Total Knee Arthroplasty With or Without Prior Bariatric Surgery: A Systematic Review and Meta-Analysis.

BACKGROUND: Studies comparing the outcomes of bariatric surgery followed by total knee arthroplasty (TKA) versus TKA alone in obese patients have disparate results. This systematic review and meta-analysis sought to compare TKA with and without prior bariatric surgery in obese patients. METHODS: MEDLINE, PubMed, and Embase were searched from inception to April 9, 2023. There were twelve included studies that yielded 2,876,547 patients, of whom 62,818 and 2,813,729 underwent TKA with and without prior bariatric surgery, respectively. Primary outcomes were medical complications (ie, urinary tract infection, pneumonia, renal failure, respiratory failure, venous thromboembolism [VTE], arrhythmia, myocardial infarction, and stroke); surgical complications (ie, wound complications [eg, infection, hematoma, dehiscence, delayed wound healing, and seroma], periprosthetic joint infection, mechanical complications, periprosthetic fracture, knee stiffness, and failed hardware); revision, and mortality. Secondary outcomes were blood transfusion, length of stay (day), and readmission. RESULTS: The odds ratios (OR) of 90-day VTE (OR = 0.75 [0.66, 0.85], P < .00001), 90-day stroke (OR = 0.58 [0.41, 0.81], P = .002), and 1-year periprosthetic fracture (OR = 0.74 [0.55, 0.99], P = .04) were lower in those who underwent bariatric surgery before TKA. Although the mean difference in hospital stays (-0.19 days [-0.23, -0.15], P < .00001) was statistically less in those who underwent bariatric surgery before TKA, it was not clinically relevant. The other outcomes were similar between the groups. CONCLUSIONS: Bariatric surgery before TKA is beneficial in terms of a lower risk of VTE, stroke, and periprosthetic fracture. This analysis suggests surgeons consider discussing bariatric surgery before TKA in obese patients, especially those who are at risk of VTE and stroke.

Characterizing Osteophyte Formation in Knee Osteoarthritis: Application of Machine Learning Quantification of a Computerized Tomography Cohort: Implications for Treatment.

BACKGROUND: Osteophytes are commonly used to diagnose and guide knee osteoarthritis (OA) treatment, but their causes are unclear. Although they are not typically the focus of knee arthroplasty surgeons, they can predict case difficulty and length. Furthermore, their extent and location may yield much information about the knee joint status. The aims of this computed tomography-based study in patients awaiting total or partial knee arthroplasty were to: (1) measure osteophyte volume in anatomical subregions and relative change as total volume increases; (2) determine whether medial and/or lateral OA affects osteophyte distribution; and (3) explore relationships between osteophytes and OA severity. METHODS: Data were obtained from 4,928 computed tomography scans. Machine-learning-based imaging analyses enabled osteophyte segmentation and quantification, divided into anatomical regions. Mean three-dimensional joint space narrowing was assessed in medial and lateral compartments. A Bayesian model assessed the uniformity of osteophyte distribution. We correlated femoral osteophyte volumes with B-scores, a validated OA status measure. RESULTS: Total tibial (25%) and femoral osteophyte volumes (75%) within each knee correlated strongly (R2 = 0.85). Medial osteophytes (65.3%) were larger than lateral osteophytes (34.6%), with similar proportions in both the femur and tibia. Osteophyte growth was found in all compartments, and as total osteophyte volume increased, the relative distribution of osteophytes between compartments did not markedly change. No evidence of variation was found in the regional distribution of osteophyte volume between knees with medial, lateral, both, or no three-dimensional joint space narrowing in the femur or tibia. There was a direct relationship between osteophyte volume and OA severity. CONCLUSIONS: Osteophyte volume increased in both medial and lateral compartments proportionally with total osteophyte volume, regardless of OA location. The peripheral position of femoral osteophytes does not appear to contribute to load-bearing. This suggests that osteophytic growth represents a 'whole-knee'/global response. This work may have broad applications for knee OA, both surgically and nonoperatively.

Risk of Venous Thromboemboli, Readmissions, and Costs in Opioid Use Disorder Patients Following Revision Total Knee Arthroplasty.

INTRODUCTION: Opioid use disorder (OUD) patients have an increased risk of venous thromboembolism (VTE), readmissions, and higher costs following primary elective primary total joint arthroplasty, but these risks have not yet been clarified for other arthroplasty surgeries. Thus, the purpose of this study was to investigate whether OUD patients undergoing revision total knee arthroplasty (RTKA) have higher rates of: VTEs, readmissions, and costs of care. MATERIALS AND METHODS: Patients who had a 90-day history of OUD prior to undergoing RTKA were identified and randomly matched to a comparison cohort in a 1:4 ratio by age, sex, Elixhauser-Comorbidity Index (ECI), diabetes mellitus, hyperlipidemia, hypertension, obesity, and tobacco use with a total of 16,851 patients collectively in both groups. The 90-day frequency and odds (OR) of developing VTE, deep vein thrombosis (DVTs), and PEs along with 90-day readmission rates and 90-day costs of care were analyzed. A p-value less than 0.01 was considered statistically significant. RESULTS: OUD patients undergoing RTKA were found to have a higher incidence and odds of VTE (2.91 vs. 1.88; OR: 1.58, p<0.0001) 90 days following RTKA. Compared to the matched cohort, patients who have OUD had a higher incidence and increased risk of lower extremity DVT (2.61 vs. 1.73; OR: 1.52, p=0.0008) and PE (0.97 vs. 55%; OR: 1.74, p=0.007). Furthermore, the likelihood (25.7 vs. 21.4%; OR: 1.26, p<0.0001) of being readmitted within 90 days was higher in OUD patients. Additionally, OUD was associated with significantly higher total global 90-day episode-of-care costs ($19,289.31 ± $17,378.71 vs. $17,292.87 vs. $11,690.61; p<0.0001). CONCLUSION: Patients who have OUD undergoing RTKA have higher rates of thromboembolic complications, readmission rates, and total global 90-day episode-of-care costs. Orthopaedic surgeons should educate OUD patients about these risks and titrate patient opioid consumption through multi-specialty interventions prior to surgery to improve outcomes and reduce costs.

Increased In-Hospital Lengths of Stay, Readmission Rates, Complications, and Costs in Patients Who Have Depressive Disorders Following Primary Total Hip Arthroplasty.

INTRODUCTION: Recent studies have shown the prevalence of depressive disorders has increased within the United States. Studies investigating the impact of depressive disorders following primary THA are limited. Therefore, the purpose of this study was to determine whether patients with depressive disorders have higher rates of: 1) in-hospital lengths of stay (LOS); 2) readmission rates; 3) medical complications; and 4) implant-related complications. MATERIALS AND METHODS: A retrospective query of the Humana claims database was performed. Patients undergoing primary THA with a history of depressive disorders were identified by International Classification of Disease, Ninth Revision (ICD-9), and Current Procedural Terminology (CPT) codes. Study group patients were matched to controls in a 1:5 ratio by age, sex, and comorbidities. The query yielded 67,245 patients with (n=11,255) and without (n=55,990) depressive disorders. Welch's t-tests were used to test for significance in LOS between the cohorts; whereas, logistics regression analyses were used for complications and readmissions. A p-value less than 0.003 was statistically significant. RESULTS: Patients with depressive disorders undergoing primary THA had significantly longer in-hospital LOS (6.59 days vs. 2.96 days, p <0.0001). Additionally, patients with depressive disorders had higher incidence and odds of readmission rates (46.02 vs. 35.43%; OR: 1.55, p <0.0001), medical complications (7.05 vs. 1.84%; OR: 4.04, p <0.0001), and implant-related complications (5.76 vs. 2.75%; OR: 2.16, p <0.0001) compared to patients without depressive disorders. CONCLUSION: After matching age, sex, and medical comorbidities, the results of the study demonstrate patients with depressive disorders have longer in-hospital LOS and increased rates of complications and readmission rates. The study is useful as it can allow orthopedic surgeons to properly counsel these patients of the potential complications which may arise following their procedure.

A Novel Biofilm-Disrupting Wound Care Technology for the Prevention of Surgical Site Infections Following Total Joint Arthroplasty: A Conceptual Review.

Surgical site infections (SSIs) are a major driver for increased costs following lower extremity joint arthroplasty procedures. It has been estimated that these account for over $2 billion in annual costs in the United States. While many of the current strategies for the prevention and treatment of SSIs target planktonic bacteria, 80 to 90% of bacterial pathogens exist in a sessile state. These sessile bacteria can produce extracellular polymeric substance (EPS) as protective barriers from host immune defenses and antimicrobial agents and thus, can be exceedingly difficult to eradicate. A novel wound care gel that disrupts the EPS and destroys the inciting pathogens has been developed for the treatment and prevention of biofilm-related infections. This is achieved by the simultaneous action of four key ingredients: (1) citric acid; (2) sodium citrate; (3) benzalkonium chloride; and (4) polyethylene glycol. Together, these constituents create a high osmolarity, pH-controlled environment that deconstructs and prevents biofilm formation, while destroying pathogens and promoting a moist environment for optimal wound healing. The available clinical evidence demonstrating the efficacy of this technology has been summarized, as well as the economic implications of its implementation and the authors' preferred method of its use. Due to the multifaceted burden associated with biofilm-producing bacteria in arthroplasty patients, this technology may prove to be beneficial for patients who have higher risks for infection, or perhaps, as a prophylactic measure to prevent infections for all patients.

The Utility of Telehealth in the Recovery From the COVID-19 Pandemic.

Telehealth has recently been used more often in an attempt to protect practitioners and patients during the 2019 coronavirus infectious disease (COVID-19) crisis. Despite telehealth's existence, there was no prior need to fully realize its potential. Recently, technological innovations in orthopaedic surgery have assisted in making this modality more useful. However, it is important to continually educate the medical community regarding these technologies and their interplay to improve patient care. Therefore, our purpose is to provide information on telehealth by assessing: (1) steps the hospital/system are taking to reduce COVID-19 exposure for teams and patients; (2) new technologies allowing for the optimization of patient safety; and (3) use of telehealth for postoperative follow up. We will demonstrate that telehealth and its associated strategies can be used effectively to decrease COVID-19 exposure risks for both medical staff and patients during these rapidly changing and uncertain times.

Bundled-Care Program for the Prevention of Surgical-Site Infections Following Lower Extremity Total Joint Arthroplasty.

Surgical-site infections (SSIs) are among the most difficult-to-manage complications after lower extremity total joint arthroplasty (TJA). While the rates of most implant-related complications have decreased over time due to improvements in prosthetic materials and surgical techniques, the incidence of periprosthetic joint infections (PJIs) continues to increase. They place a tremendous economic burden on healthcare systems that is projected to reach $1.8 billion by the year 2030. A number of perioperative infection mitigation strategies exist that are often implemented concurrently to minimize the risk of these complications. A multicenter randomized controlled trial is underway to evaluate the efficacy of a bundled care program for the prevention of PJIs in lower extremity TJA. This bundle includes five infection-reduction strategies that are used pre-, peri-, and postoperatively, including: (1) povidone-iodine skin preparation and nasal decolonization; (2) iodine-alcohol surgical prepping solution; (3) iodophor-impregnated incise drapes; (4) forced-air warming blankets; and (5) negative pressure wound therapy for select patients. The aim of this review is to describe these products and their appropriate usage, review the available literature evaluating their use, and compare them with other commercially available products. Based on the available literature, each of these strategies appear to be important components for SSI-prevention protocols. We believe that implementing all five of these mitigation strategies concurrently will lead to a synergistic effect for infection control following lower extremity TJA.

Robotic-Assisted Total Hip Arthroplasty in Patients Who Have Developmental Hip Dysplasia.

INTRODUCTION: Total hip arthroplasty (THA) in the setting of developmental dysplasia of the hip (DDH) presents more inherent complexities than routine primary THA for osteoarthritis. These include acetabular bone deficiency, limb length discrepancy (LLD), and abnormal femoral anteversion. Three-dimensional planning and robot-assisted (RA) bone preparation may simplify these complex procedures and make them more reproducible. The purpose of this study was to evaluate radiographic and clinical outcomes in a cohort of patients who had DDH and underwent an RA THA. MATERIALS AND METHODS: We retrospectively analyzed 26 DDH patients who underwent RA THA by a single surgeon between 2013 and 2019. Their mean age was 54 years (range, 29 to 72 years) and mean follow up was approximately two years. Medical records were reviewed for demographics, clinical scores, Crowe classifications, and complications. There were thirteen Crowe I and seven Crowe II DDH hips, who were routinely managed with primary cementless implants. Two patients who had Crowe III and four patients who had Crowe IV DDH were also identified. All hips were reconstructed with cementless hemispherical acetabular components with or without the use of screws, but no acetabular augments or bulk allografts. Implants allowing control of femoral anteversion were selected in 23.1% of cases, including all six cases with Crowe III or IV dysplasia, and the need for these implants was uniformly identified using preoperative information about femoral version provided by the three-dimensional planning software. No patient was managed with a shortening femoral osteotomy. Postoperative radiographs were examined for LLD, center of rotation (COR), cup position (inclination and anteversion), and component osseous-integration. RESULTS: Mean radiographic LLD was 1.7mm (range, -9 to +14) in patients who had Crowe I DDH, and there was no clinical LLDs greater than 5mm observed. Although patients who had Crowe II and greater DDH had a mean radiographic LLD of -11.6mm (range, -26 to +2.2), again no clinical LLD greater than 5mm was observed other than one patient who had bilateral Crowe II DDH in whom 10mm of clinical lengthening was accepted at the index arthroplasty with the plan to match lengths when her contralateral THA was performed. There were no cases of dislocation or acetabular fixation failure. One patient who had a femoral deformity and an intra-osseous blade plate from a prior femoral osteotomy suffered a failure of femoral osseous-integration, resulting in revision. A 32-point increase in mean modified Harris Hip Score (mHHS) was found (p=0.002), from 48 points preoperatively to 80 points postoperatively. DISCUSSION: RA THA provides an excellent option for the arthroplasty surgeon to both preoperatively localize and characterize the acetabular deficiency, while providing a targeted, optimal, and secure placement of the components intraoperatively. Our results suggest favorable outcomes when compared to previous research on manual THA in DDH. Further studies, including comparative analyses, could discern possible advantages over traditional THA without robotic assistance in DDH. CONCLUSION: Total hip arthroplasty (THA) in the setting of developmental dysplasia presents more inherent complexities than routine primary THA. Robotic-assisted THA may simplify these complex procedures.

Range of Motion to Impingement Curves Create a New Patient-Specific Impingement-Free Zone for Acetabular Cup Placement.

INTRODUCTION: The acetabular "safe zone" has recently been questioned as a reliable reference for predicting total hip arthroplasty impingement and instability as many dislocations occur within the described parameters. Recently, an improved understanding of spino-pelvic mechanics has provided surgeons useful information to both identify those at a higher risk of dislocation and, in some cases, allows altering component positioning to accommodate the patient's individual "functional" range of motion. The purpose of this study was to create a new patient-specific impingement-free zone by considering range of motion (ROM) to prosthetic impingement for both high flexion and extension poses, thus demarcating a zone that avoids both anterior and posterior impingement, thereby creating an objective approach to identifying a patient's ideal functional safe zone. MATERIALS AND METHODS: A validated hip ROM three-dimensional simulator was utilized to create ROM-to-impingement curves for both high flexion as well as pivot and turn poses. The user imported a computerized tomography (CT) with a supine pelvic tilt (PT) value of zero and implant models (tapered wedge stem, 132° neck angle, 15° stem version, 36mm femoral head). Femur-to-pelvis relative motions were determined for three upright seated poses (femur flexed at 90° and 40° internal rotation, with 0°, 10°, and 20° posterior PT), one chair rise pose (femur flexed at 90° and 0° internal rotation, with the pelvis flexed anteriorly until the pelvis made contact with the femur), and three standing pivot and turn poses (femur set at 5° extension, and 35° external rotation, with 5° posterior PT, 0°, and 5° anterior PT). ROM-to-impingement curves for cup inclination versus anteversion were graphed and compared against the Lewinnek safe zone. RESULTS: The ROM-to-impingement curves provide an objective assessment of potential impingement sites as they relate to femoral rotation and pelvic tilt. The area between the stand and sit curves is the impingement-free area. A sitting erect pose with a simulated stiff spine (0° PT) yielded less impingement-free combinations of cup inclination and version than poses with greater than 0° posterior pelvic tilt. CONCLUSION: The results demonstrate that the acetabular target zone has a relatively small margin for error between the sitting and standing ROM curves to impingement. Importantly, anterior and posterior pelvic tilt can markedly increase the risk of impingement, potentially leading to posterior or anterior dislocations, respectively. This study highlights the importance of correctly identifying the patient-specific functional range of motion to execute optimal component positioning.

Diagnosis and Treatment of Femoral Head Osteonecrosis: A Protocol for Development of Evidence-Based Clinical Practice Guidelines.

INTRODUCTION: There are many treatment options for patients who have osteonecrosis of the femoral head (ONFH) and management strategies vary widely both among and within individual countries. Although many researchers have attempted to elucidate the optimal strategies for managing this disease, the lack of large-scale randomized control trials and the lack of agreement on disease staging have curtailed the development of clear-cut guidelines. MATERIALS AND METHODS: The Association Research Circulation Osseous (ARCO) group sought to address three questions for the management of patients who have ONFH: 1) What imaging studies are most sensitive and specific for the diagnostic evaluation of patients who have ONFH?; 2) What is the best treatment strategy for preventing disease progression in patients who have pre-collapse lesions?; and 3) What is the best treatment strategy for patients who have post-collapse disease? The Patient, Intervention, Comparison, and Outcome (PICO) format was used to formulate the search strategy for each research question. A systematic review will be performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. ARCO participants have been allocated to three groups, each representing one of the PICO questions. After qualitative and quantitative analysis of the data extracted from studies pertaining to each of the three research questions, a set of evidence-based clinical practice guidelines will be proposed for the management of patients who have ONFH. DISCUSSION: It is not always clear which treatment method is optimal for the management of ONFH. Thus, many surgeons have developed and performed various procedures based on patient-specific factors. As there is no consensus on the optimal treatment for various stages of disease, it was clear that developing evidence-based clinical practice guidelines would provide more structure and uniformity to management of these patients. Therefore, the results of this systematic review will lead to the development guidelines that may improve patient-care strategies and result in better outcomes for patients who have ONFH.

Is Iron Deficiency Anemia a Risk Factor for Poorer Outcomes in Primary Total Knee Arthroplasty?

BACKGROUND: Patients undergoing total knee arthroplasty (TKA) commonly have concomitant iron deficiency anemia (IDA). The purpose of this study is to investigate the effect of IDA on (1) total in-hospital lengths of stay (LOS); (2) 90-day readmissions; (3) costs of care; (4) medical complications; and (5) and implant-related complications in patients who underwent primary TKA. METHODS: Patients with and without IDA undergoing primary TKA were identified and matched through a nationwide administrative claims database that yielded 94,053 and 470,264 patients, respectively. Primary outcomes that were statistically analyzed included in-hospital LOS, readmission rates, costs of care, medical complications, and implant-related complications. RESULTS: Patients with IDA had longer in-hospital LOS (4 days vs 3 days; P < .0001), 90-day readmission rates (25.8% vs 16.3%; odds ratio [OR], 1.77; P < .0001), higher day of surgery ($13,079.42 vs $11,758.25; P < .0001), and total global 90-day episode of care costs ($17,635.13 vs $14,439.06; P < .0001) compared to patients who do not have IDA. Furthermore, IDA patients were found to have significantly higher incidence and odds of medical (3.53% vs 1.33%; OR, 2.71; P < .0001) and implant-related (3.80% vs 2.68%; OR, 1.43; P < .0001) complications following primary TKA. CONCLUSION: The effect of IDA on TKA outcomes may make a large impact on healthcare usage. We found that patients with IDA had poorer results in all the outcomes that were measured. Orthopedic surgeons can use this information to evaluate the need for IDA interventions before TKA which may contribute to lower rates of morbidity and mortality in TKA.

The Use of New Technology for Wound Management Following Total Knee Arthroplasty: Implications for the COVID-19 Crisis.

With constantly evolving materials and techniques used in wound closure management for total knee arthroplasty (TKA), it is imperative that we continuously evaluate new modalities and techniques to optimize healing. This article provides a concise review of the current closure and wound management methods for each of the following three layers and dressing: 1) deep fascia layer, or arthrotomy; 2) subdermal layer or subcutaneous layer; 3) skin and subcuticular layer; and 4) dressing application. By introducing a comprehensive and systematic approach to TKA wounds, this report also incorporates newer modalities such as barbed sutures and adhesive dressings, which have increasingly replaced traditional suture and staple methods. Furthermore, we examine how various layers of modern wound closure compare to conventional methods while discussing both the clinical and economic impacts of each. Newer wound management methods, such as the adhesive and occlusive dressings with varying monofilament subcuticular sutures, can eliminate the need for staple and suture removal, increase the value of care provided, limit unnecessary postoperative visits, and potentially address wound issues by communicating safely with patients via telemedicine, an ever-relevant discussion in the era of coronavirus disease 2019 (COVID-19).

Evolution of 3-Dimensional Functional Planning for Total Hip Arthroplasty with a Robotic Platform.

Robotic-assisted surgery was introduced to make various mechanical aspects of a total hip arthroplasty more reproducible. When paired with sophisticated three-dimensional preoperative planning, robotic surgery offers the promise that a surgeon might select and reliably achieve targets for component position to optimize hip center-of-rotation, acetabular anteversion and inclination, femoral offset, as well as limb length. This paper describes a patient-specific step-by-step approach to performing these procedures including taking into account pelvic tilt. It is hoped that these described techniques will further optimize robotic-assisted hip arthroplasty procedures.

Surgical Tray Optimization and Efficiency: The Impact of a Novel Sealed Sterile Container and Instrument Tray Technology.

INTRODUCTION: As bundle payments have begun focusing on orthopaedic procedures, particularly total knee arthroplasties (TKAs), surgeons and hospitals have evaluated methods for improving efficiency. Few studies have investigated the impact of novel, sealed-container and instrument-tray technology on turnover and costs. Therefore, the purpose of this study was to compare traditional and sealed container-sterilized TKA surgical trays by: 1) investigating the setup and clean-down time in the operating room (OR); 2) examining trays processing time in central sterile supply (CS); and 3) estimating OR and CS costs and waste produced. MATERIALS AND METHODS: An interdisciplinary team determined points throughout a TKA tray single-case life cycle that could cause variations in turnover time. The times were recorded for two different TKA tray configurations. Process A utilized instruments housed in vendor trays that were "blue" wrap sterilized, while Process B employed optimized trays that were sealed container-sterilized. Times were recorded during preoperative setup and postoperative clean down in the OR and CS. Reductions in mean OR or CS times were used to estimate cost savings. Wastes were analyzed for each method. Statistical analyses using Student t-tests were used to determine statistical differences and a p-value of less than 0.05 was considered significant. RESULTS: Overall, the use of optimized trays and sealed sterilization containers reduced the turnover time by 57 minutes and the number of trays by a mean of three. OR and CS processing yearly savings were estimated to be $249,245. Waste disposal was an estimated 10,590 ounces and 450 ounces for traditional and sealed containers, respectively. CONCLUSION: Novel sealed sterilization containers demonstrated increased efficiency in the total turnover time of TKA trays. This is important for surgeons participating in bundle payments who perform surgery in a hospital and ambulatory surgery center. Reduced turnover time could potentially increase case load and decrease the need for extra instrumentation or loaner trays. This simple means of increasing efficiency could be used as a model for surgeons wishing to streamline surgical trays and reduce costs.

Dual Mobility Acetabular Systems for Total Hip Arthroplasty: A Multicenter Study and Technique Report.

INTRODUCTION: Dual mobility constructs for THA have been a tremendous advancement for hip arthroplasty surgeons, especially in scenarios where instability is a possibility. While some researchers have reported events of malseating with their use, the authors of the current study believe that this may be avoided by ensuring appropriate surgical technique. Therefore, the purpose of this study was to: (1) describe the surgical techniques that we employ to ensure that the liner is adequately seated; and (2) report the rates of malseating, dislocation, and aseptic loosening among our collective cohort of dual mobility THA patients. MATERIALS AND METHODS: All patients who underwent THA with a dual mobility construct between January 1, 2010 and December 31, 2018 at four institutions were identified. Those who had less than two years of follow up were excluded. Outcomes of interest included radiographic evidence of liner malseating, aseptic loosening, and dislocation. A total of 1,826 patients who underwent THA with a dual mobility construct were identified. Among these patients, 504 had less than two years of follow up and were excluded from our analysis. The remaining 1,322 patients met our criteria including 941 primary THAs (71.2%) and 381 revision THAs (28.8%). RESULTS: After a minimum follow-up period of two years, there were only two cases of malseated liners (0.15%). Serial follow ups have demonstrated no movement or changes in the position of the liners over time for both patients. In addition, they have been shown to have normal serum metal ion levels and no clinical complaints after 5.3- and 7.1-year follow up. Seven of 1,322 patients (0.53%) experienced a dislocation. Aseptic loosening of the acetabular cup was diagnosed in one patient 3.4 years postoperatively. In three patients, femoral component loosening occurred after a mean follow-up period of 2.3 years, (1.3 to 3.1 years). Among the 941 primary cases, the incidence of liner malseating was 0.21%, as both patients who experienced this complication were in this subgroup. As stated above, these patients have demonstrated normal serum metal ion levels and no clinical or radiographic sequelae as a result of the liner malseating. The dislocation rate among primary cases was 0.21% (2 of 941). Aseptic loosening of the acetabular component occurred in two (0.21%) while one patient (0.1%) was found to have femoral component loosening at final follow up. Of the 381 revision THAs, there were no cases of liner malseating. Five revision THA patients (1.3%) experienced a dislocation over our study period. Two revision THA patients experienced aseptic loosening of the femoral component (0.79%) at final follow up. CONCLUSIONS: The results of this paper demonstrate that malseating is not a prevalent issue with dual mobility THA when appropriate surgical techniques are used. It is hoped that that this paper clarifies the techniques for implantation of these implants and that excellent results can be achieved when care is taken to ensure that liners are well-seated intraoperatively.

Estimation of Femoral Version During Total Hip Arthroplasty: Surgeon Visual Assessment versus Robotic-Arm Assisted Technology.

INTRODUCTION: Malposition of THA implants can lead to many complications, some of which may necessitate reoperation. Thus, proper implant placement is critical for optimizing patient outcomes. In addition, intraoperative visual estimation of stem position has been shown to be unreliable. Therefore, the purpose of this study was to compare a surgeon's visual estimation of femoral version to the actual version captured using a three-dimensional robotic-arm assisted platform. MATERIALS AND METHODS: A prospective study of 25 THAs performed by a single surgeon was performed. The mean version, as estimated by intraoperative visual assessment, was compared to that measured by the robotic-arm assisted technology software using a two-sided t-test. Outliers were evaluated for the following intervals: 1 to 5°, 6 to 10°, and greater than 10°. A separate analysis was performed for anteverted versus retroverted stems. RESULTS: The mean version, as estimated by intraoperative visual assessment, was 9.16 ± 4.02° (range, 3 to 18°) compared to 3.52 ± 8.66° (range, -12 to 19) as measured by the robotic-arm assisted software (P=0.005). The surgeon's estimates of broach version and those measured by the robotic-arm assisted software were identical in three cases (12%). The evaluation methods differed by 1 to 5° in six cases (24%), 6 to 10° in 10 cases (40%), and greater than 10° in six cases (24%). Larger differences between methods were noted for cases in which the stem was found to be in anteversion by the robotic-arm assisted software. CONCLUSIONS: Visual estimation of femoral implant version differed significantly from measurements captured by three-dimensional robotic-arm assisted imaging. This suggests that estimating stem position intraoperatively by eye is not reliable, even when done by an experienced surgeon. The use of robotic-arm assisted technology may be recommended for determining femoral stem version intraoperatively.

Robotic-Assisted versus Manually Implanted Total Hip Arthroplasty: A Clinical and Radiographic Comparison.

INTRODUCTION: Component positioning during THA is one of the more critical surgeon-controlled factors as malposition has been associated with higher rates of hip dislocations, poor biomechanics, accelerated wear rates, leg length discrepancies (LLDs), and revision surgeries. In order to reduce the rates of component malposition and improve surgical accuracy, robotic-assisted THA has developed increased interest. The primary objective of this study was to compare patient outcomes following THA using the Mako Stryker robotic system (Stryker Orthopaedics, Mahwah, New Jersey) to outcomes in patients who underwent conventional instrumented THA. MATERIALS AND METHODS: Consecutive patients undergoing THA with a direct-lateral surgical approach from a single surgeon were reviewed. Patients were treated with either a robotic-arm assisted total hip arthroplasty (RTHA) or a conventional-instrumented total hip arthroplasty (CTHA). Minimum follow up was 16 months. RESULTS: Robotic-assisted THA significantly improved patient outcomes compared to conventional THA. No significant differences were observed in postoperative radiographic outcomes between the RTHA and CTHA cohorts. In our analysis, patients in the RTHA cohort compared to the CTHA cohort had significantly higher Western Ontario and McMaster Universities Arthritis Index (WOMAC) (P<0.001) and Harris Hip Scores (P<0.05) at final follow up. There were no significant differences between the RTHA cohort and CTHA cohorts in regard to cup inclination (°) (P=0.10), hip length difference (mm) (P=0.80), hip length discrepancy (mm) (P=0.10), and global offset difference (mm) (P=0.20). CONCLUSION: Further studies, particularly prospective randomized studies, are necessary to investigate the short- and long-term clinical outcomes, possible long-term complications, and cost-effectiveness of robotic-assisted THA in regard to improving outcomes and accuracy.

Newer Generation of Cementless Total Knee Arthroplasty: A Systematic Review.

INTRODUCTION: Although the use of cementless implants in total knee arthroplasty (TKA) has increased in recent years, there is still ongoing debate regarding the optimal method of fixation. The purpose of this review was to evaluate the evidence regarding cementless versus cemented total knee arthroplasty (TKA) with regard to: (1) all-cause survivorship and aseptic survivorship; and (2) patient-reported outcome measures (PROMs) of newer generation TKAs. MATERIALS AND METHODS: A systematic review of all reports on cementless TKA published from January 2010 to February 2019 was performed. A total of 221 articles were evaluated and 39 studies met inclusion criteria for final analysis. Metrics evaluated included all-cause survivorship, aseptic survivorship, and Knee Society Scores (KSS). RESULTS: Modern cementless TKA provides excellent survivorship and patient-reported outcomes as compared to cemented designs. CONCLUSIONS: Recent studies have demonstrated that newer generation cementless TKAs provide similar functional outcomes and survivorship as compared to cemented TKA. However, additional prospective, randomized trials with long-term follow up are necessary to further compare the outcomes of cementless versus cemented TKA.

Robotic-Assisted Versus Manual Unicompartmental Knee Arthroplasty: A Systematic Review.

INTRODUCTION: Unicompartmental knee arthroplasty (UKA) is a feasible alternative to total knee arthroplasty (TKA) for selected patients with severe single-compartment knee osteoarthritis. Robotic-assisted UKA (rUKA) has recently emerged as a complementary tool to ameliorate previous difficulties with manual UKA (mUKA). However, the influence of rUKA compared to mUKA on patient outcomes are still largely unknown. PURPOSE: To compare outcomes of the manual technique and a single robotic-assisted system in patients undergoing unicompartmental knee arthroplasty. MATERIALS AND METHODS: The PubMed-Medline was searched using terms: "robotic," "unicompartmental," "knee," and "arthroplasty" to identify all studies comparing outcomes of mUKA and rUKA. Data pertaining to the following outcomes were extracted: (1) studies comparing robotic-assisted UKA to manual UKA; (2) reports which only included the Mako UKA system (Mako Surgical Corporation, Fort Lauderdale, Florida) as the robotic-assisted system; and (3) studies which discussed implant survivorship, complications, early postoperative parameters, functional outcomes, or implant positioning. Review articles were excluded. RESULTS: A total of eight publications with 337 patients who underwent rUKA and 481 who underwent mUKA were included in our analysis. Two studies reported that early postoperative pain was decreased with rUKA compared to mUKA. In one study, pain levels in the first eight postoperative weeks were 54% lower in the rUKA group and in the other, pain scores based on the numeric rating scale were significantly lower in rUKA (2.5) compared to mUKA (4.2) upon discharge (p<0.001). Furthermore, mean time to hospital discharge in this study was reduced with rUKA (42.5 ± 5.9 hours) compared to mUKA (71.1 ± 14.6 hours) (p<0.001). One study demonstrated a significant improvement in range of motion at two-year follow up in the rUKA group (15°, range, 5° to 25°) compared to the mUKA group (10°, range 0° to 20°; p=0.04). One study reported that at three-month follow up, mean Knee Society scores were significantly better in the rUKA group (164; interquartile range [IQR] 131 to 178) compared the mUKA group (143; IQR 132 to 166; p=0.04). Three studies reported more accurate implant positioning with rUKA compared to mUKA. Among the five studies that reported implant survivorship, four studies (including a randomized control trial) found no difference between techniques in implant survival rate, while one retrospective analysis reported improved survivorship with mUKA. CONCLUSIONS: In conclusion, unicompartmental knee arthroplasty implants demonstrated comparable survivorship rates whether performed manually or with robotic assistance. However, compared to the manually performed procedure, robotic-assisted unicompartmental knee arthroplasty were found to offer benefits including shorter lengths of hospital stays, decreased postoperative pain scores, and improved functional outcomes.

An Economic Evaluation of Over 200,000 Revision Total Hip Arthroplasties: Is the Current Model Sustainable?

INTRODUCTION: Revision total hip arthroplasties (rTHAs) are typically more complicated than primaries and may have a greater economic burden. To date, the current economic model supporting these procedures has not been evaluated. Therefore, the purpose of this study was to determine the 10-year temporal changes in charges, reimbursement rates, and net losses in patients undergoing an rTHA utilizing a large, nationwide database. MATERIALS AND METHODS: A query was performed from 2005 to 2014 to identify patients who underwent rTHA. Analyzed outcomes included trends in costs of care, reimbursement rates, and net losses per annum within the last 10 years. Charges are defined as those by the provider to the insurance company, whereas, reimbursements were those payments received from the insurance company. Net losses were calculated as the difference in charges from reimbursement rates. RESULTS: Total charges increased from $1,119,725,881 in 2005 to $2,066,842,547 in 2014. Total reimbursements increased from $287,461,852 in 2005 to $478,430,569 in 2014. Per patient charges increased 67.4% from 2005 to 2014 and from $51,963.18 in 2005 to $86,791.07 in 2014. There was an increase in reimbursement per patient of 61.4% from $12,450.70 in 2005 to $20,090.31 in 2014. Net losses increased 68.80%, from $39,512.48 to $66,700.76 from 2005 to 2014. CONCLUSION: This study indicates substantial increases in charges and reimbursements over a 10-year period for patients undergoing rTHA. However, reimbursement increased at a lower rate than that of charges, resulting in major net losses. This study highlights the need to reevaluate the economic models behind rTHA for longer-term sustainment.