Continuing Home Oral Hypoglycemic Medications Was Associated With Superior Postoperative Glycemic Control Versus Initiating Sliding Scale Insulin After Total Hip Arthroplasty.

BACKGROUND: This retrospective study investigated the impact of continuing vs discontinuing home oral hypoglycemic medications for patients with diabetes undergoing total hip arthroplasty. MATERIALS AND METHODS: Patients who were not exclusively receiving home oral hypoglycemic regimens were excluded. Additionally, patients whose diabetes was not managed inpatient postoperatively were excluded. Included patients were retrospectively evaluated for early postoperative glycemic control, renal function, and metabolic abnormalities. Patients were then compared based on whether their home oral hypoglycemic regimen was continued vs discontinued in favor of initiating insulin while inpatient and analyzed using multivariable regression analysis. RESULTS: A total of 532 patients undergoing total hip arthroplasty met inclusion criteria, with 78.6% continuing their home oral hypoglycemic regimen. Those who continued showed significantly lower median maximum inpatient blood glucose (178.5 mg/dL vs 249.5 mg/dL; P<.001) and median average inpatient blood glucose (138.4 mg/dL vs 178.6 mg/dL; P<.001). Linear regression analysis, adjusting for various potential confounding factors, revealed a positive correlation between discontinuation of home hypoglycemic medications and higher maximum in-patient blood glucose (ß=70.15 [95% CI, 59.27-81.03]; P<.001). Patients in the continuation group had lower proportions of acute kidney injury (18.7% vs 41.2%; P<.001) and metabolic acidosis (4.3% vs 17.5%; P<.001), along with a shorter length of stay (1.0 d vs 2.0 d; P<.001). CONCLUSION: These findings suggest that continuing a home oral hypoglycemic regimen for patients with diabetes after total hip arthroplasty is associated with superior glycemic control without exacerbating renal abnormalities or increasing metabolic complications. [Orthopedics. 202x;4x(x):xx-xx.].

Unsuspected Positive Intraoperative Cultures in Aseptic Revision Knee Arthroplasty: Prevalence, Management, and Infection-Free Survivorship.

BACKGROUND: The purpose of this study was to evaluate the management and outcomes of aseptic revision total knee arthroplasty (arTKA) with unsuspected positive cultures (UPCs) compared to those with sterile cultures. METHODS: The institutional database at a single tertiary center was retrospectively reviewed for arTKA from January 2013 to October 2023. Patients who met Musculoskeletal Infection Society (MSIS) criteria for periprosthetic infection (PJI) based on available preoperative infectious workup, received antibiotic spacers, or did not have at least 1 year of follow-up were excluded. Patients were stratified based on intraoperative cultures into 4 cohorts: sterile cultures, 1 UPC, ≥ 2 UPCs with different organisms, and ≥ 2 UPCs with the same organism. Univariable analyses were used to compare these groups. Kaplan-Meyer survivorship analysis assessed infection-free survival at 5 years, and Cox proportional hazards regressions were used to evaluate factors that influence infection-free survival. A total of 691 arTKAs at a mean follow-up of 4.2 years were included in the study. Of these, 49 (7.1%) had 1 UPC with a new organism, 10 (1.4%) had ≥ 2 UPCs of the same organism, and 2 (0.2%) had ≥ 2 UPCs with different organisms. RESULTS: Postoperative antibiotics were prescribed to 114 (16.5%) patients - 13 (26.5%) with 1 UPC, 6 (60.0%) with ≥ 2 UPCs of the same organism, and 0 (0.0%) of patients who had ≥ 2 UPCs of different organisms. There were no differences in infection-free survival at 5 years between patients who had sterile cultures and 1 UPC (96 versus 89%; P = 0.39) nor between sterile cultures and ≥ 2 UPCs of different organisms (96 versus 100%; P < 0.72). However, patients who had ≥ 2 UPCs of the same organism had significantly worse infection-free survival at 5 years compared to patients who had sterile cultures (58 versus 96%; P < 0.001). Cox proportional hazards regression suggested that when adjusting for covariates, an American Society of Anesthesiologists classification of ≥ 3 (hazard ratio [HR] = 3.1; P = 0.007), ≥ 2 UPCs of the same organism (HR = 11.0; P < 0.001), 1 UPC (HR = 4.2; P = 0.018), and arTKA with hinge constructs (HR = 4.1; P = 0.008) were associated with increased risk of re-revision for PJI. CONCLUSION: Patients who had 1 UPC or ≥ 2 UPCs with different organisms had similar infection-free survival at 5 years as patients who had sterile cultures. However, patients who had ≥ 2 UPCs of the same organism had significantly worse infection-free survival at five years. Overall, 1 UPC or ≥ 2 UPCs of the same organism at the time of arTKA may suggest the patient is at higher risk of re-revision for PJI. More studies are needed to determine what interventions can be implemented to mitigate this risk.

The relationship between pseudotumours and infected complications in patients who have undergone metal-on-metal total hip arthroplasty.

Aims: This study aims to assess the relationship between history of pseudotumour formation secondary to metal-on-metal (MoM) implants and periprosthetic joint infection (PJI) rate, as well as establish ESR and CRP thresholds that are suggestive of infection in these patients. We hypothesized that patients with a pseudotumour were at increased risk of infection. Methods: A total of 1,171 total hip arthroplasty (THA) patients with MoM articulations from August 2000 to March 2014 were retrospectively identified. Of those, 328 patients underwent metal artefact reduction sequence MRI and had minimum two years' clinical follow-up, and met our inclusion criteria. Data collected included demographic details, surgical indication, laterality, implants used, history of pseudotumour, and their corresponding preoperative ESR (mm/hr) and CRP (mg/dl) levels. Multivariate logistic regression modelling was used to evaluate PJI and history of pseudotumour, and receiver operating characteristic curves were created to assess the diagnostic capabilities of ESR and CRP to determine the presence of infection in patients undergoing revision surgery. Results: The rate of PJI for all identified MoM THAs was 3.5% (41/1,171), with a mean follow-up of 10.9 years (2.0 to 20.4). Of the patients included in the final cohort, 8.2% (27/328) had PJI, with a mean follow-up of 12.2 years (2.3 to 20.4). Among this cohort, 31.1% (102/328) had a history of pseudotumour. The rate of PJI in these patients was 14.7% (15/102), which was greater than those without pseudotumour, 5.3% (12/226) (p = 0.008). Additionally, logistic regression analysis showed an association between history of pseudotumour and PJI (odds ratio 4.36 (95% confidence interval 1.77 to 11.3); p = 0.002). Optimal diagnostic cutoffs for PJI in patients with history of pseudotumour versus those without were 33.1 mm/hr and 24.5 mm/hr for ESR and 7.37 mg/dl and 1.88 mg/dl for CRP, respectively. Conclusion: Patients with history of pseudotumour secondary to MoM THA had a higher likelihood of infection than those without. While suspicion of infection should be high for these patients, ESR and CRP cutoffs published by the European Bone and Joint Infection Society may not be appropriate for patients with a history of pseudotumour, as ESR and CRP levels suggestive of PJI are likely to be higher than for those without a pseudotumour. Additional investigation, such as aspiration, is highly recommended for these patients unless clinical suspicion and laboratory markers are low.

Risk Factors of Failure to Discharge Before "Two Midnights" in Outpatient-Designated Total Hip Arthroplasty.

INTRODUCTION: The Centers for Medicare and Medicaid Services removed total hip arthroplasty (THA) from the inpatient-only list but continued to classify admissions as inpatient if they include two midnights, complicating care if an outpatient THA requires extended hospitalization. This study evaluates risk factors of patients undergoing outpatient-designated THA with a length of stay (LOS) ≥ 2 days. METHODS: A total of 17,063 THA procedures designated as outpatient in the National Surgical Quality Improvement Program database between 2015 and 2020 were stratified by LOS < 2 days (n = 2,294, 13.4%) and LOS ≥ 2 days (n = 14,765, 86.6%). Demographics, comorbidities, and outcomes were compared by univariate analysis. Multivariable regression analysis identified predictors of LOS ≥ 2 days. RESULTS: Outpatients with extended LOS were older (mean 65.3 vs. 63.5 years; P < 0.01); were more likely to have body mass index (BMI) > 35 (24.0 vs. 17.8%; P < 0.01); and had higher incidences of smoking (15.1% vs. 10.3%; P < 0.01), diabetes (15.4% vs. 9.9%; P < 0.01), chronic obstructive pulmonary disease (4.4% vs. 2.3%; P < 0.01), and hypertension (57.6% vs. 49.2%; P < 0.01). Patients with LOS ≥ 2 days had a higher incidence of surgical site infection (P < 0.01), hospital readmission (P < 0.01), and revision surgery (P < 0.01) over 30 days. Multivariable analysis demonstrated advanced age, female sex, African American race, Hispanic ethnicity, diabetes, smoking, and hypertension were independent risk factors for LOS ≥ 2 days. CONCLUSION: Despite removal from the inpatient-only list, a subset of outpatient THA remains at risk of an extended LOS. This study informs surgeons on the relevant risk factors of extended stay, enabling early inpatient preauthorization.

The Removal of Total Knee Arthroplasty From the Inpatient-Only List has Improved Patient Optimization.

INTRODUCTION: On January 1, 2018, the Centers for Medicare and Medicaid Services removed total knee arthroplasty (TKA) from the inpatient-only (IPO) list, expanding outpatient TKA (oTKA) to include patients with insurance coverage through their programs. These regulatory changes reinforced the need for preoperative optimization to ensure a safe and timely discharge after surgery. This study compared modifiable preoperative optimization metrics in patients who underwent oTKA pre-IPO and post-IPO removal. The authors hypothesized that patients post-IPO removal would demonstrate improvement in the selected categories. METHODS: Outpatient TKA in a national database was identified and stratified by surgical year (2015 to 2017 versus 2018 to 2020). Preoperative optimization thresholds were established for the following modifiable risk factors: albumin, hematocrit, sodium, smoking, and body mass index. The percentage of patients who did not meet thresholds pre-IPO and post-IPO removal were compared. RESULTS: In total, 2,074 patients underwent oTKA from 2015 to 2017 compared with 46,480 from 2018 to 2020. Patients undergoing oTKA after IPO removal were significantly older (67.0 versus 64.4 years; P < 0.01). A lower percentage of patients in the post-IPO cohort fell outside the threshold for all modifiable risk factors. Results were significant for preoperative sodium (10.7% versus 8.8%; P < 0.01), body mass index (12.4% versus 11.0% P = 0.05), and smoking history (9.9% versus 6.6%; P < 0.01). CONCLUSION: Outpatient TKA has increased considerably post-IPO removal. As this regulatory change has allowed older patients with increased comorbidities to undergo oTKA, the need for appropriate preoperative optimization has increased. The current data set demonstrates that surgeons have improved preoperative optimization efforts for select modifiable risk factors.

Continuation of Oral Antidiabetic Medications Was Associated With Better Early Postoperative Blood Glucose Control Compared to Sliding Scale Insulin After Total Knee Arthroplasty.

BACKGROUND: This study evaluated blood glucose (BG), creatinine levels, metabolic issues, length of stay (LOS), and early postoperative complications in diabetic primary total knee arthroplasty (TKA) patients. It examined those who continued home oral antidiabetic medications and those who switched to insulin postoperatively. The hypothesis was that continuing home medications would lead to lower BG levels without metabolic abnormalities. METHODS: Patients who had diabetes who underwent primary TKA from 2013 to 2022 were evaluated retrospectively. Diabetic patients who were not on home oral antidiabetic medications or who were not managed as an inpatient postoperatively were excluded. Patient demographics and laboratory tests collected preoperatively and postoperatively as well as 90-day emergency department visits and 90-day readmissions, were pulled from electronic records. Patients were grouped based on inpatient diabetes management: continuation of home medications versus new insulin coverage. Acute postoperative BG control, creatinine levels, metabolic abnormalities, LOS, and early postoperative complications were compared between groups. Multivariable regression analyses were performed to measure associations. RESULTS: A total of 867 primary TKAs were assessed; 703 (81.1%) patients continued their home oral antidiabetic medications. Continuing home antidiabetic medications demonstrated lower median maximum inpatient BG (180.0 mg/dL versus 250.0 mg/dL; P < .001) and median average inpatient BG (136.7 mg/dL versus 173.7 mg/dL; P < .001). Logistic regression analyses supported the presence of an association (odds ratio = 17.88 [8.66, 43.43]; P < .001). Proportions of acute kidney injury (13.5 versus 26.7%; P < .001) were also lower. There was no difference in relative proportions of metabolic acidosis (4.4 versus 3.7%; P = .831), LOS (2.0 versus 2.0 days; P = .259), or early postoperative complications. CONCLUSIONS: Continuing home oral antidiabetic medications after primary TKA was associated with lower BG levels without an associated worsening creatinine or increase in metabolic acidosis. LEVEL III EVIDENCE: Retrospective Cohort Study.

Inertial Sensor Gait Analysis of Trendelenburg Gait in Patients Who Have Hip Osteoarthritis.

BACKGROUND: Gait abnormalities such as Trendelenburg gait (TG) in patients who have hip osteoarthritis (OA) have traditionally been evaluated using clinicians' visual assessment. Recent advances in portable inertial gait sensors offer more sensitive, quantitative methods for gait assessment in clinical settings. This study sought to compare sensor-derived metrics in a cohort of hip OA patients when stratified by clinical TG severity. METHODS: There were 42 patients who had hip OA and were grouped by TG severity (mild, moderate, and severe) through visual assessment by a single arthroplasty surgeon who had > 30 years of experience. After informed consent, wireless inertial sensors placed at the midpoint of the intercristal line collected gait parameters including pelvic shift, support time, toe-off symmetry, impact, and cadence. Clinical data on hip strength, range of motion, and Kellgren-Lawrence grade were collected. RESULTS: Worsening TG severity had a higher mean Kellgren-Lawrence grade (2.5 versus 3.2 versus 3.4; P = .014) and reduced passive hip abduction (P = .004). Severe TG group demonstrated predominantly contralateral pelvic shift (n = 9 of 10, 90.0%), while ipsilateral shift was more frequently detected in moderate (n = 10 of 18, 55.6%) and mild groups (n = 9 of 14, 64.3%; P = .021). Contralateral single support time bias was greatest in severe TG (35.7% versus 50.0 versus 90.0%; P = .027). Asymmetric toe-off, impact, and support times were observed in all groups. CONCLUSIONS: Traditional understanding of TG is that truncal shift occurs to the ipsilateral side. Using sensor-based measurements, the present study demonstrates a shift of the weight-bearing axis toward the contralateral side with increasing TG severity, which has not been previously described. Inertial sensors are feasible, quantitative gait measuring tools, and may reveal subtle patterns not readily discernible by traditional methods.

Risk factors for failure after rotational muscle flap coverage for prosthetic knee infections.

INTRODUCTION: Soft tissue defects are a devastating complication of prosthetic joint infections (PJI) after total knee arthroplasty (TKA). Rotational flaps are commonly utilized to address these defects with variable reports of success. This study aimed to identify predictors of poor outcomes in rotational muscle flap placement after prosthetic knee infections. The authors hypothesized that outcomes may vary based on infecting pathogen and treatment characteristics. METHODS: 44 cases of rotational muscle flaps for prosthetic knee infection were retrospectively evaluated at a tertiary referral hospital from 2007 to 2020. Muscle flap types included 39 medial and four lateral gastrocnemius, and one anterior tibialis. Minimum follow-up was 1 year (median: 3.4 years). Primary outcome was flap-related complications. Secondary outcomes included recurrent infection requiring additional surgery, final joint outcomes, and mortality. RESULTS: One-year complication-free flap survivorship was 83.9%, recurrent infection-free survivorship was 65.7%, and amputation-free survivorship was 79%. Multivariable cox regression revealed that rheumatoid arthritis diagnosis (HR: 3.4; p = .028) and methicillin-resistant Staphylococcus aureus-positive culture (HR: 4.0; p = .040) had increased risk, while Coagulase-negative Staphylococcus infections had reduced risk for recurrent or persistent infection (HR: 0.2; p = .023). Final joint outcome was retained TKA implant in 18 (40.9%), amputation in 15 (34.1%) patients, and definitive treatment with articulating spacer in 10 (22.7%). 5-years survivorship from death was 71.4%. CONCLUSION: Rotational muscle flaps for soft tissue coverage of the knee are often performed in limb salvage situations with poor survivorship from flap complications, reinfections, and amputation. When considering surgical options for limb salvage, patients should be counseled on these risks.

Does Medically Supervised Weight Loss Prior to Total Knee Arthroplasty Improve Patient-Reported Pain and Physical Function?

BACKGROUND: Weight loss is commonly recommended before total knee arthroplasty (TKA) despite inconsistent evidence for better outcomes. This study sought to examine the impacts of preoperative weight loss on patient-reported and adverse outcomes among TKA patients supervised by a medical weight management clinic. METHODS: This study retrospectively analyzed patients who underwent medical weight management supervision within 18 months before TKA comparing patients who did and did not have clinically relevant weight loss. Preoperative body mass indices, demographics, Patient-Reported Outcomes Measurement Information System physical function and pain interference scores, pain intensity scores, and adverse outcomes were extracted. Multivariable linear regressions were performed to determine if preoperative weight loss correlated with patient-reported outcomes after controlling for confounders. RESULTS: There were 90 patients, 75.6% women, who had a mean age of 65 years (range, 42-82) and were analyzed. There were 51 (56.7%) patients who underwent clinically relevant weight loss with a mean weight loss of 10.4% and experienced no difference in adverse outcomes. Preoperative weight loss predicted significantly improved 3-month postoperative physical function (ß = 15.2 [13.0-17.3], P < .001), but not pain interference (ß = -18.9 [-57.1-19.4], P = .215) or pain intensity (ß = -1.8 [-4.9-1.2], P = .222) scores. CONCLUSION: We found that medically supervised preoperative weight loss predicted improvement in physical function 3 months after TKA. This weight loss caused no major adverse effects. Further research is needed to understand the causal relationships between preoperative weight loss, medical supervision, and outcome after TKA and to elucidate potential longer-term benefits in a larger sample.

Assessing the Diagnostic Accuracy of Next-Generation Sequencing in Patients With Antibiotic Spacers Before Reimplantation.

Use of molecular sequencing modalities in periprosthetic joint infection diagnosis and organism identification has gained popularity recently. To date, there is no diagnostic test that reliably predicts infection eradication in patients with antibiotic spacers. The purpose of this study was to compare the diagnostic accuracy of next-generation sequencing (NGS), culture, the Musculoskeletal Infection Society (MSIS) criteria, and the criteria by Parvizi et al in patients with antibiotic spacers. In this retrospective study, aspirate or tissue samples were collected from 38 knee and 19 hip antibiotic spacers for routine diagnostic workup for the presence of persistent infection and sent to the laboratory for NGS. The kappa statistic along with statistical differences between diagnostic studies were calculated using the chi-square test for categorical data. The kappa coefficient for agreement between NGS and culture was 0.27 (fair agreement). The percentages of positive and negative agreement were 22.8% and 42.1%, respectively, with a total concordance of 64.9%. There were 12 samples that were culture positive and NGS negative. Eight samples were NGS positive but culture negative. The kappa coefficient was 0.42 (moderate agreement) when comparing NGS with MSIS criteria. In our series, NGS did not provide sufficient agreement compared with culture or MSIS criteria in the setting of an antibiotic spacer. A reliable diagnostic indicator for reimplantation has yet to be identified. [Orthopedics. 2024;47(1);46-51.].

Cost Savings Associated With Implementing 4 Total Joint Replacement Electronic Clinical Quality Measures Nationally: 2020-2040.

BACKGROUND: Digital transformation using widely available electronic data is a key component to improving health outcomes and customer choice and decreasing cost and measurement burden. Despite these benefits, existing information on the potential cost savings from electronic clinical quality measures (eCQMs) is limited. METHODS: We assessed the costs of implementing 4 eCQMs related to total hip and/or total knee arthroplasty into electronic health record systems across healthcare systems in the United States. We used published literature and technical expert panel consultation to calculate low-, mid-, and high-range hip and knee arthroplasty surgery projections, and used empirical testing, literature, and technical expert panel consultation to develop an economic model to assess projected cost savings of eCQMs when implemented nationally. RESULTS: Low-, mid-, and high-range projected cost savings for year's 2020, 2030, and 2040 were calculated for 4 orthopedic eCQMs. Mid-range projected cost savings for 2020 ranged from $7.9 to $31.9 million per measure per year. A breakeven of between 0.5% and 5.1% of adverse events (measure dependent) must be averted for cost savings to outweigh implementation costs. CONCLUSIONS: All measures demonstrated potential cost savings. These findings suggest that eCQMs have the potential to lower healthcare costs and improve patient outcomes without adding to physician documentation burden. The Centers for Medicare and Medicaid Services' investment in eCQMs is an opportunity to reduce adverse outcomes and excess costs in orthopedics.

Subsidence of All-Polyethylene Tibial Components Used in Unicondylar Knee Arthroplasty: A Cohort Study.

INTRODUCTION: Unicompartmental designs and techniques have been developed to preserve bone stock and minimize soft tissue trauma. Early modern designs and techniques have been introduced with little support in the peer-reviewed literature. MATERIAL AND METHODS: From October 2002 to May 2004, 64 consecutive DePuy Preservation unicondylar knee arthroplasties (UKAs) were performed in 56 patients. Two patients died of unrelated consequences, leaving 62 UKAs for review (55 medial, 7 lateral). All procedures were performed through a quadriceps-sparing approach. All components were cemented, including an all polyethylene tibial component. Clinical and radiographic follow-up data were reviewed and analyzed. RESULTS: At an average follow-up of 2.5 years, six (11%) of the medial tibial components have subsided. Of these, four had moderate-to-severe pain, one did require a revision to a total knee arthroplasty (TKA), and another did stabilize. An additional two patients continued to have knee pain (one requiring conversion to TKA), leaving a total of 55 UKAs (89%) functioning well at early follow-up. Additional complications have included four deep vein thromboses, three cardiac issues following the index procedure, one surgical site infection, one intraoperative medial femoral condyle fracture, and one reoperation for loose cement fragments. CONCLUSION: This study demonstrates a high rate of subsidence for all-polyethylene tibial components used in UKA, resulting in pain and failure of the arthroplasty. Despite the less invasive approach, we found complications that are usually associated with TKA surgery as well as those unique to UKA.

Does Preoperative Weight Loss Within 6 Months or 1 Year Change the Risk of Adverse Outcomes in Total Knee Arthroplasty by Initial Body Mass Index Classification?

BACKGROUND: High body mass index (BMI) is associated with adverse outcomes after total knee arthroplasty (TKA). Thus, many patients are advised to lose weight before TKA. This study examined how weight loss before TKA is associated with adverse outcomes depending on patients' initial BMI. METHODS: This was a retrospective study of 2,110 primary TKAs at a single academic center. Data on preoperative BMIs, demographics, comorbidities, and incidences of revision or prosthetic joint infection (PJI) were obtained. Multivariable logistic regressions segmented by patients' initial (1-year preoperative) BMI classifications were performed to determine if a > 5% BMI decrease from 1 year or 6 months preoperatively predicted PJI and revision controlling for patient age, race, sex, and Elixhauser comorbidity index. RESULTS: Preoperative weight loss did not predict adverse outcomes for patients who had Obesity Class II or III. 6-month weight loss had greater odds of adverse outcomes than 1-year weight loss and most significantly predicted the occurrence of 1-year PJI (adjusted odds ratio: 6.55, P < .001) for patients who had Obesity Class 1 or lower. CONCLUSION: This study does not show a statistically significant effect to patients who had Obesity Class II and III losing weight preoperatively with respect to PJI or revision. For patients who have Obesity Class I or lower pursuing TKA, future research should consider potential risks associated with weight loss. Further study is needed to determine if weight loss can be implemented as a safe and effective risk reduction strategy for specific BMI classes of TKA patients.

Evaluation of anterior translation in total knee arthroplasty utilizing stress radiographs.

BACKGROUND: Flexion instability is a common cause for revision after total knee arthroplasty (TKA); however, little objective criteria exist to determine excessive laxity in flexion. This study sought to determine the reliability of stress radiographs for flexion laxity using manual stress as well as a commercially available flexion stress device, with the hypothesis that a commercially available force device would provide increased translation compared to manual stress, and radiographic measurements would be reproducible. METHODS: Ten patients who previously underwent TKA with non-hinged components were prospectively and consecutively enrolled at a single center to undergo stress radiographs. Three lateral radiographs with the knee at 90° of flexion were obtained for each patient: rest, commercial stress device at 150N, and manual stress. Calibrated radiographs were evaluated by two raters, and inter-rater and intra-rater reliability were determined using intraclass correlation coefficients (ICC). RESULTS: Ten patients (seven female) with mean age 72 (range 55-82) years and average duration from surgery 36 (range 12-96) months were evaluated. The commercial stress device provided significantly less anterior translation than manual stress (- 0.3 mm vs. 3.9 mm; p < 0.01). Two patients reported pain with use of the stress device. Inter-observer reliability of measurements was good for commercial stress (ICC = 0.86) and excellent for manual stress (ICC = 0.94). Eighty-five percent of measurements were within 1 mm between observers. Intra-observer reliability of measurements was good to excellent for both the stress device and manual stress. CONCLUSIONS: Lateral stress radiographs may assist in the objective evaluation of flexion instability. A commercially available product provided less translation than manual stress; however, measurements were reliable and reproducible between observers. Further research is required to correlate translation with stress radiographs to patient outcomes following revision arthroplasty.

Periarticular Injection in Total Knee Arthroplasty.

Optimal pain management after total knee arthroplasty (TKA) can expedite postoperative recovery, improve perioperative outcomes, and increase patient satisfaction. Periarticular injections (PAIs) have become increasingly used to improve pain management after TKA. Similar to peripheral nerve blocks, the use of intraoperative PAIs can lower pain scores and expedite discharge from the hospital. However, there is notable variability in the ingredients and administration techniques of PAIs. Currently, no standard of care exists for PAIs, especially in the setting of adjuvant peripheral nerve blocks. This study seeks to evaluate the ingredients, administration techniques, and outcomes of PAIs used during TKA.

A Permanent Articulating Spacer Versus Two-Stage Exchange for Chronic Periprosthetic Joint Infection: A Propensity Score-Matched Study.

BACKGROUND: Although 2-stage revision has been proposed as gold standard for periprosthetic joint infection treatment, limited evidence exists for the role of articulating spacers as definitive management. The purpose of this study was to compare clinical outcomes and costs associated with articulating spacers (1.5-stage) and a matched 2-stage cohort. METHODS: A retrospective review was performed for patients who had chronic periprosthetic joint infections after total knee arthroplasty defined by Musculoskeletal Infection Society criteria and were matched via propensity score matching using cumulative Musculoskeletal Infection Society scores and a comorbidity index. Patients who maintained an articulating spacer (cemented cobalt-chrome femoral component and all-poly tibia) were included in the 1.5-stage cohort. Patients who underwent a 2-stage reimplantation procedure were included in the 2-stage cohort. Outcomes included visual analog scale pain scores, 90-day emergency department visits, 90-day readmission, unplanned reoperation, reinfection, as well as cost at 1 and 2-year intervals. A total of 116 patients were included for analyses. RESULTS: The 90-day pain scores were lower in the 1.5-stage cohort compared to the 2-stage cohort (2.9 versus 4.6, P = .0001). There were no significant differences between readmission and reoperation rates. Infection clearance was equivalent at 79.3% for both groups. Two-stage exchange demonstrated an increased cost difference of $26,346 compared to 1.5-stage through 2 years (P = .0001). Regression analyses found 2 culture-positive results with the same organism decreased the risk for reinfection [odds ratio: 0.2, 95% confidence interval 0.04-0.8, P = .03]. CONCLUSION: For high-risk candidates, articulating spacers can preserve knee function, reduce morbidity from second-stage surgery, and lower the costs with similar rates of infection clearance as 2-stage exchange. LEVEL OF EVIDENCE: Level III, therapeutic study.

D-Dimer, Erythrocyte Sedimentation Rate, and C-Reactive Protein Sensitivities for Periprosthetic Joint Infection Diagnosis.

BACKGROUND: There is contradicting evidence on the diagnostic value of inflammatory biomarkers for periprosthetic joint infection (PJI). We sought to quantify the sensitivity of D-dimer for acute and chronic PJI diagnosis and evaluate D-dimer lab values in the 90-day postoperative window in a control cohort of primary joint arthroplasty patients for comparison. METHODS: An institutional database was queried for patients undergoing revision procedures for PJI after total hip arthroplasty (THA) and total knee arthroplasty (TKA) from 2014 to present. CRP, ESR, and D-dimer were collected within 90 days pre and postoperatively and sensitivities for the diagnosis of PJI were calculated. The control group included patients who underwent a negative diagnostic workup for deep venous thrombosis (DVT) or pulmonary embolus (PE) and had a D-dimer lab collected within 90 days postoperatively from primary total joint arthroplasty (TJA). RESULTS: A total of 604 PJI patients were identified, and 81 patients had D-dimer, ESR, and CRP collected. There were 50/81 acute PJI patients and 31/81 chronic PJI patients who had median D-dimer values of 2,136.5 ng/mL [interquartile range (IQR): 1,642-3,966.5] and 3,336 ng/mL [IQR: 1,976-5,594]. Only the chronic PJI group had significantly higher D-dimer values when compared to the control cohort (P = .009). The sensitivity of D-dimer was calculated to be 92% and 93.5% in the acute and chronic PJI groups, respectively. CONCLUSION: Serum D-dimer may not have high diagnostic utility for acute PJI, especially in the setting of recent surgery; however, it still may be useful for patients who have chronic PJI.

A Validated Pre-operative Risk Prediction Tool for Extended Inpatient Length of Stay Following Primary Total Hip or Knee Arthroplasty.

BACKGROUND: As value-based reimbursement models mature, understanding the potential trade-off between inpatient lengths of stay and complications or need for costly postacute care becomes more pressing. Understanding and predicting a patient's expected baseline length of stay may help providers understand how best to decide optimal discharge timing for high-risk total joint arthroplasty (TJA) patients. METHODS: A retrospective review was conducted of 37,406 primary total hip (17,134, 46%) and knee (20,272, 54%) arthroplasties performed at two high-volume, geographically diverse, tertiary health systems during the study period. Patients were stratified by 3 binary outcomes for extended inpatient length of stay: 72 + hours (29%), 4 + days (11%), or 5 + days (5%). The predictive ability of over 50 sociodemographic/comorbidity variables was tested. Multivariable logistic regression models were created using institution #1 (derivation), with accuracy tested using the cohort from institution #2 (validation). RESULTS: During the study period, patients underwent an extended length of stay with a decreasing frequency over time, with privately insured patients having a significantly shorter length of stay relative to those with Medicare (1.9 versus 2.3 days, P < .0001). Extended stay patients also had significantly higher 90-day readmission rates (P < .0001), even when excluding those discharged to postacute care (P < .01). Multivariable logistic regression models created from the training cohort demonstrated excellent accuracy (area under the curve (AUC): 0.755, 0.783, 0.810) and performed well under external validation (AUC: 0.719, 0.743, 0.763). Many important variables were common to all 3 models, including age, sex, American Society of Anesthesiologists (ASA) score, body mass index, marital status, bilateral case, insurance type, and 13 comorbidities. DISCUSSION: An online, freely available, preoperative clinical decision tool accurately predicts risk of extended inpatient length of stay after TJA. Many risk factors are potentially modifiable, and these validated tools may help guide clinicians in preoperative patient counseling, medical optimization, and understanding optimal discharge timing.

Erratum to 'Corynebacterium Total Hip and Knee Arthroplasy Prosthetic Joint Infections' [Arthroplasty Today 6 (2020) 163-168].

[This corrects the article DOI: 10.1016/j.artd.2020.03.008.].

Testing a Novel Inpatient Respiratory Depression Electronic Clinical Quality Measure (eCQM) for Orthopedic Practice in Two Large U.S. Health Systems.

The objective of this study was to assess the feasibility of using an electronic clinical quality measure (eCQM) to assess inpatient respiratory depression rates following elective primary total hip or total knee arthroplasty using data routinely collected in electronic health records. Measure testing was conducted at two large urban, academic health systems - Mass General Brigham and a geographically distant system in southern U.S. The risk-adjusted inpatient respiratory depression rates were 3.83 and 2.73% for the two health systems, respectively. Clinician group rates ranged from 1.40 to 4.35%, demonstrating opportunity for improvement. Both the data and measure specifications showed strong reliability and validity to allow for calculation of accurate and comparable rates of inpatient respiratory depression.