Does Time to Aseptic Failure After Primary Total Hip Arthroplasty Affect Clinical and Patient-Reported Outcomes?

BACKGROUND: Evidence on the effects of time-to-failure from primary total hip arthroplasty (THA) to aseptic first-revision on clinical results and patient-reported outcome measures (PROMs) is scarce. Therefore, we sought to compare demographics, operative times, lengths of stay, discharge dispositions, 90-day readmissions, re-revision rates, mortalities, and PROMs between early and late aseptic THA revisions. METHODS: This study is a retrospective review of a prospectively collected institutional database of all elective hip procedures. In total, 572 patients who underwent aseptic revision after primary THA from August 2015 to December 2018 were analyzed. Patients were stratified into either early revision (<3-years; n = 176) or late revision (≥3-years; n = 396) cohorts. RESULTS: Significantly more patients were revised earlier for bone-related (ie, periprosthetic fractures) (22.7% versus 8.3%) or other various complications (19.9% versus 5.8%), whereas more late revisions were performed to treat implant-related failures (6.8% versus 37.1%), respectively. Operative time was significantly shorter in early versus late revisions (133 versus 157 minutes). A significantly higher delta-change/improvement from baseline/preoperative to 1-year postoperative was found for hip disability and osteoarthritis outcome score physical function (HOOS-PS), veterans-RAND-12 physical and mental components (VR-12-PCS and MCS, respectively) of early revisions. However, HOOS-PS and HOOS-Pain at 1-year of follow-up were significantly worse in early revisions. CONCLUSION: With exception of operative time, time-to-failure had no significant influence on clinical results. Despite greater improvements on PROMs from preoperative to postoperative, patients undergoing early revisions after primary THA perceive significantly higher levels of pain and worse physical functionality at 1-year of follow-up.

Similar Healthcare Utilization and 1-Year Patient-Reported Outcomes between Cemented and Cementless Primary Total Knee Arthroplasty: A Propensity Score-Matched Analysis.

Cementless fixation for total knee arthroplasty (TKA) has gained traction with the advent of newer fixation technologies. This study assessed (1) healthcare utilization (length of stay (LOS), nonhome discharge, 90-day readmission, and 1-year reoperation); (2) 1-year mortality; and (3) 1-year joint-specific and global health-related patient-reported outcome measures (PROMs) among patients who received cementless versus cemented TKA. Patients who underwent cementless and cemented TKA at a single institution (July 2015-August 2018) were prospectively enrolled. A total of 424 cementless and 5,274 cemented TKAs were included. The cementless cohort was propensity score-matched to a group cemented TKAs (1:3-cementless: n = 424; cemented: n = 1,272). Within the matched cohorts, 76.9% (n = 326) cementless and 75.9% (n = 966) cementless TKAs completed 1-year PROMs. Healthcare utilization measures, mortality and the median 1-year change in knee injury and osteoarthritis outcome score (KOOS)-pain, KOOS-physical function short form (PS), KOOS-knee related quality of life (KRQOL), Veteran Rand (VR)-12 mental composite (MCS), and physical composite (PCS) scores were compared. The minimal clinically important difference (MCID) for PROMs was calculated. Cementless TKA exhibited similar rates of median LOS (p = 0.109), nonhome discharge disposition (p = 0.056), all-cause 90-day readmission (p = 0.226), 1-year reoperation (p = 0.597), and 1-year mortality (p = 0.861) when compared with cemented TKA. There was no significant difference in the median 1-year improvement in KOOS-pain (p = 0.370), KOOS-PS (p = 0.417), KOOS-KRQOL (p = 0.101), VR-12-PCS (p = 0.269), and VR-12-MCS (p = 0.191) between the cementless and cemented TKA cohorts. Rates of attaining MCID were similar in both cohorts for assessed PROMs (p > 0.05, each) except KOOS-KRQOL (cementless: n = 313 (96.0%) vs. cemented: n = 895 [92.7%]; p = 0.036). Cementless TKA provides similar healthcare-utilization, mortality, and 1-year PROM improvement versus cemented TKA. Cementless fixation in TKA may provide value through higher MCID improvement in quality of life. Future episode-of-care cost-analyses and longer-term survivorship investigations are warranted.

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.

Should an Age Cutoff Be Considered for Elective Total Knee Arthroplasty Patients? An Analysis of Operative Success Based on Patient-Reported Outcomes.

Total knee arthroplasty (TKA) is increasing in the elderly population; however, some patients, family members, and surgeons raise age-related concerns over expected improvement and risks. This study aimed to (1) evaluate the relationship between age and change in patient-reported outcome measures (PROMs); (2) model how many patients would be denied improvements in PROMs if hypothetical age cutoffs were implemented; and (3) assess length of stay (LOS), readmission, reoperation, and mortality per age group. A prospective cohort of 4,396 primary TKAs (August 2015-August 2018) was analyzed. One-year PROMs were evaluated via Knee injury and Osteoarthritis Outcome Score (KOOS)-pain, -physical function short form (-PS), and -quality of life (-QOL), as well as Veterans Rand-12 (VR-12) physical (-PCS) and mental component (-MCS) scores. Positive predictive values (PPVs) of the number of postoperative "failures" (i.e., unattained minimal clinically important difference in PROMs) relative to number of hypothetically denied "successes" from a theoretical age-group restriction was estimated. KOOS-PS and QOL median score improvements were equivalent among all age groups (p = 0.946 and p = 0.467, respectively). KOOS-pain improvement was equivalent for ≥80 and 60-69-year groups (44.4 [27.8-55.6]). Median VR-12 PCS improvements diminished as age increased (15.9, 14.8, and 13.4 for the 60-69, 70-79, and ≥80 groups, respectively; p = 0.002) while improvement in VR-12 MCS was similar among age groups (p = 0.440). PPV for failure was highest in the ≥80 group, yet remained <34% for all KOOS measures. Overall mortality was highest in the ≥80 group (2.14%, n = 9). LOS >2, non-home discharge, and 90-day readmission were highest in the ≥80 group (8.11% [n = 24], p < 0.001; 33.7% [n = 109], p < 0.001; and 34.4% [n = 111], p = 0.001, respectively). Elderly patients exhibited similar improvement in PROMs to younger counterparts despite higher LOS, non-home discharge, and 90-day readmission. Therefore, special care pathways should be implemented for those age groups.

Does the Timing of the Second Surgery of a Staged Bilateral Total Joint Arthroplasty Affect the Rate of Hospital Adverse Events and Perioperative Outcomes?

BACKGROUND: The optimal timing of the second surgery in primary staged bilateral total hip/knee arthroplasty remains uncertain. Perioperative hospital adverse events represent a significant issue, even "minor events" lead to substantial costs in workup tests, interconsultations, and/or increased hospital length-of-stay (LOS). Therefore, we sought to ascertain whether the timing of the second arthroplasty affects perioperative outcomes and/or rates of adverse events. METHODS: We retrospectively reviewed a consecutive series of 670 primary staged bilateral total hip/knee arthroplasty performed by 2 surgeons (2010-2016) at a single institution. The days between both arthroplasties were calculated for each pair of hips or knees. We evaluated demographics and LOS, discharge disposition, adverse events (ie, nausea, pulmonary embolism), and transfusion rates. The second arthroplasties (n = 335) were set apart in 2 groups based on the time they were done with respect to their corresponding contralateral first arthroplasty using 3 different thresholds: (1) ≤90 vs >90 days, (2) ≤180 vs >180 days, and (3) ≤365 vs >365 days. RESULTS: No significant differences in outcome comparisons were observed using either 90 or 180 days thresholds. However, using the 365 days thresholds, the mean LOS (2.21 vs 1.92 days, P = .015), adverse event (26% vs 15.3%, P = .021), total transfusion (7.4% vs 1.5%, P = .020), and allogeneic transfusion (6.9% vs 1.5%, P = .033) rates were significantly higher in second arthroplasties performed at or less than 1 year apart from the first, respectively. CONCLUSION: Staging the second arthroplasty more than a year apart from the first one seems to offer better LOS and rates of hospital adverse events, transfusions. However, unless patients are willing to wait a year between surgeries, our data also suggest no increased risk in regards to adverse events when proceeding before or after 90/180 days. LEVEL OF EVIDENCE: Level III.

The Utility of Serum d-Dimer for the Diagnosis of Periprosthetic Joint Infection in Revision Total Hip and Knee Arthroplasty.

BACKGROUND: There is scarce and contradicting evidence supporting the use of serum d-dimer for the diagnosis of periprosthetic joint infection in revision total hip (THA) and knee (TKA) arthroplasty. Therefore, the purpose of this study is to test the accuracy of serum d-dimer against the 2013 International Consensus Meeting (ICM) criteria. METHODS: A retrospective review was performed on a consecutive series of 172 revision THA/TKA surgeries performed by 3 fellowship-trained surgeons at a single institution (August 2017 to May 2019) and that had d-dimer performed during their preoperative workup. Of this cohort, 111 (42 THAs/69 TKAs) cases had complete 2013 ICM criteria tests and were included in the final analysis. Septic and aseptic revisions were categorized per 2013 ICM criteria ("gold standard") and compared against serum d-dimer using an established threshold (850 ng/mL). Sensitivity, specificity, likelihood ratios, and positive/negative predictive values were determined. Independent t-tests, Fisher's exact tests, chi-squared tests, and receiver operating characteristic curve analysis were performed. RESULTS: There was no statistically significant difference in baseline demographics between septic and aseptic cases per 2013 ICM criteria. When compared to ICM criteria, d-dimer demonstrated high sensitivity (95.9%) and negative predictive value (90.9%) but low specificity (32.3%), positive predictive value (52.8%), and overall, poor accuracy (61%) to diagnose periprosthetic joint infection. Positive likelihood ratio was 1.42 while negative likelihood ratio was 0.13. The area under the curve (AUC) was 0.742. CONCLUSION: Serum d-dimer has poor accuracy to discriminate between septic and aseptic cases using a described threshold in the setting of revision THA and TKA.

Dual Antibiotic Prophylaxis in Total Knee Arthroplasty: Where Do We Stand?

The risk of surgical site infection in primary total knee arthroplasty (TKA) has been reduced with the use of prophylactic antibiotics. First or second generation cephalosporins are still recommended as the primary prophylactic choice, but with the rise in the incidence of methicillin-resistant Staphylococcus aureus (MRSA) infections, evidence has emerged in favor of using dual antibiotics including vancomycin. However, it is unclear whether these combinations of antibiotic regimens further reduce postoperative infection rates. As a result, the objective of this review is to summarize the current literature concerning the use of dual prophylactic antibiotics in TKA. The most common dual prophylactic antibiotic combination is cefazolin (C) and vancomycin (V). In general, when comparing the effectiveness of single versus dual antibiotics, conflicting results have been reported. Three studies demonstrated no substantial decrease in overall postoperative infection rates with the use of dual antibiotics when compared with cefazolin alone. One found a significant decrease only in MRSA infection rates when using cefazolin and vancomycin (CV) (0.8% C alone vs. 0.08% CV, p < 0.05). Another investigation evaluated revision TKA patients who had combined cefazolin and vancomycin prophylaxis and showed a significant decline in both overall infection (7.89% [C] vs. 3.13% [CV]) and MRSA infection rates (4.21% [C] vs. 0.89% [CV]; p < 0.05). Concerning the safety profile of dual antibiotics, particular precautions must be adopted with the use of vancomycin because of the risk of acute kidney injury. Instead of vancomycin, an alternate less nephrotoxic antibiotic option might be teicoplanin. Unfortunately, this latter agent is only available outside of the United States. In conclusion, the value of dual antibiotic prophylaxis for the prevention of periprosthetic knee infections remains unclear primarily because all comparative studies performed between dual and single antibiotics have been of low evidence with retrospective designs. Larger multicenter randomized controlled trials are warranted.

Serum D-Dimer in the Diagnosis of Periprosthetic Knee Infection: Where Are We Today?

Periprosthetic joint infection (PJI) continues to impact a remarkable number of patients who undergo total knee arthroplasty (2.0-2.1%). Substantial efforts to curtail these rates have been seen in the past decade including various attempts to reach a clear definition of PJI that the orthopaedic community could adopt as a gold standard. The Musculoskeletal Infection Society (MSIS) criteria, slightly modified by the International Consensus Meeting (ICM), has gained widespread acceptance and it is a step closer to that goal. Research on markers such as serum cross-linked D-fragments (D-dimer) seems promising in the diagnosis of infection. In the setting of PJI, a recent publication has established a threshold of 850 ng/mL as the optimal cutoff value for serum D-dimer. Therefore, our objective is to present a summary of the current literature on the changing indications of D-dimer and its rising importance in the setting of PJI. Serum D-dimer has been shown to outperform other conventional tests such as erythrocyte sedimentation rate and C-reactive protein that have been a major part of the ICM criteria and it has been included in the newly proposed diagnostic criteria for PJI that correctly diagnoses infection in 95.5% of septic patients (overall sensitivity: 97.7%, specificity: 99.5%). In comparison with the ICM and MSIS infection definitions, the new criteria revealed a higher sensitivity (97.7 vs. 86.9% and 97.7 vs. 79.3%, respectively), while specificity was similar. In conclusion, high D-dimer levels in primary or revision knee arthroplasty seem indicative of diagnosis of PJI. However, future studies are warranted to conclusively support the routine use of this marker and to validate the performance of the newly developed PJI diagnostic criteria under different clinical scenarios.

Hospital Adverse Events and Perioperative Outcomes in Bilateral Direct Anterior Approach Total Hip Arthroplasty.

BACKGROUND: Perioperative hospital adverse events represent a significant outcome that is often overlooked. Even "minor events" such as fever or tachycardia may lead to significant costs due to workup tests, interconsultations, and/or increased length of stay (LOS). The optimal timing of bilateral direct anterior approach total hip arthroplasty (DAA-THA) remains unsettled. Consequently, we wanted to compare hospital LOS, discharge disposition, hospital adverse events (major and minor), and transfusion rates between simultaneous and staged bilateral DAA-THA. METHODS: A retrospective chart review was conducted on a consecutive series of 347 primary bilateral DAA-THAs (204 patients) performed by 2 surgeons in a single institution (2010-2016). The hips finally included were categorized as simultaneous (Sim-n = 61), staged 1 (Stg1-n = 143), or staged 2 (Stg2-n = 143). We also compared simultaneous with staged surgeries performed ≤1 and >1 year apart. Baseline demographics, LOS, discharge disposition, hospital adverse events, and transfusions were assessed. RESULTS: The simultaneous group had significantly younger patients and a higher proportion of males when compared with the staged groups and showed significant longer LOS [2.61 (Sim) vs 2.06 (Stg1) vs 1.63 (Stg2) days, P < .001], lower proportion of home discharge [77% (Sim) vs 91.6% (Stg1) vs 96.5% (Stg2), P < .001], as well as higher (overall) rate of adverse events [31.1% (Sim) vs 28.7% (Stg1) vs 14.0% (Stg2), P = .003] and transfusions [45.9% (Sim) vs 6.3% (Stg1) vs 7.0% (Stg2), P < .001]. However, most transfusions were autologous [37.7% (Sim) vs 3.5% (Stg1) vs 0% (Stg2), P < .001]. CONCLUSION: Our data show that bilateral DAA-THAs performed in a staged fashion, rather than simultaneously, have a shorter hospital LOS and decreased rates of adverse events and overall transfusions. Notwithstanding, simultaneous surgery should still be considered an option in selected patients. LEVEL OF EVIDENCE: Level III.

The trends in robotic-assisted knee arthroplasty: A statewide database study.

OBJECTIVE: Recent technological advancements have led to the utilization of robotic-assisted knee arthroplasty (raKA) in the operating room. METHODS: All patients who underwent knee arthroplasty from 2009 to 2013 in NYS SPARCS were reviewed. raKAs and non-raKAs were compared for utilization and institutional trends. RESULTS: Robotic-assistance increased by 500%. 80% of raKAs were performed in teaching hospitals. The trend increase was greater in teaching hospitals. Blood transfusion rates differed between raKA and non-raKA (6.6% vs. 10.9%, p < 0.001). CONCLUSION: raKA utilization increased in NYS, moreso within teaching hospitals. raKA transfusion rates were lower but higher in teaching hospitals, potentially related to learning curve.

Are Patients More Satisfied With a Balanced Total Knee Arthroplasty?

BACKGROUND: Patient-reported outcome measures are increasingly recognized as an important tool in quantifying the clinical success of arthroplasty surgery. The aim of this study is to measure post-operative joint awareness and satisfaction in patients with and without a quantitatively balanced knee following primary total knee arthroplasty (TKA). METHODS: In this multi-center study, a total of 318 eligible patients were assigned to one of the 2 patient groups: sensor-guided TKA or surgeon-guided TKA. In the sensor-guided group, quantitative balancing was performed according to intercompartmental tibiofemoral load measurements measured by an instrumented tibial trial component. In contrast, for the surgeon-guided group, the knees were balanced according to the surgeons' standard manual techniques while blinding the surgeon to the sensor measurements. Patients were blinded to their allocation and filled out the validated Forgotten Joint Score and 2011 Knee Society Satisfaction questionnaires at 6 weeks and 6 months. For the purposes of this study, the subjects were pooled and stratified by their state of soft tissue balance, based on the mediolateral load differential through the range of motion. RESULTS: In the surgeon-guided group, approximately 50% of the cases yielded a quantitatively balanced knee. Significantly more balanced knees were observed in the sensor-guided group (84.0%). More importantly, for both outcome measures, the balanced group of patients reported significantly better outcomes scores. CONCLUSION: This demonstrates that using sensor feedback during knee arthroplasty surgery results in a more reproducible procedure, resulting in a higher percentage of balanced patients who in turn demonstrate superior clinical outcomes compared to unbalanced patients.

The Practice of Overlapping Surgery Is Safe in Total Knee and Hip Arthroplasty.

BACKGROUND: Overlapping surgery occurs when a surgeon performs 2 procedures in an overlapping time frame. This practice is commonplace in the setting of total joint arthroplasty and is intended to increase patient access to experienced surgeons, improve efficiency, and advance the surgical competence of surgeons and trainees. The practice of overlapping surgery has been questioned because of safety and ethical concerns. As the literature is scarce on this issue, we evaluated the unplanned hospital readmission and reoperation rates associated with overlapping and non-overlapping total joint arthroplasty procedures. METHODS: We reviewed 3,290 consecutive primary total knee and hip arthroplasty procedures that had been performed between November 2010 and July 2016 by 2 fellowship-trained senior surgeons at a single institution. Overlapping surgery was defined as the practice in which the attending surgeon performed a separate procedure in another room with an overlapping room time of at least 30 minutes. Patient baseline characteristics and 90-day rates of complications, readmissions, and reoperations were compared between overlapping and non-overlapping procedures. Subanalyses also were done on patients with a body mass index (BMI) of ≥30 kg/m2 and those with an American Society of Anesthesiologists (ASA) score of 3 or 4. The level of significance was set at 0.05. RESULTS: Of the 2,833 procedures that met the inclusion criteria, 57% (1,610) were overlapping and 43% (1,223) were non-overlapping. Baseline demographics, BMI, and ASA scores were similar between the groups. No significant differences were found between the overlapping and non-overlapping procedures in terms of the 90-day rates of complications (5.2% vs. 6.6%, respectively; p = 0.104), unplanned readmissions (3.4% vs. 4.3%; p = 0.235), or reoperations (3.1 vs. 3.1; p = 1.0) in the analysis of the entire cohort or in subgroup analyses of obese patients and patients with an ASA score of 3 or 4. The total mean operating room time was 5.8 minutes higher for overlapping procedures. CONCLUSIONS: Overlapping procedures showed no increase in terms of the 90-day rates of complications, readmissions, or reoperations when compared with non-overlapping procedures. There was just over a 5-minute increase in mean operating room time for overlapping procedures. Our data suggest that overlapping surgery does not lead to detrimental outcomes following total knee arthroplasty or total hip arthroplasty. Future investigations evaluating patient-oriented outcomes and satisfaction are warranted. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Caregiver Burden for Patients With Severe Osteoarthritis Significantly Decreases by One Year After Total Knee Arthroplasty.

BACKGROUND: The impact of total knee arthroplasty (TKA) on patients' informal caregivers (eg, family members, friends) has gone largely ignored. The goals of this study are to measure the impact of TKA on the caregiver and identify factors contributing to higher burden. METHODS: One hundred fifty primary TKA patients and their designated caregivers were prospectively enrolled. The Caregiver Strain Index (CSI) was completed by caregivers preoperatively, at 4 weeks, and at 1 year after surgery. Additional outcomes included the Knee injury and Osteoarthritis Outcome Score for patients only and the Veterans Rand 12 Item Health Survey for both patients and caregivers. Univariate analysis and multivariate regression modeling were performed. RESULTS: Mean CSI scores at 1 year were significantly lower than preoperative values (P < .01), where lower scores indicate better results. Higher mean CSI values for younger caregivers were identified preoperatively (r = -0.21, P < .01) and at 4 weeks (r = -0.26, P < .01). There were higher mean CSI values for employed caregivers preoperatively (P = .01) and at 4 weeks (P < .01). A negative correlation was identified between CSI and the caregiver's Veterans Rand 12 Item Health Survey Mental Component Score preoperatively (r = -0.15, P = .03) and at 4 weeks (r = -1.5, P = .03). CONCLUSION: Caregiver burden nearly doubled in the early postoperative period, which was related to several caregiver and patient factors. However, the burden was close to zero by 1 year postoperatively. Thus, TKA is a beneficial intervention for both patient and caregiver.

Effectiveness of Novel Adjuncts in Pain Management Following Total Knee Arthroplasty: A Randomized Clinical Trial.

BACKGROUND: Total knee arthroplasty (TKA) can be associated with significant pain which can negatively impact outcomes. Multiple strategies have been employed to reduce pain. The aim of this study is to compare the effectiveness of 3 different pain management modalities after TKA that included (1) our standardized knee injection cocktail and oral acetaminophen, (2) liposomal bupivacaine periarticular injection and oral acetaminophen, and (3) our standardized knee injection cocktail and intravenous (IV) acetaminophen. METHODS: A prospective randomized clinical trial was conducted with 3 perioperative pain management regimes: oral acetaminophen and our standardized knee injection cocktail (standard group), oral acetaminophen and liposomal bupivacaine periarticular injection (LB group), and IV acetaminophen and our standardized knee injection cocktail (IVA group). Primary outcome measures included visual analog scale, total morphine equivalents, and the opioid-related symptoms distress scale at 24 and 48 hours postoperatively. RESULTS: There were no significant differences on visual analog scale/opioid-related symptoms distress scale scores 24 hours after surgery. The LB group required significantly more narcotics (total morphine equivalents) than the standard (P = .025) and IVA groups (P = .032). No significant differences were observed on any of the outcomes measured at 48 hours after surgery. CONCLUSION: Our data suggest that there is no added benefit in the routine use of IV acetaminophen or liposomal bupivacaine after TKA.

What Is the Optimal Criteria to Use for Detecting Periprosthetic Joint Infections Before Total Joint Arthroplasty?

BACKGROUND: The purposes of this study were to (1) test the accuracy of α-defensin and combined α-defensin-aspiration cultures in diagnosing periprosthetic joint infection (PJI) before revision total knee and hip arthroplasty and (2) evaluate Musculoskeletal Infection Society (MSIS) criteria and α-defensin as predictors of successful reimplantation (second-stage) at 1 year after surgery. METHODS: We retrospectively evaluated a total of 97 synovial fluid aspirations performed between August 2014 and September 2016 before revision due to septic or aseptic failures (n = 70) or before second-stage (n = 27) joint arthroplasty. Revisions were categorized as either septic or aseptic according to the MSIS criteria. Synovial fluid was tested for α-defensin, cell count with differential, and cultures. Reimplantations were assessed for success or failure (defined as the need for reoperation due to infection) within 1 year after surgery. RESULTS: For septic and aseptic revision arthroplasty, the sensitivity, specificity, positive predictive value, and negative predicted value of α-defensin was 97% while for the combined α-defensin and aspiration culture, it was 96%, 100%, 100%, and 97%. Despite being performed with negative MSIS criteria and α-defensin test results, 11% (3/27) of reimplantations (second-stage) failed within 1 year postoperatively because of infection. CONCLUSION: Alpha-defensin is an accurate diagnostic test for the diagnosis of PJI before revision arthroplasty. The combination of α-defensin and aspiration cultures has higher specificity and positive predictive value. MSIS criteria and α-defensin may help predict the success of reimplantations within 1 year after surgery.

Robotic-Assisted and Computer-Navigated Unicompartmental Knee Arthroplasties: A Systematic Review.

INTRODUCTION: Unicompartmental knee arthroplasty (UKA) effectively improves pain and function associated with isolated compartmental knee arthritis. The developments of computer-navigated and robotic-assisted UKA are among the most significant changes that have improved patient outcomes. This study aimed to systematically review the literature to identify differences between computer-navigated and robotic-assisted UKAs. MATERIALS AND METHODS: Twenty total articles were identified. Data pertaining to demographics, outcomes, and complications/failures were extracted from each study. Reoperation/revision rates, indications for reoperation/revision, type of procedure, and number of patients who underwent conversion to TKA (when available) were recorded. RESULTS: Nine studies reported 451 computer-navigated medial UKAs, with 19 (3.9%) reportedly requiring reoperation: primary revision (n=8; 42.1%), conversion to TKA (n=6), and manipulation under anesthesia (n=5). Eleven studies reported 2,311 robotic-assisted UKAs (74 lateral UKAs), with 106 (5.0%) requiring reoperation: conversion to TKA (n=46; 43.4%), primary revision (n=43), reoperations without component-removal (n=15), subchondroplasty, and partial meniscectomy/synovectomy (both n=1). Reoperation rate discrepancy between computer-navigated and robotic-assisted UKA was not statistically significant (p=0.495); age and BMI differed between both groups (p<0.0001). DISCUSSION: This study represents the first known comparison of revision rates of computer-navigated and robotic-assisted UKA, suggesting that these methods can benefit orthopaedic surgeons, especially those new to UKA or in a low-volume practice.

Accuracy of Fluoroscopic Guided Acetabular Component Positioning During Direct Anterior Total Hip Arthroplasty.

Acetabular component malposition contributes to increased complications and early revision. Supine positioning during direct anterior approach (DAA) THA facilitates the use of fluoroscopy to improve component positioning. This study evaluated the accuracy of acetabular component orientation using intraoperative fluoroscopy in DAA THA. A total of 780 surgeries by two surgeons were retrospectively reviewed over a 3-year period. Ranges for abduction (30°-50°) and version (5°-250) were employed. Overall, 92% fell within the targeted abduction range, 93% fell within the targeted anteversion range, and 88% met both criteria. The accuracy of component positioning for combined abduction and anteversion improved yearly (79.2%, 2011; 90.9%, 2012; and 95.6%, 2013). Fluoroscopy in DAA THA is a useful tool to improve acetabular component orientation, though a learning curve exists with its interpretation.

Evaluation of wound healing after direct anterior total hip arthroplasty with use of a novel retraction device.

Use of shorter incisions in minimally invasive surgery total hip arthroplasty (THA) may come at the cost of poorer cosmesis, possibly a result of the excessive retraction needed for visualization. This may be particularly relevant in the direct anterior approach, in which wound-healing issues are common. We prospectively investigated whether a specialized ring retractor was effective in minimizing wound-edge trauma, as evidenced by improved scar cosmesis. Fifty patients having direct anterior THA were randomized to surgery with or without ring retractor. Incisional photographs 2, 6, and 12 weeks after surgery were graded by 2 blinded plastic surgeons. Wound scores and patient satisfaction with scar appearance were similar between groups. Our results suggest no improvement in wound cosmesis with use of this retraction device.

Incidence of heterotopic ossification in direct anterior total hip arthroplasty: a retrospective radiographic review.

Heterotopic ossification (HO) is a complication following total hip arthroplasty (THA) with traditional approaches. The direct anterior approach (DAA) has become a popular approach for THA; however, no study has evaluated HO formation following DAA THA. We examined the incidence of HO in a consecutive series of THA using the DAA in two separate hospitals. Standard preoperative radiographs were examined to determine the type of degenerative arthritis, and follow-up radiographs of at least 6 months after surgery were evaluated for the presence and classification of HO. The overall incidence of HO after DAA THA in this study was 98/236, or 41.5%, which falls within the reported range from recent studies involving more traditional approaches to the hip.