Silver Coatings in Reconstructive Orthopaedics: Basic Science and Clinical Rationale.

Prosthetic joint infection (PJI) is one of the most devastating complications that can occur following total hip and total knee arthroplasty. Despite the remarkable advances that have been made in surgical techniques and implant technology, the incidence of PJI has remained largely unchanged over the past two decades. One approach that has been described in the literature to minimize the risk of PJI has been the use of silver-coated prostheses. Silver has been reported to have antimicrobial properties when added to a variety of orthopaedic materials including bone cement, hydroxyapatite coatings and wound dressings. Silver is also being increasingly used as a surface coating for endoprostheses used for reconstruction around the hip and the knee with the specific aim of reducing the incidence of prosthetic joint infection. Despite the increasing adoption of this technology, the use of silver coatings remains controversial. The optimal method for preparation and the thickness of the coating, as well as the mechanism(s) of action in reducing the incidence of PJI, are unclear. The issue of silver toxicity is also an important consideration. This paper provides an overview of the use of silver coatings in reconstructive orthopaedics, as well as the types available and techniques used to coat endoprostheses. We also review the basic science as well as the clinical applications of silver coatings in the prevention of PJIs.

Probability of Undiagnosed Obstructive Sleep Apnea Does Not Correlate With Adverse Pulmonary Events nor Length of Stay in Hip and Knee Arthroplasty Using Intrathecal Opioid.

BACKGROUND: Recent emphasis on bundled payments and outcomes tracking has increased the focus on preoperative optimization in patients undergoing elective lower extremity arthroplasty. Since patients with obstructive sleep apnea (OSA) have an increased risk of adverse perioperative pulmonary events, screening for undiagnosed OSA is sometimes included as part of preoperative risk assessment. However, there are limited data regarding quantification of OSA risk in lower extremity arthroplasty patients, and little is known about the utility of quantitative OSA screening and the risk of pulmonary complications in hip and knee arthroplasty patients who receive intrathecal morphine anesthetic. METHODS: A retrospective review of 990 patients at a tertiary care, urban academic medical center who underwent lower extremity arthroplasty with a multimodal pain regimen including intrathecal morphine anesthesia, comparing the rate of pulmonary complications and length of stay between patients previously diagnosed with OSA and those identified as low, moderate, and high risk of undiagnosed OSA established by screening with the STOP-BANG questionnaire in the preoperative setting. RESULTS: Using logistic regression and adjusting for age, gender, and body mass index, the results suggested the rate of complications was not different across the sleep apnea risk groups (P = .4024). In addition, linear regression suggested length of stay did not differ significantly by sleep apnea risk group (P = .2823). CONCLUSION: In patients receiving intrathecal morphine as part of a multimodal pain regimen undergoing hip or knee arthroplasty, neither risk of adverse pulmonary events nor length of stay appeared to correlate with preoperative risk of undiagnosed OSA.

Rotating Hinge Distal Femur Replacement: A Turn for the Worse.

Preoperatively periprosthetic joint infection with a postoperative complication of 180° rotation of the press-fit femoral component is a rare event, and knowledge of this possible complication is important for arthroplasty surgeons.

Differentiation in Posterior Tibial Slope by Sex, Age, and Race: A Cadaveric Study Utilizing 3-Dimensional Computerized Tomography.

BACKGROUND: Posterior tibial slope (PTS) has recently gained increased attention for its possible role in anterior cruciate ligament and posterior cruciate ligament injury. The possible differences among age, sex, and ethnicity in PTS have not yet been reported. PURPOSE: To describe demographic variances of proximal tibial anatomy and to detect differences in regard to ethnicity, sex, and age. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: In total, 250 cadaveric specimens with full-body computerized tomography scans from the New Mexico Descendant Imaging Database were randomly selected (inclusion/exclusion criteria: older than 18 years, complete imaging of the knee without previous surgery or arthroplasty) and reviewed by 3 independent observers measuring medial posterior tibial slope (MPTS), lateral posterior tibial slope (LPTS), and global posterior tibial slope (PTS), which was calculated as the mean of the MPTS and LPTS. Individuals were evenly divided among male and female and ethnicities/races: African American/Black, Asian American, Hispanic, Native American, and White. Intraclass correlation coefficient was calculated for interobserver reliability and analysis of variance statistical testing to determine statistical significance between groups. Fisher exact test was also used to understand PTS differences among ethnicities when looking at clinically significant values for potential ligamentous injury. RESULTS: Measurements were obtained from 250 specimens with a mean age of 49.4 years (range, 19 to 103 years). The mean PTS was 8.92° (range, -9.4° to 14.95°). Asian Americans had a 1.7° greater mean MPTS than Whites (P = .016), and African Americans/Blacks had a 1.6° greater mean PTS than Whites (P = .022). No difference in mean PTS was seen between age and sex. When looking at clinically significant PTS, 61 (24.4%) individuals had tibial slopes <6° or >12°, 32 (12.8%) and 29 (11.6%), respectively. Statistically significant differences were seen among ethnicities with PTS <6° (P = .017) but not with PTS >12° (P = .106). No sex-based differences were seen in the percentage of specimens with a PTS of >12° or <6°. CONCLUSION: Among ethnicities, African Americans/Blacks and Asian Americans have increased PTS in comparison with Whites. Nearly 25% of individuals have clinically significant slopes of <6° or >12°, with no difference in tibial slope among sex or age groups.

Dexamethasone and postoperative hyperglycemia in diabetics undergoing elective hip or knee arthroplasty: a case control study in 238 patients.

BACKGROUND: Dexamethasone has been routinely used in the pre-operative setting to enhance analgesia and decrease the incidence of nausea and vomiting in patients undergoing primary arthroplasty. However, dexamethasone has the potential to increase blood glucose levels postoperatively, which is a known risk factor for complications after total joint arthroplasty. The aim of this study was to analyze the effect of dexamethasone administration on post-operative blood glucose levels in diabetic patients after primary hip and knee arthroplasty. METHODS: This study was a retrospective review of 238 diabetic patients who underwent primary hip and knee arthroplasty between May 1, 2014 and September 30, 2016 at a single urban academic medical center. A total of 77 patients (32.4%) received dexamethasone and 161 (67.7%) did not. Oral hyperglycemic agents were held during the inpatient stay and blood glucose was controlled either with sliding scale insulin or home insulin regimens were continued. All analyses were adjusted for age, BMI, gender, type of diabetes, pre-operative diabetic medication, type of surgical procedure, and pre-operative HgbA1c level. The primary outcome was post-operative hyperglycemia within 72 h of surgery defined as any blood glucose level greater than or equal to 200 mg/dL. RESULTS: Post-operative hyperglycemia was observed in 17.1 and 20.6% of the measurements during the first 24 and 72 h respectively. After controlling for confounding variables, patients who received dexamethasone had 4.07 (95% CI: 2.46, 6.72) and 3.08 (95% CI: 2.34, 4.04) higher odds of post-operative hyperglycemia in the first 24 and 72 h respectively. CONCLUSIONS: Dexamethasone administration in diabetic patients undergoing primary arthroplasty increases post-operative hyperglycemia during the first 24 and 72 h. While our data did not investigate causation, dexamethasone use in this patient population should be thoughtfully considered, as post-operative hyperglycemia is a known risk factor for complications.