Local Soft-Tissue Thickness vs. Body Mass Index as Predictors of Complications After Total Knee or Hip Arthroplasty: A Literature Review.

¼ Body mass index (BMI) is a nonspecific measure of general fat composition that demonstrates little conclusive or definitive association with surgical site complications after total knee and total hip arthroplasty.¼ Quantifying soft-tissue thickness (STT) around the joint of interest has shown positive correlations with complications and is arguably a better predictor than BMI.¼ In this literature review, 14 articles (7 discussing hips and 7 discussing knees) discussing the association of STT, BMI, and surgical site complications after total hip and knee arthroplasty were scrutinized and summarized to present relevant information necessary to compare STT with BMI.¼ Five of the 7 studies involving hips and 4 of the 7 studies involving knees show a positive relationship between STT and outcomes including complications and infection, with some claiming STT as a stronger predictor of surgery site problems than BMI.¼ Since many variables, such as STT measurement technique, surgical outcomes, sample sizes, and surgical approach, varied between the studies, definitive inferences are difficult to make and future studies of bigger sample size and higher power should focus on the described measurement techniques.

Morbidly Obese Patients Undergoing Unicompartmental Knee Arthroplasty Compared to Total Knee Arthroplasty: A Retrospective Case-Controlled Analysis.

BACKGROUND: In this study, we assess the effects that morbid obesity (body mass index (BMI) ≥ 40) has on: (1) Ninety-day medical complications and readmission rates; (2) costs of care and lengths of stay (LOS); and (3) 2-year implant complications in patients undergoing unicompartmental knee arthroplasty (UKA) versus total knee arthroplasty (TKA). METHODS: A retrospective query of TKA and UKA patients were identified using a national database. Morbidly obese UKA patients were matched 1:5 to morbidly obese TKA patients by demographic and comorbidity profiles. Subgroup analyses were conducted using the same process between morbidly obese UKA patients and BMI <40 TKA patients, as well as to BMI <40 UKA patients. RESULTS: Morbidly obese patients who underwent UKA had significantly fewer medical complications, readmissions, and periprosthetic joint infections than TKA patients; however, UKA patients had greater odds of mechanical loosening (ML). The TKA patients had significantly longer LOS (3.0 versus 2.4 days, P < .001), as well as significantly greater costs of care than UKA patients ($12,869 versus $7,105). Morbidly obese UKA patients had similar rates of medical complications, and significantly lower readmissions, decreased LOS, and decreased costs when compared to TKA patients who had a BMI <40. CONCLUSION: In patients who have morbid obesity, complications were decreased in UKA compared to TKA. Moreover, morbidly obese UKA patients had lower medical utilizations and similar complication rates when compared to TKA patients with the recommended cutoff of BMI <40. However, UKA patients had greater rates of ML than TKA patients. A UKA may be an acceptable treatment option for unicompartmental osteoarthritis in morbidly obese patients.

Does Performance of D-Dimer for Diagnosis of Periprosthetic Joint Infection Change With the Virulence of Infecting Organism?

BACKGROUND: The impact of the organism virulence on diagnostic accuracy of D-Dimer for periprosthetic joint infection (PJI) is unknown. Our objective was to assess if the performance of D-Dimer in PJI diagnosis changes with the virulence of the organism(s). METHODS: We retrospectively reviewed 143 consecutive revision total hip arthroplasties/total knee arthroplasties with D-Dimer ordered preoperatively. Operations were performed by 3 surgeons at a single institution (November 2017 through September 2020). There were 141 revisions with complete 2013-International Consensus Meeting-criteria initially included. This criteria was used to classify revisions as aseptic versus septic. Culture-negative septic revisions (n = 8) were excluded, and 133 revisions (47-hips/86-knees; 67-septic/66-aseptic) were analyzed. Based on culture results, septic-revisions were categorized into 'low-virulence (LV/n = 40)' or 'high-virulence (HV/n = 27)'. The D-Dimer threshold (850-ng/mL) was tested against 2013-International Consensus Meeting-criteria ("standard") in identifying septic-revisions (LV/HV) from aseptic-revisions. Sensitivity, specificity, and positive predictive values/negative predictive values (NPV) were determined. Receiver-operating-characteristic-curve-analyses were performed. RESULTS: Plasma D-Dimer showed high sensitivity (97.5%) and NPV (95.4%) in LV septic cases, which appeared to reduce by about 5% in HV septic cases (sensitivity = 92.5% and NPV = 91.3%). However, this marker had poor overall accuracy (LV = 57%; HV = 49.4%), low specificity (LV and HV = 31.8%), and positive predictive values (LV = 46.4%; HV = 35.7%) to diagnose PJI. The area under the curve was 0.647 and 0.622 in LV and HV versus aseptic revisions, respectively. CONCLUSION: D-Dimer performs poorly to identify septic from aseptic revisions in the setting of LV/HV infecting organisms alike. However, it shows high sensitivity for PJI diagnosis in cases of LV organisms which might be missed by most diagnostic tests.

Is a Higher Number of Total Hip and Knee Arthroplasty Revisions Associated With Increased Mortality?

BACKGROUND: It remains uncertain whether patients who undergo numerous total hip arthroplasty (THA) and/or knee arthroplasty (TKA) revisions exhibit decreased survival. Therefore, we sought to determine if the number of revisions per patient was a mortality predictor. METHODS: We retrospectively reviewed 978 consecutive THA and TKA revision patients from a single institution (from January 5, 2015-November 10, 2020). Dates of first-revision or single revision during study period and of latest follow-up or death were collected, and mortality was assessed. Number of revisions per patient and demographics corresponding to first revision or single revision were determined. Kaplan-Meier, univariate, and multivariate Cox-regressions were utilized to determine mortality predictors. The mean follow-up was 893 days (range, 3-2,658). RESULTS: Mortality rates were 5.5% for the entire series, 5.0% among patients who only underwent TKA revision(s), 5.4% for only THA revision(s), and 17.2% for patients who underwent TKA and THA revisions (P = .019). In univariate Cox-regression, number of revisions per patient was not predictive of mortality in any of the groups analyzed. Age, body mass index (BMI), and American Society of Anesthesiologists (ASA) were significant mortality predictors in the entire series. Every 1 year of age increase significantly elevated expected death by 5.6% while per unit increase in BMI decreased the expected death by 6.7%, ASA-3 or ASA-4 patients had a 3.1 -fold increased expected death compared to ASA-1 or ASA-2 patients. CONCLUSION: The number of revisions a patient underwent did not significantly impact mortality. Increased age and ASA were positively associated with mortality but higher BMI was negatively associated. If health status is appropriate, patients can undergo multiple revisions without risk of decreased survival.

The Learning Curve of Reaching the Planned Limb Alignment in Robotic-Arm-Assisted Total Knee Arthroplasty.

Evidence on the learning curve associated with robotic-arm-assisted total knee arthroplasty (ra-TKA) is scarce and mostly based on operative time. Thus, the objective of this study was to assess a surgeon's learning experience based on accuracy to reach planned limb alignment and its impact on surgical-characteristics, limb-alignment, and perioperative-outcomes. A retrospective chart review was conducted on a consecutive series of 204 primary ra-TKAs (patients), performed by a single surgeon in a single institution (3/7/2018-to-6/18/2019). Cumulative summation control sequential analysis was used for the assessment of the learning curve using accuracy of reaching the planned limb alignment establishing that surgeries had an initial-learning-phase, followed by a second-consolidation-phase. Baseline demographics, operative/tourniquet times, prosthesis type, and limb alignment were compared between these two phases. Length of stay, discharge disposition, complications, reoperation/readmission (90 days), and total morphine equivalents (TMEs) prescribed were compared between phases. Independent sample t-tests, and chi-squared analyses were performed. ra-TKA demonstrated a learning curve of 110 cases for reaching planned limb alignment (p = 0.012). Robotic experience resulted in significantly more proportion of knees in neutral-axis postoperatively (p = 0.035) and significant reduction in TMEs prescribed (p = 0.04). The mean operative and tourniquet time were found to be significantly lower in second-phase versus the first-phase (p for both < 0.0001). ra-TKA has a significant learning curve in clinical practice. A surgeon can reach the planned limb alignment with increased accuracy over time (110-cases). Progressive robotic learning and associated operative time efficiency can lead to significantly lower opioid consumption in patients undergoing TKA.

Nephrotoxicity Related to Antibiotic-Loaded Spacers in a 2-Stage Revision for Periprosthetic Joint Infection.

Antibiotic-loaded bone cement (ALBC) spacers are the mainstay in 2-stage revision, but antibiotics (vancomycin plus aminoglycosides) may undergo systemic absorption, resulting in acute kidney injury (AKI). Data on spacer antibiotics are heterogeneous. Our objective was to review risk factors for AKI and dosage of antibiotics. Significant AKI risk factors were antibiotic concentration greater than 3 or 3.6 g per cement batch, comorbidities, chronic kidney disease, and hypovolemia. Despite similar spacer antibiotic dosing, there was remarkable variability in serum concentrations. To err on the side of caution, it appears that antibiotic dose below 3 g per cement batch might be relatively safe until more evidence surfaces. Consideration of risk factors for AKI calls for appropriate antibiotic use in 2-stage revision. [Orthopedics. 2023;46(3):e136-e142.].

Extended Oral Antibiotic Prophylaxis After Aseptic Total Hip or Knee Arthroplasty Revisions: A Preliminary Report.

BACKGROUND: It is unknown whether extended oral antibiotic (EOA) prophylaxis reduces periprosthetic joint infection (PJI) rates after aseptic revision total hip (THA) and knee arthroplasty (TKA). The literature is scarce. Therefore, we sought to ascertain whether EOA prophylaxis decreases PJI rates after aseptic first-time revision THA and TKA when compared to standard prophylaxis. METHODS: This is a retrospective review of 328 consecutive revisions (3 surgeons, single institution, from September 27, 2017 to December 31, 2019). Preoperative 2013 Musculoskeletal Infection Society (MSIS) criteria, radiographs, and medications were reviewed. Inclusion criteria included aseptic first-time revision THA and TKA. Exclusion criteria were positive intraoperative cultures and/or histology, PJI (2013 MSIS criteria), hemiarthroplasty/partial arthroplasty revision, revision using foreign material (ie, mesh), metastatic bone disease, and intravenous antibiotics >24 hours after surgery. A total of 178 revisions were included, and 2 groups were set apart based on antibiotic prophylactic regime. The following were the groups: (1) EOA prophylaxis (>24 hours, n = 93) and (2) standard prophylaxis (≤24 hours, n = 85). Demographics, joint types, lengths of stay, skin-to-skin operative times, revision types, transfusions, discharge dispositions, and PJIs (per 2013 MSIS criteria) after the first-time revision were compared between groups. There were no significant differences in demographics. However, skin-to-skin operative time was significantly higher in the EOA group (123 minutes versus 98 minutes, P = .01). Mean follow-up was 849 days (range, 15-1,671). Statistical significance was set at a P value lower than .05. RESULTS: Postoperative PJI rates were not significantly different: 2.2% EOA prophylaxis versus 3.5% standard prophylaxis (P = .671). CONCLUSION: No significant difference was found between PJI rates between both prophylactic regimens. A large multicenter study with a larger sample size is needed to support EOA after aseptic revisions. LEVEL OF EVIDENCE: Level III.

Synovial White Blood Cell Count and Differential to Predict Successful Infection Management in a Two-Stage Revision.

BACKGROUND: An array of synovial white blood cell (WBC) count and polymorphonuclear differential (PMN%) thresholds have been reported using 2013 Musculoskeletal Infection Society (MSIS) definition which has a poor accuracy to confirm infection control before reimplantation. The workgroup of MSIS recently developed a comprehensive definition of successful infection management. Our objectives were to determine optimal thresholds for WBC count and PMN% associated with reimplantation success based on this new MSIS definition and assess if values above these thresholds indicate decreased survival time. METHODS: A retrospective review was conducted on a consecutive series of 133 two-stage hip/knee arthroplasties performed by 15 surgeons (2014-2020) at 2 institutions. All surgeries had a minimum follow-up of 1 year. The inclusion criteria included reporting of preoperative synovial fluid aspiration results. Thus, 88 were finally included. Surgical success was defined by MSIS outcome reporting tool (Tiers 1-4). Receiver operating characteristic curve analyses were performed to estimate optimal thresholds of WBC count and PMN%. A Kaplan-Meier survival analyses with log-rank test were performed. RESULTS: With area under the curve of 0.65, synovial PMN% showed superior accuracy than WBC count (area under the curve = 0.52) in determining outcome of reimplantation. The optimal PMN% threshold (62%) demonstrated sensitivity of 57% and specificity of 77%. The calculated WBC count threshold (2,733/µL) showed poor sensitivity (21%) but high specificity (95%). There was a significant difference in failure-free survival (24 months) between the cases with WBC count higher vs lower than 2,733/µL (P = .002). This was also true for PMN% at 5 months postoperatively (P = .009). CONCLUSION: WBC count (2,733/µL) shows very high specificity to confirm successful reimplantation. Both WBC count and PMN% (62%) thresholds can significantly determine reimplantation survival.

Paradoxical Behavior of Plasma d-Dimer From Explantation to Reimplantation in a Two-Stage Revision for Periprosthetic Joint Infection.

BACKGROUND: The variation of plasma d-dimer, an inflammatory marker, from pre-explantation to pre-reimplantation in two-stage revision remains unclear. Our objective was to evaluate delta-changes (Δ) in d-dimer, erythrocyte sedimentation rate (ESR), and C-reactive-protein (CRP), to ascertain whether these delta-changes are associated with the outcome of reimplantation. We hypothesized a decrease in d-dimer before reimplantation. METHODS: A retrospective review was performed on a consecutive series of 95 two-stage revisions indicated for periprosthetic joint infection. Surgeries were performed by 3 surgeons at a single institution (2018-2020). The minimum follow-up was 1 year. The inclusion criteria comprised availability of d-dimer results at pre-explantation and pre-reimplantation. As a result, only 30 reimplantations were included. Success of reimplantation was defined by Musculoskeletal Infection Society outcome reporting tool: Tier 1/Tier 2 vs Tier 3/Tier 4. Nonparametric tests and Mann-Whitney U-tests were conducted to compare Δd-dimer% (pre-explantation value - pre-reimplantation value/pre-explantation value × 100). The bootstrapped receiver operating characteristic curve analyses with 2,000 replicates of 30 cases were conducted. RESULTS: The median time between explantation and reimplantation was 86 days (interquartile range [IQR] = 77.7-138.5 days). Overall, a paradoxical median percent increase (Δd-Dimer% [INCREMENT] = 12.6%) in d-dimer was found from pre-explantation to pre-reimplantation (IQR = -28.06% to 77.3%). However, there was a percentage decrease in ESR (ΔESR% [DECREMENT] = -40%; IQR = -70.52% to 3.85%) and CRP (ΔCRP% [DECREMENT] = -75%; IQR = -87.43% to -61.34%). The changes in all these markers were not different between Musculoskeletal Infection Society Tier 1/2 and 3/4 outcomes (Δd-Dimer%, P = .146; ΔESR%, P = .946; ΔCRP%, P = .463). With area under curve of 0.676, Δd-dimer% (INCREMENT) appeared to be performing best in diagnosing infection control, which was nonexplanatory. CONCLUSION: Plasma d-dimer paradoxically increases before reimplantation while other inflammatory markers (ESR/CRP) decrease, emphasizing that surgeons shall adopt caution using d-dimer to make clinical decisions.

A major increase of thromboembolic events in total hip and knee arthroplasty patients during the COVID-19 pandemic.

OBJECTIVES: The first known COVID-19 patient in the United States was reported on 1/20/2020. Since then, we noted increased thromboembolic events among our THA/TKA patients. Therefore, we sought to determine: (1) monthly incidences of pulmonary embolism (PE)/deep vein thrombosis (DVT) before and after January/2020 and (2) thromboembolic event rates for primary and revision patients. METHODS: We retrospectively obtained from our electronic-medical-records the total monthly number of patients (December/2018-March/2021) who underwent primary or revision THA/TKA, and among them, those who had PE/DVT during each month. Monthly rates of thromboembolic events were calculated and figures were created showing rates throughout time. The cutoff month to define before and after COVID-19 was January/2020. RESULTS: During the study period, 1.6% of patients (312/19068) had PE/DVT [PE (n = 102), DVT (n = 242), both (n = 32)]. Overall rate of PE/DVT before January/2020 was 1.2% (119/9545) and it was 2.0% (193/9523) after that month. Incidences of PE/DVT on April/June/July of 2020 were 3.4%, 3%, 3.4%, respectively. A major increase, when compared to 2019 (1.3%, 1%, 1%, respectively). An unusually high rate of PE was observed on April/2020 (3.4%), more than three times the one observed in any other month. After January/2020, there was an overall major increase of PE/DVT rates, but particularly among revision patients: 6% in five different months including 11.5% on November/2020. CONCLUSION: There was a major increase of thromboembolic events among THA/TKA patients during the COVID-19 pandemic, predominantly in revision patients. Patients need counseling about this increased risk. It remains uncertain whether more aggressive thromboprophylactic regimes should be followed.

The Fate of Periprosthetic Joint Infection With Corynebacterium striatum: A Rare but Catastrophic Causative Organism.

BACKGROUND: The virulence and antibiotic resistance profile of an infecting organism have been shown to impact the outcomes of periprosthetic joint infection (PJI). However, there are no existing data on the outcomes of PJI caused by Corynebacterium striatum, a rare organism. Thus, our objective is to ascertain: (1) the treatment success of PJI caused by this rare organism and (2) patient characteristics in the setting of C striatum PJI. METHODS: A retrospective review was conducted on 741 consecutive PJIs managed at 2 hospital facilities by 8 surgeons (February 4, 2015 to October 30, 2019). The inclusion criteria represented the presence of minimum 1 positive culture of C. striatum. After excluding 1 patient with no follow-up, 15 patients were finally analyzed (9 hips/6 knees). Out of 15 patients, 9 underwent explantation with spacer insertion, 5 underwent irrigation and debridement with polyexchange (I&D), and 1 underwent Girdlestone. Out of 9 explanted patients, only 6 cleared infection and were reimplanted. The clinical staging system for PJI was determined using McPherson classification. The mean follow-ups for I&D and explantation were 35 and 23.5 months, respectively. Success of reimplantation was determined using Delphi criteria. RESULTS: Out of 5 I&D patients, 40% had to be reoperated because of persistent infection. Out of 6 explanted patients who were reimplanted, 67% failed. According to McPherson, 40% of I&D and 22.2% of explanted patients were significantly compromised hosts. CONCLUSION: C. striatum PJI has a high-treatment failure rate in patient undergoing I&D or 2-stage revision surgery. Surgeons should be aware of the difficulty controlling this PJI and advise patients accordingly.

Diagnosis and management of infected arthroplasty.

Periprosthetic joint infection (PJI) is one of the most dreadful complications after THA and TKA. Though prevention is of utmost importance in PJI management, the last decade has seen many remarkable developments in PJI diagnosis, including the introduction of several standardized PJI diagnostic definitions and biomarkers. Depending on the specific clinical situation, a myriad of treatment options for PJI are offered. Our review aims to summarize the pertinent information on PJI diagnosis and synthesize literature on the different treatment methods currently used in clinical practice. One of the most accepted PJI diagnostic definitions was developed by the Musculoskeletal Infection Society (MSIS) in 2011, later modified in the 2013 International Consensus Meeting (ICM). After promising results from studies, alpha-defensins and D-dimer were recently incorporated into the 2018 ICM PJI definition. The management choices for PJI include irrigation and debridement (DAIR), one-stage exchange arthroplasty, or two-stage exchange arthroplasty, to name a few. While two-stage revision has traditionally been the treatment of choice in the United States, there has been a growing body of evidence framing one-stage revision as a comparable choice. One-stage revision should be offered in patients meeting strict selection criteria: no sinus tract, proper soft tissue available for wound closure, appropriate bone stock, a favorable identifiable organism with encouraging antibiotic sensitivities (for cement and oral suppression later), and robust immunological status. DAIR can be considered in case of early infections with sensitive infecting organisms. Patients with multiple unsuccessful revisions or those who refuse further surgical intervention for PJI can be offered antibiotic suppression. If nothing seems to work, salvage procedures (resection arthroplasty and arthrodesis) are available as a last resort. Further research is encouraged to improve on diagnostic capabilities and develop evidence on the best treatment of choice for PJI.

Variability and Interpretation of Synovial Cell Count and Differential: A Perspective in Hip and Knee Arthroplasty.

Multiple threshold values have been proposed for synovial leukocyte count (white blood cell count) and synovial neutrophil percentage (percent polymorphonuclear neutrophils) in the diagnosis of periprosthetic joint infection (PJI). The objective of this study was to elucidate the variability of these criteria under diverse patient/surgical settings. Hip PJIs yield higher synovial white blood cell counts and percent polymorphonuclear neutrophils than knee PJIs. Periprosthetic joint infection of failed unicompartmental knee arthroplasty produces a higher white blood cell count than that of failed total knee arthroplasty. Synovial white blood cell count and percent polymorpho-nuclear neutrophils PJI thresholds also vary in patients with antibiotic cement spacers and depend on the timing from primary arthroplasty (<6 weeks vs >6 weeks). Similarly, test results should be carefully interpreted for patients with comorbidities so that PJI is not missed or falsely identified. [Orthopedics. 2021;44(3):e320-e325.].

Plasma D-dimer Does Not Anticipate the Fate of Reimplantation in Two-stage Exchange Arthroplasty for Periprosthetic Joint Infection: A Preliminary Investigation.

BACKGROUND: Inflammatory markers such as the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels have always been a part of the diagnostic criteria for periprosthetic joint infection (PJI), but they perform poorly anticipating the outcome of reimplantation. D-dimer has been reported in a small series as a potential marker to measure infection control after single-stage revisions to treat PJI. Nonetheless, its use to confirm infection control and decide the proper timing of reimplantation remains uncertain. QUESTIONS/PURPOSES: (1) What is the best diagnostic threshold and accuracy values for plasma D-dimer levels compared with other inflammatory markers (ESR and CRP) or what varying combinations of these tests are associated with persistent infection after reimplantation? (2) Do D-dimer values above this threshold, ESR, CRP, and varying test combinations at the time of reimplantation indicate an increased risk of subsequent persistent infection after reimplantation? METHODS: We retrospectively studied the electronic medical records of all 53 patients who had two-stage revisions for PJI and who underwent plasma D-dimer testing before reimplantation at one of two academic institutions from November 22, 2017 to December 5, 2020. During that period, all patients undergoing two-stage revisions also had a D-dimer test drawn. The minimum follow-up duration was 1 year. We are reporting at this early interval (rather than the more typical 2-year time point) because of the poorer-than-expected performance of this diagnostic test. Of these 53 patients, 17% (9) were lost to follow-up before 1 year and could not be analyzed; the remaining 44 patients (17 hips and 27 knees) were studied here. The mean follow-up was 503 ± 135 days. Absence or persistence of infection after reimplantation were defined according to the Delphi criteria. The conditions included in these criteria were: (1) control of infection, as characterized by a healed wound without fistula, drainage, or pain; (2) no subsequent surgical intervention owing to infection after reimplantation; and (3) no occurrence of PJI-related mortality. The absence of any of the aforementioned conditions until the final follow-up examination was deemed a persistent infection after reimplantation. Baseline patient characteristics were not different between patients with persistent infection (n = 10) and those with absence of it after reimplantation (n = 34) as per the Delphi criteria. Baseline patient characteristics evaluated were age, gender, self-reported race (white/Black/other) or ethnicity (nonHispanic/Hispanic), BMI, American Society of Anesthesiologists (ASA) status, smoking status(smoker/nonsmoker), and joint type (hip/knee). The optimal D-dimer threshold to differentiate between persistence of infection or not after reimplantation was calculated using the Youden index. A receiver operating characteristic curve analysis was performed to test the accuracy of D-dimer, ESR, CRP, and their combinations to establish associations, if any, with persistent infection after reimplantation. A Kaplan-Meier survival analysis (free of infection after reimplantation) with a log-rank test was performed to investigate if D-dimer, ESR, and CRP were associated with absence of infection after reimplantation. Survival or being free of infection after reimplantation was determined as per Delphi criteria. Alpha was set at p < 0.05. RESULTS: In the receiver operating characteristic curve analysis, with an area under the curve of 0.62, D-dimer showed low accuracy and did not anticipate persistent infection after reimplantation. The optimal D-dimer threshold differentiating between persistence of infection or not after reimplantation was 3070 ng/mL. When using this threshold, D-dimer demonstrated a sensitivity of 90% (95% CI 55.5% to 99.7%) and negative predictive value of 94% (95% CI 70.7% to 99.1%), but low specificity (47% [95% CI 29.8% to 64.9%]) and positive predictive value (33% [95% CI 25.5% to 42.2%]). Although D-dimer showed the highest sensitivity, the combination of D-dimer with ESR and CRP showed the highest specificity (91% [95% CI 75.6% to 98%]) defining the persistence of infection after reimplantation. Based on plasma D-dimer levels, with the numbers available, there was no difference in survival free from infection after reimplantation (Kaplan-Meier survivorship free from infection at minimum 1 year in patients with D-dimer below 3070 ng/mL versus survivorship free from infection with D-dimer above 3070 ng/mL: 749 days [95% CI 665 to 833 days] versus 615 days [95% CI 471 to 759 days]; p = 0.052). Likewise, there were no associations between high ESR and CRP levels and persistent infection after reimplantation, but the number of events was very small, and insufficient power is a concern with this analysis. CONCLUSION: In this preliminary series, with the numbers available, D-dimer alone had poor accuracy and was not associated with survival free from infection after reimplantation in patients who underwent two-stage exchange arthroplasty. D-dimer alone might be used to establish that PJI is unlikely, and the combination of D-dimer, ESR, and CRP should be considered to confirm PJI diagnosis in the setting of reimplantation.Level of Evidence Level IV, diagnostic study.

Florida State Opioid Prescription Restriction Law: Impact on Opioid Utilization After Total Joint Arthroplasty.

BACKGROUND: In response to the opioid epidemic, Florida recently passed the opioid prescription limiting law, effective since July 1st, 2018. However, its impact on opioid prescription after total joint arthroplasty (TJA) has not been elucidated. Thus, our objective was to assess if this new law led to reduced opioid prescription after TJA and to determine its impact on perioperative clinical outcomes. METHODS: A retrospective chart review was conducted on a consecutive series of 658 primary TJAs (618 patients), performed by four surgeons in a single institution [1/2/2018-10/23/2018]. Based on effective date of the law, cases were divided into: prelaw (327 cases; 168 hips/159 knees) and postlaw (331 cases; 191 hips/140 knees) phases. Baseline demographics and surgical characteristics were compared. The effect of the law on perioperative outcomes: length of stay, complications, emergency department/office visits, patient phone calls, reoperation or readmission (90 days), and total morphine equivalents prescribed was investigated. Independent sample t-tests and chi-square analyses were performed. RESULTS: Prelaw and postlaw phases had no significant difference in baseline demographics and characteristics. No difference was found in length of stay. Opioid law implementation led to significantly lower total oral morphine equivalents after TJAs [Prelaw: 1059.9 ± 825.4 vs postlaw: 942.8 ± 691.7; P = .04], but did not result in a significant increase in 90-day complications, patient visits (office or emergency) or phone calls, and reoperation or readmission. CONCLUSION: Our data suggest that Florida state opioid prescription limiting law has resulted in a marked decline in opioid prescription without any increase in rates of patient visits, phone calls, or readmission after TJA.

Direct Anterior Approach for Total Hip Arthroplasty with Subtrochanteric Shortening Osteotomy: A Case Report.

CASE: A patient with Aitken type A proximal focal femoral deficiency (PFFD) and significant limb length discrepancy managed with total hip arthroplasty making use of a novel technique that features a direct anterior approach (DAA) and a subtrochanteric shortening osteotomy. CONCLUSION: Although the current description of the shortening osteotomy is for PFFD, it is versatile enough to allow its application in other hip pathologies requiring subtrochanteric shortening in the setting of total hip arthroplasty. The authors believe that the description of this case report and surgical technique may be an option for the experienced DAA surgeon.

Meta-analysis Comparing Allograft to Synthetic Reconstruction for Extensor Mechanism Disruption after Total Knee Arthroplasty.

Extensor mechanism disruption following total knee arthroplasty (TKA) is a devastating complication that causes high failure rates. There is controversy on what is the best way to do an extensor mechanism reconstruction. This study aims to compare both allograft and synthetic reconstructive techniques for success, reoperation, and infection rates and functional outcomes. The search on PubMed, MEDLINE, Embase, BIOSIS, and Cochrane databases was performed on March 15, 2019, using the following keyword groups: (1) "extensor mechanism" and "total knee arthroplasty," (2) "extensor mechanism" and "knee arthroplasty," (3) "extensor mechanism" and "revision total knee arthroplasty," and (4) "extensor mechanism" and "revision knee arthroplasty". Only studies on extensor mechanism disruption after TKA that included sufficient data to compare these two surgical techniques were included. Meta-analysis was performed with random effect model using the DerSimonian-Laird method. Thirty studies were included. The overall success rate of the reconstruction was 73.3% (95% confidence interval [CI]: 0. 651, 0.814). The success rate of allograft (72.8%, 95% CI: 0.626, 0.829) was not significantly different from synthetic material (78%, 95% CI: 0.707, 0.852, p = 0.416). There was no significant difference in revision rates between allograft (14.2%, 95% CI: 0.095, 0.189) and synthetic material (16%, 95% CI: 0.096, 0.223, p = 0.657). The overall relative risk of infection was 4.301 (95% CI: 1.885, 9.810). There was no significant difference in relative risk of infection between allograft (3.886, 95% CI: 1.269, 11.903) and synthetic material (4.851, 95% CI: 1.433, 16.419, p = 0.793). No statistically significant difference was found in mean postoperative Knee Society score (73.109 [95% CI: 67.296, 78.922] vs. 72.679 [95% CI: 69.184, 76.173], p = 0.901) between allograft and mesh reconstruction groups. There were no significant differences in overall failures, infections, functional outcomes, or revision reconstructions between allograft and synthetic material extensor mechanism reconstructions. Our results demonstrate the difficulty in treating this serious injury, independent of technique, as well as the significant risk for overall failure and infection.