Faculty Bibliography

Total joint arthroplasty relies on the use of biomaterials that are biologically inert and capable of forming wear-resistant articulating surfaces. Polyethylene use in arthroplasty has become ubiquitous since its introduction in the 1960s. Early arthroplasty procedures of the hip utilized poly-tetra-flouroethylene, or "Teflon," due to its low coefficient of friction that was presumed to closely mimic the hyaline cartilage of native joints. Early catastrophic wear of Teflon caused a significant local tissue reaction contributing to osteolysis, aseptic loosening, and clinical failure ultimately limiting the material's surgical utility. Advancements in biomaterial synthesis and processing led to the fortuitous discovery of ultra-high-molecular-weight-polyethylene (UHMWPE) and the eventual evolution to highly cross-linked polyethylene (HXLPE) as a bearing surface in hip arthroplasties with robust, long-term clinical success. Ultra-high-molecularweight-polyethylene was readily adopted for use in total knee arthroplasty following the material's successful use in hip replacement, however, the unique biomechanics of the knee have posed unique challenges. The use of HXLPE in knee arthroplasty has increased, however, clear data regarding its benefit over UHMWPE are conflicting. Recently, clinical as well as research and development studies of UHMWPE and HXLPE have focused on alternative postprocessing methods to optimize material stability and wear resistance. Second generation HXLPE utilizing sequential annealing processes or vitamin E to stabilize free radicals are promising means to improve mechanical stability and wear resistance for use in joint arthroplasty, however, more data is required to evaluate long-term outcomes and cost-effectiveness. In this review, we discuss the history and innovation of polyethylene use in orthopedic surgery and evaluate the current literature on outcomes of polyethylene use in hip and knee replacement.

BACKGROUND:Concerns regarding the effects of dexamethasone on diabetics' glucose control have stymied its use following total joint arthroplasty. This study aimed to evaluate the effects of 2 intravenous (IV) perioperative doses of dexamethasone on glucose levels, pain scores, and inpatient opioid consumption following total joint arthroplasty in diabetic patients. METHODS:A retrospective review of 523 diabetic patients who underwent primary elective THA and 953 diabetic patients who underwent primary elective total knee arthroplasty (TKA) between May 6, 2020, and December 17, 2021 was conducted. Patients who received 1 dose (1D) of perioperative dexamethasone 10 mg IV were compared to patients who received 2 doses (2D). Primary outcomes included postoperative glucose levels, opioid consumption as morphine milligram equivalences, postoperative pain as Verbal Rating Scale pain scores, and postoperative complications. RESULTS:The 2D TKA cohort had significantly greater average and maximum blood glucose levels from 24 to 60 hours compared to the 1D TKA cohort. The 2D THA cohort had significantly greater average blood glucose levels at 24 to 36 hours compared to the 1D THA cohort. However, the 2D TKA group had significantly reduced opioid consumption from 24 to 72 hours and reduced total consumption compared to the 1D TKA group. Verbal Rating Scale pain scores did not differ between cohorts for both TKA and THA at any interval. CONCLUSION/CONCLUSIONS:Administration of a second perioperative dose of dexamethasone was associated with increased postoperative blood glucose levels. However, the observed effect on glucose control may not outweigh the clinical benefits of a second perioperative dose of glucocorticoids.

INTRODUCTION/BACKGROUND:Infection after total knee arthroplasty (TKA) impacts the patient, surgeon, and healthcare system significantly. Surgeons routinely use antibiotic-loaded bone cement (ALBC) in attempts to mitigate infection; however, little evidence supports the efficacy of ALBC in reducing infection rates compared to non-antibiotic-loaded bone cement (non-ALBC) in primary TKA. Our study compares infection rates of patients undergoing TKA with ALBC to those with non-ALBC to assess its efficacy in primary TKA. METHODS:A retrospective review of all primary, elective, cemented TKA patients over the age of 18 between 2011 and 2020 was conducted at an orthopedic specialty hospital. Patients were stratified into two cohorts based on cement type: ALBC (loaded with gentamicin or tobramycin) or non-ALBC. Baseline characteristics and infection rates determined by MSIS criteria were collected. Multilinear and multivariate logistic regressions were performed to limit significant differences in demographics. Independent samples t test and chi-squared test were used to compare means and proportions, respectively, between the two cohorts. RESULTS:) and Charlson Comorbidity Index values (4.51 ± 2.15 vs. 4.04 ± 1.92) were more likely to receive ALBC. The infection rate in the non-ALBC was 0.8% (63/7,980), while the rate in the ALBC was 0.5% (7/1,386). After adjusting for confounders, the difference in rates was not significant between the two groups (OR [95% CI]: 1.53 [0.69-3.38], p = 0.298). Furthermore, a sub-analysis comparing the infection rates within various demographic categories also showed no significant differences between the two groups. CONCLUSION/CONCLUSIONS:Compared to non-ALBC, the overall infection rate in primary TKA was slightly lower when using ALBC; however, the difference was not statistically significant. When stratifying by comorbidity, use of ALBC still showed no statistical significance in reducing the risk of periprosthetic joint infection. Therefore, the advantage of antibiotics in bone cement to prevent infection in primary TKA is not yet elucidated. Further prospective, multicenter studies regarding the clinical benefits of antibiotic use in bone cement for primary TKA are warranted.

BACKGROUND:The impact of preoperative nasal colonization with methicillin resistant staphylococcus aureus (MRSA) on total joint arthroplasty (TJA) outcomes is not well understood. This study aimed to evaluate complications following TJA based on patients' preoperative staphylococcal colonization status. METHODS:We retrospectively analyzed all patients undergoing primary TJA between 2011 and 2022 who completed a preoperative nasal culture swab for staphylococcal colonization. Patients were 1:1:1 propensity matched using baseline characteristics, and stratified into 3 groups based on their colonization status: MRSA positive (MRSA+), methicillin sensitive staphylococcus aureus positive (MSSA+), and MSSA/MRSA negative (MSSA/MRSA-). All MRSA+ and MSSA + underwent decolonization with 5% povidone iodine, with the addition of intravenous vancomycin for MRSA + patients. Surgical outcomes were compared between groups. Of the 33,854 patients evaluated, 711 were included in final matched analysis (237 per group). RESULTS:The MRSA + TJA patients had longer hospital lengths of stay (P = .008), were less likely to discharge home (P = .003), and had higher 30-day (P = .030) and 90-day (P = .033) readmission rates compared to MSSA+ and MSSA/MRSA-patients, though 90-day major and minor complications were comparable across groups. MRSA + patients had higher rates of all-cause (P = .020), aseptic (P = .025) and septic revisions (P = .049) compared to the other cohorts. These findings held true for both total knee and total hip arthroplasty patients when analyzed separately. CONCLUSION/CONCLUSIONS:Despite targeted perioperative decolonization, MRSA + patients undergoing TJA have longer lengths of stay, higher readmission rates, and higher septic and aseptic revision rates. Surgeons should consider patients' preoperative MRSA colonization status when counseling on the risks of TJA.

BACKGROUND:Few studies have assessed how socioeconomic status (SES) influences patient-reported outcomes (PROMs) after total knee arthroplasty (TKA). This study evaluated the impact of patient median ZIP code income levels on PROMs after TKA. METHODS:We retrospectively reviewed patients at our institution undergoing primary, unilateral TKA from 2017 to 2020. Patients who did not have one-year postoperative PROMs were excluded. Patients were stratified based on the quartile of their home ZIP code median income from United States Census Bureau data. There were 1,267 patients included: 98 in quartile 1 (median income ≤ $46,308) (7.7%); 126 in quartile 2 (median income $46,309-$57,848) (10.0%); 194 in quartile 3 (median income $57,849-$74,011) (15.7%); and 849 in quartile 4 (median income ≥ $74,012) (66.4%). We collected baseline demographic data, 2-year outcomes, and PROMs preoperatively, as well as at 12 weeks and one year, postoperatively. RESULTS:The Knee Injury and Osteoarthritis Outcome Score for Joint Replacement was significantly higher in quartile 4 preoperatively (P < .001), 12 weeks postoperatively (P < .001), and one year postoperatively (P < .001). There were no significant differences in delta improvements of Knee Injury and Osteoarthritis Outcome Score for Joint Replacement from preoperative to 12 weeks or one year postoperatively. There were no significant differences in lengths of stay, discharge dispositions, readmissions, or revisions. CONCLUSION/CONCLUSIONS:Patients from lower income areas have slightly worse knee function preoperatively and worse outcomes following TKA. However, improvements in PROMs throughout the first year postoperatively are similar across income quartiles, suggesting that patients from lower income quartiles achieve comparable therapeutic benefits from TKA. LEVEL III EVIDENCE/METHODS:Retrospective Cohort Study.

BACKGROUND:Intra-articular hyaluronic acid (IAHA) has been commonly used in the management of knee osteoarthritis (OA). This study sought to assess patient-reported outcomes (PRO) following different formulations of hyaluronic acid injections for patients who have knee OA. METHODS:A retrospective analysis was performed on patients who have knee OA and received IAHA knee injections from October 2018 to May 2022 in sports medicine (SM) and adult reconstructive (AR) clinics. Patients completed PRO measures including the Patient-Reported Outcome Measurement Information System (PROMIS) Mobility, Pain Interference, and Pain Intensity at baseline, 6-week, 6-month, and 12-month follow-up. Univariate and multivariate analyses were used to evaluate changes in PRO measures between baseline and follow-up periods and to evaluate differences between the SM and AR divisions. A total of 995 patients received IAHA for knee OA and completed PRO assessments. RESULTS:There was no difference in the PROMIS measures based on molecular weight at 6 weeks, 6 months, and 12 months. Except for 6-month Mobility scores between the SM and AR patients (-0.52 ± 5.46 versus 2.03 ± 6.95; P = .02), all other PROMIS scores were similar. Mobility scores at 6 months were significantly different based on Kellgren and Lawrence grade (P = .005), but all other PROMIS scores were similar. CONCLUSION/CONCLUSIONS:Average change in PROMIS scores were significantly different only for 6-month Mobility scores based on divisions and Kellgren and Lawrence grade but did not achieve minimally clinical important difference at most timepoints. Further studies are needed to investigate whether improvement is observed in specific patient populations.

BACKGROUND:In response to physician and patient concerns, many institutions have adopted protocols aimed at reducing postoperative opioid consumption after total knee arthroplasty (TKA). Thus, this study sought to examine how consumption of opioids has changed following TKA in the past 6 years. METHODS:We conducted a retrospective review of all 10,072 patients who received primary TKA at our institution from January 2016 to April 2021. We collected baseline demographic data including patient age, sex, race, body mass index (BMI), American Society of Anesthesiologist (ASA) classification, as well as dosage and type of opioid medication prescribed on each postoperative day while the patient was hospitalized following TKA. This data was converted to milligram morphine equivalents (MME) per day hospitalized to compare rates of opioid use over time. RESULTS:Our analysis found the greatest daily opioid use was in 2016 (43.2 ± 68.6 MME/day) and the least was in 2021 (15.0 ± 29.2 MME/day). Linear regression analyses found a significant linear downward trend in postoperative opioid consumption over time, with a decrease of 5.55 MME per day per year (Adjusted R-squared: 0.982, P < .001). The highest visual analog scale (VAS) score was 4.45 in 2016 and the lowest was 3.79 in 2021 (P < .001). CONCLUSION/CONCLUSIONS:Opioid reducing protocols have been implemented for patients recovering from primary TKA in an effort to decrease reliance on opioids for postoperative pain control. The results of this study demonstrate that such protocols have been successful in reducing overall opioid use during hospitalization following TKA. LEVEL III EVIDENCE/METHODS:Retrospective Cohort.

INTRODUCTION/BACKGROUND:Operating room air quality can be affected by several factors including temperature, humidity, and airborne particle burden. Our study examines the role of operating room (OR) size on air quality and airborne particle (ABP) count in primary total knee arthroplasty (TKA). MATERIALS AND METHODS/METHODS:We analyzed all primary, elective TKAs performed within two ORs measuring 278 sq ft. (small) and 501 sq ft. (large) at a single academic institution in the United States from April 2019 to June 2020. Intraoperative measurements of temperature, humidity, and ABP count were recorded. p values were calculated using t test for continuous variables and chi-square for categorical values. RESULTS:91 primary TKA cases were included in the study, with 21 (23.1%) in the small OR and 70 (76.9%) in the large OR. Between-groups comparisons revealed significant differences in relative humidity (small OR 38.5% ± 7.24% vs. large OR 44.4% ± 8.01%, p = 0.002). Significant percent decreases in ABP rates for particles measuring 2.5 μm (- 43.9%, p = 0.007) and 5.0 μm (- 69.0%, p = 0.0024) were found in the large OR. Total time spent in the OR was not significantly different between the two groups (small OR 153.09 ± 22.3 vs. large OR 173 ± 44.6, p = 0.05). CONCLUSIONS:Although total time spent in the room did not differ between the large and small OR, there were significant differences in humidity and ABP rates for particles measuring 2.5 μm and 5.0 μm, suggesting the filtration system encounters less particle burden in larger rooms. Larger studies are required to determine the impact this may have on OR sterility and infection rates.

INTRODUCTION/BACKGROUND:Previous studies have shown lower morbidity and mortality rates after total hip arthroplasty (THA) at academic teaching hospitals. This study sought to determine the relationship between hospital teaching status and patient-reported outcome measures (PROMs) following primary THA. METHODS:Using American Joint Replacement Registry data from 2012 to 2020, 4,447 primary, elective THAs with both preoperative and one-year postoperative Hip Disability and Osteoarthritis Outcome Score, Joint Replacement (HOOS, JR) scores were analyzed. The main exposure variable was hospital teaching status, with three cohorts: major teaching hospitals; minor teaching hospitals; and non-teaching hospitals. Mean preoperative and one-year postoperative HOOS, JR scores were compared. RESULTS:Preoperative HOOS, JR scores (non-teaching: 49.69±14.42 vs. major teaching: 47.68±15.10 vs. minor teaching: 42.46±19.19, P<0.001) were significantly higher at non-teaching hospitals than major and minor teaching hospitals, and these differences persisted at one-year postoperatively (87.40±15.14 vs. 83.87±16.68 vs. 80.37±19.27, P<0.001). Both preoperative and postoperative differences in HOOS, JR scores were less than the Minimum Clinically Important Difference (MCID) at both time points. In multivariate regressions, non-teaching and minor teaching hospitals had similar odds of MCID achievement in HOOS, JR scores compared to major teaching hospitals. CONCLUSION/CONCLUSIONS:Using the HOOS, JR score as a validated outcome measure, undergoing primary THA at an academic teaching hospital did not correlate with higher postoperative HOOS, JR scores or greater chances of MCID achievement in HOOS, JR scores compared to non-teaching hospitals. Further work is required to determine the most important factors that may lead to improvement in patient-reported outcomes following THA.

Background:National projections of future joint arthroplasties are useful for understanding the changing burden of surgery and related outcomes on the health system. The aim of this study is to update the literature by producing Medicare projections for primary total joint arthroplasty (TJA) procedures until 2040 and 2060.Methods:The present study used data from the Centers for Medicare & Medicaid Services (CMS) Medicare/Medicaid Part B National Summary and combined procedure counts with use of Current Procedural Terminology (CPT) codes to identify whether the procedure was a primary total hip arthroplasty (THA) or total knee arthroplasty (TKA) procedure. In 2019, the annual volume of primary TKA was 480,958 and that of primary THA was 262,369. These values formed a baseline from which we generated point forecasts for 2020-2060 and 95% forecast intervals (FIs).Results:Between 2000 and 2019, the estimated annual volume of THA increased by 177% and that of TKA increased by 156% on average. Regression analysis projected an annual growth rate of 5.2% for THA and 4.44% for TKA. Based on these yearly projected increases, an estimated increase of 28.84% and 24.28% is expected for each 5-year period after 2020 for THA and TKA, respectively. By 2040, the number of THAs is projected to be 719,364 (95% FI, 624,766 to 828,286) and the number of TKA is projected to be 1,222,988 (95% FI, 988,714 to 1,512,772). By 2060, the number of THAs is projected to be 1,982,099 (95% FI, 1,624,215 to 2,418,839) and the number of TKAs is projected to be 2,917,959 (95% FI, 2,160,951 to 3,940,156). In 2019, Medicare data showed that THA constituted approximately 35% of TJA procedures performed.Conclusions:Based on 2019 total volume counts, our model forecasts an increase in THA procedures of 176% by 2040 and 659% by 2060. The estimated increase for TKA is projected to be 139% by 2040 and 469% by 2060. An accurate projection of future primary TJA procedure demands is important in order to understand future health-care utilization and surgeon demand. This finding is only applicable to a Medicare population and demands further analysis to see if this extends to other population groups.Level of Evidence:Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.