Coupled Single-Cell CRISPR Screening and Epigenomic Profiling Reveals Causal Gene Regulatory Networks.

Here, we present Perturb-ATAC, a method that combines multiplexed CRISPR interference or knockout with genome-wide chromatin accessibility profiling in single cells based on the simultaneous detection of CRISPR guide RNAs and open chromatin sites by assay of transposase-accessible chromatin with sequencing (ATAC-seq). We applied Perturb-ATAC to transcription factors (TFs), chromatin-modifying factors, and noncoding RNAs (ncRNAs) in ∼4,300 single cells, encompassing more than 63 genotype-phenotype relationships. Perturb-ATAC in human B lymphocytes uncovered regulators of chromatin accessibility, TF occupancy, and nucleosome positioning and identified a hierarchy of TFs that govern B cell state, variation, and disease-associated cis-regulatory elements. Perturb-ATAC in primary human epidermal cells revealed three sequential modules of cis-elements that specify keratinocyte fate. Combinatorial deletion of all pairs of these TFs uncovered their epistatic relationships and highlighted genomic co-localization as a basis for synergistic interactions. Thus, Perturb-ATAC is a powerful strategy to dissect gene regulatory networks in development and disease.

Early Discharge for Revision Total Knee and Hip Arthroplasty: Predictors of Success.

BACKGROUND: The rate of revision total joint arthroplasties is expected to increase drastically in the near future. Given the recent pandemic, there has been a general push toward early discharge. This study aimed to assess for predictors of early postoperative discharge after revision total knee arthroplasty (rTKA) and revision total hip arthroplasty (rTHA). METHODS: There were 77 rTKA and 129 rTHA collected between January 1, 2019 and December 31, 2021. Demographic data, comorbidities, a comorbidity index, the modified frailty index (mFI-5), and surgical history were collected. The Common Procedural Terminology codes for each case were assessed. Patients were grouped into 2 cohorts, early discharge (length of stay [LOS] <24 hours) and late discharge (LOS >24 hours). RESULTS: In the rTHA cohort, age >65 years, a history of cardiac or liver disease, an mFI-5 of >1, a comorbidity index of >2.7, a surgical time >122 minutes, and the need for a transfusion were predictors of prolonged LOS. Only the presence of a surgical time of >63 minutes or an mFI-5 >1 increased patient LOS in the rTKA cohort. In both rTHA and rTKA patients, periprosthetic joint infection resulted in a late discharge for all patients, mean 4.8 and 7.1 days, respectively. Dual component revision was performed in 70.5% of rTHA. Only 27.6% of rTKA were 2-component revisions or placements of an antibiotic spacer. CONCLUSIONS: Several patient and surgical factors preclude early discharge candidacy. For rTHA, an mFI-5 of >2/5, comorbidity index of >4, or a surgical time of >122 minutes is predictive of prolonged LOS. For rTKA, an mFI-5 of >2/5, Charlson Comorbidity Index of >5, or a surgical time of >63 minutes predicts prolonged LOS.

Success of Same-Day Discharge Total Hip and Knee Arthroplasty: Does Location Matter?

BACKGROUND: Same calendar day discharge (SCDD) following total joint arthroplasty is desirable for patients and surgeons alike. The aim of this study was to compare the success rate of SCDD in an ambulatory surgical center (ASC) versus hospital setting. METHODS: A retrospective analysis was performed on 510 patients who underwent primary hip and knee total joint arthroplasty over a 2-year period. The final cohort was divided into 2 groups based on location of surgery: ASC (N = 255) or hospital (N = 255). Groups were matched for age, sex, body mass index, American Society of Anesthesiologists score, and Charleston Comorbidity Index. Successes of SCDD, reasons for failure of SCDD, length of stay (LOS), and 90-day readmission and complication rates were recorded. RESULTS: All SCDD failures were from the hospital setting (36 [65.6%] total knee arthroplasty [TKA] and 19 [34.5%] total hip arthroplasty [THA]). There were no failures from the ASC. The main causes of failed SCDD in both THA and TKA included failed physical therapy and urinary retention. Regarding THA, the ASC group had a significantly shorter total LOS (6.8 [4.4 to 11.6] versus 12.8 [4.7 to 58.0] hours, P < .001). Similarly, TKA patients had a shorter LOS in the ASC (6.9 [4.6 to 12.9] versus 16.9 [6.1 to 57.0], P < .001). Total 90-day readmission rates were higher in the ASC group (2.75% versus 0%), where all but 1 patient underwent TKA. Similarly, complication rates were higher in the ASC group (8.2% versus 2.75%), where all but 1 patient underwent TKA. CONCLUSION: TJA performed in the ASC, compared to the hospital setting, allowed for reduced LOS and improved success of SCDD.

Does Automated Impaction Improve Femoral Component Sizing and Alignment in Total Hip Arthroplasty?

BACKGROUND: While automated impaction can provide a more standardized process for femoral canal preparation, little is known regarding its effect on femoral component sizing and position. The purpose of our study was to directly compare femoral component canal fill ratio (CFR) and coronal alignment between primary total hip arthroplasty (THA) procedures performed with automated impaction versus manual mallet impaction. METHODS: A retrospective analysis was performed on 184 patients who underwent primary THA by a single arthroplasty surgeon between 2017 and 2021 with a modern cementless femoral component using either the direct anterior or posterolateral approach. The final cohort was divided into 2 groups based on impaction technique during broaching: automated (N = 122) or manual (N = 62). A propensity score match was used to match for age, body mass index, sex, high versus standard offset stem, and preoperative femoral bone quality. Radiographic review was performed to measure intramedullary prosthetic CFR and coronal alignment. RESULTS: The automated cohort trended toward the use of a larger stem (5.67 versus 4.82, P = .006) and had a larger CFR at all 4 levels within the proximal femur (P = .004). The automated cohort had a more valgus and reliable coronal alignment (-0.57 (SD 1.50) versus -0.03 (SD 2.17) degrees, P = .03) and significantly shorter operative time (mean 78 versus 90 minutes, P < .001). There were no intraoperative or postoperative periprosthetic fractures in either cohort. CONCLUSION: Automated impaction in primary THA is a safe technique for femoral preparation, which resulted in improved stem coronal alignment, optimized canal fill within the proximal femur, and reduced operative times.

Clinical and Radiographic Outcomes of Novel 3D-Printed Highly Porous Knee Cone Design.

INTRODUCTION: Metaphyseal bone defects seen at revision total knee replacement (TKA) have traditionally been treated with bone graft or cement. Recently, metal augments have surfaced as viable alternatives to conventional methods previously used in these patients. Newer 3D-printed metal cones offer better biological fixation as a means of improving construct stability. This study aimed to determine clinical and radiographic outcomes of the novel 3D-printed titanium cone augments for femoral and tibial metaphyseal bone defects. MATERIALS AND METHODS: A retrospective review was undertaken of 72 patients who underwent revision TKA with metaphyseal cones (Stryker) and stemmed implants from 2015-2017. Knee Injury and Osteoarthritis Outcome Scores (KOOS Jr) and VR/SF-12 scores were recorded. Knee Society radiographic scores were calculated at latest follow up to evaluate for radiolucency and biological fixation. Loosening noted on radiographs and reoperation for any reason were the endpoints to determine survivorship. RESULTS: A total of 68 patients with 78 cones (58 tibial, 20 femoral) met inclusion criteria. Mean follow up was 3.4 years (range 2-5.4 years). The average KOOS Jr score increased from 38 preoperatively to 66 at two years. The average VR/SF-12 PH score increased from 33 preoperatively to 37 at two years. The average VR/SF-12 MH score increased from 46 preoperatively to 54 at two years. Twelve percent of tibial implants and 10% of femoral implants with cones were found to have lucency in at least one radiographic zone. Overall survivorship at latest follow up was 93% with two patients requiring revision for infection, two revised following mechanical complications, and one patient who underwent polyethylene exchange after experiencing mechanical complications. When considering only aseptic loosening, survivorship was 100%. CONCLUSION: This 3D-printed titanium femoral and tibial cone augment system showed excellent survivorship, biological fixation, clinical outcomes, and radiographic outcomes in the setting of TKA. Further studies are needed for assessment of long-term survivorship.

Survivorship, Clinical and Radiographic Outcomes of a Novel Cementless Metal-Backed Patella Design.

BACKGROUND: Enhanced implant longevity through biological fixation is achievable using cementless total knee arthroplasty but concerns about patellar component failure have lingered because of prior experiences with older component designs. A new metal-backed patella (MBP) design was released which features a 3-dimensional printed porous titanium metal backing to improve biologic fixation potential and a unique compression molding technique to create a stronger interlock layer between the polyethylene and metal backing. Our study purpose was to determine the clinical and radiographic outcomes and survivorship of this novel cementless MBP. METHODS: Our institutional registry identified 388 cementless MBP with minimum 2-year and 80 with minimum 5-year follow-up. Knee Injury and Osteoarthritis Outcome Score for Joint Replacement and 12-item Veterans RAND/Short Form Health Survey (VR/SF-12) scores were used to evaluate clinical outcomes. Aseptic loosening noted on radiographs as well as revision for any reason were the end points used to determine survivorship. RESULTS: Improvement in the preoperative Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, VR/SF-12 physical health and mental health scores were all statistically significant at 2-year follow-up and the VR/SF-12 mental health score at 5-year follow-up. By radiologic criteria, biologic fixation of the patellar component was present in all except 1 case at 2 years (99.6%) and at 5 years (97.7%). Radiolucent lines were present in 15 cases (6.2%) at 2 years and in 6 cases (14%) at 5 years, but progressive increase in radiolucent lines was seen in only 4 cases. No component was revised for loosening; aseptic survivorship was 100%. CONCLUSION: This 3-dimensional printed cementless patellar component shows excellent survivorship at 2-year and 5-year follow-up. We are hopeful about the long-term durability of this implant.

Lateral Trochanteric Pain Following Primary Total Hip Arthroplasty: Incidence and Success of Nonoperative Treatment.

BACKGROUND: Our study aimed at quantifying the overall incidence of lateral trochanteric pain (LTP) following total hip arthroplasty (THA) and risk based on surgical approach. The success of conservative treatment and potential risk factors for failure of conservative treatment were evaluated. METHODS: This is a retrospective review of patients who underwent primary THA between 2010 and 2019 and had a postoperative diagnosis of ipsilateral LTP. Chart review revealed patient demographics/comorbidities, preoperative diagnosis, surgical approach, femoral components, and nonoperative treatment modalities. Radiographic analysis was performed to measure leg length discrepancy, femoral offset, and femoral head lateralization. RESULTS: The incidence of LTP following primary THA was 1.70% (573/33,761) with an average time to diagnosis of 27.3 months. The direct anterior approach demonstrated the highest risk and the direct lateral demonstrated the lowest risk for LTP (P < .001). Also, 82.4% (472/573) were diagnosed greater than 6 months postoperatively (P < .001). Of 573 patients, 95 (16.6%) were treated with physical therapy, home exercises, or oral medications with a success rate of 96.8% (92/95). Remaining 478 (83.4%) were treated with corticosteroid injection (CSI). And 89.5% (428/478) of the CSI cohort demonstrated clinical improvement with 3 or less CSIs. Risk factors for failure of conservative treatment were depression (P = .034), kidney disease (P = .040), and osteoporosis (P = .007). CONCLUSION: Postoperative LTP after THA is rare with an incidence of 1.70%. The direct anterior approach presented higher risk of LTP. Non-CSI modalities and CSIs were both successful treatment options. In patients with depression, kidney disease, and osteoporosis, conservative treatment may be less efficacious.

A Role for Modern Primary Cementless Femoral Stems in Revision Hip Arthroplasty.

BACKGROUND: In revision total hip arthroplasty (THA) cases with preserved femoral metaphyseal bone, tapered proximally porous-coated "primary" femoral stems may be an option. The objective of this study was to compare outcomes of patients with Paprosky I or II femoral bone loss undergoing revision THA with either a primary metaphyseal-engaging cementless stem or a revision diaphyseal-engaging stem. METHODS: This was a retrospective analysis of 70 patients with Paprosky I or II femoral bone loss who underwent femoral revision. 35 patients who were revised using a primary cementless femoral stem were compared with 35 patients who underwent femoral revision using a revision diaphyseal-engaging stem. The groups were similar regarding age, gender, body mass index, and American Society of Anesthesiologists. Clinical and radiographic outcomes and complications were compared over an average follow-up of 2.9 years (SD 1.4). RESULTS: Revision THA was most commonly performed for periprosthetic joint infection (N = 27, 38.6%). The groups were similar with regards to Paprosky femoral classification (P = .56), length of stay (P = .68), discharge disposition (P = .461), operative time (P = .20), and complications (P = .164). There were no significant differences between primary and revision femoral stem subsidence (0.12 vs. 0.75 mm, P = .18), leg length discrepancy (2.3 vs. 4.05 mm, P = .37), and Hip Disability and Osteoarthritis Outcome Score Jr (73.1 [SD 21.1] vs. 62.8 [SD 21.7], P = .088). No patient underwent additional revision surgery involving the femoral component. CONCLUSION: Use of modern primary cementless femoral stems is a viable option for revision hip arthroplasty in the setting of preserved proximal femoral metaphyseal bone. Outcomes are not inferior to those of revision stems and offer potential benefits.

Mycobacterial periprosthetic joint infection after primary total knee arthroplasty.

PURPOSE: Mycobacterial periprosthetic joint infection (PJI) is very rare and is generally associated with an immunosuppressive environment. Few large-scale studies of this unusual PJI have been conducted. The current study was performed to assess the clinical features and outcomes following two-stage re-implantation for mycobacterial PJI after primary total knee arthroplasty (TKA). METHODS: We conducted a retrospective review of data collected from our database involving ten cases of two-stage re-implantation manifesting mycobacterial PJI. Patients were followed for at least five years or until recurrent infection. The mean follow-up duration in patients who remained free of infection was 7.5 years (range 5-9.5 years). RESULTS: Seven patients (70%) belonged to the American Society of Anesthesiologists' grade 3 or 4. The surgical protocol entailed resection arthroplasty and cement spacer insertion with vigorous debridement, followed by at least six weeks of systemic antimicrobial therapy and delayed re-implantation in all patients. The median duration from resection arthroplasty to re-implantation was 5.3 months (range 2-10.5 months). Following re-implantation, five patients with Mycobacterium fortuitum were treated with amikacin for six weeks and oral clarithromycin for three months. Five patients infected with M. tuberculosis received anti-tuberculosis medications immediately after pathogen isolation, for a period of 12 months. CONCLUSION: Mycobacterial PJI can be treated successfully via resection arthroplasty and delayed re-implantation combined with proper antimicrobial agents. Suspicious infection or loosening after primary TKA, particularly in an immunosuppressive environment, warrants the attention of an orthopedic surgeon to consider the possibility of unusual PJI.

A Surgeon's handedness in direct anterior approach-hip replacement.

BACKGROUND: The impact of handedness on clinical outcomes was easily overlooked in hip replacement. This study aimed to find whether the component positioning and hip function were affected by the handedness in total hip arthroplasty (THA) through direct anterior approach (DAA). METHODS: Total 102 patients who underwent bilateral DAA-THAs simultaneously between May 2016 and November 2018 in our institute were reviewed. All surgeries were operated by one right-handed surgeon. Their demographic, cup positioning, stem alignment, femoral stem fit, Harris hip score (HHS), intraoperative and postoperative complications were used to evaluate the role of handedness in DAA. RESULTS: The inclination of left cups was significantly larger than that of right cups (42.61 ± 7.32 vs 39.42 ± 7.19, p = 0.000). The stem fit of left femur was significantly larger than that of right femur (84.34 ± 4.83 vs 82.81 ± 6.07, p = 0.043). No significant differences in safe zone ratio, HHS and complications between bilateral hips were found. CONCLUSIONS: A surgeon's handedness had significant impact on cup's inclination and femoral stem fit in DAA-THA. However, there were no significant differences of cup malpositioning, stem alignment, hip function scores and complications between bilateral DAA-THAs.

Modular stem in total hip arthroplasty for patients with trochanter valgus deformity: surgical technique and case series.

BACKGROUND: Trochanter valgus deformity (TVD) is a rare condition of total hip arthroplasty (THA). Femoral osteotomy could be required in correcting the deformity to implant femoral stem in severe TVD. In this study, we described one unpublished technique of reverse sleeve of S-ROM to get through the complex situation. This study aimed to summarize and evaluate its technical challenges, safety and effectiveness. METHODS: From January 2006 to December 2014, we enrolled patients whose sleeves were implanted towards the great trochanter in THA with TVD. Their demographics, perioperative and postoperative information were recorded. To explore its indication, we measured and analyzed the ratio of greater trochanter/lesser trochanter (G/L ratio) and trochanter valgus angle (TVA). RESULTS: Twelve patients (1 male and 11 female, average age 42.30 ± 10.23) had mean follow-up of 6 years. Among them, only two patients had intraoperative femoral fracture. The survivorship of femoral prosthesis was 100%. The Harris hip score (HHS) increased from preoperative 34.31 ± 14.43 to postoperative 84.12 ± 11.33. All patients' G/L ratio were larger than 1.50. CONCLUSIONS: The reverse sleeve of S-ROM was a reliable method for the patients with severe TVD, which brought satisfying clinical outcomes in mid-term follow-up.

Short-Term Follow-Up of Patellar Component Revision in Patients With Isolated Patellar Component Loosening.

BACKGROUND: The etiology of patellar component loosening can be multifactorial, including component malposition, trauma, infection, and poor implant design. These cases may be managed with isolated patellar component revision or simultaneous patellar component with femoral and/or tibial component revision. Isolated patellar revision in the setting of aseptic loosening historically has had limited success with high rates of repeat revision. METHODS: We performed a retrospective cohort study of 75 cases diagnosed with patellar component loosening that underwent revision. Patients were followed for a minimum of 2 years. Cases were categorized as either isolated patellar (IP) revision or patellar with femoral and/or tibial component (P + O) revisions. Survivorship and re-revision causes were compared between groups. Secondary outcomes included surgical time, estimated blood loss, range of motion, and length of stay. RESULTS: Fifty patients underwent IP revision, and 25 patients had P + O revision. Overall survivorship at the 2-year follow-up interval was 94.6%. Survivorship of IP revision undertaken for aseptic loosening was 94%. Survivorship of P + O revision was 96%. Eight percent of patients required reoperation from the P + O revision group, while 12% of patients in the IP revision group underwent a reoperation. Patients undergoing IP revision had better postoperative range of motion, lower surgical times, lower estimated blood loss, and decreased length of stay. CONCLUSION: IP revision demonstrates excellent survivorship and clinical outcomes comparable to P + O revision. When appropriate, IP revision should be considered as a potential treatment option. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Predictors of Perioperative Vancouver B Periprosthetic Femoral Fractures Associated With the Direct Anterior Approach to Total Hip Arthroplasty.

BACKGROUND: There is an association between intraoperative and postoperative femoral fractures and the direct anterior approach (DAA) to total hip arthroplasty (THA). The purpose of our study is to identify risk factors for Vancouver B fractures and to establish a predictable timeline for when these occur. METHODS: We retrospectively identified patients with Vancouver B periprosthetic femoral fractures (n = 49) after 11,509 elective primary cementless THA procedures through the DAA between 2012 and 2018 at a single institution. Fracture patients were matched to nonfracture patients (n = 267) by date of surgery and surgeon. Clinical and radiographic factors were collected for multivariable analysis to identify predictors of fracture. RESULTS: Periprosthetic Vancouver B femoral fracture incidence was 0.4%. 48 (98%) fractures were postoperative. Fractures occurred at an average of 44 days after surgery (range: 1 to 653 days) with >85% of fractures occurring in the first 6 weeks postoperatively. Significant variables predictive of fracture included >3 degrees valgus and >5 degrees varus coronal stem malalignment, Dorr B and C femoral geometry, lower canal flare index (2.75 vs 3.20), advanced age, increased comorbidities, greater stem canal fill, and right-sided procedures. CONCLUSION: Despite an overall low rate of Vancouver B perioperative periprosthetic femoral fractures, it is a devastating complication that typically presents within the first 6 weeks after DAA THA surgery. The risk is increased in patients with unfavorable proximal femoral geometry, coronal stem malalignment, advanced age, increased comorbidities, and right-sided procedures.

The Efficacy of Liposomal Bupivacaine Over Traditional Local Anesthetics in Periarticular Infiltration and Regional Anesthesia During Total Knee Arthroplasty: A Systematic Review and Meta-Analysis.

BACKGROUND: Since its Food and Drug Administration approval in 2011 as a local anesthetic for postsurgical analgesia, liposomal bupivacaine (LB) has been incorporated into the periarticular injection (PAI) of many knee surgeons. The slow release of this medication from vesicles should significantly extend the duration of its analgesic effect, but current evidence has not clearly demonstrated this benefit. METHODS: We systematically searched electronic databases including PubMed, MEDLINE, Cochrane Library, EMBASE, ScienceDirect, and Scopus, as well as the Journal of Arthroplasty web page for relevant articles. All calculations were made using Review Manager 5.3. RESULTS: We identified 42 studies that compared LB to an alternate analgesic modality. Seventeen of these studies were controlled trials that were included in meta-analysis. Significant differences were seen in pain scores with LB over a peripheral nerve block (mean difference = 0.45, P = .02) and LB over a traditional PAI (standard mean difference = -0.08, P = .004). CONCLUSION: While LB may offer a statistically significant benefit over a traditional PAI, the increase in pain control may not be clinically significant and it does not appear to offer a benefit in reducing opioid consumption. However, there is no standardization among current studies, as they vary greatly in design, infiltration technique, and outcome measurement, which precludes any reliable summarization of their results. Future independent studies using a standardized protocol are needed to provide clear unbiased evidence.

A Simple Protocol to Stratify Pulmonary Risk Reduces Complications After Total Joint Arthroplasty.

BACKGROUND: Pulmonary complications after total joint arthroplasty are a burden to patients and the healthcare system. The aim of this study is to demonstrate the effectiveness of a pulmonary screening questionnaire and intervention protocol developed at our institution to prevent pulmonary complications. METHODS: Between 2010 and 2015, 7658 consecutive total joint arthroplasty patients at our institution were reviewed. Based on our pre-operative pulmonary risk assessment tool, 1625 patients were flagged as high pulmonary risk. Patients were determined to be high risk if they were a current or former heavy smoker with an abnormal spirometry, had a positive obstructive sleep apnea screening, required continuous positive airway pressure/bi-level positive airway pressure use, had a history of significant pulmonary disease, had an oxygen saturation <90%, or had body mass index >40. A standardized monitoring protocol and interventions including smoking cessation, treatment and optimization of primary pulmonary conditions, peri-operative inhaler use, spinal anesthesia, aspiration precautions, elevated head of bed >20° resting and >45° while eating, maintaining oxygen saturation ≥92%, early use of incentive spirometer, avoidance of narcotics and early respiratory therapy consult were initiated for all high risk patients. RESULTS: Only 7 of 7658 (0.091%) patients suffered pulmonary complications after initiating our intervention protocol. These included 3 aspiration pneumonias, 1 asthma exacerbation, 1 chronic obstructive pulmonary disease exacerbation, 1 continuous positive airway pressure intolerance in a patient with obstructive sleep apnea, and 1 requirement of bi-level positive airway pressure. The pulmonary risk questionnaire accurately identified all patients who had pulmonary complications. The overall pulmonary complication rate at our institution decreased from 5.7% to 0.09% after implementing our screening questionnaire and intervention protocol (P < .0001). CONCLUSION: Our results demonstrate a more than 63-fold reduction in pulmonary complications at our institution. Our screening questionnaire and intervention protocol is an effective way of identifying and preventing pulmonary complications.

Primary Total Knee Arthroplasty Implants as Functional Prosthetic Spacers for Definitive Management of Periprosthetic Joint Infection: A Multicenter Study.

BACKGROUND: There are limited data on the utility of a standard primary total knee arthroplasty (TKA) femoral component with an all polyethylene tibia as a functional prosthetic spacer in place of a conventional all cement spacer for the management of periprosthetic joint infection (PJI). The aim of this multicenter study was to retrospectively review (1) ultimate treatment success; (2) reimplantation rates; (3) reoperation rates; and (4) change in knee range of motion in patients managed with functional prosthetic spacers following TKA PJI. METHODS: A retrospective review was performed for patients at 2 tertiary care centers who underwent a functional prosthetic spacer implantation as part of a functional single-stage (n = 57) or all cement spacer conventional two-stage (n = 137) revision arthroplasty protocol over a 5-year period. Outcomes including reinfection, reimplantation, and reoperation rates, success rate as defined by the Delphi criteria, and final range of motion were compared between the 2 cohorts at a minimum of 2-year follow-up. RESULTS: There was no significant difference in reinfection (14.0 vs 24.1%), reoperation (19.3 vs 27.7%), or success rates (78.9 vs 70.8%; P > .05 for all) between the one-stage and two-stage revision TKA cohorts. Mean final total arc of motion was also similar between the 2 groups (105.8 vs 101.8 degrees, respectively). CONCLUSION: Functional prosthetic spacers offer the advantage of a single procedure with decreased overall hospitalization and improved cost-effectiveness with analogous success rates (78.9%) compared with two-stage exchange (70.8%) at mid-term follow-up. Although long-term data are required to determine its longevity and efficacy, the outcomes in this study are encouraging. LEVEL OF EVIDENCE: 3.

A novel technique of reshaping the post of a constrained liner to avoid post and primary box mismatch in a case of recurrent dislocation after total knee arthroplasty.

Knee dislocation after total knee arthroplasty, although rare, is a dangerous injury that can lead to neurovascular compromise and permanent disability. With the increase in number of total knee arthroplasty, more and more cases of dislocations are being reported. We describe a novel technique of reshaping the post of a constrained liner to fit into the box of a vanguard primary knee system in a patient with recurrent posterior knee dislocation after a PS TKA with a follow-up of 5 years.

A Proactive Approach to High Risk Delirium Patients Undergoing Total Joint Arthroplasty.

BACKGROUND: Delirium is a common complication among elderly patients undergoing total joint arthroplasty (TJA). Its incidence has been reported from 4% to 53%. The Centers for Medicare and Medicaid Services consider delirium following TJA a "never-event." The purpose of this study is to evaluate a simple perioperative protocol used to identify delirium risk patients and prevent its incidence following TJA. METHODS: Our group developed a protocol to identify and prevent delirium in patients undergoing TJA. All patients were screened and scored in the preoperative assessment, on criteria such as age, history of forgetfulness, history of agitation or visual hallucinations, history of falls, history of postoperative confusion, and inability to perform higher brain functions. Patients were scored on performance in a simple mental examination. The patients were classified as low, medium, or high risk. Patients who were identified as high risk were enrolled in a delirium avoidance protocol that minimized narcotics and emphasized nursing involvement and fluids administration. RESULTS: Five of 7659 (0.065%) consecutive TJA patients from 2010 to 2015 developed delirium. A total of 422 patients were identified as high risk. All 5 patients who suffered delirium were within the high risk group. No low or medium risk patients suffered a delirium complication. Three (0.039%) patients suffered drug-induced delirium, 1 (0.013%) had delirium related to alcohol withdrawal, and 1 (0.013%) had delirium after a systemic infection. CONCLUSION: This protocol is effective in identifying patients at high delirium risk and diminishing the incidence of this complication by utilizing a simple screening tool and perioperative protocol.

When Does the Knee Feel Normal Again: A Cross-Sectional Study Assessing the Forgotten Joint Score in Patients After Total Knee Arthroplasty.

BACKGROUND: The forgotten joint score (FJS) is a recent scoring system that assesses how natural the prosthesis feels after total joint arthroplasty. Although the FJS has been extensively applied in populations with total hip prosthetics, less is known about the patients undergoing total knee arthroplasty (TKA). The purpose of this study is to investigate the temporal relationship between TKA and the FJS. METHODS: We evaluated 566 patients after TKA using the FJS questionnaire. Scores were calculated at the follow-up intervals of 1 (n = 79), 6 (n = 78), 12 (n = 81), 24 (n = 100), 36 (n = 76), 48 (n = 75), and 60 (n = 77) months. The scores ranged from 0-100, with a higher score indicating a more natural or "forgotten" joint. RESULTS: Postoperative FJS averages were 39.3 ± 27.4 at 1 month, 59.4 ± 28.3 at 6 months, 72.5 ± 24.2 at 1 year, 76.4 ± 23.4 at 2 years, 75.1 ± 24.2 at 3 years, 68.6 ± 28.7 at 4 years, and 64.4 ± 29.0 at 5 years. The average score at 1 month was significantly lower than the average scores at all other intervals. The average score at 6 months was significantly lower than the average scores at 12, 24, and 36 months. The average score at 60 months was significantly lower than the average score at 24 months. CONCLUSION: Based on the findings of this study, patients can expect marked improvement in the natural feel of the prosthesis during the first year after TKA, slight continued improvement at 2 and 3 years, and a decline after 4 years.

Incidence and Risk Factors for Postoperative Urinary Retention in Total Hip Arthroplasty Performed Under Spinal Anesthesia.

BACKGROUND: The objective of this study is to determine the risk factors for postoperative urinary retention (POUR) following total hip arthroplasty (THA) under spinal anesthesia. METHODS: Consecutive patients who underwent a primary THA without preoperative catheterization under spinal anesthesia were identified in a prospectively collected institutional patient database. All patients were monitored postoperatively for urinary retention on the basis of symptoms and the use of bladder ultrasound scans performed by a hospital technician. If necessary, straight catheterization was performed up to 2 times prior to indwelling catheter insertion. RESULTS: One hundred eighty patients were included in the study. Six patients who required indwelling catheterization for intraoperative monitoring were excluded. Seventy-six patients experienced POUR and required straight catheterization. Fourteen patients ultimately required indwelling catheterization. One patient who was not catheterized developed a urinary tract infection versus none of the patients who were catheterized. POUR was significantly associated with intraoperative fluid volume and a history of urinary retention (P = .018 and .023, respectively). Intraoperative fluid volumes of 2025, 2325, 2875, and 3800 mL were associated with a specificity for POUR of 60%, 82.7%, 94.9%, and 98%, respectively. No significant associations were found among catheterization and gender, body mass index, American Society of Anesthesiologists class, history of polyuria, history of incontinence, postoperative oral narcotics use, or surgical duration. CONCLUSION: Patients with a history of prior urinary retention and those who receive high volumes of intraoperative fluid volume are at higher risk for POUR following THA performed under spinal anesthesia.