Patient-related risk factors for infection following knee arthroscopy: An analysis of over 700,000 patients from two large databases

Editorial Commentary: Obesity Is Associated With Lower Hip Function Pre- and Postoperatively and Increased Time to Patient Acceptable Symptom State After Hip Arthroscopy

In 2015, worldwide, there were more than 1.9 billion adults classified as having overweight (body mass index [BMI] >25), with 600 million of these individuals meeting the definition of obesity (BMI >30). Hip arthroscopy in patients with obesity can lead to improve outcomes, albeit with lower absolute levels of patient-reported outcome scores and with increased risk of complications and conversion rates to total hip arthroplasty when compared with their counterparts without obesity. Importantly, a significantly longer time to patient acceptable symptoms state achievement is seen for patients with class I obese than patients with normal BMI. Unfortunately, the hip is quite susceptible to the effects of obesity, with greater acetabular depth/deformity, reduced femoral head cartilage, greater forces experienced with ambulation, and a predisposition to femoroacetabular impingement syndrome. Thus, almost 42% of patients operated on in North America for femoroacetabular impingement syndrome are classified as having overweight or obesity. This does not need to deter from the consideration of arthroscopic hip surgery in the population with obesity; rather, it supports a discussion between surgeon and patient on expectations and timeline for improvement.

Risk Factors for Surgical Site Infections After Single-Level Anterior Lumbar Interbody Fusion

Abstract Background: Anterior lumbar interbody fusion (ALIF) has become an increasingly popular and effective treatment modality for various conditions of the lumbar spine. However, complications after this procedure can be costly. Surgical site infections (SSIs) are one of these types of complications. The present study identifies independent risk factors for SSI after single-level ALIF to identify high-risk patients better. Patients and Methods: The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was queried to identify single-level ALIF patients from 2005 to 2016. Multilevel fusions and non-anterior approach procedures were excluded. Mann-Pearson χ² tests analyzed categorical variables, whereas one-way analysis of variance (ANOVA) and independent t-tests analyzed differences in mean values of continuous variables. Risk factors for SSI were identified via a multivariable logistic regression model. A receiver operating characteristic (ROC) curve was generated utilizing the predicted probabilities. Results: A total of 10,017 patients met inclusion criteria; 80 (0.80%) had developed SSI and 9,937 (99.20%) had not. On multivariable logistic regression models, class 3 obesity (p = 0.014), dialysis (p = 0.025), long-term steroid use (p = 0.010), and wound classification 4 (dirty/infected) (p = 0.002) all independently increased the risk for SSI in single-level ALIF. The area under the receiver operating characteristic curve (AUROC; C-statistic) was 0.728 (p < 0.001), indicating relatively strong reliability of the final model. Conclusions: Several independent risk factors including obesity, dialysis, long-term steroid use, and dirty wound classification all increased risk for SSI after single-level ALIF. By identifying these high-risk patients, surgeons and patients can have more informed pre-operative discussions. In addition, identifying and optimizing these patients prior to operative intervention may help to minimize infection risk.

The incidence of deep vein thrombosis after anterior cruciate ligament reconstruction: An analysis using routine ultrasonography of 260 patients

BACKGROUND

Recent studies regarding deep vein thrombosis (DVT) after anterior cruciate ligament (ACL) reconstruction investigated only symptomatic complications. The purpose of this study was to assess the true incidence of DVT after ACL reconstruction, regardless of symptom manifestation.

MATERIALS AND METHODS

Medical records of 260 patients who underwent isolated ACL reconstruction between January 2014 and December 2019 were retrospectively reviewed. Regardless of symptom manifestation, DVT was examined for all patients at 1 week postoperatively using ultrasonography. Demographics, injury mechanism (high energy direct injury and low energy indirect injury), soft tissue injury, preoperative anterior laxity, tourniquet time, and surgical technique (transtibial, anteromedial portal, and outside-in techniques) were investigated. Soft tissue injury was evaluated on magnetic resonance imaging (MRI) scans, based on the Tscherne classification. Risk factors for proximal DVT were identified using logistic regression analyses.

RESULTS

A total of 21 (8.1%) patients showed DVT. 5 (1.9%) patients had thrombosis at the popliteal vein; however, none of them exhibited symptoms. The other 16 patients had thrombosis at the distal veins: 1 patient at the anterior tibial vein, 5 patients at the posterior tibial vein, 3 patients at the peroneal vein, 6 patients at the soleal vein, and 1 patient at the muscular branch vein. The risk factors for proximal DVT included high energy direct injury (p = 0.013, odds ratio = 10.62) and grade 2 soft tissue injury (p = 0.039, odds ratio = 6.78).

CONCLUSIONS

The true incidence of DVT, including symptomatic and asymptomatic complications, were 8.1% after ACL reconstruction. This rate is higher than the previously known incidence which has been investigated only for symptomatic patients. Injury mechanism and soft tissue injury should be assessed when considering thromboprophylaxis.

Corticosteroid injections 2 months before arthroscopic meniscectomy increases the rate of postoperative infections requiring surgical irrigation and debridement

PURPOSE

Consensus guidelines recommend administering a corticosteroid injection (CSI) for patients with a symptomatic degenerative meniscus lesion prior to arthroscopic partial meniscectomy (APM). A recent study found that CSI administered within 1 month prior to meniscectomy is associated with an increased risk of postoperative infection. However, infections may range in severity from superficial infections to serious infections requiring surgical interventions. The aim of this analysis was to define the rate of infections requiring surgery after APM and determine its relationship to preoperative CSI.

METHODS

The PearlDiver Mariner administrative claims database was queried for patients > 35 years old who had a CSI in the year prior to isolated APM. Rates of deep infection and infection requiring surgery within 6 months were reported between matched patients with a CSI and no injection.

RESULTS

After matching, there were 16,009 patients per group with a mean age of 59.4 years (SD = 9.6), 53.5% obesity, and 40% male. Forty-four of 113 patients who developed a postoperative deep infection went on to have a reoperation for irrigation and/or debridement (0.1% of all APM). Of these 44 patients, 30 had a preoperative CSI and 14 were controls unadjusted odds ratio (unadj-OR) if given CSI = 1.95, 95% CI 1.03-3.68, P = 0.04). Having a CSI within the month before surgery conferred a 4.56-fold increase in odds of an infection warranting surgery (95% CI 1.96-10.21, P < 0.01), whilst having a CSI 4-8 weeks before surgery conferred a 2.42-fold increase in odds (95% CI 1.04-5.42, P = 0.03). Receiving multiple CSI in the year prior to APM was associated with 5.27-fold increased odds of an infection requiring surgery (95% CI 1.19-23.27, P = 0.03), compared to having a single CSI.

CONCLUSIONS

Serious infections requiring a surgical intervention are rare after a meniscectomy, occurring in 0.1% of APMs in a matched cohort of patients over 35. Patients were five times more likely to return to the operating room for infection after APM if they had a CSI in the month before or had multiple CSIs in the year before surgery. The risk of infection was no longer significant if there was at least a 2-month interval between preoperative CSI and APM.

LEVEL OF EVIDENCE

Level III.

Musculoskeletal Pain Management and Patient Mental Health and Well-being

Orthopaedic trauma patients have high rates of psychiatric disorders, which put them at risk for worse outcomes after injury and surgery, including worse pain. Mental health conditions, such as depression and anxiety, can affect the perception of pain. Pain can also exacerbate or contribute to the development of mental illness after injury. Interventions to address both mental health and pain among orthopaedic trauma patients are critical. Balancing safety and comfort amid a drug overdose epidemic is challenging, and many clinicians do not feel comfortable addressing mental health or have the resources necessary. We reviewed the literature on the complex relationship between pain and mental health and presented examples of scalable and accessible interventions that can be implemented to promote the health and recovery of our patients. Interventions described include screening for depression in the orthopaedic trauma clinic and the emergency department or inpatient setting during injury and using a comprehensive and evidence-based multimodal pain management regimen that blends pharmacologic alternatives to opioids and physical and cognitive strategies to manage pain.

Depression Screening and Behavioral Health Integration in Musculoskeletal Trauma Care

OBJECTIVES

To report our experiences in implementing a behavioral health integration pathway, including a validated depression screening and referral to care.

DESIGN

Retrospective case series.

SETTING

Single surgeon's musculoskeletal trauma outpatient practice during calendar year 2019.

PATIENTS

All patients presenting to the practice during 2019 were included (n = 573).

INTERVENTION

We piloted the usage of Patient Health Questionnaire (PHQ)-2 and PHQ-9 screening. An evidence-based, real-time treatment protocol embedded in the electronic health record was triggered when a patient screened positive for depression including an automated behavioral health integration pathway.

MAIN OUTCOME MEASUREMENTS

The percentage of patients screened, the results of the PHQ screening, and the number of patients referred and enrolled in behavioral health programs were collected.

RESULTS

Of the 573 patients, 476 (83%) received the PHQ-2 screening, 80 (14%) had a current screening on file (within 1 year), and 17 (3.0%) were not screened. One hundred seventy-two patients (36%) had a PHQ-2 score of 2 or greater and completed the PHQ-9; of them, 60 (35% of patients screened with full PHQ-9, 13% of patients screened) screened positive for symptoms of moderate depression (PHQ-9 score ≥10), and 19 (4.0%) reported passive suicidal ideation (PHQ-9 item 9). Fifty of these patients were referred to behavioral health through the pathway, and 8 patients enrolled in the program. Ten patients were not referred because of a technical error that was quickly resolved. Patients reporting suicidal ideation were managed with psychiatric crisis resources including immediate virtual consult in the examination room.

CONCLUSIONS

This case series demonstrates the feasibility of screening patients for depressive symptoms and making necessary referrals to behavioral health in outpatient musculoskeletal trauma care. We identified 50 patients with depression and appropriately triaged them for further care in our community.

Prospective associations between depression and risk of hospitalisation for infection: Findings from the UK Biobank

BACKGROUND

Associations between depression and non-communicable disease have been well-described. However, the evidence for its role in the development of infectious disease is less understood. We aimed to examine prospective associations between depression and risk of hospitalisation for infection in middle-aged adults from the UK Biobank (linked with Hospital Episode Statistics) and assessed the role of several depression-related factors.

METHODS

We assessed prospective associations between depression status at the baseline assessment (2006-2010) and hospitalisations for infection up to the end of March 2016 in 460,418 middle-aged adults enrolled in the UK Biobank (mean age = 56.23 ± 8.11 years, 53.5% female). Cox regression was used to assess associations between depression and subsequent hospitalisations for any infections, as well as infection subtypes, viral infections, and bacterial infections. Amongst those with depression, we also examined the role of depression duration, the age of onset, and the use of antidepressants in hospitalisation risk.

RESULTS

Depression at baseline was prospectively associated with an increased risk of hospitalisation for infection (adjusted hazard ration (aHR) = 1.20, 95% confidence interval (CI) = 1.16 to 1.25). This association was found for all infection subtypes apart from infections of the central nervous system (p = 0.911) and the skin (p = 0.313). Receipt of a depression diagnosis in late adulthood and use of antidepressants (but only in those with none/mild depressive symptoms at baseline) increased the risk of hospitalisation for infection amongst those with depression.

CONCLUSIONS

These findings suggest that depression might be a risk factor which could be used to identify those at risk of hospitalisation for infection. Future research is required to understand the underlying factors that might result in this increased risk, so that targeted interventions can be developed.

FUNDING

AD and AR are funded by Guy's Charity grant number EIC180702 (MLTC Challenge Fund); AD and JAT are co-funded by MRC and NIHR through grant number MR/S028188/1. IB is supported by the NIHR Maudsley BRC and by the NIHR Collaboration for Leadership in Applied Health Research and Care South Londnoo at King's College Hospital NHS Foundation Trust, King's College London. The views expressed are those of the author[s] and not necessarily those of the ESRC, NIHR, the Department of Health and Social Care or King's College London.

Intra-articular steroid injection at the time of knee arthroscopy increases risk of post-operative infection

PURPOSE

To evaluate the risk of post-operative infection after intra-articular steroid injection at the time of knee arthroscopy at a single institution high-volume sports medicine practice.

METHODS

The electronic medical record at a single institution was queried for all patients who underwent knee arthroscopy from 2011 to 2019. Patients were included if they underwent more simple arthroscopic procedures: diagnostic arthroscopy, meniscectomy, loose body removal, synovectomy, or microfracture. Patients were excluded if they underwent more complex procedures, such as ligament reconstruction, meniscus repair, or any open procedures. These patients' medical records were then queried for current procedural terminology and international classification of disease codes indicating post-operative infection. Individual chart review was performed on this group of patients to determine if a true postoperative infection occurred within 6 months of the index arthroscopy. Patients were then categorized into "intra-operative steroid injection" versus "no steroid" based on each surgeon's preferred intra-operative analgesic injection cocktail.

RESULTS

A total of 6889 patients were identified, including 2416 (35.1%) who were given intra-articular steroid at the time of knee arthroscopy. Post-operative infection occurred in 10 patients (0.15%) at a median of 18 days (range 9-42 days), 7 who received intra-operative steroid injection (0.29%) and 3 who did not (0.067%), p = 0.040. The relative risk of infection for those who received intra-operative steroid injection was 4.32 times higher than those who did not, with a number needed to harm of 448. There were no significant differences in age, body mass index, smoking status, or the prevalence of diabetes between those who got infected and those who did not.

CONCLUSIONS

Knee infection following arthroscopic surgery is rare. Intra-operative steroid injection during arthroscopic knee surgery is associated with a 4.3-fold increased risk of subsequent knee infection. While the overall risk remains low, the use of intra-operative steroids is expected to result in one additional knee infection for every 448 arthroscopic procedures performed.

LEVEL OF EVIDENCE

IV.

Postoperative Infection: Prevention, Diagnosis, and Treatment Guidelines for the Sports Surgeon

Postoperative infection remains a potentially devastating complication facing the sports medicine surgeon. Infection prevention begins with a thorough history and physical examination to identify patient specific risk factors and aid in risk stratification. Perioperative steroid injections should be used cautiously, with increased time prior to or following surgery being associated with lower infection risk. Sterile preparation with an alcohol containing solution is typically preferred, though there is limited evidence to identify which product is superior. Diagnosis can be challenging with a high index of suspicion needed to identify and appropriately manage patients. Treatment involves prompt irrigation and debridement with deep cultures. Antibiotic coverage should begin with empiric broad treatment and be tailored based on culture results. Early consultation with an infectious disease specialist is recommended to ensure appropriate antibiotic coverage and duration of treatment.

Male Sex, Cartilage Surgery, Tobacco Use, and Opioid Disorders are Associated with an Increased Risk of Infection After Anterior Cruciate Ligament Reconstruction

PURPOSE

To identify patient-related risk factors for infection following anterior cruciate ligament reconstruction (ACLR).

METHODS

The Mariner database within PearlDiver was queried for patients from 2010 to 2019 undergoing primary arthroscopic ACLR. Patients undergoing ACLR with concomitant open surgery or additional ligament reconstructions were excluded. Postoperative diagnoses or procedures for superficial or deep infection within 6 months were assessed. A multivariable logistic regression analysis was then used to evaluate patient-related risk factors for postoperative infection. Adjusted odds ratios (OR) and 95% confidence intervals (CIs) were calculated for each risk factor, with P < .05 considered statistically significant.

RESULTS

In total, 217,541 patients underwent ACLR and 1779 (0.8%) patients had a postoperative infection within 6 months. Significant independent risk factors included male sex (OR 1.58, 95% CI 1.43-1.75, P < .001), obesity (OR 1.22, 95% CI 1.05-1.43, P = .020), morbid obesity (OR 2.54, 95% CI 2.11-3.06, P = .002), tobacco use (OR 1.36, 95% CI 1.19-1.55, P < .001), age younger than 40 years (OR 1.21, 95% CI 1.07-1.37, P = .033), depression (OR 1.18, 95% CI 1.04-1.34, P = .012), opioid disorder (OR 1.50, 95% CI 1.22-1.85, P < .001), concomitant simple cartilage surgery (OR 1.63, 95% CI 1.43-1.86, P < .001), and complex cartilage surgery (OR 1.67, 95% CI 1.20-2.32, P = .002). Partial meniscectomy and meniscal repair at the time of ACLR were not associated with an increased risk of infection.

CONCLUSIONS

In a large national sample, male sex, obesity, tobacco use, older age, depression, opioid disorders and concomitant cartilage surgery were significant risk factors for infection following ACLR.

LEVEL OF EVIDENCE

Therapeutic Level IV, retrospective case series.

Infection complicating 794 primary and revision arthroscopies. Accuracy of actual prophylactic procedures against infection and results from a single orthopedic center in Poland

Introduction

Septic arthritis after arthroscopy (SAAA) is a devasting complication which reported frequency varies about 0.04%–5.7%. The aim of the study is to analyze frequency of SAAA at one orthopedic center, risk factors and accuracy of actual prophylactic measures.

Materials and Methods

A retrospective study (level of evidence: V) includes 794 (665 primary and 129 revision) “clean” arthroscopies performed in the years 2017–2018 with confirmed joint infection during 30 days after operation without the use of non-resorbable implants and up to 1 year after procedures with non-resorbable implants. Demographic and medical data about potential risk factors of SAAA were analyzed: patients age, sex, operated joint, type of procedure, primary or revision procedure, the use of drains, usage of non-absorbable implant, time of surgery, BMI, time lapse from index operation to diagnosis of SAAA, length of hospital stay, causative microorganisms. All operations were performed by eight different but experienced surgeons, in operation theatre with vertical laminar flow with the capacity of 50 air exchanges per hour. The perioperative antibiotic prophylaxis consisted of one preoperative dose 1 g cefazolin in simple arthroscopies, which was prolonged to 24 hours with 3 doses in cases of implantation of non-absorbable implant (55.8% of patients).

Results

From 794 cases 4 have been infected: 2 after knee arthrolysis, one after ACL reconstruction and one after rotator cuff repair. There were 2 early, with manifestation within 30 days, and 2 late-onset SAAA. Infections occurred in 0.5% of all arthroscopies and in 0.47% of knee arthroscopies alone. Patients age and time of surgery have not been found significantly different in infected and non-infected cases, whereas age and time of surgery have been significantly different in revision and non-revision cases.

Conclusions

Primarily aseptic arthroscopic procedures performed with respect to actual perioperative preventive measures have a low risk of postoperative septic arthritis. The risk increases with patients age and time of operation, but not significantly.

A Safe Interval between Preoperative Intra-articular Corticosteroid Injections and Subsequent Knee Arthroscopy

The purpose of this study is to evaluate the influence of intra-articular corticosteroid injections prior to knee arthroscopy on the rate of postoperative infection and define a safe timing interval between intra-articular corticosteroid injections and subsequent knee arthroscopy. The PearlDiver Database was used to identify patients who underwent a knee arthroscopy from 2007 to 2017. Patients were sorted into an injection cohort if they received any intra-articular corticosteroid injections within 6 months before surgery and a control cohort if they received no such injections. The injection cohort was then stratified into subgroups based on the timing of the most recent injection. We identified two types of postoperative infection in the 6 months following surgery: a broad definition of infection using knee infection diagnoses, and a narrow definition of infection requiring surgical treatment. The effects of the timing of preoperative corticosteroid injections on the rates of postoperative infection were investigated. The rate of broadly defined postoperative infection was significantly higher in the 0 to 2 weeks injection group (6.90%, 20/290) than the control group (2.01%, 1,449/72,089, p < 0.001; odds ratio [OR]:3.61 [95% confidence interval [CI]: 2.29, 5.70]). We observed a significant difference regarding the rate of narrowly defined postoperative infection requiring surgical treatment between the 0 and 2 weeks injection group (1.38%, 4/290) and the control group (0.27%, 192/72,089, p < 0.001, OR:5.24 [95% CI: 1.94, 14.21]). No significant differences were observed between other subgroups and the control group in both types of postoperative infection. Intra-articular corticosteroid injections within 2 weeks of knee arthroscopy were statistically significantly associated with higher rates of postoperative infection. This is a Level III, retrospective comparative study.

Corticosteroid Injections 1 Month Before Arthroscopic Meniscectomy Increase the Risk of Surgical-Site Infection

PURPOSE

To define the incidence of postoperative infections in patients who receive corticosteroid injections prior to arthroscopic meniscectomy, to determine whether there is a temporal relation between injections and the risk of surgical-site infections, and to identify corresponding risk factors.

METHODS

The Humana administrative claims database was reviewed for patients undergoing arthroscopic meniscectomy within 1 year of injection and those undergoing arthroscopic meniscectomy without prior injection. Patients with preoperative injections were further stratified by the duration in months between the injection and the surgical procedure. Surgical-site infection within 6 months of surgery was recorded. Univariate analysis and binary logistic regression were performed to determine independent risk factors for surgical-site infection. Statistical significance was defined as P < .05.

RESULTS

We identified patients with (n = 11,652) and without (n = 37,261) a history of a knee corticosteroid injection within 1 year of arthroscopic meniscectomy with at least 6 months of database activity from 2007 to 2017. In patients who received knee injections within 1 month prior to surgery, the rate of development of postoperative infections was twice that in patients who did not receive an injection (1.28% vs 0.63%; odds ratio [OR], 1.84; 95% confidence interval [CI], 1.24-2.62; P = .001). Multivariate logistic regression identified male sex (OR, 1.39; 95% CI, 1.14-1.71; P = .001), diabetes (OR, 1.48; 95% CI, 1.19-1.85; P < .001), chronic obstructive pulmonary disease (OR, 1.57; 95% CI, 1.27-1.94; P < .001), obesity (OR, 1.32; 95% CI, 1.07-1.63; P = .010), tobacco use (OR, 1.61; 95% CI, 1.30-1.98; P < .001), and preoperative injections within 1 month of surgery (OR, 1.78; 95% CI, 1.21-2.54; P = .002) as significant predictors, whereas injections administered more than 1 month before surgery were not significantly associated with postoperative surgical-site infection after arthroscopic meniscectomy.

CONCLUSIONS

Injections 1 month before arthroscopic meniscectomy significantly increase the risk of surgical-site infection. However, injections can be safely administered more than 1 month prior to surgery because there is no increased risk of postoperative infection at this time point.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Evaluation of the effect of triclosan coated sutures in the prevention of surgical site infections in a Spanish hospital setting: A prospective, observational study

Background

Surgical site infections (SSIs) are one of the most frequently reported types of hospital-acquired infection and are associated with substantial clinical and economic burden.

Aim

To assess the incidence of SSIs and analyze contributing risk factors in a real-world Spanish hospital setting before and after the implementation of triclosan-coated sutures (TCS).

Methods

A prospective, observational study was conducted at Hospital Clínico Universitario de Santiago de Compostela, Spain. Enrolled patients underwent surgery in the following specialties: general surgery, urology, neurosurgery, gynaecology, and traumatology. The primary outcome of the study was SSI incidence, assessed at a 30-day follow-up. Secondary outcomes were length of hospital stay, and readmission, reintervention, and mortality rates, also at 30 days.

Findings

5,081 patients were included in the study, of which 2,591 were treated using non-coated sutures (NCS) and 2,490 using TCS. After adjusting for potential confounders, TCS significantly reduced SSI rate by 36%, compared with NCS (odds ratio [OR]: 0.64; 95% confidence interval [CI]: 0.48-0.85; P<0.003). When stratified by wound classification, a statistically significant reduction in SSI incidence, in favour of TCS use, was observed for Class IV (dirty) wounds (35.6% versus 22.7% for NCS and TCS, respectively; OR: 0.53; 95% CI: 0.31-0.90).

Conclusion

The use of TCS reduced SSI risk when compared with NCS. This reduction was significant for Class IV wounds, providing evidence that supports the use of TCS for this type of wound.

Post-operative septic arthritis after arthroscopy: modern diagnostic and therapeutic concepts

PURPOSE

Septic arthritis is a significant complication following arthroscopic surgery, with an estimated overall incidence of less than 1%. Despite the low incidence, an appropriate diagnostic and therapeutic pathway is required to avoid serious long-term consequences, eradicate the infection, and ensure good treatment outcomes. The aim of this current review article is to summarize evidence-based literature regarding diagnostic and therapeutic options of post-operative septic arthritis after arthroscopy.

METHODS

Through a literature review, up-to-date treatment algorithms and therapies have been identified. Additionally, a supportive new algorithm is proposed for diagnosis and treatment of suspected septic arthritis following arthroscopic intervention.

RESULTS

A major challenge in diagnostics is the differentiation of the post-operative status between a non-infected hyperinflammatory joint versus septic arthritis, due to clinical symptoms, (e.g., rubor, calor, or tumor) can appear identical. Therefore, joint puncture for microbiological evaluation, especially for fast leukocyte cell-count diagnostics, is advocated. A cell count of more than 20.000 leukocyte/µl with more than 70% of polymorphonuclear cells is the generally accepted threshold for septic arthritis.

CONCLUSION

The therapy is based on arthroscopic or open surgical debridement for synovectomy and irrigation of the joint, in combination with an adequate antibiotic therapy for 6-12 weeks. Removal of indwelling hardware, such as interference screws for ACL repair or anchors for rotator cuff repair, is recommended in chronic cases.

LEVEL OF EVIDENCE

IV.

Certificate-of-Need Programs Are Associated with a Reduced Incidence, Expenditure, and Rate of Complications with Respect to Knee Arthroscopy in the Medicare Population

BACKGROUND

To curb costs at the state level, improve care quality, and promote access to care, certificate-of-need (CON) laws were established in many states in 1974. It is not known how CON regulations have affected the provision of knee arthroscopy, one of the most common orthopedic procedures performed in the USA.

QUESTIONS/PURPOSES

We sought to characterize the effects of CON regulations on knee arthroscopy in the national Medicare population by examining trends in procedure volumes, comparing trends in procedure charges, evaluating distribution of procedure volumes between high-, mid-, and low-volume facilities, and comparing adverse event and complication rates after knee arthroscopy between states with and without CON regulations.

METHODS

States with CON regulations covering both inpatient and outpatient operating rooms formed the study group (n = 25 states) and were compared with states without CON laws or laws that did not cover operating rooms during the study period (n = 20 states). The 100% Medicare Standard Analytical Files from 2005 through 2014 were used to compare knee arthroscopy procedure volumes, charges, reimbursements, distribution of procedures based on facility volumes and adverse events between the two groups.

RESULTS

The rate of decrease in the incidence of knee arthroscopy was significantly greater in CON states than that in non-CON states. CON states also had significantly lower charges at all time points, and overall, compared with non-CON states. There were significantly more high- and mid-volume facilities in CON states than in non-CON states, and there were significantly more low-volume facilities in non-CON states than in CON states. Finally, there were significantly higher rates of emergency room visits within 30 days and infection within 6 months in non-CON states than in CON states.

CONCLUSIONS

CON regulations appear to have achieved several of their intended goals for knee arthroscopy. Further research is needed to determine if CON regulations affect the quality and sustainability of care provided to patients undergoing knee arthroscopy.

Skin Preparation Techniques for Orthopedic Foot and Ankle Surgery: A Current Concepts Review

Surgical site infection (SSI) following orthopedic foot and ankle surgery is associated with morbidity, mortality, and cost to the healthcare system. The local anatomy and physiology predispose patients undergoing procedures to elevated risk. In particular, sterilizing of the webspaces, nailfolds, and subungual areas presents challenges, and the preferred skin antisepsis technique for foot and ankle procedures has not yet been defined. Skin antiseptic solutions (SASs) consist of 3 main categories: alcohol, chlorhexidine, and iodine-based solutions. This review of the literature supports a combined chlorhexidine and alcohol preparation technique; however, there are a number of studies that suggest otherwise. In addition, there is variable evidence for the use of alternatives to the standard soft sponge application technique, including immersion, bristled brush, and cotton gauze application. These alternatives may have a particular advantage in the forefoot. Most studies to date use growth from skin swab cultures after skin preparation as the primary outcome. Higher-level studies with large subject populations and more meaningful clinical outcomes will be required to solidify guidelines for preoperative skin antisepsis prior to foot and ankle procedures.Level of Evidence: Level V, expert opinion.

Malnutrition in Orthopaedic Sports Medicine: A Review of the Current Literature

CONTEXT

Malnutrition is well-studied in various aspects of the orthopaedic literature, most commonly in relation to arthroplasty, spine surgery, and trauma. However, the management of nutritional deficiencies is commonly overlooked among orthopaedic sports medicine providers. The purpose of this article is to analyze the available sports medicine literature to review the associations between malnutrition and the management of orthopaedic sports medicine patients from a treatment and performance standpoint.

EVIDENCE ACQUISITION

PubMed was searched for relevant articles published from 1979 to 2019.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

Few studies exist on the implications of macronutrient deficiencies specific to orthopaedic sports medicine procedures. Interestingly, micronutrient disorders-namely, hypovitaminosis D and iron deficiency-have been well studied and may lead to worse postoperative outcomes, injury rates, and athletic performance. Nutritional supplementation to correct such deficiencies has been shown to mitigate these effects, though further study is required.

CONCLUSION

Nutritional deficiencies are highly prevalent in orthopaedic sports medicine patients, and practitioners should be aware of their potential effects on treatment and performance outcomes. Management of such deficiencies and their effect on surgical patients remain an area of potential future research. Future studies are warranted in order to explore the potential therapeutic role of nutritional supplementation to prevent complications after common orthopaedic sports medicine procedures, improve athletic performance, and reduce injury rates.

Magnetic resonance imaging can increase the diagnostic accuracy in symptomatic meniscal repair patients

PURPOSE

The purpose of this study was to evaluate meniscal repair healing in symptomatic patients through combined clinical assessment, magnetic resonance imaging (MRI) and re-arthroscopy. This study investigated the diagnostic accuracy of MRI and clinical assessment in determining failed meniscal repair in symptomatic meniscal repair patients, as verified by re-arthroscopy.

METHODS

Eighty patients were included. All had undergone a primary meniscal repair followed by an MRI and re-arthroscopy due to clinical symptoms of a meniscal lesion. A validated semi-quantitative scoring system was employed for identifying MRI-diagnosed healing failure. The clinical assessment was divided into joint swelling, joint-line tenderness, locking and a positive McMurray's test. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of MRI and positive clinical findings were calculated using second-look arthroscopy as a standard.

RESULTS

The MRI results showed healing of 22 (27.5%) of the menisci and 58 (72.5%) unhealed menisci, whereas second-look arthroscopy identified 15 (19%) healed menisci and 65 (81%) unhealed menisci. The isolated MRI findings were 0.85, 0.8, 0.95 and 0.55 for sensitivity, specificity, PPV and NPV, respectively. The PPVs of the clinical assessments were 0.78, 0.85 and 0.94, with one, two and three clinical findings, respectively. A grade 3 MRI combined with joint-line tenderness presented a PPV of 0.98.

CONCLUSION

A supplementary MRI will increase diagnostic accuracy when fewer than three clinical findings are present in a symptomatic meniscal repair patient. The clinical relevance of this finding is that MRI contributes to enhancing the diagnostic accuracy of an unhealed meniscal repair when there are limited clinical signs of meniscal pathology.

LEVEL OF EVIDENCE

III.

Procedure length is independently associated with overnight hospital stay and 30-day readmission following anterior cruciate ligament reconstruction

PURPOSE

The purpose was to characterize the independent effect of procedure length on the rates of 30-day perioperative complications, hospital readmissions, and overnight hospital stay in patients undergoing arthroscopic anterior cruciate ligament reconstruction (ACLR). We hypothesized that longer procedure length in primary ACLR increases the risk for post-operative complications.

METHODS

Primary ACLR cases from 2005 to 2015 were identified in the American College of Surgeons National Surgical Quality Improvement Program registry. Patients were categorized into two cohorts based on procedure length, either less than or greater than 90 min. Two equal-sized propensity-matched cohorts were generated to account for differences in baseline and operative characteristics. Thirty-day clinical outcomes were compared using bivariate analyses between propensity-matched groups that controlled for patient-specific factors and concurrent meniscal repair. Multivariate logistic regression models were used to identify independent predictors of hospital readmission and overnight hospital stay.

RESULTS

In total, 12,077 ACLR cases were identified. The rate of any 30-day complication was increased in longer procedures relative to shorter procedures (1.6% vs 0.9%, p = 0.006), as were the rates of returning to the operating room (0.6% vs 0.3%, p = 0.03), hospital readmission (1.0% vs 0.3%, p = 0.001), and overnight hospital stay (16.2% vs 6.0%, p < 0.001). Obesity was a risk factor for both hospital readmission and overnight hospital stay, while hypertension, diabetes, chronic obstructive pulmonary disease, and a smoking history were associated with increased rates of overnight hospital stay. The most common reasons for hospital readmission were deep vein thrombosis or pulmonary embolism (25.0% of all readmitted patients), surgical site infection (25.0%), and post-operative pain (14.1%).

CONCLUSIONS

In this propensity-matched analysis adjusting for baseline patient characteristics and operative factors, procedure length of greater than or equal to 90 min in ACLR was independently associated with an increased risk of hospital readmission and overnight hospital stay. As a surrogate measure of surgical complexity, operative time may be a useful perioperative variable for post-operative risk stratification and patient counseling.

LEVEL OF EVIDENCE

III.

Validation of predictive factors for infection in adults with chronic leg ulcers: A prospective longitudinal study

AIMS AND OBJECTIVES

To validate the ability of factors to predict infection in adults with chronic leg ulcers over a 12-week period.

BACKGROUND

Leg ulcers affect ~3% of older adults and are often hard to heal. Infection is a leading contributor for delayed healing, causing delayed wound healing, increased hospitalisation, increased healthcare costs and reduced patient quality of life. The importance of early identification of infection has been highlighted for decades, yet little is known about factors that are associated with increased risk of infection in this specific population.

DESIGN

A longitudinal, prospective observational study in a single centre.

METHODS

Between August 2017 and May 2018, a total of 65 adults with chronic leg ulcers were prospectively observed for a 12-week period. Patients were recruited from an outpatient wound clinic at a tertiary hospital in Australia. Data were collected from recruitment (baseline) and each visit (weekly or fortnightly) up until 12 weeks. Descriptive statistics were calculated for all variables. A Cox proportional hazards regression model was used to identify predictive factors for infection. The TRIPOD guidelines for reporting were followed (See Data S1).

RESULTS

The sample consisted of 65 adults with chronic leg ulcers, and 9.2% of these had their ulcer infected at baseline. Two predictive factors, using walking aids and gout, were found to be significantly related to increased likelihood of developing infection within 12 weeks.

CONCLUSION

The present study showed that patients who either used walking aids or were diagnosed with gout were at greater risk of infection compared to those without these factors.

RELEVANCE TO CLINICAL PRACTICE

These findings provide new information for clinicians in early identification of patients at risk of infection, and for patients in enhancing their awareness of their own risk.

Rapid Progression of Knee Pain and Osteoarthritis Biomarkers Greatest for Patients with Combined Obesity and Depression: Data from the Osteoarthritis Initiative

OBJECTIVE

To compare the progression of biochemical biomarkers of osteoarthritis (OA), knee pain, and function between nonobese patients (NON), obese patients without depression (OBESE), and obese patients with comorbid depression (O + D).

DESIGN

Utilizing the FNIH OA Biomarkers Consortium dataset, we categorized knee OA patients into NON, OBESE, and O + D groups based on body mass index and Center for Epidemiological Studies-Depression (CES-D) scores. Subjective symptoms (Knee injury and Osteoarthritis Outcome Score Quality of Life subscale (KOOS QOL), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Pain and Physical Function scores, and the Short Form-12 (SF-12) Physical Component Score [PCS]) and objective measures of cartilage degradation and bone remodeling (urinary CTXII and CTXIα) were compared among groups at baseline and 2-year follow-up.

RESULTS

Of the 600 patients, 282 (47%) were NON, 285 (47.5%) OBESE, and 33 (5.5%) O + D. The O + D group had significantly worse pain and function both at baseline and 2-year follow-up (P < 0.001 for all comparisons) as evidenced by self-reported measures on KOOS QOL, WOMAC Pain, WOMAC Physical Function, and SF-12 PCS. The O + D group also demonstrated significant increases in CTXII (P = 0.01) and CTXIα (P = 0.005), whereas the NON and OBESE groups did not.

CONCLUSIONS

The combination of inferior knee pain, physical function, and significantly greater increases in biomarkers of cartilage degradation and bony remodelling suggest a more rapid progression for obese OA patients with comorbid depression. The link between systemic disease, inflammatory burden, and progressive cartilage degradation is in line with increasing concerns about a degenerative synovial environment in early osteoarthritic knees that progress to treatment failure with biologic restoration procedures.

An Overview of Skin Antiseptics Used in Orthopaedic Surgery Procedures

Surgical site infections (SSIs) in orthopaedics are a common complication, with more than half a million SSIs occurring in the United States each year. SSIs can carry a notable burden for patients and physicians alike. Skin antiseptic solution plays an important role in preventing SSI. Many studies have looked at different skin antiseptic solution in preventing SSIs. Different surgical preps can decrease bacterial loads at surgical sites in varying degrees. Yet, the amount of bacterial load does not always correlate with a lower risk of infection.Chlorhexidine, for example, has been shown to cause markedly less SSIs compared with povidone-iodine prep in general surgery cases. Whereas chlorhexidine with alcohol may best work in the forefoot, iodine povacrylex with alcohol is equivalent in the spine. Conversely, joint arthroplasty SSIs were markedly decreased with a combination of preps. Because of all these differences, understanding which prep solution to use and when can be invaluable to the orthopaedic surgeons.

High Resiliency Linked to Short-Term Patient Reported Outcomes and Return to Duty Following Arthroscopic Knee Surgery

Introduction

Resilience is a psychometric construct of a patient’s ability to recover from adversity and has been used to predict outcomes but its use in orthopedics has been limited. The purpose of this study was to examine the association between resilience and outcomes.

Materials and Methods

We performed a retrospective analysis of prospectively collected data of patient who underwent sports knee surgery at a single institution performed by 6 orthopedic surgeons from January 2017 to December 2017. We included active-duty patients with complete preoperative outcomes and a minimum of 6 month follow-up. All patients completed the Brief Resilience Scale (BRS), Veteran’s Rand-12 (VR-12), Patient-Reported Outcomes Measurement Information System 43 (PROMIS-43), International Knee Documentation Committee function score (IKDC), and Knee Injury and Osteoarthritis Outcome Score (KOOS). Patients were divided into low resilience (LR) and high resilience (HR) groups based on a score of less than 24 for low and greater than or equal to 24 according to BRS. Outcomes were then compared.

Results

We identified 50 active-duty patients who had complete preoperative and postoperative outcomes at a minimum of 6 months. Mean preoperative and postoperative BRS were significantly different (25.8 HR v 18.6 LR, p < 0.001). We found a difference in postop KOOS in pain, sports, and short form (pain 70.9 HR v 55.7 LR, p = 0.03; sports 50.3 HR v 32.2 LR, p = 0.03; short form (72.1 HR v 62.5 LR, p = 0.04). Similarly, there was a significant difference in postoperative IKDC score (58.0 HR v 44.0 LR, p = 0.03). Similarly we found significant differences in postoperative PROMIS-43 (anxiety 44.4 HR v 60.3 LR, p = 0.004; depression 41.6 HR v 58.1 LR, p = 0.004; fatigue 45.1 HR v 58.6 LR, p = 0.001; sleep 52.6 HR v 62.5 LR, p = 0.02; social participation 36.2 HR v 47.6 LR, p < 0.001). Postoperative VR-12 mental was also statistically different between the two groups (53.5 HR v 41.6 LR; p = 0.01). In addition, 2.3% of the HR group changed MOS as a result of their sports knee surgery compared to 22.2% of the LR group.

Conclusions

Active-military patients with high preoperative resilience appear to have significantly better early postoperative outcomes following sports knee surgery in terms of PROMIS-43, KOOS, and IKDC. There was also a lower rate of changing MOS secondary to sports knee surgery in patients with high resilience.

The Timing of Corticosteroid Injections Following Simple Knee Arthroscopy Is Associated With Infection Risk

PURPOSE

To examine any association between the timing of ipsilateral postoperative corticosteroid injection following simple knee arthroscopy and infection.

METHODS

Private payer (PP) and Medicare (MC) national insurance databases were queried for patients who underwent simple arthroscopic knee procedures. Patients undergoing concomitant open or more complex procedures with grafts were excluded. Patients who underwent ipsilateral corticosteroid injections within 2, 4, 6, and 8 weeks postoperatively were then identified. Postoperative infection within 90 days after the injection was assessed using International Classification of Diseases, 9th Revision, and Current Procedural Terminology coding and compared using a multivariate binomial logistic regression analysis.

RESULTS

A total of 5,533 patients were identified, including 725 that received an injection within 2 weeks; 1,236 patients within 4 weeks; 1,716 patients within 6 weeks; and 1,856 patients that received an injection within 8 weeks postoperatively. In both the PP and MC datasets, the rate of infection was significantly higher in the 2-week group compared with the 6- (PP: odds ratio [OR] 3.81, P = .012; MC: OR 9.36, P = .001) and 8-week (PP: OR 8.59, P = .003; MC: OR 7.80, P = .001) groups. The rate of infection was also higher in the 4-week group compared with the 6- (PP: OR 2.54, P = .024; MC: OR 8.91, P = .001) and 8-week (PP: OR 5.64, P = .009; MC: OR 7.80, P = .001) groups. There was no difference in infection rates between the 2- and 4-week groups in either dataset (PP: P = .278; MC: P = .861).

CONCLUSIONS

There is a significant association between intra-articular knee corticosteroid injections within 4 weeks of surgery and an increased incidence of postoperative infection in both MC and PP patients after knee arthroscopy compared with patients with steroid injections more than 4 weeks postoperatively and matched controls who did not receive injections.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Patient-Related Risk Factors for Periprosthetic Ankle Joint Infection: An Analysis of 6977 Total Ankle Arthroplasties

Periprosthetic joint infection (PJI) after total ankle arthroplasty (TAA) is a devastating complication that often results in explantation to resolve the infection. The purpose of the present investigation was to determine the patient-related risk factors for PJI after TAA. A national insurance database was queried for patients undergoing TAA using the Current Procedural Terminology and International Classification of Diseases, ninth revision, procedure codes from 2005 to 2012. Patients undergoing TAA with concomitant fusion procedures or more complex forefoot procedures were excluded. PJI within 6 months was then assessed using the International Classification of Diseases, ninth revision, codes for diagnosis or treatment of postoperative PJI. Multivariate binomial logistic regression analysis was performed to evaluate the patient-related risk factors for PJI. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for each risk factor, with p < .05 considered statistically significant. A total of 6977 patients were included in the present study. Of these 6977 patients, 294 (4%) had a diagnosis of, or had undergone a procedure for, PJI. The independent risk factors for PJI included age <65 years (OR 1.44; p = .036), body mass index <19 kg/m² (OR 3.35; p = .013), body mass index >30 kg/m² (OR 1.49; p = .034), tobacco use (OR 1.59; p = .002), diabetes mellitus (OR 1.36; p = .017), inflammatory arthritis (OR 2.38; p < .0001), peripheral vascular disease (OR 1.64; p < .0001), chronic lung disease (OR 1.37; p = .022), and hypothyroidism (OR 1.32; p = .022). The independent patient-related risk factors identified in the present study should help guide physicians and patients considering elective TAA and develop risk stratification algorithms that could decrease the risk of deep, postoperative infection.

Spinal Cord Stimulation Infection Rate and Risk Factors: Results From a United States Payer Database

Objective

Surgical site infections can cause negative clinical and economic outcomes. A recent international survey on Spinal Cord Stimulation (SCS) infection control practices demonstrated low compliance with evidence‐based guidelines. This study defines infection rate for SCS implants and identifies infection risk factors.

Materials and Methods

A retrospective analysis of the MarketScan® Databases identified patients with SCS implant (2009–2014) and continuous health plan enrollment for ≥12‐months (12 m) preimplant. For logistic regression analysis, patients were enrolled for 12 m postimplant. Kaplan–Meier and Cox Proportional Hazard survival analyses assessed time to infection, with infection rate reported at 12 m postimplant. Logistic regression characterized risk factors based on demographics, comorbidities, and clinical characteristics.

Results

In the logistic regression (n = 6615), 12 m device‐related infection rate was 3.11%. Infection risk factors included peripheral vascular disease (OR, 1.784; 95% CI: 1.011–3.149; p = 0.0457) and infection in 12 m before implant (OR, 1.518; 95% CI: 1.022–2.254; p = 0.0386). The odds of patients experiencing an infection decreased by 3.2% with each additional year of age (OR, 0.968; 95% CI: 0.952–0.984; p < 0.0001). Survival analysis (n = 13,214) identified prior infection (HR, 1.770; 95% CI: 1.342–2.336; p < 0.0001) as a risk factor. Infection was less likely in older patients (HR, 0.974; 95% CI: 0.962–0.986; p < 0.0001). Expected risk factors including obesity, diabetes, and smoking were not identified as risk factors in this analysis. There was no significant difference between infection rate for initial and replacement implants.

Conclusions

The 3.11% SCS‐related infection rate within 12 m of implant emphasizes the need for improved infection control practices. Research is needed to limit SCS infections in younger patients and those with infection history.

Medical Malpractice Litigation Following Arthroscopic Surgery

PURPOSE

Our study aims to analyze a variety of factors involving malpractice lawsuits following arthroscopy, focusing on reasons for lawsuit and establishing predictors for the outcome of the lawsuit.

METHODS

Two legal databases, VerdictSearch and Westlaw, were queried for arthroscopic cases in adult patients. For all included cases, clinical and demographic data were recorded. The effects of plaintiff demographics, joint involved, lawsuit allegation, case ruling, and size of indemnity payments were assessed.

RESULTS

Of the 240 included cases, 62 (26%) resulted in plaintiff verdict, 160 (67%) resulted in defense verdict, and 18 (8%) were settled without trial. Plaintiff demographics (age and sex) had no effect on the case ruling. There was no statistical difference between indemnity awards for plaintiff verdicts ($1,013,494) and settled cases ($848,331; P = .13). Patient death was noted in 20 cases (8.3%); a significantly higher proportion of these cases were settled versus went to trial (P = .0022), including 19 patients (95%) who had knee arthroscopy and 16 deaths (80%) resulting from a pulmonary embolus. Plaintiff verdict or settlement were seen significantly more frequently for vascular complications and wrong-sided surgery. Alternatively, defense verdicts followed lawsuits alleging surgeon technical error. Wrong-sided surgery, retained instruments, deep venous thrombosis, and postoperative infections were seen at a significantly higher proportion after knee arthroscopy than after arthroscopy of other joints. Similarly, neurological injury was significantly associated with elbow and hip arthroscopy, while allegations of technical error by the surgeon and block-related complications were associated with shoulder arthroscopy.

CONCLUSIONS

Plaintiff verdict or settlement were seen for vascular complications and wrong-sided surgery, while defense verdicts followed lawsuits alleging surgeon technical error and block-related complications. We also identified types of allegations that were associated with arthroscopy of different joints. All but one case of patient death (20 cases) were noted to involve knee arthroscopy, and an overwhelming majority resulted due to a pulmonary embolism. This information helps the arthroscopic surgeon better counsel patients and employ strategies to mitigate preventable complications.

LEVEL OF EVIDENCE

Level IV, case series.

Hip Arthroscopy: Common Problems and Solutions

The use of hip arthroscopy continues to expand. Understanding potential pitfalls and complications associated with hip arthroscopy is paramount to optimizing clinical outcomes and minimizing unfavorable results. Potential pitfalls and complications are associated with preoperative factors such as patient selection, intraoperative factors such as iatrogenic damage, traction-related complications, inadequate correction of deformity, and nerve injury, or postoperative factors such as poor rehabilitation. This article outlines common factors that contribute to less-than-favorable outcomes.

Not All Patients With Diabetes Have the Same Risks: Perioperative Glycemic Control Is Associated With Postoperative Infection Following Knee Arthroscopy

PURPOSE

To determine the association between glycemic control and infection following knee arthroscopy, and to determine the clinical utility of a threshold HbA1c level.

METHODS

A national database identified patients who underwent knee arthroscopy from 2007 to 2016. Patients with concomitant open portions, more complex knee procedures, procedures performed for infection and patients with prior septic knee arthritis were excluded. Patients with an HbA1c level checked within 3 months of surgery were compared to control groups of nondiabetics and diabetics undergoing knee arthroscopy without a perioperative HbA1c. The study group was then stratified based on their HbA1c. The incidence of deep infection within 6 months was identified and compared to those in the control groups. A subgroup analysis was performed to investigate any trend in the timing of postoperative infection. A receiver operating characteristic (ROC) analysis was performed to determine and test a threshold value of HbA1c.

RESULTS

13,470 study patients were included, with an overall rate of infection of 0.33%. The rate of infection ranged from 0.25% to 1.03%. The rate of infection in study patients was greater than the nondiabetes control group's (P < .0001) and not significantly different from that in the nonstudy diabetes control (P = .765). The inflection point of the ROC curve corresponded to an HbA1c level of 8.0 mg/dL (P = .006, specificity = 76%, sensitivity = 44%, area under curve [AUC] = 0.619).

CONCLUSIONS

The risk of infection following knee arthroscopy increases as the perioperative HbA1c increases. ROC analysis determined that an HbA1c above 8.0 mg/dL could serve as a threshold level; however, the AUC and low sensitivity reflected the poor utility of this test as an independent predictor for infection.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Risk Factors for Infection After Shoulder Arthroscopy in a Large Medicare Population

BACKGROUND

Shoulder arthroscopy is well established as a highly effective and safe procedure for the treatment for several shoulder disorders and is associated with an exceedingly low risk of infectious complications. Few data exist regarding risk factors for infection after shoulder arthroscopy, as previous studies were not adequately powered to evaluate for infection.

PURPOSE

To determine patient-related risk factors for infection after shoulder arthroscopy by using a large insurance database.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

The PearlDiver patient records database was used to query the 100% Medicare Standard Analytic Files from 2005 to 2014 for patients undergoing shoulder arthroscopy. Patients undergoing shoulder arthroscopy for a diagnosis of infection or with a history of prior infection were excluded. Postoperative infection within 90 days postoperatively was then assessed with International Classification of Diseases, Ninth Revision codes for a diagnosis of postoperative infection or septic shoulder arthritis or a procedure for these indications. A multivariate binomial logistic regression analysis was then utilized to evaluate the use of an intraoperative steroid injection, as well as numerous patient-related risk factors for postoperative infection. Adjusted odds ratios (ORs) and 95% CIs were calculated for each risk factor, with P < .05 considered statistically significant.

RESULTS

A total of 530,754 patients met all inclusion and exclusion criteria. There were 1409 infections within 90 days postoperatively (0.26%). Revision shoulder arthroscopy was the most significant risk factor for infection (OR, 3.25; 95% CI, 2.7-4.0; P < .0001). Intraoperative steroid injection was also an independent risk factor for postoperative infection (OR, 1.46; 95% CI, 1.2-1.9; P = .002). There were also numerous independent patient-related risk factors for infection, the most significant of which were chronic anemia (OR, 1.58; 95% CI, 1.4-1.8; P < .0001), malnutrition (OR, 1.42; 95% CI, 1.2-1.7; P = .001), male sex (OR, 2.71; 95% CI, 2.4-3.1; P < .0001), morbid obesity (OR, 1.41; 95% CI, 1.2-1.6; P < .0001), and depression (OR, 1.36; 95% CI, 1.2-1.5; P < .0001).

CONCLUSION

Intraoperative steroid injection was a significant independent risk factor for postoperative infection after shoulder arthroscopy. There were also numerous significant patient-related risk factors for postoperative infection, including revision surgery, obesity, male sex, chronic anemia, malnutrition, depression, and alcohol use, among others.