A distinct human cell type expressing MHCII and RORγt with dual characteristics of dendritic cells and type 3 innate lymphoid cells.

Recent studies have characterized various mouse antigen-presenting cells (APCs) expressing the lymphoid-lineage transcription factor RORγt (Retinoid-related orphan receptor gamma t), which exhibit distinct phenotypic features and are implicated in the induction of peripheral regulatory T cells (Tregs) and immune tolerance to microbiota and self-antigens. These APCs encompass Janus cells and Thetis cell subsets, some of which express the AutoImmune REgulator (AIRE). RORγt+ MHCII+ type 3 innate lymphoid cells (ILC3) have also been implicated in the instruction of microbiota-specific Tregs. While RORγt+ APCs have been actively investigated in mice, the identity and function of these cell subsets in humans remain elusive. Herein, we identify a rare subset of RORγt+ cells with dendritic cell (DC) features through integrated single-cell RNA sequencing and single-cell ATAC sequencing. These cells, which we term RORγt+ DC-like cells (R-DC-like), exhibit DC morphology, express the MHC class II machinery, and are distinct from all previously reported DC and ILC3 subsets, but share transcriptional and epigenetic similarities with DC2 and ILC3. We have developed procedures to isolate and expand them in vitro, enabling their functional characterization. R-DC-like cells proliferate in vitro, continue to express RORγt, and differentiate into CD1c+ DC2-like cells. They stimulate the proliferation of allogeneic T cells. The identification of human R-DC-like cells with proliferative potential and plasticity toward CD1c+ DC2-like cells will prompt further investigation into their impact on immune homeostasis, inflammation, and autoimmunity.

Mitochondrial Pyruvate Import Promotes Long-Term Survival of Antibody-Secreting Plasma Cells.

Durable antibody production after vaccination or infection is mediated by long-lived plasma cells (LLPCs). Pathways that specifically allow LLPCs to persist remain unknown. Through bioenergetic profiling, we found that human and mouse LLPCs could robustly engage pyruvate-dependent respiration, whereas their short-lived counterparts could not. LLPCs took up more glucose than did short-lived plasma cells (SLPCs) in vivo, and this glucose was essential for the generation of pyruvate. Glucose was primarily used to glycosylate antibodies, but glycolysis could be promoted by stimuli such as low ATP levels and the resultant pyruvate used for respiration by LLPCs. Deletion of Mpc2, which encodes an essential component of the mitochondrial pyruvate carrier, led to a progressive loss of LLPCs and of vaccine-specific antibodies in vivo. Thus, glucose uptake and mitochondrial pyruvate import prevent bioenergetic crises and allow LLPCs to persist. Immunizations that maximize these plasma cell metabolic properties might thus provide enduring antibody-mediated immunity.

Significant Cost Savings and Improved Early Clinical Outcomes in Medicare Patients Utilizing a Clinician-Controlled Telerehabilitation System Following Total Knee Arthroplasty.

BACKGROUND: The costs and benefits of different rehabilitation protocols following total knee arthroplasty are unclear. The emergence of telerehabilitation has introduced the potential for enhanced patient convenience and cost reduction. The purpose of this study was to assess the cost difference between standard physical therapy (SPT) and a telerehabilitation home-based clinician-controlled therapy system (HCTS). METHODS: A prospectively enrolled, consecutive series of 109 Medicare patients who received SPT were compared to 101 Medicare patients who were treated with a HCTS. The analysis focused on total rehabilitation costs and the assessment of outcome measures: knee range of motion, visual analog scale pain levels, and Knee Injury and Osteoarthritis Outcome Score for Joint Replacement. RESULTS: The HCTS group demonstrated not only statistically significantly lower average costs but also faster and sustained knee range of motion improvements. Furthermore, in comparison to SPT, the HCTS group exhibited superior visual analog scale pain scores and Knee Injury and Osteoarthritis Outcome Score for Joint Replacement functional scores at all assessment points postoperatively, which were statistically significant (all P < .001) and surpassed the minimal clinically important difference thresholds. CONCLUSIONS: The HCTS used in this study exhibited a remarkable cost-saving advantage of $2,460 per patient compared to standard therapy. As approximately 500,000 primary total knee arthroplasties in the United States are covered by Medicare annually, a switch to HCTS could yield total cost savings of more than $1.23 billion per year for our taxpayer-funded health care system. Furthermore, the HCTS cohort demonstrated superior functional outcomes and improved pain scores across all assessment time points, exceeding the minimal clinically important difference.

International Delphi Study on Wound Closure and Dressing Management in Joint Arthroplasty: Part 1: Total Knee Arthroplasty.

BACKGROUND: The purpose of this modified Delphi study was to obtain consensus on wound closure and dressing management in total knee arthroplasty (TKA). METHODS: The Delphi panel included 20 orthopaedic surgeons from Europe and North America. There were 26 statements identified using a targeted literature review. Consensus was developed for the statements with up to three rounds of anonymous voting per topic. Panelists ranked their agreement with each statement on a five-point Likert scale. An a priori threshold of ≥ 75% was required for consensus. RESULTS: All 26 statements achieved consensus after three rounds of anonymous voting. Wound closure-related interventions that were recommended for use in TKA included: 1) closing in semi-flexion versus extension (superior range of motion); 2) using aspirin for venous thromboembolism prophylaxis over other agents (reduces wound complications); 3) barbed sutures over non-barbed sutures (lower wound complications, better cosmetic appearances, shorter closing times, and overall cost savings); 4) mesh-adhesives over other skin closure methods (lower wound complications, higher patient satisfaction scores, lower rates of readmission); 5) silver-impregnated dressings over standard dressings (lower wound complications, decreased infections, fewer dressing changes); 6) in high-risk patients, negative pressure wound therapy over other dressings (lower wound complications, decreased reoperations, fewer dressing changes); and 7) using triclosan-coated over non-antimicrobial-coated sutures (lower risks of surgical site infection). CONCLUSIONS: Using a modified Delphi approach, the panel achieved consensus on 26 statements pertaining to wound closure and dressing management in TKA. This study forms the basis for identifying critical evidence supported by clinical practice for wound management to help reduce variability, advance standardization, and ultimately improve outcomes during TKA. The results presented here can serve as the foundation for knowledge, education, and improved clinical outcomes for surgeons performing TKAs.

International Delphi Study on Wound Closure and Incision Management in Joint Arthroplasty Part 2: Total Hip Arthroplasty.

BACKGROUND: This modified Delphi study aimed to develop a consensus on optimal wound closure and incision management strategies for total hip arthroplasty (THA). Given the critical nature of wound care and incision management in influencing patient outcomes, this study sought to synthesize evidence-based best practices for wound care in THA procedures. METHODS: An international panel of 20 orthopedic surgeons from Europe, Canada, and the United States evaluated a targeted literature review of 18 statements (14 specific to THA and 4 related to both THA and total knee arthroplasty). There were 3 rounds of anonymous voting per topic using a modified 5-point Likert scale with a predetermined consensus threshold of ≥ 75% agreement necessary for a statement to be accepted. RESULTS: After 3 rounds of voting, consensus was achieved for all 18 statements. Notable recommendations for THA wound management included (1) the use of barbed sutures over non-barbed sutures (shorter closing times and overall cost savings); (2) the use of subcuticular sutures over skin staples (lower risk of superficial infections and higher patient preferences, but longer closing times); (3) the use of mesh-adhesives over silver-impregnated dressings (lower rate of wound complications); (4) for at-risk patients, the use of negative pressure wound therapy over other dressings (lower wound complications and reoperations, as well as fewer dressing changes); and (5) the use of triclosan-coated sutures (lower risk of surgical site infection) over standard sutures. CONCLUSIONS: Through a structured modified Delphi approach, a panel of 20 orthopedic surgeons reached consensus on all 18 statements pertaining to wound closure and incision management in THA. This study provides a foundational framework for establishing evidence-based best practices, aiming to reduce variability in patient outcomes and to enhance the overall quality of care in THA procedures.

A Home-Based, Remote-Clinician-Controlled, Physical Therapy Device Leads to Superior Outcomes When Compared to Standard Physical Therapy for Rehabilitation After Total Knee Arthroplasty.

BACKGROUND: The optimal postoperative rehabilitation regimen following total knee arthroplasty (TKA) is not clearly defined. The advent of telerehabilitation offers potential for increased patient convenience and decreased cost, while maintaining similar outcomes to traditional physical therapy (PT). Therefore, we evaluated a novel, home-based, clinician-controlled, multi-modal evaluation and therapy device with telerehabilitation functionality for TKA. METHODS: A total of 135 consecutive TKA patients receiving standard therapy protocol (STP) were compared to 135 consecutive patients receiving a home-based clinician-controlled therapy system (HCTS). Outcomes were assessed at 2, 6, and 12 weeks, including visual analog scale (VAS) for pain, knee injury and osteoarthritis outcome score JR (KOOS JR), and knee range of motion (ROM) measured by the same certified physical therapists. RESULTS: Postoperative knee ROM was greater in the HCTS group at all time points throughout the study period (P < .001 at 2, 6, and 12 weeks). VAS and the KOOS JR functional scores were statistically better (P < .001) in the HCTS group at all time points and exceeded the threshold for minimal clinically important difference (MCID) for both VAS and KOOS JR. There were significantly fewer cases of arthrofibrosis requiring manipulation under anesthesia (MUA) in the HCTS group (1.48 versus 4.44%). CONCLUSION: Following TKA, a novel, home-based, clinician-controlled, multi-modal therapy device was superior to standard PTduring the first 12 weeks postoperatively for ROM, KOOS JR, and VAS (with all scores exceeding the MCID) and had substantially fewer manipulations for arthrofibrosis.

Posterior Approach Total Hip Arthroplasty Utilizing a Monoblock Dual-Mobility Construct Without Posterior Hip Precautions: A Series of 580 Hips With One Dislocation.

BACKGROUND: Instability remains a devastating complication following total hip arthroplasty. Here we describe a mini-posterior approach with a monoblock dual-mobility implant without "traditional posterior hip precautions" yielding excellent results. METHODS: There were 580 consecutive hips in 575 patients who underwent total hip arthroplasty utilizing a monoblock dual-mobility implant and a mini-posterior approach. With this technique, the acetabular component positioning does not rely on tradition intra-operative radiographic abduction and anteversion goals but rather uses patient-specific anatomic landmarks (anterior acetabular rim and, when visible, the transverse acetabular ligament) to set cup position; stability is assessed with a significant, dynamic intra-operative test of range of motion. Patients' mean age was 64 years (range, 21 to 94), and 53.7% were women. RESULTS: Mean abduction was 48.4° (range, 29° to 68°) and mean anteversion was 24.7° (range, -1° to 51°). Patient Reported Outcomes Measurement Information System scores improved in every measured domain from preoperative to final postoperative visit. There were seven (1.2%) patients who required reoperation, with mean time to reoperation of 1.3 months (range, one to 176 days). Only one patient (0.2%) who had a preoperative history of spinal cord injury and Charcot arthropathy dislocated. CONCLUSION: A posterior approach hip surgeon may want to consider using a monoblock dual-mobility construct and avoidance of traditional posterior hip precautions to achieve early hip stability with an extremely low dislocation rate and high patient satisfaction scores.

Manipulation Under Anesthesia is Safe After Cementless Total Knee Arthroplasty: A Multicenter Study.

BACKGROUND: Cementless total knee arthroplasty (TKA) is thought to facilitate durable, biological fixation between the bone and implant. However, the 4-12 weeks required for osseointegration coincides with the optimal timeframe to perform a manipulation under anesthesia (MUA) if a patient develops postoperative stiffness. This study aims to determine the impact of early MUA on cementless fixation by comparing functional outcomes and survivorship of cementless and cemented TKAs. METHODS: A consecutive series of patients who underwent MUA for postoperative stiffness within 90 days of primary, unilateral TKA at 2 academic institutions between 2014 and 2018 were identified. Cases involving extensive hardware removal were excluded. Cementless TKAs undergoing MUA (n = 100) were propensity matched 1:1 to cemented TKAs undergoing MUA (n = 100) using age, gender, body mass index, and year of surgery. Both groups had comparable baseline Knee Injury and Osteoarthritis Outcome Scores (KOOS), Short Form (SF)-12 Physical, and SF-12 Mental scores. MUA-related complications as well as postoperative KOOS and SF-12 scores were compared. RESULTS: MUA-related complications were equivalently low in both groups (P = .324), with only 1 patella component dissociation in the cementless group. No tibial or femoral components acutely loosened in the perioperative period. Postoperative KOOS (P = .101) and SF-12 Mental scores (P = .380) were similar between groups. Six-year survivorship free from any revision after MUA was 98.0% in both groups (P = 1.000). CONCLUSION: Early postoperative MUA after cementless TKA was not associated with increased MUA-related complications or worse patient-reported outcomes compared to cemented TKA. Short-term survivorship was also comparable, suggesting high durability of the bone-implant interface.

Chitranjan S. Ranawat Award: Tourniquet Use Does Not Impact Trajectory of Total Knee Arthroplasty Early Recovery: A Prospective, Randomized Controlled Trial.

BACKGROUND: The impact of tourniquet use on recovery after total knee arthroplasty (TKA) remains controversial. The purpose of this prospective, single blinded, randomized controlled trial was to investigate the effect of tourniquet use on early recovery after TKA using a smartphone app-based patient engagement platform (PEP) with a wrist-based activity monitor to obtain more robust data on early recovery. METHODS: There were 107 patients undergoing primary TKA for osteoarthritis who were enrolled (54 tourniquet [TQ+]; 53 no tourniquet [TQ-]). All patients utilized a PEP and wrist-based activity sensor for 2 weeks preoperatively and 90 days postoperatively to collect Visual Analog Scale (VAS) pain scores and opioid consumption, as well as weekly Oxford Knee Score (OKS) and monthly Forgotten Joint Score (FJS). There was no difference in demographics between groups. Formal physical therapy assessments were performed preoperatively and 3 months postoperatively. Independent sample t-tests were used for continuous data and Chi-square and Fisher's exact tests were used for discrete data. RESULTS: Tourniquet use did not have a statistically significant impact on daily VAS pain or opioid consumption during the first 30 days postoperatively (P > .05). Tourniquet use did not have a significant impact on OKS or FJS at 30 or 90 days postoperatively (P > .05), or on performance of formal physical therapy testing at 3 months postoperatively (P > .05). CONCLUSION: Using a digital technology to collect daily patient data, we found that tourniquet use has no clinically significant negative impact on pain and function in the first 90 days after primary TKA.

The Impact of Component Design and Fixation on Stress Shielding After Modern Total Knee Arthroplasty.

BACKGROUND: Total knee arthroplasty (TKA) tibial baseplate thickness, metallurgy, and implant fixation with cement may influence stress shielding. The purpose of the present study is to compare bone mineral density of 2 cemented and press-fit TKA designs with differing tibial baseplate thicknesses and metallurgy over a 2-year period to assess for changes in stress shielding. METHODS: One-hundred one TKAs were performed in this Institutional Review Board-approved, prospective study. There were 4 cohorts: DePuy Attune cemented and press-fit, and Stryker Triathlon cemented and press-fit. The Attune tibial baseplate was thicker; both cemented tibial and femoral components were cobalt-chromium. The DePuy Attune press-fit had a cobalt-chromium sintered bead porous coating while the Stryker Triathlon was 3-dimensional printed highly porous titanium alloy. All patients had quantitative dual-energy X-ray absorptiometry scans performed at baseline (4-6 weeks postoperatively) and at 1 and 2 years postoperatively. Stress shielding was evaluated by comparing percent change in bone mineral density in 11 radiographic zones over 2 years. RESULTS: Over a 2-year period, there were no differences in stress shielding on the tibial side in either cemented or press-fit between Stryker Triathlon and DePuy Attune; however, there were differences on the femoral side. The press-fit tibial components of the Stryker Triathlon and DePuy Attune had either similar or less stress shielding over a 2-year period compared to their cemented counterparts. CONCLUSION: This study comparing 2 TKA implants with differing tibial tray thickness did not find significant differences in tibial stress shielding between designs. There was a difference in stress shielding on the femoral side between designs, suggesting that longer term follow-up is warranted.

Implant Malalignment may be a Risk Factor for Poor Patient-Reported Outcomes Measures (PROMs) Following Total Knee Arthroplasty (TKA).

BACKGROUND: Implant malalignment may be a risk factor for poor patient-reported outcomes measures (PROMs) following total knee arthroplasty (TKA). METHODS: Postoperative surveys were administered to assess PROMs regarding satisfaction, pain, and function in 262 patients who underwent surgery at 4 centers in the U.S. and U.K (average age, 67.2) at a mean 5.5 years after primary TKA. Postoperative distal femoral angle (DFA), proximal tibial angle (PTA), and posterior tibial slope angle (PSA) were radiographically measured, and outliers were recorded. PROMs were compared between patients with aligned versus malaligned knees using univariate analysis. RESULTS: Patients with DFA, PTA, and PSA outliers were more likely to experience similar or decreased activity levels postoperatively than patients with no alignment outliers, as were patients with 1 or 2 outliers of any kind (P < .05). Patients with DFA, PTA, and PSA outliers were significantly more likely to be dissatisfied with their ability to perform activities of daily living (ADLs), as were patients with 1 or 2 outliers of any kind (P < .05). Patients with DFA and PSA outliers were more likely to be dissatisfied with their degree of pain relief, as were patients with 2 outliers of any kind (P < .05). Finally, patients with DFA and PSA outliers, as well as those with 1 outlier of any kind, were more likely to be dissatisfied with their overall knee function (P < .05). CONCLUSION: DFA, PTA, and PSA outliers represent a significant risk factor for decreased satisfaction with activities of daily living(ADLs), pain relief, and knee function, as well as decreased activity levels. LEVEL OF EVIDENCE: Level III.

James A. Rand Young Investigator's Award: Questioning the "Nickel Free" Total Knee Arthroplasty.

BACKGROUND: A study was performed to measure metal ions present in the knee joint after performing a total knee arthroplasty (TKA) with standard cobalt chromium (CoCr) components as well as with "nickel-free" oxidized zirconium femoral and titanium tibial (OxZr/Ti) components. METHODS: Knee joint fluid was collected prior to arthrotomy, and on postoperative day one to determine the amount of metal debris generated when performing a TKA with standard instrumentation from consecutive cases with CoCr components (n = 24) and OxZr/Ti components (n = 16). RESULTS: CoCr implant patients had statistically higher levels of nickel (Ni) (29.7%, P = .033), cobalt (Co), (1,100.7%, P < .0001) and chromium (Cr) (118.9%, P < .0001) postoperatively. The cutting blocks and sawblades do not contain Co, which therefore must have come from the components. The metal ions generated from the sawblades and cutting blocks, therefore, could be discerned from the OxZr/Ti whose components don't contain Co, Cr, or Ni. The OxZr patients had significantly higher Cr (9.5×, P < .001) and Ni (5.1×, P < .001) post-TKA vs pre-TKA; Co levels were not significantly different as expected with the absence of Co in the components (P = .60). The Ni levels generated in performing an Oxinium TKA was 3.3 times higher than when performing a CoCr TKA (1.37 vs. 41 ppb, P < .001). CONCLUSIONS: The substantial degree of Ni generation resulting from performing a hypoallergenic "nickel-free" TKA calls into questions the rationale of utilizing more expensive lower Ni components on the basis of known or suspected Ni or Cr allergy.

Applying the Hip-Spine Relationship: What X-Rays and Measurements Are Important?

Understanding spinopelvic motion and the dynamic relationship of the hip, spine, and pelvis is essential in decreasing the risk of instability after total hip arthroplasty. The hip-spine relationship is complex, and a detailed analysis of each patient's spinopelvic mobility is warranted to help guide safe acetabular component positioning. Through the use of a standing anteroposterior pelvis X-ray, lateral spinopelvic radiographs in the standing and seated position, and advanced functional imaging, key spinopelvic parameters can be obtained. A systematic preoperative workup can help to identify hip-spine pathology that predisposes patients to instability, and can help in planning and establishing a patient-specific "safe zone." Based on the presence of concomitant hip-spine pathology, patients must be evaluated thoroughly with preoperative imaging to plan for the optimal target acetabular cup position. This paper guides readers through important parameters and imaging associated to spinopelvic motion as it relates to total hip arthroplasty stability.

Allergies, Preoperative Narcotic Use, and Increased Age Predict Failed Same-Day Discharge After Joint Replacement.

BACKGROUND: Identifying predictors of failed same-day discharge (SDD) is critical for patient selection. We evaluated patient factors associated with failure of SDD in patients undergoing elective total joint arthroplasty (TJA) in a hospital setting. METHODS: We retrospectively reviewed consecutive patients who underwent primary total knee arthroplasty (TKA) and total hip arthroplasty (THA) between January 31, 2018 and February 1, 2020 by one of the 3 fellowship-trained arthroplasty surgeons. Patient demographics, comorbidities, and clinical data were collected. Analysis was performed to assess risk factors for failed SDD. RESULTS: In total, 2615 TJAs (1425 TKAs, 1190 THAs) were performed over the study period. Two hundred seventy-one (10.4%) were SDDs (80 TKAs, 191 THAs). There were fewer TKAs than THAs (5.6% vs 16.1%, P < .001). Forty-five patients failed SDD (16.6%). Failure rates were similar in TKA and THA (18.8%, 15.7%, P = .54). The most common reasons for failure of SDD were hypotension (11, 24.4%), delayed resolution of spinal anesthesia (11, 24.4%), and nausea (5, 11.1%). Age over 70 years (P = .007), greater than 2 self-reported allergies (P < .001), and preoperative narcotic use (P = .01) were associated with failure of SDD. Gender, body mass index, American Society of Anesthesiologists class, and prior TJA were not significantly associated (P > .05). CONCLUSION: Success of SDD was greater than 80%. Hypotension, delayed resolution of spinal anesthesia, and nausea accounted for 60% of failures of SDD. Patients >70 years, those with >2 self-reported drug allergies, or patients who used preoperative narcotics were at high risk for failure of SDD after THA or TKA.

Is Apixaban Safe and Effective for Venous Thromboembolism Prophylaxis After Primary Total Hip and Total Knee Arthroplasties?

BACKGROUND: Venous thromboembolism (VTE) is a serious complication of total hip arthroplasty (THA) and total knee arthroplasty (TKA). Apixaban is approved for VTE prophylaxis. This study seeks to ascertain the risk of VTE and bleeding complications in patients undergoing primary THA and TKA receiving apixaban for postoperative VTE prophylaxis for one of the following indications: high risk for VTE, previously on apixaban, and contraindication to the use of aspirin. METHODS: This is a retrospective cohort study of patients who underwent primary THA or TKA over a 17-month period and were prescribed apixaban for thromboprophylaxis postoperatively. RESULTS: 230 patients were included in the study, 110 TKA and 120 THA. The primary reasons for high-risk VTE status included personal and family history of VTE, and 13% were taking apixaban preoperatively for atrial fibrillation. 1 patient (0.43%) who underwent TKA had a DVT with PE. 2.6% of patients had wound complications requiring operative treatment, and 0.87% of THA patients underwent revision arthroplasty. CONCLUSION: The use of apixaban for VTE prophylaxis after primary THA and TKA in patients at high risk for VTE, in patients previously on apixaban, and in patients with a contraindication to the use of aspirin is associated with a low risk of VTE and bleeding complications.

Total Hip Arthroplasty in Patients With Osteoarthritis Associated With Legg-Calve-Perthes Disease: Perioperative Complications and Patient-Reported Outcomes.

BACKGROUND: Complications and patient-reported outcomes (PROs) of total hip arthroplasty (THA) in patients with Legg-Calve-Perthes disease (LCPD) have demonstrated variable results. The purpose of this study was to use a validated grading scheme to analyze complications associated with THA in patients with residual LCPD deformities. Second, we report PROs and intermediate-term survivorship in this patient population. METHODS: A retrospective, single-center review was performed on 61 hips in 61 patients who underwent THA for residual Perthes disease. Average patient age was 42 years and 26% of hips had previous surgery. Complications were determined and categorized using a validated grading scheme that included five grades based on the treatment required to manage the complication and on persistent disability. PROs were compared from preoperative to most recent follow-up time points. RESULTS: Major complications (grade III) occurred in three patients (5%) which each required a second surgical intervention. The most common minor grade I or II complications (11.5%) were asymptomatic heterotopic ossification (3.3%). Patients were lengthened on the surgical side an average of 1.4 cm with no nerve palsies. All patient PROs improved from preoperative to postoperative time points with the modified Harris Hip Score improving from 46.9 preoperatively to 85.4 postoperatively (P < .01). Patients free from revision for any reason at final follow-up (5.6 years; range 2-13 years) was 98.4% with one patient needing a revision of their femoral component. CONCLUSIONS: THA for the sequelae of the LCPD has an acceptable complication rate and provides excellent patient reported outcomes at mid-term follow-up.

Distinct expression pattern of periostin splice variants in chondrocytes and ligament progenitor cells.

Periostin (POSTN), a secretory matricellular matrix protein, plays a multitude of biologic functions. Various splice variants of POSTN have been described; however, their expression pattern and functional implications are not completely understood. This study was undertaken to decipher the differential expression pattern of POSTN and its splice variants in various tissues and cell types. We show that POSTN was more highly expressed in anterior cruciate ligament (ACL) remnants compared with articular cartilage at the cellular and tissue level. Isoforms 1 and 8 were highly expressed only in articular chondrocytes, suggesting their splice-specific regulation in chondrocytes. To discern the role of total POSTN and full-length human POSTN isoform 1 (hPOSTN-001), we stably transfected human chondrosarcoma 1 (hCh-1) cell line with hPOSTN-001 using a pcDNA3.1-hPOSTN-001 construct. RNA-sequencing analysis of hCh-1 cells identified differentially expressed genes with a known role in chondrocyte function and osteoarthritis. Similar expression of a subset of candidate genes was revealed in ACL progenitor cells and chondrocytes as well as in ACL progenitor cells in which POSTN activity was altered by overexpression and by small interfering RNA gene knockdown. Cells expressing total POSTN, not isoform 1, exhibited increased cell adhesion potential. These findings suggest an important role for POSTN in the knee.-Cai, L., Brophy, R. H., Tycksen, E. D., Duan, X., Nunley, R. M., Rai, M. F. Distinct expression pattern of periostin splice variants in chondrocytes and ligament progenitor cells.

It's a Brave New World: Alternative Payment Models and Value Creation in Total Joint Arthroplasty.

Alternative payment models are constantly evolving in an attempt to create value by decreasing cost while improving or maintaining quality. The Bundled Payments for Care Improvement initiative was implemented in 2011, and many institutions have seen early success by using the seven pillars of total joint arthroplasty episode management. Private insurers have seen improvements in care and cost savings by adopting private bundle programs. In each organization, alignment among all stakeholders is paramount to the success of the bundled payment programs. Gainsharing offers a unique opportunity to incentivize physicians to change their care practices in an attempt to reduce costs and improve outcomes. As bundled payments evolve, the cooperation of physicians, health care institutions, payers, and patients will lead to value creation for all stakeholders.

Effect of Adductor Canal Block on Acute Perioperative Pain and Function in Total Knee Arthroplasty.

BACKGROUND: Multimodal pain management strategies are commonplace in perioperative management of total knee arthroplasty (TKA), although controversy remains regarding the role of adductor canal blocks (ACB) in this algorithm. The purpose of this study is to independently evaluate the effect of ACB on short-term postoperative outcomes including (1) length of stay (LOS), (2) postoperative narcotic utilization, and (3) function with physical therapy in the era of modern TKA. METHODS: We retrospectively identified a cohort of consecutive patients from January 2014 to January 2018 who had undergone unilateral primary TKA using a single-shot ACB in addition to a standardized multimodal pain regimen vs those who only received a multimodal pain regimen. These 2 groups were compared using independent sample t-tests with primary end points of interest being LOS, distance ambulated with therapy, and inpatient narcotic use. RESULTS: There were 624 patients in the ACB group, with a mean age of 64.5 years. The group without ACB consisted of 69 patients, with a mean age of 67.2 years. We observed no significant difference in narcotic utilization postoperatively (2.361 vs 2.097, P = .088). The ACB group ambulated significantly further with therapy (75.8 vs 59.9 ft, P = .008) and had a shorter LOS in both total hours and percentage of postoperative day 1 (%POD1) discharges (34.8 vs 40.6 hours, P = .01, 83% vs 66.6%, P = .01). CONCLUSION: ACB did not decrease postoperative pain medication utilization. The modest improvement in distance ambulated with therapy on POD1 (16 ft) and LOS (16% greater POD1 discharges) may not support the cost-effectiveness of this intervention. LEVEL OF EVIDENCE: III, Retrospective Cohort.

Patient Attitudes Toward Resident and Fellow Participation in Orthopedic Surgery.

BACKGROUND: Residents' and fellows' participation in orthopedic surgery is a potential source of anxiety and concern for patients. The purpose of this study was to determine patients' attitudes toward trainee involvement in orthopedic surgery, surgeons as educators, and disclosure of trainee involvement. METHODS: Three hundred two consecutive patients with preoperative and postoperative appointments at three arthroplasty practices in academic medical centers were surveyed with an anonymous, self-administered questionnaire. The questionnaire was developed in consultation with an expert in survey design. RESULTS: Two hundred thirty-four patients completed the questionnaire (response rate 77.5%). Respondents were 60.5% female, 79.6% white, 66.5% privately insured, and 82.8% had at least some college education. About 65.9% of the respondents felt that surgeons who teach are better surgeons. Nearly all felt residents and fellows should perform surgeries as part of their education (94.1% and 95.3%, respectively). However, 39.7% of the respondents were not satisfactory with a second-year resident assisting in their own surgery. Patients dissatisfied with their most recent orthopedic surgery were more likely to respond that they did not want residents helping with their surgery. Respondents agreed that resident or fellow involvement in surgery should be disclosed (92.2% and 90.1%, respectively). CONCLUSIONS: Insured and educated patients in the United States overwhelmingly desire disclosure of trainee involvement in their surgery. To address the need for orthopedic training in the context of a patient population that is not fully comfortable with trainee involvement in their own surgery, an open discussion between patients and surgeons regarding trainees' roles may be the best course of action.