More Data on Periprosthetic Hip Infections
Among >100,000 total hip arthroplasty (THA) patients ≥55 years of age whose data resides in a Canadian arthroplasty database, the 15-year cumulative incidence of periprosthetic joint infection (PJI) was 1.44%, according to a study by the McMaster Arthroplasty Collaborative in the March 18, 2020 issue of JBJS.
In addition to finding that the overall risk of developing PJI after THA has not changed over the last 15 years in this cohort, the authors found the following factors associated with increased risk of developing a PJI:
- Male sex (absolute increased risk of 0.48% at 10 years)
- Type 2 diabetes (absolute increased risk of 0.64% at 10 years)
- Discharge to a convalescent-care facility (absolute increased risk of 0.46% at 10 years)
The authors view the third bulleted item above as “a surrogate marker of frailty and poorer general health.”
Patient age, surgical approach, surgical setting (academic versus rural), use of cement, and patient income were not associated with an increased risk of PJI. Nearly two-thirds of PJI cases occurred within 2 years after surgery, and 98% occurred within 10 years postoperatively.
The authors conclude that these and other substantiated findings about PJI risk factors “should be reviewed with the patient during preoperative risk counseling.”
Extended Oral Antibiotics May Cut PJI Risk When Risk Factors Aren’t Modifiable
Periprosthetic joint infections (PJIs) create a significant burden for patients, surgeons, and healthcare systems. That is why so much research has gone into how best to optimize certain patients preoperatively—such as those with obesity, diabetes, or kidney disease—to decrease the risk of these potentially catastrophic complications. Still, it is not always possible or feasible to optimize every “high-risk” patient who would benefit from a total hip or knee replacement, and therefore many such patients undergo surgery with an increased risk of infection. In such cases, surgeons need additional strategies to decrease PJI risk.
In the December 19, 2018 issue of JBJS, Inabathula et al. investigate whether providing high-risk total joint arthroplasty (TJA) patients with extended postoperative oral antibiotics decreased the risk of PJI within the first 90 days after surgery. In their retrospective cohort study, the authors examined >2,100 total hip and knee replacements performed at a single suburban academic hospital. The patients in 68% of these cases had at least one risk factor for infection. Among those high-risk patients, about half received 7 days of an oral postoperative antibiotic, while the others received only the standard 24 hours of postoperative intravenous (IV) antibiotics.
Relative to those who received IV antibiotics only, those who received extended oral antibiotics experienced an 81% reduction in infection for total knee arthroplasties and a 74% reduction in infection for total hip arthroplasties. I was stunned by such large reductions in infection rates obtained simply by adding an oral antibiotic twice a day for 7 days. Most arthroplasty surgeons go to great lengths to decrease the risk of joint infection by percentages much less than that.
While further investigations are needed and legitimate concerns exist regarding the propagation of antimicrobial-resistant organisms from medical antibiotic misuse, these data are very exciting. I agree with Monti Khatod, MD, who, in his commentary on this study, says that “care pathways that aim to improve modifiable risk factors should not be seen as obsolete based on the findings of this paper.” Furthermore, the study itself is at risk for treatment and selection biases that could greatly influence its outcomes. Nevertheless, getting a successful result in these patients is challenging and, if validated with further data, this research may help surgeons obtain better outcomes when treating high-risk patients in need of hip or knee replacements.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media
Fructosamine Bests HbA1c for Preop Glycemic Screening
Patients with diabetes have an increased risk of postoperative complications following total joint arthroplasty (TJA). Additionally, perioperative hyperglycemia has been identified as a common and independent risk factor for periprosthetic joint infection, even among patients without diabetes. Therefore, knowing a patient’s glycemic status prior to surgery is very helpful.
In the November 15, 2017 edition of The Journal of Bone & Joint Surgery, Shohat et al. demonstrate that serum fructosamine, a measure of glycemic control obtainable via a simple and inexpensive blood test, is a good predictor of adverse outcomes among TJA patients—whether or not they have diabetes.
Researchers screened 829 patients undergoing TJA for serum fructosamine and HbA1c—a common measure, levels of which <7% are typically considered good glycemic control. Patients with fructosamine levels ≥292 µmol/L had a significantly higher risk of postoperative deep infection, readmission, and reoperation, while HbA1c levels ≥7% showed no significant correlations with any of those three adverse outcomes. Among the 51 patients who had fructosamine levels ≥292 µmol/L, 39% did not have HbA1c levels ≥7%, and 35% did not have diabetes.
In addition to being more predictive of postsurgical complications than HbA1c, fructosamine is also a more practical measurement. A high HbA1c level during preop screening could mean postponing surgery for 2 to 3 months, while the patient waits to see whether HbA1c levels come down. Fructosamine levels, on the other hand, change within 14 to 21 days, so patients could be reassessed for glycemic control after only 2 or 3 weeks.
While conceding that the ≥292 µmol/L threshold for fructosamine suggested in this study should not be etched in stone, the authors conclude that “fructosamine could serve as the screening marker of choice” for presurgical glycemic assessment. However, because the study did not examine whether correcting fructosamine levels leads to reduced postoperative complications, a prospective clinical trial to answer that question is needed.
Certain Comorbidities Boost Risk of Acute Kidney Injury after THA
The relationship between chronic kidney disease (CKD) and acute kidney injury (AKI) is circular: surgical patients with preexisting CKD are at increased risk of AKI, and even mild or transient AKI is associated with future development of CKD.
In the November 1, 2017 JBJS, Gharaibeh et al. report findings from a retrospective cohort study with a nested case-control analysis that assessed the rate and risk factors associated with AKI after total hip arthroplasty (THA).
From a total of 10,323 THAs analyzed, AKI developed postoperatively in only 114 cases (1.1%). A multivariate analysis of the entire cohort identified four preoperative comorbidities that increased the risk of AKI by 2- to 4-fold: CKD, heart failure, diabetes, and hypertension. In addition to those risk factors, an analysis of the case-control cohort found that increasing BMI and perioperative blood transfusions were also associated with a higher risk of AKI.
Using data from the entire cohort, the authors developed an AKI risk calculator focused on presurgical variables (see graph). Based on that model, which will require independent validation, a 65-year-old man with either CKD or heart failure would have a 2% risk of AKI; the risk would increase to 4% if that patient had CKD and hypertension and to 16.1% in the presence of CKD, hypertension, and heart failure.
The anticipated increase in demand for joint replacements could lead to US surgeons performing approximately 572,000 THAs during the year 2030. A certain (and possibly increasing) proportion of those future procedures will occur in patients who have hypertension, diabetes, heart failure, and/or chronic kidney disease. The findings from Gharaibeh et al., especially the yet-to-be-validated AKI risk score, could help hip surgeons better counsel patients and identify those who might benefit from heightened postsurgical monitoring of kidney function.
JBJS Case Connections—Induced Membrane Technique Fills Many Bone Voids
Since its introduction in the late 20th century, the 2-stage induced membrane technique has been lauded for its bone-reconstruction advantages over alternatives such as distraction osteogenesis and vascularized bone. The cases presented in this month’s “Case Connections” demonstrate that the technique can work with a variety of bone-defect shapes, sizes, and locations.
The springboard case, from the August 10, 2016 edition of JBJS Case Connector, describes 3 cases of chronic post-infection osteomyelitis in children in whom large diaphyseal defects were successfully treated with the induced membrane technique. Three additional JBJS Case Connector case reports summarized in the article focus on:
- a 50-year-old diabetic man with a necrotic foot ulcer in whom an extensive midfoot defect was successfully treated with this technique
- successful induced-membrane treatment of a 7-year-old girl with congenital pseudarthrosis of the clavicle
- 2 cases of trauma-caused segmental bone loss that were treated successfully with the induced membrane technique
It is imperative to resolve all active infection before or during stage 1 of this procedure, and careful spacer removal prior to stage 2 is of paramount importance to prevent damage to the induced membrane.
JBJS Reviews Editor’s Choice–Team Approach to Diabetic Foot Ulcers
One of the newest features from JBJS Reviews is the “Team Approach” article. Team Approach articles highlight the individual and collective importance of the multiple physician and nonphysician providers who are involved in the care of a patient. Determining how the multidisciplinary interactions and contributions are key to the understanding of a medical condition and its treatment can be essential to a successful musculoskeletal health process.
In the July 2016 issue of JBJS Reviews, Pinzur et al. describe the team approach to the treatment of diabetic foot ulcers. The authors note that an estimated 29.1 million people in the U.S. have diabetes and that, at any point in time, 3% to 4% have a foot ulcer, both of which are sobering statistics. Diabetic foot ulcers and their associated infections lead to >70,000 lower-extremity amputations yearly. Between one-third and one-half of diabetic patients undergoing major lower-extremity amputation will die within 2 years after the amputation. In order to most effectively deal with this devastating outcome, a team approach with multidisciplinary involvement is needed.
It is now accepted that the best-performing health systems are those that address challenges by developing a strategy of population management in which patients with resource-consuming medical conditions receive care across multiple medical disciplines. This strategy begins with the identification of modifiable risk factors. The most efficient patient-safety methodology for avoiding complications following surgery is to operate on healthier patients. Indeed, if we look at our orthopaedic trauma colleagues as an example, we see that survival rates and patient outcomes following hip fracture have improved since the development of systems that rapidly optimize patients prior to operative repair. This experience has taught us how important it is to have a hospitalist co-managing our orthopaedic patients. Similarly, our arthroplasty colleagues have learned that outcomes are worse and complications rates are increased in patients who have multiple medical comorbidities. Prior to urgent surgery, many of these medical conditions can be stabilized. Thus, the most proactive health systems are those that use interventions to identify and minimize health risk. When modifiable risk factors are improved, patient safety is improved.
Pinzur et al. reintroduce the concept of the so-called diabetic educator. The responsibilities of the modern diabetic educator have progressed from simple patient education on diet, glycemic control, and lifestyle change to using the educator-patient relationship to empower the educator to serve as a patient navigator/case manager. The diabetic educator and the physician also work closely with a certified pedorthist. This provider’s knowledge and skill of health maintenance through the use of therapeutic footwear are important in the prevention and treatment of diabetic foot ulcers. Patients are taught to self-examine their feet, and this level of empowerment becomes important from a psychosocial perspective.
The primary surgeon is the “captain of the ship,” and it is his or her responsibility to coordinate the management and the function of the multidisciplinary team. It is important to identify the roles of the consultants such as the certified pedorthist (who will provide guidelines on therapeutic footwear and prefabricate a custom foot orthosis as needed), the vascular surgeon (who will be needed for patients with a nonhealing foot ulcer and a nonpalpable pedal pulse), the radiologist (who will be essential for suggesting imaging modalities for understanding the disease and its progression), the infectious disease specialist (who will guide duration of therapy and monitor associated antibiotic-induced organ-system morbidity), and the plastic surgeon (who may have unique requirements for wound care and developing relationships in clinical-care algorithms).
The multidisciplinary team approach involves the use of a consistent strategy throughout the hospital or health system. This is the first step in an attempt to decrease the negative impact on quality of life and resource consumption and is essential to diabetic foot care.
Thomas A. Einhorn, MD
Editor, JBJS Reviews
JBJS Reviews Editor’s Choice–Steroid Injections in Patients with Diabetes
It is well known that parenterally administered steroids affect the metabolism of glucose and cause abnormal blood glucose levels in diabetic patients. For this reason, physicians are careful regarding the use of parenteral steroids in the presence of diabetes. However, one of the most common procedures in the outpatient setting, a local, intra-articular steroid injection, seems to be done without as much consideration or knowledge regarding the potential systemic effects of peripherally absorbed steroid. In the March 2016 issue of JBJS Reviews, Choudhry et al. address the question of potential abnormal blood glucose levels in diabetic patients who undergo intra-articular steroid injection.
The investigators performed a literature search of 4 different databases and identified 532 manuscripts. After applying inclusion criteria, 7 studies with a total of 72 patients were analyzed. The studies showed that a rise in blood glucose levels follows intra-articular steroid injection. Four of the 7 studies showed that this rise was substantial. Indeed, peak values as high as 500 mg/dL were reached. In most patients, hyperglycemia occurred within 24 to 72 hours after injection; however, peak increases in blood glucose levels did not occur immediately in all patients and in some cases took several days to occur.
Diabetes mellitus affects 9.3% of the general population of the United States, and nearly half of adults with diabetes also have osteoarthritis. Based on the data presented in this report, careful consideration should be given to administering intra-articular steroids to patients with diabetes. Indeed, current evidence suggests that diabetic patients should be advised to monitor their blood glucose levels following an intra-articular steroid injection. Patients with Type-1 diabetes should check their blood glucose levels 3 to 4 times a day for 7 days and should seek advice from a physician if levels exceed 360 mg/dL. Patients with Type-2 diabetes should check blood glucose levels at least twice a day for 7 days and should seek advice from a physician if levels exceed 540 mg/dL.
Intra-articular steroid injection is one of the most frequently performed outpatient procedures, and the data in this report shed important light on this process. This is a “must read” article.
Thomas Einhorn, Editor
JBJS Reviews
Powdered Vancomycin Cuts Surgical Infection Risk in Diabetic Patients
A recent case-control study in Foot & Ankle International found that high-risk diabetic patients (mean age of 60) undergoing reconstructive foot and/or ankle surgery were 80% less likely to develop a deep surgical-site infection when surgeons applied vancomycin powder to the surgical wound than when they didn’t. The overall likelihood of any surgical-site infection (deep or superficial) was decreased by 73% in patients who received powdered vancomycin. The cost of vancomycin and the risk of complications associated with it are both low, the study noted.
The authors concluded that “based on this study, orthopaedic foot and ankle surgeons may consider applying 500 mg to 1,000 mg of vancomycin powder prior to skin closure in diabetic patients who are not allergic to vancomycin.”
History of Diabetes Predicts Symptom Recurrence after Steroid Injection for CTS
Among a prospectively enrolled group of 49 patients (54 wrists) with mild or moderate carpal tunnel syndrome (CTS) who received a single corticosteroid injection, 79% experienced symptom relief at six weeks. Reporting in the October 7, 2015 edition of The Journal of Bone & Joint Surgery, Blazar et al. found that the rate of freedom from symptom recurrence in this cohort was 53% at six months and 31% at one year after injection. During the study period, 19 wrists underwent surgical carpal tunnel release at a median time of 181 days post-injection.
Diabetic patients in the study (13% of the wrists enrolled) were at a 2.6-fold greater risk of reporting recurring symptoms within one year of follow-up. In a univariable analysis, a 1-point increase in the baseline Boston Carpal Tunnel Questionnaire symptom score increased the risk of patients reporting post-injection symptoms by 5%, but that association became nonsignificant during multivariable analysis. Pre-injection symptom duration, patient age, and pre-injection electrophysiologic grade did not predict either symptom recurrence or subsequent intervention.
Blazar et al. add that their exclusion of people with normal electromyography results and those with severe carpal tunnel syndrome created a rather homogenous study population. Thus, they say, “these results may not be generalizable to all patients who present with clinical signs or symptoms of carpal tunnel syndrome.” Still, the findings should help orthopaedists counsel patients with CTS about the results they might expect from a single corticosteroid injection.
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