Patient Optimization
Frank Johannes Plate, MD, PhD
Andrew M. Schwartz, MD
Thorsten M. Seyler, MD, PhD, FAAOS
Dr. Plate or an immediate family member serves as a paid consultant to or is an employee of Smith & Nephew and Total Joint Orthopedics; has stock or stock options held in Eventum Orthopaedics; and has received research or institutional support from Biocomposites Inc. Dr. Seyler or an immediate family member has received royalties from Pattern Health, Restor3d, and Total Joint Orthopedics, Inc.; serves as a paid consultant to or is an employee of Smith & Nephew and Total Joint Orthopedics, Inc.; has received research or institutional support from Next Science and Zimmer; and serves as a board member, owner, officer, or committee member of American Association of Hip and Knee Surgeons and Musculoskeletal Infection Society. Neither Dr. Schwartz nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter.
ABSTRACT
Patients presenting for orthopaedic procedures may have underlying comorbidities or medical conditions that expose them to an increased risk for intraoperative or postoperative surgical or medical complications. Comprehensive evaluation and preoperative optimization of patient comor-bidities before any planned or unplanned surgical procedure may alleviate perioperative risk and subsequent resource utilization. A thorough understanding of how medical comorbidities can influence perioperative management is needed for an orthopaedic surgeon to provide optimal patient care throughout the episode of care. Further evaluation and consultation of medical specialists may be necessary when patient comorbidities are identified properly.
Keywords: comorbidities; medical optimization; perioperative management; preoperative clearance; risk factors
Introduction
Optimizing treatment strategies for patient comorbidities has been shown to decrease the surgical risk for orthopaedic patients. Specifically, for planned elective cases, appropriate perioperative management of medical conditions that may mitigate surgical risk needs to be implemented. In the era of value-based care, the mitigation of surgical risk through collaboration with anesthesia providers in a perioperative surgical home or with medicine providers to establish surgical clearance will provide improved patient care with the aim of decreasing postoperative resource utilization. It is important to discuss common patient medical conditions and comorbidities and how these influence surgical risk and propose treatment strategies to modify these risk factors.
Modifiable Risk Factors
Modifiable risk factors are medical conditions or patient behaviors that influence the risk of perioperative complications of an orthopaedic procedure. Although some patient characteristics are inherent and cannot be changed (eg, age, end-organ damage), others are modifiable and can be changed through medical optimization (eg, diabetes control, hypertension management) or cessation of patient behavior (eg, smoking, alcohol). Therefore, modifiable risk factors can positively or negatively influence the outcomes of a surgical procedure, and their optimization needs to be attempted to decrease perioperative risk for the patient.
Obesity
Classification
Obesity has been classified by the World Health Organization into five body mass index (BMI) categories: less than 25 kg/m2, normal weight; 25 to 29.9 kg/m2, preobesity; 30 to 34.9 kg/m2, obesity class I; 35 to 39.9 kg/m2, obesity class II; and greater than or equal to 40 kg/m2, obesity class III. For further risk stratification, class III obesity can be further categorized into severe
obesity BMI greater than or equal to 35 kg/m2, morbid obesity BMI greater than or equal to 40 kg/m2, and extreme obesity greater than or equal to 50 kg/m2.
obesity BMI greater than or equal to 35 kg/m2, morbid obesity BMI greater than or equal to 40 kg/m2, and extreme obesity greater than or equal to 50 kg/m2.
The utilization of BMI for risk stratification for total joint arthroplasty remains disputed, with authors proposing body fat percentage as a more accurate predictor of perioperative complications.1
Pathophysiology
Obesity increases the risk of complications throughout the perioperative episode of care. Patients with obesity have a high prevalence of obstructive sleep apnea, decreased lung volumes with atelectasis, and hypercapnic syndrome leading to an increased risk of respiratory complications intraoperatively and postoperatively. In patients with obesity, regional blocks are more difficult to place, leading to a higher rate of block failure.2 There is a higher risk for postoperative deep vein thrombosis and pulmonary embolism in these patients. Accumulation of mitochondrial oxidative stress affecting the immune system, vascular insufficiency, and nutritional deficiencies increase the risk for wound-healing complications such as delayed wound healing, prolonged drainage, and superficial and deep surgical site infection.
Metabolic Syndrome
Metabolic syndrome is closely related to obesity and affects approximately 40% of individuals in the United States.3 Metabolic syndrome is characterized by increased waist circumference, hypertension, dyslipidemia, and elevated fasting glucose levels.
Benefits of BMI Optimization
Increased BMI is associated with inferior postarthroplasty outcomes in all domains. Furthermore, there is a sharp inflection point for perioperative surgical and medical risk in patients whose BMI exceeds 40 kg/m2, and this defines the point at which risk may outweigh benefit.4 Of similar concern, the average improvement in joint function conferred by joint arthroplasty is stunted in patients who have BMI greater than 40 kg/m2. Thus, although it is understandably difficult for patients with morbid obesity to lose weight, it is highly advisable for these patients to put forth an exhaustive effort to lose weight, especially those with BMI in excess of 40 kg/m2.
Diabetes
Pathophysiology
Type 1 diabetes mellitus is caused by autoimmune destruction of β cells and resulting lack of insulin production. Type 2 diabetes mellitus is characterized by decreased insulin secretion from β cells in the pancreas and impaired response of insulin-sensitive tissues in the periphery, leading to glucose dyshomeostasis.3 Approximately 90% of individuals with diabetes mellitus have type 2; these patients present with obesity and high body fat percentage. Decreased insulin production from β cells in combination with peripheral insulin resistance caused by inflammatory processes in adipose tissue leads to a disruption of the physiologic feedback loop between insulin action and insulin secretion, resulting in abnormally high blood glucose levels.
The stress response from surgery in conjunction with perioperative fasting leads to increased adrenaline, noradrenaline, cortisol, glucagon, and growth hormone release, leading to an increase in glucose levels and insulin resistance.
Diabetes and associated perioperative hyperglycemia lead to impaired leukocyte function, resulting in increased risk for surgical site infection following surgery.5
Serologic Studies
Quantifying Disease Severity
Poor preoperative and perioperative glycemic control is associated with increased risk of postoperative complications.6 More than 30% of patients undergoing total joint arthroplasty were found to have undiagnosed diabetes mellitus.7 Guidelines from the American Diabetes Association recommend preoperative evaluation of hemoglobin A1C (HbA1C) as an indirect measure of the average patient blood glucose level over the past 3 months of the life cycle of erythrocytes.6,8 Patients with HbA1C between 5.7% and 6.4% are classified as having prediabetes and HbA1C ≥ 6.5% is considered diabetes. Uncontrolled diabetes is considered with HbA1C greater than 7%. Although a threshold of HbA1C of greater than 7.5% or 7% has been generally used as an indication for further preoperative optimization of glycemic control, the predictive value of HbA1C levels for postoperative complications was found to be equivocal after total joint arthroplasty.6
Serum fructosamine measures the level of glycated serum proteins, mostly albumin over the prior 2 to 3 weeks based on serum protein turnover.6 A serum fructosamine level greater than 293 µmol/L was found to be more predictive of postoperative infection, readmission, and revision surgery following total joint arthroplasty than HbA1C.9
Basis for Correction
Patients with diabetes are at greater risk for perioperative morbidity and mortality, including surgical site
infection, urinary tract infection, myocardial infarction, blood transfusion, revision surgery, and increased length of hospital stay after total ankle arthroplasty or ankle fusion.10 Patients with HbA1C level greater than 7% had a significantly higher risk of surgical site infection after spinal fusions.11 Similarly, patients with elevated fructosamine levels who underwent total knee arthroplasty had a greater risk for prosthetic joint infection, readmission, and revision surgery.9 Preoperative optimization of glucose control with a goal of HbA1C below 7% and fructosamine level below 293 µmol/L is recommended to decrease postoperative patient morbidity and resource utilization.
infection, urinary tract infection, myocardial infarction, blood transfusion, revision surgery, and increased length of hospital stay after total ankle arthroplasty or ankle fusion.10 Patients with HbA1C level greater than 7% had a significantly higher risk of surgical site infection after spinal fusions.11 Similarly, patients with elevated fructosamine levels who underwent total knee arthroplasty had a greater risk for prosthetic joint infection, readmission, and revision surgery.9 Preoperative optimization of glucose control with a goal of HbA1C below 7% and fructosamine level below 293 µmol/L is recommended to decrease postoperative patient morbidity and resource utilization.
Malnutrition
Malnutrition describes the excess of nutrition as observed in elevated BMI and metabolic syndrome as well as nutritional deficiency. Malnutrition most commonly describes nutritional deficiency. Several measures of malnutrition have been used, including serologic markers, anthropometric measurements, and nutrition scoring tools.
Serologic markers are most commonly used in orthopaedic surgery to assess nutritional status. A total serum lymphocyte count less than 1,500 cells/mm3 is indicative of nutritional deficiency resulting in immunocompromise associated with an increased risk for postoperative infection. A serum albumin concentration less than 3.5 g/dL reveals chronic malnutrition (half-life of approximately 3 weeks). Alternatively, prealbumin levels indicate acute changes in protein levels with a half-life of approximately 2 days. Serum prealbumin levels between 11 and 19 mg/dL indicate mild, 7 and 10 mg/dL moderate, and less than 7 mg/dL severe hypoproteinemia.12 Protein depletion has been associated with impaired wound healing and surgical site infections following spine surgery and joint arthroplasty.12 In addition, serum transferrin levels less than 200 mg/dL and serum zinc levels less than 95 µg/dL are signs of malnutrition and associated with delayed wound healing.13,14
Anthropometric measurements of anatomic body areas assess physical signs of decreases in body fat and skeletal muscle. Changes in body composition are a marker of severe chronic malnourishment, including calf circumference less than 31 cm, arm circumference less than 22 cm, and a decreased triceps skinfold thickness.13 However, anthropometric changes appear late and thus are unable to detect marginal malnutrition in a perioperative setting.13
Several nutritional screening tools have been devised to identify patient malnutrition. The Rainey-MacDonald nutritional index is a formula based on serum albumin and transferrin level, and a low preoperative score predicted delayed wound healing in patients who underwent surgical fixation or hemiarthroplasty for femoral neck and intertrochanteric hip fractures.15 The Mini Nutritional Assessment includes dietary questions, anthropometric measures, and other variables for assessment in the geriatric population.13 When compared with other tools such as the Malnutrition Screening Tool and the Nutrition Risk Screening 2002, the Mini Nutritional Assessment similarly predicted postoperative morbidity and mortality following surgical fixation or arthroplasty for geriatric hip fractures.16 The Perioperative Nutrition Screen specifically assesses preoperative nutritional status of ambulatory patients and includes serum albumin, BMI, dietary intake, and weight changes intended to improve patient nutrition before orthopaedic surgical interventions.17
Vitamin D Deficiency
Importance
Vitamin D deficiency is a common problem among adult and pediatric orthopaedic patients in foot and ankle surgery, trauma, joint arthroplasty, and spine surgery.18 Estimates suggest a worldwide vitamin D deficiency rate of one billion.19 Vitamin D is obtained from ultraviolet light exposure, diet, and dietary supplements. The active form of vitamin D, 1,25-dihydroxy vitamin D increases calcium absorption in the small intestine and promotes receptor activator of nuclear factor kappa B ligand expression in osteoblasts, leading to osteoclast activation and bone mineralization and turnover. Vitamin D acts on skeletal muscle, and deficiency has been shown to be a cause of muscle weakness and increased frequency of falls.20 Vitamin D also is an immunomodulator that activates monocytes and macrophages and may be implicated in a patient’s postoperative inflammatory response.21
Based on the recommendation by the Endocrine Society, vitamin D insufficiency is defined as serum 1,25-dihydroxy vitamin D levels below 30 ng/mL and deficiency below 20 ng/mL. A 2020 systematic review of 12 studies assessing vitamin D levels in patients before total hip arthroplasty and total knee arthroplasty reported a pooled vitamin D insufficiency of 53.4% and pooled vitamin D deficiency rate of 39.4%.20
Patients with vitamin D deficiency who underwent total hip arthroplasty were found to have decreased postoperative functional scores at short-term follow-up.22 Following revision total hip arthroplasty and total knee arthroplasty, patients had a higher risk for postoperative infection and complications within 90 days from surgery.23
Treatment
Sunlight exposure between 5 and 30 minutes, two to three times weekly is recommended. There are several dietary sources of vitamin D, such as oil-rich fish, red meat, egg yolk, cow’s milk, and fortified foods. Vitamin D supplementation is available as vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol), which is more effective as a supplement. For adult patients with vitamin D deficiency, 1,500 to 2,000 IU daily is recommended. Because of the high prevalence of vitamin D insufficiency and deficiency in the orthopaedic patient population, universal screening versus prophylactic vitamin D supplementation due to low cost and minimal adverse effects remains debated. However, vitamin D supplementation may be a cost-effective way to potentially decrease readmissions and associated increase in resource utilization and health care costs.
Smoking
Pathophysiology
Despite declining rates of cigarette smoking in the United States, 20.8% of adults reported using tobacco products (4.5% electronic cigarettes) in 2019.24 Smoking causes atherosclerosis with associated hypotension, chronic obstructive pulmonary disease, and malignancies, increasing overall mortality in smokers.25 Tobacco smoke contains reactive oxygen species, carbon monoxide, and nicotine. Oxidative stress from smoking with release of free radicals leads to protein and DNA damage, cell apoptosis, and necrosis with impediment of reparative processes within cells.25 Carbon monoxide binds to hemoglobin with 200 times greater affinity than oxygen, causing a decreased oxygen-carrying capacity of blood to the periphery with resulting tissue hypoxemia.25 Nicotine causes vasoconstriction by inhibiting nitric oxide synthase and thereby decreasing endothelium-mediated vasodilation, which is further increased through nicotine-induced catecholamine release. Nicotine induces thromboxane A2 generation in platelets, causing vasoconstriction with increased vascular resistance and platelet aggregation and increasing the risk of thrombosis. Smoking suppresses the immune system, leading to increased risk for postoperative infection. In combination, the effects of nicotine lead to decreased local blood flow and tissue perfusion with a suppressed immune response, increasing the risk for wound-healing complications and postoperative infection. Respiratory effects of tobacco use lead to an increased risk for pulmonary complications and increased length of hospital stay with greater resource utilization in the perioperative period.
The influence of nicotine on bone healing remains debated. Although some authors have found decreased fracture healing and osteointegration of titanium implants with decreased production of bone morphogenetic proteins in animal models,26 others reported a possible dose-dependent effect of nicotine on posterior spinal fusion mass in a rabbit model.27
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Orthopaedic Patient Safety: Core Competencies and Communication Skills
Structure and Biology of Normal and Diseased Bone
Polytrauma Care
Rotator Cuff Disease, Calcific Tendinitis, Adhesive Capsulitis, Throwing Shoulder, and Instability
Ligament Injuries of the Wrist
Articular Cartilage of the Knee: Defects, Degeneration, and Preservation
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