Adam I. Edelstein

Can the American College of Surgeons Risk Calculator Predict 30-Day Complications After Knee and Hip Arthroplasty?

Accurate risk stratification of patients undergoing total hip (THA) and knee (TKA) arthroplasty is essential in the highly scrutinized world of pay-for-performance, value-driven healthcare. We assessed the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) surgical risk calculators ability to predict 30-day complications using 1066 publicly-reported Medicare patients undergoing primary THA or TKA. Risk estimates were significantly associated with complications in the categories of any complication (P = .005), cardiac complication (P < .001), pneumonia (P < .001) and discharge to skilled nursing facility (P < .001). However, predictability of complication occurrence was poor for all complications assessed. To facilitate the equitable provision and reimbursement of patient care, further research is needed to develop accurate risk stratification tools in TKA and THA surgery.

Impact of Resident Involvement on Orthopaedic Surgery Outcomes: An Analysis of 30,628 Patients from the American College of Surgeons National Surgical Quality Improvement Program Database

BACKGROUND Operative procedural training is a key component of orthopaedic surgery residency. The influence of intraoperative resident participation on the outcomes of surgery has not been studied extensively using large, population-based databases. METHODS We identified 30,628 patients who underwent orthopaedic procedures from the 2011 American College of Surgeons National Surgical Quality Improvement Program. Outcomes as measured by perioperative complications, readmission rates, and mortality within thirty days were compared for cases with and without intraoperative resident involvement. RESULTS Logistic regression with propensity score analysis revealed that intraoperative resident participation was associated with decreased rates of overall complications (odds ratio, 0.717 [95% confidence interval, 0.657 to 0.782]), medical complications (odds ratio, 0.723 [95% confidence interval, 0.661 to 0.790]), and mortality (odds ratio, 0.638 [95% confidence interval, 0.427 to 0.951]). Resident presence in the operating room was not predictive of wound complications (odds ratio, 0.831 [95% confidence interval, 0.656 to 1.053]), readmission (odds ratio, 0.962 [95% confidence interval, 0.830 to 1.116]), or reoperation (odds ratio, 0.938 [95% confidence interval, 0.758 to 1.161]). A second analysis by propensity score stratification into quintiles grouped by similar probability of intraoperative resident presence showed resident involvement to correlate with decreased rates of overall and medical complications in three quintiles, but increased rates of overall and medical complications in one quintile. All other outcomes were equivalent across quintiles. CONCLUSIONS Orthopaedic resident involvement during surgical procedures is associated with lower risk of perioperative complications and mortality in the National Surgical Quality Improvement Program database. The results support resident participation in the operative care of orthopaedic patients. LEVEL OF EVIDENCE Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Risk Factors for Postoperative Infections Following Single Level Lumbar Fusion Surgery

Study Design. Retrospective multivariate analysis of a prospectively collected, multicenter database. Objective. To identify patient characteristics and perioperative risk factors associated with postoperative infectious complications after single-level lumbar fusion (SLLF) surgery. Summary of Background Data. Postoperative infection is a known complication after lumbar fusion. Risk factors for infectious complications after lumbar fusion have not been investigated using select set of SLLF procedures. Methods. Patients who underwent SLLF between 2006 and 2011 were identified from the American College of Surgeons National Surgical Quality Improvement Program database. Multivariate logistic regression analyses were performed to identify pre- and intraoperative risk factors associated with postoperative infection. Results. A total of 3353 patients were analyzed in this study. Overall, 173 (5.2%) patients experienced a postoperative infection, including 86 (2.6%) surgical site infections (SSIs) and 111 (3.3%) non-SSI infectious complications (pneumonia, urinary tract infection, sepsis/septic shock). Twenty-four (0.7%) patients experienced both SSI and non-SSI infectious complications. Postoperative SSI were associated with obesity (odds ratio [OR], 1.628; 95% confidence interval [CI], 1.042–2.544), American Society of Anesthesiologists class more than 2 (OR, 2.078; 95% CI, 1.309–3.299), and operative time more than 6 hours (OR, 2.573; 95% CI, 1.310–5.056). Risk factors for non-SSI infectious complications included age (60–69 yr; OR, 3.279; 95% CI, 1.541–6.980; and ≥70 yr; OR, 3.348; 95% CI, 1.519–7.378), female sex (OR, 1.791; 95% CI, 1.183–2.711), creatinine more than 1.5 mg/dL (OR, 2.400; 95% CI, 1.138–5.062), American Society of Anesthesiologists class more than 2 (OR, 1.835; 95% CI, 1.177–2.860), and operative time more than 6 hours (OR, 3.563; 95% CI, 2.082–6.097). Conclusion. Across a wide study population, we identified that obesity, advanced American Society of Anesthesiologists classification, and longer operative time were predictive of postoperative SSI. We also demonstrated that increased age, female sex, serum creatinine more than 1.5 mg/dL, and prolonged operative duration are associated with non-SSI infectious complications after SLLF. Continued efforts to elucidate and optimize perioperative risk factors are warranted to improve outcomes in patients requiring spinal fusion. Level of Evidence: 3

Perioperative Outcomes Following Unilateral Versus Bilateral Total Knee Arthroplasty.

Simultaneous bilateral total knee arthroplasty (SB-TKA) is potentially a cost saving manner of caring for patients with bilateral symptomatic knee arthritis. We performed a retrospective analysis using the 2010-2012 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) to evaluate the risk of perioperative complication following SB-TKA. Demographic characteristics, comorbidities, and 30-day complication rates were studied using a propensity score-matched analysis comparing patients undergoing unilateral TKA and SB-TKA. A total of 4489 patients met the inclusion criteria, of which 973 were SB-TKA. SB-TKA was associated with increased overall complications (P = 0.023), medical complications (P = 0.002) and reoperation (OR 2.12, P = 0.020). Further, total length of hospital stay (4.0 vs 3.4 days, P < 0.001) was significantly longer following bilateral surgery.

Spine surgeon specialty is not a risk factor for 30-day complication rates in single-level lumbar fusion: A Propensity score-matched study of 2528 patients

Study Design. Multicenter retrospective cohort study. Objective. To investigate the impact of spine surgeon specialty on 30-day complication rates in patients undergoing single-level lumbar fusion. Summary of Background Data. Operative care of the spine is delivered by surgeons who undergo either orthopedic or neurosurgical training. It is currently unknown whether surgeon specialty has an impact on 30-day complication rates in patients undergoing single-level lumbar fusion. Methods. The American College of Surgeons National Surgical Quality Improvement Program database was retrospectively reviewed to identify all patients who underwent single-level lumbar fusion procedures during 2006–2011. Propensity score matching analysis was employed to reduce baseline differences in patient characteristics. Univariate and multivariate analyses were performed to assess the impact of spine surgeon specialty on 30-day complication rates. Results. A total of 2970 patients were included for analysis. After propensity matching, 1264 pairs of well-matched patients remained in the cohort. Overall complication rates in the unadjusted data set were 7.3% and 7.1% for the neurosurgery and orthopedic surgery cohort, respectively. Our multivariate analysis revealed that compared with the neurosurgery cohort, the orthopedic surgery cohort did not have statistically significant differences in odds ratios (OR) for development of any complication (OR, 0.95; 95% confidence interval [CI], 0.69–1.30; P = 0.740). Similarly, spine surgeon specialty was not a risk factor in any of the specific complications studied, including medical complications (OR, 1.11; 95% CI, 0.77–1.60; P = 0.583), surgical complications (OR, 0.76; 95% CI, 0.46–1.26; P = 0.287), or reoperation (OR, 1.10; 95% CI, 0.76–1.60; P = 0.618). Conclusion. Our analysis demonstrates that spine surgeon specialty is not a risk factor for any of the reported 30-day complications in patients undergoing single-level lumbar fusion. These data support the currently dichotomous paradigm of training for spine surgeons. Further research is warranted to validate this relationship in other spine procedures and for other outcomes. Level of Evidence: 4

Risk Prediction Tools for Hip and Knee Arthroplasty

The current healthcare environment in America is driven by the concepts of quality, cost containment, and value. In this environment, primary hip and knee arthroplasty procedures have been targeted for cost containment through quality improvement initiatives intended to reduce the incidence of costly complications and readmissions. Accordingly, risk prediction tools have been developed in an attempt to quantify the patient-specific assessment of risk. Risk prediction tools may be useful for the informed consent process, for enhancing risk mitigation efforts, and for risk-adjusting data used for reimbursement and the public reporting of outcomes. The evaluation of risk prediction tools involves statistical measures such as discrimination and calibration to assess accuracy and utility. Furthermore, prediction tools are tuned to the source dataset from which they are derived, require validation with external datasets, and should be recalibrated over time. However, a high-quality, externally validated risk prediction tool for adverse outcomes after primary total joint arthroplasty remains an elusive goal.

Intra-articular Vancomycin Powder Eliminates Methicillin-resistant S. aureus in a Rat Model of a Contaminated Intra-articular Implant

Background: Periprosthetic joint infection following hip and knee arthroplasty leads to poor outcomes and exorbitant costs. Topical vancomycin powder has been shown to decrease infection in many procedures such as spine surgery. The role of vancomycin powder in the setting of total joint arthroplasty remains undefined. Our aim was to evaluate the efficacy of intra-articular vancomycin powder in preventing infection in a rat model of a contaminated intra-articular implant. Methods: Thirty-two female Sprague-Dawley rats underwent knee arthrotomy and implantation of a femoral intramedullary wire with 1 mm of intra-articular communication. The knee joint was also inoculated with 1.5 × 107 colony forming units (CFU)/mL of methicillin-resistant Staphylococcus aureus (MRSA). Four treatment groups were studied: (1) no antibiotics (control), (2) preoperative systemic vancomycin, (3) intra-articular vancomycin powder, and (4) both systemic vancomycin and intra-articular vancomycin powder. The animals were killed on postoperative day 6, and distal femoral bone, joint capsule, and the implanted wire were harvested for bacteriologic analysis. Statistical analyses were performed using Wilcoxon rank sum and Fisher exact tests. Results: There were no postoperative deaths, wound complications, signs of vancomycin-related toxicity, or signs of systemic illness in any of the treatment groups. There were significantly fewer positive cultures in the group that received vancomycin powder in combination with systemic vancomycin compared with the group that received systemic vancomycin alone (bone: 0% versus 75% of 8, p = 0.007; Kirschner wire: 0% versus 63% of 8, p = 0.026; whole animal: 0% versus 88% of 8, p = 0.01). Only animals that received both vancomycin powder and systemic vancomycin showed evidence of complete elimination of bacterial contamination. Conclusions: In a rat model of a contaminated intra-articular implant, use of intra-articular vancomycin powder in combination with systemic vancomycin completely eliminated MRSA bacterial contamination. Animals treated with systemic vancomycin alone had persistent MRSA contamination. Clinical Relevance: This animal study presents data suggesting that the use of intra-articular vancomycin powder for reducing the risk of periprosthetic joint infections should be investigated further in clinical studies.

Preoperative Anemia Does Not Predict Complications After Single-level Lumbar Fusion: A Propensity Score–matched Multicenter Study

Study Design. Multicenter retrospective cohort study. Objective. To estimate the impact of preoperative anemia on 30-day complications in patients undergoing single-level lumbar fusion. Summary of Background Data. Anemia has been widely implicated as a risk factor in various surgical procedures including elective spine surgery. No large-scale study has been performed to examine this relationship in single-level lumbar fusion surgery. Methods. The American College of Surgeons National Surgical Quality Improvement Program database was retrospectively reviewed to identify all patients who underwent single-level lumbar fusion procedures during 2006 to 2011. A propensity score–matching algorithm was used to match scores of anemic patients with that of nonanemic patients. Multivariate logistic regression analysis of unadjusted and propensity score–matched cohorts was performed to examine the effect of preoperative anemia on 30-day postoperative complication rates and length of hospital stay. Results. A total of 2960 patients met inclusion criteria. The propensity score–matching procedure yielded scores of 491 pairs of well-matched nonanemic and anemic patients. The multivariate analysis of propensity score–matched population found preoperative anemia to carry no significant association with any of the complications analyzed, including overall complications, medical complications, surgical complications, reoperation, mortality, or length of total hospital stay. Conclusion. For patients undergoing single-level lumbar fusion, preoperative anemia is not independently associated with increased risk of 30-day complications or increased length of stay. Further studies are needed to independently validate this relationship in other spine surgical procedures. Level of Evidence: 3

Nephrotoxicity After the Treatment of Periprosthetic Joint Infection With Antibiotic-Loaded Cement Spacers

BACKGROUND Treatment of periprosthetic joint infections commonly involves insertion of an antibiotic-loaded cement spacer (ACS). The risk for acute kidney injury (AKI) related to use of antibiotic spacers has not been well defined. We aimed to identify the incidence of and risk factors for AKI after placement of an ACS. METHODS We performed a prospective cohort study of patients with an infected primary total hip or knee arthroplasty treated with ACSs with vancomycin, gentamicin, and tobramycin. Serum creatinine and glomerular filtration rate data were collected at baseline and weekly intervals for 8 weeks. Patients were classified into Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease (RIFLE) stages to determine incidence of AKI. Risk factors for kidney injury were identified via regression analysis. RESULTS A total of 37 patients (20 total knee arthroplasty and 17 total hip arthroplasty) were included. During the 8 weeks after ACS placement, 10 patients (27%) fit RIFLE criteria for kidney injury and 2 patients (5%) fit RIFLE criteria for kidney failure. No baseline patient characteristics were associated with development of AKI. CONCLUSION Patients should be monitored closely for development of AKI after placement of ACSs for the treatment of periprosthetic joint infection. Further research into minimizing risk for AKI is warranted.

Chronic Anterior Pelvic Instability: Diagnosis and Management

Chronic anterior pelvic ring instability can cause pain and disability. Pain typically is localized to the suprapubic area or inner thigh; often is associated with lower back or buttock pain; and may be exacerbated by activity, direct impact, or pelvic ring compression. Known etiologies of chronic anterior pelvic ring instability include pregnancy, parturition, trauma, insufficiency fractures, athletics, prior surgery, and osteitis pubis. Diagnosis often is delayed. Physical examination may reveal an antalgic or waddling gait, tenderness over the pubic bones or symphysis pubis, and pain with provocative maneuvers. AP pelvic radiographs may demonstrate chronic degenerative changes at the pubic symphysis or nonhealing fractures. Standing single leg stance (flamingo view) radiographs can demonstrate pathologic motion at the pubic symphysis. CT may be useful in assessing posterior pelvic ring involvement. The initial management is typically nonsurgical and may include the use of an orthosis, activity modification, medication, and physical therapy. If nonsurgical modalities are unsuccessful, surgery may be warranted, although little evidence exists to guide treatment. Surgical intervention may include internal fixation alone in select patients, the addition of bone graft to fixation, or symphyseal arthrodesis. In some patients, additional stabilization or arthrodesis of the posterior pelvic ring may be indicated.