Electrolyte imbalance after total joint arthroplasty: risk factors and impact on length of hospital stay

The Association of Comorbidities With Total Knee Arthroplasty Health Care Utilization

BACKGROUND

Patients undergoing total knee arthroplasty (TKA) tend to have comorbidities such as obesity, hypertension, and cancer, which are associated with advanced age. This study aimed to elucidate the associations of these comorbidities with hospital charge (HC), hospital costs (HCos), and length of stay (LOS).

METHODS

A national database was queried for patients who underwent primary TKA from 2012 to 2020. There were 30 comorbidities classified using the Elixhauser comorbidity index. For each comorbidity of interest, patients were matched to another patient by age, sex, and all other comorbidities except the comorbidity of interest. Matched cohorts were analyzed via multivariable regression analyses controlled for age, sex, procedure year, hospital location, and comorbidities to predict increases in HC, HCo, and LOS. A total of 1,014,831 patients were included.

RESULTS

Mean HC, HCo, and LOS were $64,097, $17,299, and 2.5 days, respectively. Weight loss, blood loss anemia, coagulopathies, and fluid and electrolyte disorders were associated with the largest increases in HC, with 6, 5, 5, and 5% increases, respectively (P < 0.05). Pulmonary hypertension, non-metastatic tumors, paralysis, and obesity were associated with increased HCo, with 6, 4, 4, and 4% increases, respectively (P < 0.05). All comorbidities except hypothyroidism were associated with increased LOS. Pulmonary hypertension, weight loss, paralysis, fluid and electrolyte disorders, and human immunodeficiency virus/acquired immunodeficiency syndrome were associated with were associated with 53, 21, 15, 14, and 12%, respectively, increased odds of having LOS greater than or equal to 4 days' increase (P < 0.05).

CONCLUSION

This study offers targets for the reduction of HC, HCo, and LOS for patients with these ailments through protocol change. Optimization programs targeting malnourished patients, patients with pulmonary hypertension, and other comorbidities are encouraged. These results also provide clinicians with a quantifiable way to communicate financial burden and recovery time after TKA to patients' unique problem lists.

Clinicoepidemiological profile of acute postoperative hyponatraemia in patients undergoing joint replacement surgery: A prospective observational study

BACKGROUND

Postoperative hyponatraemia is frequently misunderstood or undiagnosed after orthopaedic surgery, such as total knee and hip replacements, which is associated with increased morbidity. Limited and primarily retrospective literature exists on postoperative hyponatraemia in hip and knee arthroplasties. Key risk factors include preoperative hyponatraemia, older age, female sex, lower body weight, fluid imbalance, and surgical stress.

METHODS

This prospective observational study aimed to investigate the incidence of postoperative hyponatraemia and associated factors in 225 orthopaedic surgical patients. Pre-existing hypornatremia cases were excluded. The patients' serum sodium, potassium, blood urea nitrogen, creatinine, glucose, and haemoglobin levels were measured before the surgery and on the first postoperative day.

RESULTS

Postoperative hyponatraemia was detected in 30.6% (n = 69) of the 225 participating patients; among them, 91.6% had mild, 7.2% had moderate, and 1.4% had severe hyponatraemia. People with diabetes (odds ratio = 3.4; 95% confidence interval 1.36-13.4) and patients with blood loss > 300 mL (odds ratio = 10.3; 95% confidence interval 2.98-16) were more susceptible. Patients with hyponatraemia experienced an extended hospital stay.

CONCLUSION

One-third of the normonatraemic orthopaedic surgical patients developed postoperative hyponatraemia. Significant risk factors identified include diabetes and intraoperative blood loss exceeding 300 mL. This study allows for a focused evaluation of how surgical procedures influence sodium levels by excluding patients with preoperative hyponatraemia, unlike previous research studies.

Hospital Length of Stay and Associated Factors in Patients with Osteoarthritis from Germany: A Cross-Sectional Study

Objective: There is a scarcity of data on hospital length of stay (LOS) in the osteoarthritis population. Therefore, this study aimed to investigate hospital LOS and associated factors in patients with osteoarthritis from Germany. Methods: The present cross-sectional study included patients hospitalized for osteoarthritis in one of fourteen hospitals in Germany between 2018 and 2023 (hospital database; IQVIA). The study outcome was the duration of hospital stay in days. Study covariables included age, sex, hospital department, osteoarthritis type, co-diagnosis, and hospitalization-related procedure. Associations between covariables and hospital LOS were analyzed using hierarchical linear regression models. Results: There were 8770 patients included in the study (mean [standard deviation] age 68.7 [10.8] years; 60.2% women). The mean (standard deviation) hospital LOS was 8.5 (5.0) days. Factors positively and significantly associated with hospital LOS were older age, female sex, orthopedic surgery and other medical specialty departments (compared with other surgery departments), knee and other and unspecified osteoarthritis (compared with hip osteoarthritis), multiple co-diagnoses (e.g., acute posthemorrhagic anemia, other disorders of fluid, electrolyte, and acid-base balance, and disorders of purine and pyrimidine metabolism), and several hospitalization-related procedures (i.e., geriatric rehabilitation, hip arthroplasty, and knee arthroplasty). Conclusions: The mean hospital LOS was higher than eight days in this osteoarthritis population from Germany, with a spectrum of demographic, clinical, and hospitalization-related factors associated with this hospital LOS. In this context, interventions are needed to reduce the LOS of hospitalizations for osteoarthritis in Germany.

Hyponatremia Is an Overlooked Sign of Trouble Following Total Joint Arthroplasty

BACKGROUND

Hyponatremia is a common electrolyte abnormality in arthroplasty patients. This issue, underrecognized by surgeons, can impact the postoperative course of patients. There are, however, little data on the implications of sodium disturbances following total joint arthroplasty (TJA). The primary aims of this study were to (1) report the rate of hyponatremia following TJA, and (2) examine the impact of hyponatremia on the perioperative course of TJA patients.

METHODS

This was a retrospective analysis of 3,071 primary and revision TJAs performed between 2015 and 2017. Based on preoperative and postoperative sodium values (pre-post), patients were classified into 4 groups: normonatremic-normonatremic (Group 1), normonatremic-hyponatremic (Group 2), hyponatremic-normonatremic (Group 3), and hyponatremic-hyponatremic (Group 4). Primary end points were length of stay (LOS), postoperative discharge, in-hospital complications, and 90-day readmissions.

RESULTS

The distribution of cases was 84.6% Group 1, 9.4% Group 2, 2.1% Group 3, and 3.8% Group 4. Overall, 13.2% of patients had hyponatremia after TJA. Older age, hip arthroplasty, general anesthesia, higher Charlson Comorbidity Index, congestive heart failure, revision surgery, and history of stroke, liver disease, and chronic kidney disease were risk factors for postoperative hyponatremia. Patients with postoperative hyponatremia (Groups 2 and 4) had greater likelihoods of having a 90-day complication and non-home discharge and greater LOS.

CONCLUSIONS

Postoperative hyponatremia was a relatively common occurrence in patients undergoing TJA, and was associated with greater LOS, complications, and non-home discharge. Surgeons should identify patients at risk for developing sodium abnormalities in order to optimize these patients and avoid increased resource utilization.

LEVEL OF EVIDENCE

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Effects of Preoperative Oral Electrolyte-Carbohydrate Nutrition Supplement on Postoperative Outcomes in Elderly Patients Receiving Total Knee Arthroplasty: A Prospective Randomized Controlled Trial

Objective

Patients undergoing total knee arthroplasty (TKA) were primarily geriatric, with high risk of postoperative electrolyte disorders and malnutrition. Randomized controlled trials regarding oral nutrition supplement (ONS) strategies in TKA was sparse. This study aimed to evaluate the efficacy of preoperative oral electrolyte‐carbohydrate nutrition supplement (OECNS) on patients (aged >65 years) undergoing TKA.

Methods

From April 2019 to January 2020, 94 patients undergoing primary elective unilateral TKA in our hospital were considered in this prospective randomized controlled study. This study included patients aged over 65 years with ASA I‐III, and excluded patients with electrolyte disorders, malnutrition, and comorbidities. The control group (control group) received meal nutrition supplements (preoperative 6 h [Pre 6h]) and water (Pre 2h), while OECNS group (intervention group) received meal nutrition supplements (Pre 6h) and OECNS (Pre 2). The Student's t test and χ² test was used. The primary outcomes were the patient‐reported comfort indicators (PRCIs) including hunger, thirst, nausea, vomiting, weakness, pain, anxiety, and general comfort. The secondary outcomes included indicators of electrolyte, nutrition, functional scores, clinical results, and complications.

Results

The scores of preoperative hunger (0.43 ± 0.10), pain (2.30 ± 0.34), and anxiety (9.04 ± 2.71) were significantly lower in OECNS group compared with control group (hunger, 1.19 ± 0.21; pain, 3.79 ± 0.26; anxiety, 11.21 ± 3.02) (Pre 1h) (all p < 0.05) as well as the weakness score on the first postoperative day (POD1) (OECNS group 3.57 ± 0.24; control group 5.15 ± 0.29; p < 0.001). A higher level of Na + (OECNS group 140.54 ± 3.39; control group 138.07 ± 5.21; p = 0.008) and a reduced rate of hyponatremia (OECNS group 6.4%; control group 21.3%; p = 0.036) on POD1 were found. Moreover, the higher level of blood glucose (Post 2h) and reduced rates of abnormal blood glucose (Pre 2h, Post 6h) were verified in control group (all p < 0.05). There was no significant difference regarding the other outcomes.

Conclusion

The administration of OECNS significantly improved subjective comfort, electrolytes, and blood glucose without increasing the rates of complications in patients (aged over 65 years) undergoing TKA.

Development and Internal Validation of Machine Learning Algorithms for Predicting Hyponatremia After TJA

BACKGROUND

The development of hyponatremia after total joint arthroplasty (TJA) may lead to several adverse events and is associated with prolonged inpatient length of stay as well as increased hospital costs. The purpose of this study was to develop and internally validate machine learning algorithms for predicting hyponatremia after TJA.

METHODS

A consecutive cohort of 30,703 TJA patients from an institutional registry at a large, tertiary academic hospital were included. A total of 19 potential predictor variables were collected. Hyponatremia was defined as a serum sodium concentration of <135 mEq/L. Five machine learning algorithms were developed using a training set and internally validated using an independent testing set. Algorithm performance was evaluated through discrimination, calibration, decision-curve analysis, and Brier score.

RESULTS

The charts of 30,703 patients undergoing TJA were reviewed. Of those patients, 5,480 (17.8%) developed hyponatremia postoperatively. A combination of 6 variables were demonstrated to optimize algorithm prediction: preoperative serum sodium concentration, age, intraoperative blood loss, procedure time, body mass index (BMI), and American Society of Anesthesiologists (ASA) score. Threshold values that were associated with greater hyponatremia risk were a preoperative serum sodium concentration of ≤138 mEq/L, an age of ≥73 years, an ASA score of >2, intraoperative blood loss of >407 mL, a BMI of ≤26 kg/m2, and a procedure time of >111 minutes. The stochastic gradient boosting (SGB) algorithm demonstrated the best performance (c-statistic: 0.75, calibration intercept: -0.02, calibration slope: 1.02, and Brier score: 0.12). This algorithm was turned into a tool that can provide real-time predictions (https://orthoapps.shinyapps.io/Hyponatremia_TJA/).

CONCLUSIONS

The SGB algorithm demonstrated the best performance for predicting hyponatremia after TJA. The most important factors for predicting hyponatremia were preoperative serum sodium concentration, age, intraoperative blood loss, procedure time, BMI, and ASA score. A real-time hyponatremia risk calculator was developed, but it is imperative to perform external validation of this model prior to using this calculator in clinical practice.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Oral Hydration Before and After Hip Replacement: The Notion Behind Every Action

Introduction

Even though nearly 20 patients undergo hip replacement every hour just in Italy and the United Kingdom, it is unclear what are the most appropriate oral hydration practices that patients should follow before and after surgery. Improper administration can cause postoperative fluid disturbances or exacerbate pre-existing conditions, which are not an uncommon find in older subjects.

Significance

Considering that the number of hip operations is expected to increase in the next years as well as the age of patients, it is important to recall the notions behind water balance, especially in light of modern surgical and anesthetic practices. This technical perspective discusses the perioperative changes in the hydration status that occur during hip replacement and provides the concepts that help clinicians to better manage how much water the patient can drink.

Results

The points of view of the surgeon, the anesthetist, and the nurse are offered together with the description of mineral waters intended for human consumption. Before surgery, water should be always preferred over caffeinated, sugar-sweetened, and alcoholic beverages. The drinking requirements on the day of surgery should consider the water output from urine, feces, respiration, exudation, and bleeding along with the water input from metabolic production and intravenous administration of fluids and medications. Healthy eating habits provide water and should be promoted before and after surgery.

Conclusions

The judgment on which is the most appropriate approach to oral hydration practices must be the responsibility of the multidisciplinary perioperative team. Nevertheless, it is reasonable to argue that, in the presence of a patient with no relevant illness and who follows a healthy diet, it is more appropriate to stay closer to dehydration than liberalizing water intake both prior to surgery and in the early postoperative hours until the resumption of normal physiological functions.

Increased severity of anemia is associated with postoperative complications following primary total shoulder arthroplasty

BACKGROUND

Anemia has been demonstrated as a modifiable risk factor for postoperative complications following various types of primary and revision total joint arthroplasties. However, at present, we are not aware of any studies assessing postoperative complications following total shoulder arthroplasty (TSA) in patients with varying severity of anemia. The purpose of this study was to determine the influence of preoperative anemia severity on 30-day postoperative complications following primary TSA.

METHODS

Adult patients undergoing primary TSA from 2012 to 2018 were identified in the National Surgical Quality Improvement Program database. Patients undergoing TSA were substratified into 3 cohorts: nonanemia (hematocrit >36% for women, >39% for men), mild anemia (hematocrit 33%-36% for women, 33%-39% for men), and moderate to severe anemia (hematocrit <33% for both women and men), based on World Health Organization definitions of anemia. In this analysis, 30-day wound, cardiac, pulmonary, renal, and thromboembolic complications, as well as sepsis, mortality, postoperative transfusion, extended length of stay, and reoperation were assessed. Bivariate analyses, including χ² and analysis of variance, and multivariable logistical regression were performed.

RESULTS

Of 13,921 total patients undergoing TSA, 11,330 patients (81.4%) did not have anemia, 1934 (13.9%) had mild anemia, and 657 (4.7%) had moderate to severe anemia. Following adjustment, patients with mild anemia were more likely to have a postoperative blood transfusion (odds ratio [OR] 4.7, P < .001), extended length of stay (OR 1.7, P = .002), and reoperation (OR 1.5, P = .028). Patients with moderate to severe anemia were at increased risk of cardiac complications (OR 3.0, P = .012), pulmonary complications (OR 2.2, P = .015), postoperative blood transfusion (OR 23.8, P < .001), extended length of stay (OR 6.6, P < .001), reoperation (OR 2.2, P = .003), and death (OR 3.8, P = .034).

CONCLUSION

From mild anemia to moderate to severe anemia, there was a stepwise and approximately 2-fold increase in the odds of postoperative complications for patients undergoing primary TSA. Patients with moderate to severe anemia should be medically optimized before they undergo TSA.

Predictors of hyponatremia following elective primary unilateral knee arthroplasty at a tertiary centre: A retrospective observational cohort and predictive model

Introduction

Hyponatremia is a common electrolyte disorder. This can be associated with nausea, disorientation and in more serious cases a decreased level of consciousness or neurological deficits. These symptoms may lead to increases in the cost of hospital care and significant morbidity. The purpose of this retrospective, observational cohort study is to investigate the impact of hyponatremia on patient and systems specific outcome measures in those undergoing elective, unilateral total knee arthroplasty (TKA) at two hospitals in Auckland, New Zealand over a twelve-month period.

Materials and methods

Patients were stratified into two groups based on the presence or absence of post-operative hyponatremia (defined as a blood sodium of <135 mmol/L with a concurrent decrease of ≥5 mmol/L between the pre- and post-operative recordings). Outcomes collected included Quality of Recovery - 15 (QOR) scores, time to assisted mobilisation, discharge ICD-10 complication codes and hospital length of stay.

Results

During the study period 236 patients underwent surgery. Eighty-six (36.4%) patients met criteria for post-operative hyponatremia. This finding was associated with prolongation of the hospital length of stay (4.17 (3.26-5.18) versus 4.28 (3.31-5.45) days, p = 0.031) and a reduction in the QOR score on the second post-operative day (113.0 (99.5-126.5) versus 105.0 (94.0-118.0), p = 0.039). There was no difference in the time to assisted mobilisation.

Conclusions

Hyponatremia is a common finding following TKA. This abnormality is associated with small changes in patient specific outcome measures. These implications of these findings may become more significant in settings where same day or rapid discharge from hospital is targeted.

Implications of Postpancreatectomy Hypophosphatemia

BACKGROUND

Electrolyte abnormalities are commonly found after major abdominal surgery for malignancy. We hypothesized that the severity of hypophosphatemia developed in pancreatectomy patients would be associated with the incidence of complications postoperatively.

METHODS

A retrospective analysis of an institutional database was conducted for all pancreatic resections (2009-2017). Patient charts were reviewed for demographics, clinicopathologic factors, and perioperative outcomes.

RESULTS

In a cohort of 283 pancreatectomy patients, 107 (37.8%) and 134 (47.3%) developed mild (2.0-2.5 mg/dL) and moderate/severe hypophosphatemia (<2.0 mg/dL), respectively. Nadir serum phosphate levels were shown to occur on postoperative day (POD) 2 for patients without complications and POD3 for patients who had at least 1 complication. Patients who developed severe hypophosphatemia were significantly more likely to suffer fistula-related complications (P = .0401).

CONCLUSIONS

Assessing the severity and timing of postpancreatectomy hypophosphatemia presents an opportunity for early detection of impending fistula-related complications.