 1.01-1.03), smoking (OR 1.75, CI 1.32-2.33), dialysis dependence (OR 1.67, CI 1.23-2.26), preoperative septic shock (OR 2.53, CI 1.29-4.97), and bleeding disorders (OR 1.72, CI 1.34-2.22) were associated with early re-amputation.

CONCLUSIONS

Thirty-day re-amputation rates are low, but are associated with significant morbidity, prolonged hospitalization, and frequent readmissions.

The Development and Usability of the AMPREDICT Decision Support Tool: A Mixed Methods Study

OBJECTIVE

Amputation level decision making in patients with chronic limb threatening ischaemia is challenging. Currently, evidence relies on published average population risks rather than individual patient risks. The result is significant variation in the distribution of amputation levels across health systems, geographical regions, and time. Clinical decision support has been shown to enhance decision making, especially complex decision making. The goal of this study was to translate the previously validated AMPREDICT prediction models by developing and testing the usability of the AMPREDICT Decision Support Tool (DST), a novel, web based, clinical DST that calculates individual one year post-operative risk of death, re-amputation, and probability of achieving independent mobility by amputation level.

METHODS

A mixed methods approach was used. Previously validated prediction models were translated into a web based DST with additional content and format developed by an expert panel. Tool usability was assessed using the Post-Study System Usability Questionnaire (PSSUQ; a 16 item scale with scores ranging from 1 to 7, where lower scores indicate greater usability) by 10 clinician end users from diverse specialties, sex, geography, and clinical experience. Think aloud, semi-structured, qualitative interviews evaluated the AMPREDICT DST's look and feel, user friendliness, readability, functionality, and potential implementation challenges.

RESULTS

The PSSUQ overall and subscale scores were favourable, with a mean overall total score of 1.57 (standard deviation [SD] 0.69) and a range from 1.00 to 3.21. The potential clinical utility of the DST included (1) assistance in counselling patients on amputation level decisions, (2) setting outcome expectations, and (3) use as a tool in the academic environment to facilitate understanding of factors that contribute to various outcome risks.

CONCLUSION

After extensive iterative development and testing, the AMPREDICT DST was found to demonstrate strong usability characteristics and clinical relevance. Further evaluation will benefit from integration into an electronic health record with assessment of its impact on physician and patient shared amputation level decision making.

Percutaneous deep venous arterialization at femoropopliteal segment for unhealed amputated stump ulcer after below the knee amputation

Efficacy of percutaneous deep venous arterialization (pDVA) has been reported for patients with no-option chronic limb threatening ischemia. To date, the procedure has been limited for below the knee/below the ankle occlusive disease. The present report describes the pDVA performed at a femoropopliteal segment for a patient with a stump complication after below the knee amputation. The patient was a 70-year-old male who had a history of endovascular treatment in the right superficial femoral artery (SFA) and below knee amputation 6 years before. He had an unhealed ulcer at the amputated stump for 3 years. Computed tomography angiography demonstrated occluded right SFA, with a stenotic popliteal artery. Revascularization was considered unfeasible due to the absence of run off vessels. In order to improve the perfusion at the ulcer, pDVA was performed at the distal SFA level, bridging SFA and femoral vein using stent grafts. The final angiogram demonstrated the revascularized SFA connecting to popliteal vein with a brisk flow. After pDVA, the stump ulcer improved and the stent grafts were kept patent after 6 months of the procedure. pDVA at the SFA level was technically feasible and could be a useful approach for stump complication after below knee amputation.

Is Reoperation Higher Than Expected after Below-the-knee Amputation? A Single-center Evaluation of Factors Associated with Reoperation at 1 Year

BACKGROUND

Below-the-knee amputation (BKA) is relatively common among patients with vascular disease, infection, trauma, or neoplastic disease. Many BKAs are performed in patients with incompletely treated medical comorbidities, and some are performed in patients with acute high-energy trauma or crush injuries, malignant neoplasm undergoing time-sensitive limb removal, and diabetes with active infection or sepsis. Consequently, revision is common. Prior studies of outcomes after BKA, including several based on the American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) database, have follow-up periods that do not cover the entire at-risk period.

QUESTIONS/PURPOSES

(1) What is the survivorship free from unplanned reoperation within 1 year of BKA? (2) What patient characteristics are associated with reoperation within 1 year of BKA?

METHODS

We retrospectively studied all BKAs performed by the orthopaedic surgery service at a Level 1 trauma center from 2008 to 2018, as identified by Current Procedural Terminology (CPT) codes. Twenty-eight percent (38 of 138) underwent amputation as treatment for traumatic injury, 57% (79 of 138) for infection, and 15% (21 of 138) for malignancy. A total of 17% (23 of 138) had a final follow-up encounter before the 1-year study minimum, without differential loss to follow-up by surgical indication (p = 0.43) or hemoglobin A1c (p = 0.71). Median (range) follow-up was 570 days (6 to 3375). The primary outcome was survivorship from unplanned reoperation within 1 year of BKA index surgery or last planned reoperation, as determined by Kaplan-Meier estimation. Secondarily, we identified patient characteristics independently associated with reoperation within 1 year of BKA. Collected data included age, indication, BMI, diabetes, hemoglobin A1c level, closure method, and substance use. Unplanned reoperation was defined as irrigation and débridement, stump revision, or revision to a higher-level amputation; this did not include planned reoperations for BKAs closed in a staged manner. Factors associated with reoperation were determined using multivariate logistic regression analyses. All endpoints and variables related to patients and their surgical procedures were extracted from electronic medical records by someone other than the operating surgeon.

RESULTS

Using Kaplan-Meier estimation, 38% of patients (95% confidence interval 29 to 46) who underwent BKA had an unplanned reoperation within 1 year of their index surgery. Twelve percent of patients (95% CI 7 to 17) who underwent BKA did not reach 30 days with the limb survivorship free from unplanned reoperation. The median (range) time between the initial surgery and reoperation was 54 days (6 to 315). After controlling for potential confounding variables like age, gender, platelet count, albumin, and the reason for undergoing amputation, a hemoglobin A1c level greater than 8.1% (relative to A1c ≤ 8.1%) was the only variable independently associated with increased odds of reoperation (odds ratio 4.6 [95% CI 1.3 to 18.1]; p = 0.02).

CONCLUSION

BKA carries a higher risk for reoperation than currently reported in studies that use 30-day postoperative follow-up periods. Clinicians should critically assess whether BKA is necessary, especially in patients with uncontrolled diabetes assessed by hyperglycemia. Before planned BKA, patients should have documented glycemic control to minimize the odds of reoperation. Because many of this study's limitations were due to its retrospective single center design, we recommend that future work cover a clinically appropriate surveillance period using a larger cohort such as a national database and/or employ a prospective design.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Is Reconstruction of Unstable Midfoot Charcot Neuroarthropathy Cost Effective from a US Payer's Perspective?

BACKGROUND

Charcot neuroarthropathy is a morbid and expensive complication of diabetes that can lead to lower extremity amputation. Current treatment of unstable midfoot deformity includes lifetime limb bracing, primary transtibial amputation, or surgical reconstruction of the deformity. In the absence of a widely adopted treatment algorithm, the decision to pursue more costly attempts at reconstruction in the United States continues to be driven by surgeon preference.

QUESTIONS/PURPOSES

To examine the cost effectiveness (defined by lifetime costs, quality-adjusted life-years [QALYs] and incremental cost-effectiveness ratio [ICER]) of surgical reconstruction and its alternatives (primary transtibial amputation and lifetime bracing) for adults with diabetes and unstable midfoot Charcot neuroarthropathy using previously published cost data.

METHODS

A Markov model was used to compare Charcot reconstruction and its alternatives in three progressively worsening clinical scenarios: no foot ulcer, uncomplicated (or uninfected) ulcer, and infected ulcer. Our base case scenario was a 50-year-old adult with diabetes and unstable midfoot deformity. Patients were placed into health states based on their disease stage. Transitions between health states occurred annually using probabilities estimated from the evidence obtained after systematic review. The time horizon was 50 cycles. Data regarding costs were obtained from a systematic review. Costs were converted to 2019 USD using the Consumer Price Index. The primary outcomes included the long-term costs and QALYs, which were combined to form ICERs. Willingness-to-pay was set at USD 100,000/QALY. Multiple sensitivity analyses and probabilistic analyses were performed to measure model uncertainty.

RESULTS

The most effective strategy for patients without foot ulcers was Charcot reconstruction, which resulted in an additional 1.63 QALYs gained and an ICER of USD 14,340 per QALY gained compared with lifetime bracing. Reconstruction was also the most effective strategy for patients with uninfected foot ulcers, resulting in an additional 1.04 QALYs gained, and an ICER of USD 26,220 per QALY gained compared with bracing. On the other hand, bracing was cost effective in all scenarios and was the only cost-effective strategy for patents with infected foot ulcers; it resulted in 6.32 QALYs gained and an ICER of USD 15,010 per QALY gained compared with transtibial amputation. As unstable midfoot Charcot neuroarthropathy progressed to deep infection, reconstruction lost its value (ICER USD 193,240 per QALY gained) compared with bracing. This was driven by the increasing costs associated with staged surgeries, combined with a higher frequency of complications and shorter patient life expectancies in the infected ulcer cohort. The findings in the no ulcer and uncomplicated ulcer cohorts were both unchanged after multiple sensitivity analyses; however, threshold effects were identified in the infected ulcer cohort during the sensitivity analysis. When the cost of surgery dropped below USD 40,000 or the frequency of postoperative complications dropped below 50%, surgical reconstruction became cost effective.

CONCLUSIONS

Surgeons aiming to offer both clinically effective and cost-effective care would do well to discuss surgical reconstruction early with patients who have unstable midfoot Charcot neuroarthropathy, and they should favor lifetime bracing only after deep infection develops. Future clinical studies should focus on methods of minimizing surgical complications and/or reducing operative costs in patients with infected foot ulcers.

LEVEL OF EVIDENCE

Level II, economic and decision analysis.

Postoperative negative pressure wound therapy is associated with decreased surgical site infections in all lower extremity amputations

Introduction

We hypothesize that Negative Pressure Wound Therapy (NPWT) is associated with a lower incidence of surgical site infection (SSI) in lower extremity amputations (LEAs), a potentially devastating complication.

Methods

NSQIP database from 2011 to 2018 was queried to identify all-level LEAs. Cases using NPWT were identified. One-to-one nearest-neighbor propensity score matching was performed using a binary logistic regression on NPWT status controlling for patient comorbidities.

Results

NPWT was used in 133 of 5237 total LEAs (2.54%). Compared to propensity score-matched controls, they had significantly fewer SSIs (1.50% vs. 8.27%).

Conclusions

NPWT was associated with lower incidence of SSI.

Risks and Risk Factors for Ipsilateral Re-Amputation in the First Year Following First Major Unilateral Dysvascular Amputation

OBJECTIVE

To identify timing, incidence, and risk factors for ipsilateral re-amputation within 12 months of first dysvascular amputation and to determine specific subgroups of patients at each amputation level that are at increased risk.

METHODS

A retrospective cohort study evaluating 7187 patients with first unilateral transmetatarsal (TM), transtibial (TT), or transfemoral (TF) amputation secondary to diabetes and/or peripheral artery disease (PAD) were identified in the VA Surgical Quality Improvement Program database between 2004 and 2014. Re-amputation was defined as any subsequent ipsilateral soft tissue/bony revision or amputation to a higher level. Twenty-three potential pre-operative risk factors (and nine potential interactions) were identified. A backward stepwise Cox regression was used to identify risk factors. Incidence rates and hazard ratios (HR) with 95% confidence intervals (CI) were computed.

RESULTS

The median time to highest level of re-amputation in the first year was 33 (interquartile range, 13-73) days. Risk of requiring at least one re-amputation was 41% (TM), 25% (TT), and 9% (TF). Risk factors associated with requiring re-amputation included chronic obstructive pulmonary disease, elevated white blood cell count, abnormal ankle brachial index (ABI), history of revascularisation, and alcohol misuse. TM patients who had diabetes only (HR 1.9; 95% CI 1.4-2.5), diabetes with an abnormal ankle brachial index (ABI) score (HR 2.4; 95% CI 1.8-3.2), and kidney failure (HR 1.7; 95% CI 1.3-2.1) were at the greatest risk of re-amputation. TT amputees who were smokers were also at an increased risk (HR 1.4; 95% CI 1.2-1.6).

CONCLUSION

This research identified important risk factors for failure of primary healing and need for re-amputation at the TM and TT level. If considering a TM amputation, caution should be exercised in patients with diabetes, in particular those with an abnormal ABI and/or renal failure. At the TT level, caution should be exercised in those who smoke.

Ambulatory Status following Major Lower Extremity Amputation

BACKGROUND

The ability to ambulate following major lower extremity amputation, either below (BKA) or above knee (AKA), is a major concern for all prospective patients. This study analyzed ambulatory rates and risk factors for nonambulation in patients undergoing a major lower extremity amputation.

METHODS

A retrospective review of 811 patients who underwent BKA or AKA at our institution between January 2009 and December 2014 was conducted. Demographic information and co-morbid conditions, including the patients' functional status prior to surgery, at 6 months, and at latest follow up were recorded. Following exclusion criteria, 538 patients were included. Patients who were either independent or used an assistive device were considered ambulatory, while those who were completely wheelchair-dependent or bed-bound were considered nonambulatory.

RESULTS

Pre-operatively, 83.1% of BKA patients were ambulatory, significantly more so than those undergoing AKA (44.9%, P < 0.0001). At 6-month follow-up these percentages dropped to 58.0% and 25.2%, respectively, for all patients. For patients who were ambulatory pre-operatively, 182/246 (73.9%) of BKA and 32/51 (62.7%) of AKA remained so post-amputation. Of those patients with both 6-month and greater than 1-year follow-up, there was no change in ambulatory status between the 2 time periods. On multivariable logistic regression, age greater than 70 years and female sex were associated with nonambulation post-operatively (P = 0.001, P = 0.015, respectively). None of the co-morbid conditions recorded (diabetes, renal insufficiency, end-stage renal disease, peripheral vascular disease, or body mass index > 35) was found to have a statistically significant correlation with post-operative ambulation using multivariable analysis.

CONCLUSIONS

The majority of ambulatory patients undergoing a major amputation were able to remain ambulatory. Patients who failed to ambulate 6 months after their amputation, failed to resume ambulating. Age greater than 70 and female sex were found to have a statistically significant association with becoming nonambulatory following surgery.

What is the frequency of pressure injury in vascular patients undergoing major amputations?

Individuals with peripheral arterial disease who have undergone below or above knee amputations have limited mobility and may sit for long periods of time in a wheelchair, increasing their risk for pressure injury. The aim of this descriptive cross-sectional research study was to retrospectively review the charts of those patients with peripheral arterial disease undergoing lower limb amputations from 2016 to 2017 at a major academic medical center to determine the frequency of pressure injury. Hospital data were used to identify patients discharged from 2016 to 2017 with primary International Classification of Diseases (10th Revision) codes for below knee amputations/above knee amputations and pressure injury (ulcer). From 2016 to 2017, 46 patients were admitted to the inpatient vascular surgery service for a below or above knee amputation. Seventeen of those patients had documented pressure injuries at hospital discharge for a frequency of 37%. There were 11 males and 6 females with age range of 44 to 82 years with a mean age of 66 years. There was a total of 19 pressure injuries (2 patients had 2 pressure injuries). Ten of those 19 pressure injuries were present on admission to the hospital and 9 pressure injuries were hospital-acquired pressure injuries. Thirteen of the 19 pressure injuries (68%) were on the sacrum. Three of the pressure injuries (16%) were on the heel. Two (11%) were ischial pressure injuries with one knee (5%) pressure injury. Risk assessment is an essential part of vascular nursing practice that aims to identify individuals at risk for pressure injury with appropriate interventions to prevent their occurrence. Vascular nurses should be encouraged to educate patients/family members on the increased risk of pressure injuries in those undergoing amputation during hospitalization and after discharge to prevent them from occurring.

Wound Complications and Reoperations after Transtibial Amputation of the Leg

BACKGROUND

Transtibial amputations (TTAs) of the leg have been associated with high rates of wound complications. We assessed outcomes of TTAs to determine if bundled interventions implemented at our hospital had an impact on lowering wound complications, including surgical site infections.

METHODS

We assessed the impact of a surgical site infection prevention bundle (negative-pressure wound therapy, minimizing the use of staples, and a decontamination protocol for methicillin-resistant Staphylococcus aureus) on 90-day wound complications. The year of implementation of the prevention bundle was excluded, and the pre-eras and posteras were defined as the four-year period before and after implementation. The study sample consisted of a single-center cohort, with TTA cases identified using operating room scheduling software.

RESULTS

A total of 182 TTAs were performed: 110 in the pre-era and 72 in the postera. The wound complication rate decreased from 22 to 17% despite fewer two-stage operations, less imaging to identify peripheral artery disease, and an increased proportion of patients with end-stage renal disease. Wound complications and revision to a higher level of amputation were more associated with indication (especially no-option peripheral artery disease with ischemic rest pains) than with any particular aspect of surgical technique. The use of drains was associated with reoperations but not higher level revision.

CONCLUSIONS

Higher rates of wound complications and revision to a higher level of amputations should be expected among patients with no-option peripheral artery disease with ischemic rest pains undergoing TTAs. Drains should be avoided.

Risk factors for reamputations in patients amputated after revascularization for critical limb-threatening ischemia

OBJECTIVE

Despite vascular intervention, patients with critical limb-threatening ischemia (CLTI) have a high risk of amputation. Furthermore, this group has a high risk for stump complications and reamputation. The primary aim of this study was to identify risk factors predicting reamputation after a major lower limb amputation in patients revascularized because of CLTI. The secondary aim was to investigate mortality after major lower limb amputation.

METHODS

There were 288 patients who underwent a major ipsilateral amputation after revascularization because of CLTI in Stockholm, Sweden, during 2007 to 2013. The main outcome was ipsilateral reamputation.

RESULTS

Of 288 patients, 50 patients had a reamputation and 222 died during the 11-year follow-up. Patients with ischemic pain as an indication for primary amputation had nearly four times higher risk for a reamputation compared with those with a nonhealing ulcer (subdistribution hazard ratio, 3.55; confidence interval, 1.55-8.17). Higher age was associated with an increased risk for death in the multivariable analysis (hazard ratio, 1.03; confidence interval, 1.02-1.04).

CONCLUSIONS

Patients with ischemic pain as an indication for amputation have an elevated risk of reamputation. Ischemic pain may be indicative of a more extensive and proximal ischemia compared with patients with foot tissue loss. An extended evaluation of the preoperative circulation before amputation may facilitate the choice of amputation level and could lead to a reduction of reamputations.

Predicting reamputation risk in patients undergoing lower extremity amputation due to the complications of peripheral artery disease and/or diabetes

Background

Patients undergoing amputation of the lower extremity for the complications of peripheral artery disease and/or diabetes are at risk of treatment failure and the need for reamputation at a higher level. The aim of this study was to develop a patient-specific reamputation risk prediction model.

Methods

Patients with incident unilateral transmetatarsal, transtibial or transfemoral amputation between 2004 and 2014 secondary to diabetes and/or peripheral artery disease, and who survived 12 months after amputation, were identified using Veterans Health Administration databases. Procedure codes and natural language processing were used to define subsequent ipsilateral reamputation at the same or higher level. Stepdown logistic regression was used to develop the prediction model. It was then evaluated for calibration and discrimination by evaluating the goodness of fit, area under the receiver operating characteristic curve (AUC) and discrimination slope.

Results

Some 5260 patients were identified, of whom 1283 (24·4 per cent) underwent ipsilateral reamputation in the 12 months after initial amputation. Crude reamputation risks were 40·3, 25·9 and 9·7 per cent in the transmetatarsal, transtibial and transfemoral groups respectively. The final prediction model included 11 predictors (amputation level, sex, smoking, alcohol, rest pain, use of outpatient anticoagulants, diabetes, chronic obstructive pulmonary disease, white blood cell count, kidney failure and previous revascularization), along with four interaction terms. Evaluation of the prediction characteristics indicated good model calibration with goodness-of-fit testing, good discrimination (AUC 0·72) and a discrimination slope of 11·2 per cent.

Conclusion

A prediction model was developed to calculate individual risk of primary healing failure and the need for reamputation surgery at each amputation level. This model may assist clinical decision-making regarding amputation-level selection.