Factors Associated With Unplanned Reoperation After Above-Knee 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.

Evaluating the risk of return to the operating room across all elective orthopaedic procedures

BACKGROUND

Although elective procedures have life-changing potential, all surgeries come with an inherent risk of reoperation. There is a gap in knowledge investigating the risk of reoperation across orthopaedics. We aimed to identify the elective orthopaedic procedures with the highest rate of unplanned reoperation and the reasons for these procedures having such high reoperation rates.

METHODS

Patients in the NSQIP database were identified using CPT and ICD-10 codes. We isolated 612,815 orthopaedics procedures from 2018 to 2020 and identified the 10 CPT codes with the greatest rate of unplanned return to the operating room. For each index procedure, we identified the ICD-10 codes for the reoperation procedure and categorized them into infection, mechanical failure, fracture, wound disruption, hematoma or seroma, nerve pathology, other, and unspecified.

RESULTS

Below knee amputation (BKA) (CPT 27880) had the highest reoperation rate of 6.92% (37 of 535 patients). Posterior-approach thoracic (5.86%) or cervical (4.14%) arthrodesis and cervical laminectomy (3.85%), revision total hip arthroplasty (5.23%), conversion to total hip arthroplasty (4.33%), and revision shoulder arthroplasty (4.22%) were among the remaining highest reoperation rates. The overall leading causes of reoperation were infection (30.1%), mechanical failure (21.1%), and hematoma or seroma (9.4%) for the 10 procedures with the highest reoperation rates.

CONCLUSIONS

This study successfully identified the elective orthopaedic procedures with the highest 30-day return to OR rates. These include BKA, posterior thoracic and cervical spinal arthrodesis, revision hip arthroplasty, revision total shoulder arthroplasty, and cervical laminectomy. With this data, we can identify areas across orthopaedics in which revising protocols may improve patient outcomes and limit the burden of reoperations on patients and the healthcare system. Future studies should focus on the long-term physical and financial impact that these reoperations may have on patients and hospital systems.

LEVEL OF CLINICAL EVIDENCE

IV.

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.

The Modified Frailty Index Does Not Predict Mortality After Major Lower Extremity Amputation for Peripheral Arterial Disease in an Asian Population

BACKGROUND

Patients with critical limb ischemia (CLI) who undergo major lower extremity amputation (LEA) have been associated with high one-year mortality rates. Previous western-based studies have identified risk factors that exponentiate these poor outcomes, including nonambulatory status and cardiovascular morbidity. We assessed the effect of frailty, using the modified frailty index (mFI) in a cohort undergoing major LEA for CLI to predict mortality, perioperative complications, and unplanned readmissions in a tertiary institution from Singapore.

METHODS

Data on patients who had undergone major LEA from January 2016 to December 2017 were collected retrospectively. Inclusion criteria were below-knee amputations (BKAs) or above-knee amputations (AKAs) performed for peripheral arterial disease-related tissue loss or sepsis only. Patients were categorized into 3 risk groups based on the 11-variable mFI: low mFI, 0-0.27; moderate mFI, 0.36-0.54; and high mFI ≥0.63. Univariate and multivariate analysis was performed using logistic regression analysis.

RESULTS

211 patients underwent major LEA, of whom 133 (63.0%) had undergone BKA. The mean mFI was 0.41 (range 0-0.81). 84/211 (39.8%) died within 1 year after the procedure, with mortality rates of 25/65 (38.4%), 49/127 (38.6%), and 10/19 (52.6%) in the low-, moderate-, high-mFI categories, respectively. High and moderate mFI had failed to demonstrate an increased risk of mortality when compared with the low-mFI group (P > 0.05). 91/211 (43.1%) patients had perioperative complications, whereas 27/211 (12.8%) patients were readmitted within 30 days of discharge. Myocardial infarction, chronic kidney disease, and atrial fibrillation were found to be predictive of poor outcomes after major LEA.

CONCLUSIONS

Frailty as measured with the mFI did not predict outcome after major LEA. This could be due to confounding effects such as high prevalence of renal dysfunction and the constancy of diabetes and peripheral vascular disease in this population that would reduce the differentiation of patients using the mFI.