Total knee arthroplasty (TKA) and total hip arthroplasty (THA) are two of the most common surgical procedures performed in the United States today, with projected yearly case numbers of nearly 3.5 million and 570,000, respectively, by 2030. As the technology and safety of joint replacement has improved, the indications for surgery have expanded dramatically to provide the significant benefits in quality of life and pain improvement to patients who would not previously have been considered surgical candidates. At the same time, bundled payment models, patient satisfaction, and renewed emphasis on value demand that complication rates remain as low as possible. Many patients considering joint replacement surgery have risk factors for complications during the perioperative and postoperative period and should undergo optimization prior to surgery to reduce these risks. Additionally, the increasing role of outpatient total joint arthroplasty places an increased emphasis on preoperative planning and optimization to avoid complications and maximize outcomes.
Risk Factors and Optimization
Obesity is most commonly defined according to the body mass index (BMI; kg/m 2 ). Normal BMI is considered 20 to 25, 26 to 30 is overweight, and greater than 30 is considered obese. The World Health Organization further classifies obesity into Class I (BMI 30–34.9), Class II (35–39.9), and Class III or morbidly obese (>40). Further classification in the bariatric literature considers BMI >50 to be super obese. The prevalence of obesity in patients undergoing total joint arthroplasty (TJA) is increasing. A workgroup of the American Association of Hip and Knee Surgeons (AAHKS) in 2013 conducted a literature review and found that obese patients (BMI >30) who underwent TJA were at increased risk for perioperative complications. In patients undergoing TKA, they found that BMI >40 appeared to be the threshold above which the rates of infection and overall revision increase significantly. The BMI threshold for THA was less clear. They recommended for discussion of these risks with patients prior to surgery and consideration of weight reduction prior to TJA.
This recommendation has been controversial, with concern that BMI thresholds would reduce access to care for patients with obesity. A study published in 2020 followed 158 patients with moderate to severe osteoarthritis (OA) with BMI greater than 40. Of these patients, 51.3% did not return for a second visit and only 42.9% of those who returned for follow-up went on to a TJA. Patients with higher BMI were less likely to return for follow-up. Those patients who eventually underwent surgery had a lower BMI at their initial visit and were more likely to have lost weight than those who did not follow up. When compared with a matched cohort of arthroplasty patients with BMI less than 40, there was not a higher complication rate in the group of obese patients who went on to arthroplasty. Arthroplasty has been shown to be a cost-effective , treatment for obese and morbidly obese patients, and significant improvement in both patient-reported and surgeon-reported pain and function scores are seen after arthroplasty surgery. Restricting TJA has not been found to incentivize weight loss. In one study of a cohort of 289 patients with morbid obesity, only 58 went on to arthroplasty surgery and only 23 of those 58 could achieve a BMI of less than 40 at the time of arthroplasty. The average BMI reduction for the 58 patients who underwent TJA was from 45.3 to 42.3.
The risks of arthroplasty for obese patients is well established. What is less clear is the impact that weight reduction can have on those risks. Some obese patients are referred for bariatric surgery prior to TJA. One study in 2019 found that patients who had bariatric surgery prior to TJA had a decreased length of stay, lower rates of thromboembolic disease, and lower 30-day mortality. However, the rate of obesity in the post-bariatric surgery group was unclear. A meta-analysis in 2019 of 9 pooled studies published from 2011 to 2018 found a lower incidence of medical complications in the group that had bariatric surgery prior to TJA. There was a nonsignificant trend favoring bariatric surgery for the rates of thromboembolic disease and periprosthetic infection. The bariatric group members had a significantly better length of stay and shorter operative time for their TJA. There was no difference in long-term complication rate or revision rate between the two groups. Another study in 2018 found that patients undergoing THA at least 6 months after bariatric surgery were less likely to be readmitted within 90 days of their THA, but that there was no association between the time from bariatric surgery to THA or TKA and 90-day complication rates. An analysis of Medicare data for patients who underwent TJA after bariatric surgery found a higher rate of infection in THA patients and higher rate of revision in TKA patients. A study in 2019 found that 20 lbs of weight reduction prior to arthroplasty was associated with shorter length of stay and lower risk of discharge to a facility rather than home. The authors found no changes in operative time or physical function scores.
Recommendations regarding arthroplasty for obese patients require a shared decision-making approach. Making a BMI greater than 40 a hard contraindication to arthroplasty will deprive obese patients of health care services that can provide substantial benefits to pain, physical function, and quality of life. These benefits must be carefully considered against increased risks of delayed wound healing, deep periprosthetic infection, and other complications. Patients should be made fully aware of the implications of these complications when deciding how they would like to proceed.
Diabetes mellitus is another disease that is frequently associated with obesity and other metabolic derangements. The incidence of diabetes in arthroplasty patients is high, with one study finding 20.6% of arthroplasty patients to be diabetic, and 41% of those patients previously undiagnosed. The authors of that study concluded that all patients considering arthroplasty should be screened for diabetes, with special attention paid to patients greater than 65 years old and those with risk factors for diabetes.
The most common screening tool for diabetes is hemoglobin A1c. The current recommendation for the prevention of surgical site infections (SSIs) is to have an A1c less than 7%. An A1c of 7.45% is associated with perioperative blood glucose levels of greater than 200 mg/dL. When looking specifically at A1c as a predictor of infection, a level of 7.7% may be a better cutoff for elective surgery. Serum fructosamine levels offer a picture of mean glucose levels over a shorter period of time than A1c, 2 to 3 weeks versus 3 months. Fructosamine levels greater than 292 μmol/L are associated with higher risks of deep infection, readmission, and revision surgery. The impact of decreasing fructosamine levels prior to surgery on the risk of these complications is not established.
Cigarette smoking remains a persistent cause of preventable death and disease in the United States. When compared with obesity, diabetes, and other risk factors for arthroplasty surgery, cigarette smoking is an addiction that can be treated effectively in patients who are properly motivated to quit. Smoking has associations with increased risk of bony nonunion and wound healing complications. Nicotine screening by testing for urine metabolites can reliably differentiate between active smoking, former smokers using nicotine replacement, and nonsmokers by comparing urine nicotine and urine anabasine levels. Smoking cessation within 4 weeks of surgery is associated with improved outcomes.
With regard to THA and TKA, active smokers have a higher risk of pneumonia and myocardial infarction than former or nonsmokers. They also have higher rates of opioid usage and higher mortality after 1 year. Active smoking has been found to increase the risk of deep infection by 1.8× after primary TJA, but this risk was similar to never smokers at 1 year after surgery.
Common tools to aid in smoking cessation include behavioral counseling, nicotine replacement, varenicline, and buproprion. Counseling combined with pharmacologic therapy increases success in tobacco cessation.
Intravenous Drug Use
In the setting of the national opioid epidemic, rates of intravenous (IV) drug use have increased in recent years. Patient use of IV drugs in the setting of previous arthroplasty places them at extremely high risk of infection. Previous native joint septic arthritis stemming from IV drug use has a poor prognosis when ultimately treated with arthroplasty. One series of 15 patients with a history of IV drug use underwent THA. Ten patients presented with acute bacterial hip infections that were treated with resection arthroplasty and subsequent THA and 5 presented with acute osteonecrosis. All 15 patients developed infection or recurrence of infection after undergoing a THA, and only 2 eventually achieved a THA without presence of infection after 4-year follow-up. Another series of patients with a history of IV drug use with 5- and 10-year follow-up found implant survival after THA of 61% and 52%, respectively. The authors of that study recommended hair analysis for drug metabolites for at least 1 year prior to indicating a patient for THA. This author considers a recent history of IV drug use to be an absolute contraindication to arthroplasty surgery. Patients with a remote history of IV drug use should be carefully counseled about the risks of relapse on arthroplasty.
Malnutrion may occur in up to half of orthopaedic patients, and risk of malnutrion increases with age. Complications of malnutrition in surgical patients include SSI, readmission, and mortality. Patients with BMI less than 18 and those with obesity can be malnourished. There is no single criterion or definition for malnourishment. Common tests and cutoffs for malnutrition include serum prealbumin less than 15 mg/dL, serum albumin less than 3.5 mg/dL, and serum transferrin less than 200 mg/dL. A total absolute lymphocyte count less than 1500 cells/mm is another possible marker of malnutrition. Serum albumin has the longest half-life and is a better indicator of chronic malnutrition. There is a scarcity of data on the use of oral nutritional supplementation to correct malnutrition in orthopaedic patients. However, in general, patients who are identified as malnourished should at a minimum be counseled regarding their dietary intake and encouraged to increase their normal intake of calories, protein, and lean fats.
Frailty is a term that denotes a condition of physiologic decline and multiorgan system dysfunction. Rather than age or physical function scores, frailty indices identify patients who may be at increased risk of perioperative or postoperative complications due to the cumulative effects of mild to moderate dysfunction of multiple organ systems. While frailty may not be a modifiable risk factor for elective arthroplasty, identifying patients who would qualify as frail is important for patient counseling and surgical shared decision-making. The frailty index (FI) as described by Rockwood identified the presence or absence of 20 chronic medical conditions as well as the level of independence with 14 activities of daily living. Multiple modified FIs have been established based on the relative prevalence of certain conditions in populations. Using the FI, patients classified as frail after THA have higher rates of wound complications, hematoma, reoperation during hospitalization, infection, dislocation, and mortality at 90 days and 1 year postoperatively. Similar risks were identified after TKA. ,
Rheumatologic diseases are typically disorders of the body’s immune system, which include rheumatoid arthritis, psoriatic arthritis, systemic lupus erythematosus, and ankylosing spondylitis. Historically, these diseases led to early surgical intervention due to joint destruction at relatively young ages and were causes of significant disability. The use of disease-modifying antirheumatic drugs (DMARDs) and biologic medications has substantially decreased the surgical burden for these patients and has slowed the progression of joint degeneration. Consequently, their use has led to a decrease in the rates of TJA for these patients. Patients with inflammatory arthritis have higher rates of surgical complications after TJA compared with patients with osteoarthritis. While these patients cannot be optimized per se, their medications should be managed perioperatively to maximize healing potential and minimize the risks of delayed wound healing. Published guidelines were most recently updated in 2017 regarding perioperative dosing of these medications ( Table 1.1 ).
|DMARDs: Continue these medications through surgery||Dosing Interval||Continue/Withhold|
|Sulfasalazine||Once or twice daily||Continue|
|Hydroxychloroquine||Once or twice daily||Continue|
|BIOLOGIC AGENTS: STOP these medications prior to surgery and schedule surgery at the end of the dosing cycle. RESUME medications at minimum 14 days after surgery in the absence of wound healing problems, surgical site infection, or systemic infection.||Dosing Interval||Schedule Surgery (relative to last biologic agent dose administered) during|
|Adalimumab (Humira)||Weekly or every 2 weeks||Week 2 or 3|
|Etanercept (Enbrel)||Weekly or twice weekly||Week 2|
|Golimumab (Simponi)||Every 4 weeks (SQ) or every 8 weeks (IV)||Week 5 |
|Infliximab (Remicade)||Every 4, 6, or 8 weeks||Week 5, 7, or 9|
|Abatacept (Orencia)||Monthly (IV) or weekly (SQ)||Week 5 |
|Certolizumab (Cimzia)||Every 2 or 4 weeks||Week 3 or 5|
|Rituximab (Rituxan)||2 doses 2 weeks apart every 4–6 months||Month 7|
|Tocilizumab (Actemra)||Every week (SQ) or every 4 weeks (IV)||Week 2 |
|Anakinra (Kineret)||Daily||Day 2|
|Secukinumab (Cosentyx)||Every 4 weeks||Week 5|
|Ustekinumab (Stelara)||Every 12 weeks||Week 13|
|Belimumab (Benlysta)||Week 5|
|Tofacitinib (Xeljanz): STOP this medication 7 days prior to surgery.||Daily or twice daily||7 days after last dose|
|SEVERE SLE-SPECIFIC MEDICATIONS: |
CONTINUE these medications in the perioperative period.
|Mycophenolate mofetil||Twice daily||Continue|
|Azathioprine||Daily or twice daily||Continue|
|Tacrolimus||Twice daily (IV and PO)||Continue|
|NOT-SEVERE SLE: DISCONTINUE these medications 1 week prior to surgery||Dosing Interval||Continue/Withhold|
|Mycophenolate mofetil||Twice daily||Withhold|
|Azathioprine||Daily or twice daily||Withhold|