Objectives. A patient-centred approach, usually achieved through shared decision making, has the potential to help improve decision making around knee arthroplasty surgery. However, such an approach requires an understanding of the factors involved in patient decision making. This review’s objective is to systematically examine the qualitative literature surrounding patients’ decision making in knee arthroplasty. Methods. A systematic literature review using Medline and Embase was conducted to identify qualitative studies that examined patients’ decision making around knee arthroplasty. An aggregated account of what is known about patients’ decision making in knee arthroplasties is provided. Results. Seven studies with 234 participants in interviews or focus groups are included. Ten themes are replicated across studies, namely: expectations of surgery; coping mechanisms; relationship with clinician; fear; pain; function; psychological implications; social network; previous experience of surgery; and conflict in opinions. Conclusions. This review is helpful in not only directing future research to areas that are not understood, or require confirmation, but also in highlighting areas that future interventions could address. These include those aimed at delivering information, which are likely to affect the satisfaction rate, demand, and use of knee arthroplasties. Cite this article: Bone Joint Res 2015;4;163–169

Introduction. The application of artificial intelligence (A.I) using patient reported outcomes (PROs) to predict benefits, risks, benefits and likelihood of improvement following surgery presents a new frontier in shared decision-making. The purpose of this study was to assess the impact of an A.I-enabled decision aid versus patient education alone on decision quality in patients with knee OA considering total knee replacement (TKR). Secondarily we assess impact on shared decision-making, patient satisfaction, functional outcomes, consultation time, TKR rates and treatment concordance. Methods. We performed a randomized controlled trial involving 130 new adult patients with OA-related knee pain. Patients were randomized to receive the decision aid (intervention group, n=65) or educational material only (control group, n=65) along with usual care. Both cohorts completed patient surveys including PROs at baseline and between 6–12 weeks following initial evaluation or TKR. Statistical analysis included linear mixed effect models, Mann-Whitney U tests to assess for differences between groups and Fisher's exact test to evaluate variations in surgical rates and treatment concordance. Results. The intervention group showed greater decision quality (K-DQI, Mean difference = 20%, p<0.0001), collaboration in decision-making (CollaboRATE, 12% (intervention group), 47% (control group) below median, p<0.0001), satisfaction with consultations (NRS-C, 14% (intervention group), 33% (control group) below median, p=0.008), improvement in functional outcomes from baseline up to 12 week follow-up (KOOSJR, 4.9 pts higher (intervention group), p=0.029) without significantly impacting consultation time. No differences were observed in TKR rates or treatment concordance. Conclusion. A.I-enabled decision aids incorporating PROs in predictive algorithms can improve decision quality, level of shared decision-making, satisfaction with patient-provider consultations, and functional outcomes, without extending consultation times. The combination of advanced predictive technologies and patient reported data to forecast surgical outcomes presents a paradigm shift in shared decision making and the delivery of high value care for patients with knee OA

Abstract. Introduction. Knee arthrodesis is one of the treatment options for limb salvage of a failed total knee replacement (TKR) when further revisions were contraindicated. The aim of this study is to determine patient outcomes after knee arthrodesis (KA) following a failed TKR. Methodology. A literature search was conducted for studies published from January 2000 through January 2022 via Medline, Web of Science, Embase and Cochrane databases. Only primary research studies were included with independent extraction of articles by two reviewers. Results were synthesised by narrative review according to PRISMA guidelines, with full tabulation of all included study results. Results. A total of 34 studies with 1,034 patients were included in the review; all were longitudinal observational studies, and none were conducted as randomised controlled trials. Reporting methods were very inconsistent in the included studies, and this heterogeneity led to pooled data totals that varied widely in different categories. The mean follow-up was 3.5 years. Overall, 72.0% (167 of 232) of patients used a walking stick and 12.5% (36 of 287) remained non-ambulatory after KA. Only 7.7% (58 of 752) of patients subsequently underwent above-knee amputation. Conclusion. KA is a potential limb salvage procedure after revision arthroplasties have been attempted in cases of failed TKR. Most patients were able to ambulate both at home and in the community, although with an increased rate of using a walking stick after the operation. However, in the absence of randomised controlled trials, these data may allow for a more accurate counselling and decision making

Purpose. Late stage medial unicompartmental osteoarthritic disease of the knee can be treated by either Total Knee Replacement (TKR) or Unicompartmental Replacement (UKR). As a precursor to the TOPKAT study this work tested the postulate that individual surgeons show high variation in the choice of treatment for individual patients. Method. Four surgeons representing four different levels of expertise or familiarity with partial knee replacement (UKR design centre knee surgeon, specialist knee surgeon, arthroplasty surgeon and a year six trainee) made a forced choice decision of whether they would perform a TKR or UKR based on the same pre-operative radiographic and clinical data in 140 individual patients. Consistency of decision was also evaluated for each surgeon 3 months later and the effect of additional clinical data was also evaluated. The sample consisted of the 100 patients who had subsequently undergone UKR and 40 who had undergone TKR. Results. The specialist knee surgeon from the design centre would have performed UKR in 80% of the patients. The other surgeons would have performed a UKR in between 32-43% of the patients representing a variation in decision making of up to 59%. The choice of treatment for each surgeon remained unchanged in between 80-87% of cases after viewing additional clinical data. There was high intra surgeon repeatability in decision making when assessed 3 months later. Conclusion. Despite being given identical information, surgeons show high variability in decision making for patients with medial OA of the knee. A knee surgeon with a special interest in partial knee replacement is twice as likely to choose UKR for a patient with medial compartment OA than a non specialist surgeon. The choice is predominantly based on radiological findings but decision making for each individual surgeon is reassuringly consistent. The implications are that if TKR and UKR have unequal efficacy, some patients may be undergoing a suboptimal procedure

Aims. The aim of this study was to evaluate the ability of a machine-learning algorithm to diagnose prosthetic loosening from preoperative radiographs and to investigate the inputs that might improve its performance. Methods. A group of 697 patients underwent a first-time revision of a total hip (THA) or total knee arthroplasty (TKA) at our institution between 2012 and 2018. Preoperative anteroposterior (AP) and lateral radiographs, and historical and comorbidity information were collected from their electronic records. Each patient was defined as having loose or fixed components based on the operation notes. We trained a series of convolutional neural network (CNN) models to predict a diagnosis of loosening at the time of surgery from the preoperative radiographs. We then added historical data about the patients to the best performing model to create a final model and tested it on an independent dataset. Results. The convolutional neural network we built performed well when detecting loosening from radiographs alone. The first model built de novo with only the radiological image as input had an accuracy of 70%. The final model, which was built by fine-tuning a publicly available model named DenseNet, combining the AP and lateral radiographs, and incorporating information from the patient’s history, had an accuracy, sensitivity, and specificity of 88.3%, 70.2%, and 95.6% on the independent test dataset. It performed better for cases of revision THA with an accuracy of 90.1%, than for cases of revision TKA with an accuracy of 85.8%. Conclusion. This study showed that machine learning can detect prosthetic loosening from radiographs. Its accuracy is enhanced when using highly trained public algorithms, and when adding clinical data to the algorithm. While this algorithm may not be sufficient in its present state of development as a standalone metric of loosening, it is currently a useful augment for clinical decision making. Cite this article: Bone Joint J 2020;102-B(6 Supple A):101–106

Aims. The aim of this study was to determine the long-term risk of undergoing knee arthroplasty in a cohort of patients with meniscal tears who had undergone arthroscopic partial meniscectomy (APM). Patients and Methods. A retrospective national cohort of patients with a history of isolated APM was identified over a 20-year period. Patients with prior surgery to the same knee were excluded. The primary outcome was knee arthroplasty. Hazard ratios (HRs) were adjusted by patient age, sex, year of APM, Charlson comorbidity index, regional deprivation, rurality, and ethnicity. Risk of arthroplasty in the index knee was compared with the patient’s contralateral knee (with vs without a history of APM). A total of 834 393 patients were included (mean age 50 years; 37% female). Results. Of those with at least 15 years of follow-up, 13.49% (16 256/120 493; 95% confidence interval (CI) 13.30 to 13.69) underwent subsequent arthroplasty within this time. In women, 22.07% (95% CI 21.64 to 22.51) underwent arthroplasty within 15 years compared with 9.91% of men (95% CI 9.71 to 10.12), corresponding to a risk ratio (RR) of 2.23 (95% CI 2.16 to 2.29). Relative to the general population, patients with a history of APM were over ten times more likely (RR 10.27; 95% CI 10.07 to 10.47) to undergo arthroplasty rising to almost 40 times more likely (RR 39.62; 95% CI 27.68 to 56.70) at a younger age (30 to 39 years). In patients with a history of APM in only one knee, the risk of arthroplasty in that knee was greatly elevated in comparison with the contralateral knee (no APM; HR 2.99; 95% CI 2.95 to 3.02). Conclusion. Patients developing a meniscal tear undergoing APM are at greater risk of knee arthroplasty than the general population. This risk is three-times greater in the patient’s affected knee than in the contralateral knee. Women in the cohort were at double the risk of progressing to knee arthroplasty compared with men. These important new reference data will inform shared decision making and enhance approaches to treatment, prevention, and clinical surveillance. Cite this article: Bone Joint J 2019;101-B:1071–1080

Introduction. Recent focus has queried whether of deoxyribonucleic acid (DNA) sequencing modalities of bacterial DNA found in periarticular fluid and tissues will improve in periprosthetic joint infection (PJI) diagnosis and organism identification diagnostic accuracy for periprosthetic joint infection The purpose of this study was to compare the diagnostic accuracy of next generation sequencing (NGS) to polymerase chain reaction (PCR) multiplex, and culture, the Musculoskeletal Infection Society (MSIS) criteria, and the recently proposed criteria by Parvizi et al. [1] in the diagnosis of periprosthetic knee infections. Methods. In this retrospective study, aspirate or tissue samples were collected in 70 revision and 58 primary knee arthroplasties for routine diagnostic workup for PJI and sent to the laboratory for NGS and PCR multiplex. Concordance along with statistical differences between diagnostic studies were calculated using Chi-squared test for categorical data. Results. When comparing to the MSIS criteria, concordance was 78.1% for NGS, 66.4% for PCR, and 85.9% for culture (p<0.001). There was no significant difference based on prior infection (p=0.825), or sample collection method (tissue swab or synovial fluid) (p=0.986). Fifteen samples were culture positive and NGS negative, of which 10 (66.7%) met both criteria for PJI. Thirteen patients were culture negative but NGS positive, of which 2 (15.4%) met both criteria. Concordance was 100% between the MSIS criteria and criteria proposed by Parvizi et al. [1]. Conclusion. In this initial cohort NGS was more accurate than 16s subunit PCR techniques, but less accurate than culture in the diagnosis of PJI determining the presence or absence of PJI. What is not clear is how NGS will perform against culture in terms of identifying the specific bacterial strain. Currently, laboratory tests used for either criteria for PJI diagnosis should be obtained regardless of NGS along with the overall clinical picture to help guide decision making for PJI treatment. For figures, tables, or references, please contact authors directly

Background. Implant loosening is a common cause of a poor outcome and pain after total knee arthroplasty (TKA). Despite the increase in use of expensive techniques like arthrography, the detection of prosthetic loosening is often unclear pre-operatively, leading to diagnostic uncertainty and extensive workup. The objective of this study was to evaluate the ability of a machine learning (ML) algorithm to diagnose prosthetic loosening from pre-operative radiographs, and to observe what model inputs improve the performance of the model. Methods. 754 patients underwent a first-time revision of a total joint at our institution from 2012–2018. Pre-operative X-Rays (XR) were collected for each patient. AP and lateral X-Rays, in addition to demographic and comorbidity information, were collected for each patient. Each patient was determined to have either loose or fixed prosthetics based on a manual abstraction of the written findings in their operative report, which is considered the gold standard of diagnosing prosthetic loosening. We trained a series of deep convolution neural network (CNN) models to predict if a prosthesis was found to be loose in the operating room from the pre-operative XR. Each XR was pre-processed to segment the bone, implant, and bone-implant interface. A series of CNN models were built using existing, proven CNN architectures and weights optimized to our dataset. We then integrated our best performing model with historical patient data to create a final model and determine the incremental accuracy provided by additional layers of clinical information fed into the model. The models were evaluated by its accuracy, sensitivity and specificity. Results. The CNN we built demonstrated high performance at detecting prosthetic loosening from radiographs alone. Our first model built from scratch on just the image as an input had an accuracy of 70%. Our final model which was built by fine-tuning and optimizing a publicly available model named DenseNet, combining the AP and lateral radiographs, incorporating information from the patient history, had an accuracy, sensitivity, and specificity of 98.5%, 93.9%, and 99.5% on the patients that it was trained on, and an accuracy, sensitivity, and specificity of 88.3%, 70.2%, and 95.6% on the patients it was tested on. Conclusions. The use of machine learning (ML) can accurately detect the presence of prosthetic loosening based on plain radiographs. Its accuracy is progressively enhanced when additional clinical data is added to the loosening analysis algorithm. While this type of machine learning may not be sufficient in its present state of development as a standalone metric of loosening, it is clearly a useful augment for clinical decision making in its present state. Further study and development will be needed to determine the feasibility of applying machine learning as a more definitive test in the clinical setting. For figures, tables, or references, please contact authors directly

Introduction. With the rising utilization of total joint arthroplasty, the role of simultaneous-bilateral surgery has expanding impact. The purpose of this study is to examine the risk of perioperative complications for this approach in total knee arthroplasty to inform shared decision making. Methods. We used nation-wide linked discharge data from the Hospital Cost and Utilization Project from 2005–2014 comparing outcomes of simultaneous-bilateral and staged-bilateral total knee arthroplasties (TKAs). Hierarchical logistic regression analysis was used to compare mortality within 30 days, 90 days and 1 year, perioperative risks within 30–60 days, and infection and mechanical complications within 1 year. Results. 63,579 patients were analyzed including 27,301 simultaneous-bilateral and 36,278 staged-bilateral TKAs. Patients who underwent simultaneous surgery had a significantly higher adjusted odds ratio of death within 30 days (OR=3.31, 95% CI=2.15–5.08, p<0.001), myocardial infarction (OR=2.54, 95% CI=1.96–3.28, p<0.001), ischemic stroke (OR=2, 95% CI=1.39–2.87, p=0.002), cardiac complications (OR=1.3, 95% CI=1.12–1.5, p=0.007), digestive complications (OR=1.85, 95% CI=1.59–2.15, p<0.001), deep vein thrombosis (OR=1.31, 95% CI=1.18–1.45, p<0.001), and pulmonary embolism (OR=1.76, 95% CI=1.49–2.08, p<0.001) with a lower adjusted odds ratio of hematoma (OR=0.55, 95% CI=0.45–0.68, p<0.001), knee infection (OR=0.83, 95% CI=0.71–0.98, p=0.023), and major mechanical malfunction (OR=0.78, 95% CI=0.65–0.94, p=0.009). There was no difference in the adjusted OR for minor mechanical malfunction. The absolute risk difference for any complication between groups was 1% or less. Conclusion. Despite higher odds of experiencing many complications for patients undergoing simultaneous-bilateral versus staged total knee arthroplasty, the absolute difference in perioperative risks between these groups is small. This study of a large population informs surgeons and patients regarding the safety of simultaneous surgery. Level of Evidence: Therapeutic Level III. Keywords: knee arthroplasty; simultaneous; bilateral; staged; joint replacement

Introduction. The demands placed upon joint surgeons are perhaps greatest when treating the revision arthroplasty patient, who present with complications demanding skill in diagnosis and evaluation, interpersonal communication and the technical aspects of the revision procedure. However, little information exists identifying which specific tasks in revision arthroplasty are most difficult for surgeons to master, and whether the greatest challenges arise from clinical, cognitive or technical facets of patient treatment. This study was undertaken to identify which tasks associated with revision total knee replacement (TKR) are perceived as most challenging to young surgeons and trainees to guide future efforts in surgical training and curriculum development. Methods. We developed an online survey instrument consisting of 69 items encompassing pre-operative, intraoperative, and post-operative tasks that preliminary studies identified as the essential components of revision TKR. These tasks encompassed 4 domains: clinical decision-making skills (n=9), interpersonal assessment and communication (n=7), surgical decision-making (n=35) and procedural surgical tasks (n=18). Respondents rated the difficulty of each item on a 5-level Likert scale, with an ordinal score ranging from 1 (“very easy”) to 5 (“very difficult”. The survey instrument was administered to a cohort of 109 US surgeons: 31 trainees enrolled in a joint fellowship program (Fellows) and 78 surgeons who had graduated from a joint fellowship program within the previous 10 years (Joint Surgeons). Using appropriate parametric and non-parametric tests, the responses were analyzed to examine the variation of reported difficulty of each of the 69 items, in addition to the nature of the task (cognitive, surgical, clinical and interpersonal), and differences between Fellows and Surgeons. Results. Both Fellows and Surgeons reported a wide variation in the difficulty of performing the tasks identified in each f the 4 domains. Fellows reported a higher average difficulty score than Surgeons (2.94 vs 2.74; p=0.032), corresponding to a greater frequency of tasks entailing some degree of difficulty (34.9% vs 24.4%, p<0.0001). Both groups experienced difficulty in performing tasks involving interpersonal interaction with patients (Fellows: 34.6% vs Surgeons: 34.3%, p=0.93). Fellows also found the technical aspects of revision surgery most challenging with 38.5% of items considered difficult compared to 28.7% for the Surgeon group (p<0.001). Highly significant differences between Fellows and Surgeons were also observed in facility with surgical decision making (p<0.001) and to a lesser extent, clinical decisions relating to patient care (% difficulty: p=0.0251). A compilation of the specific items cited as most difficult by the participants appears in Table 2. Conclusions. The young surgeons surveyed in this study reported difficulty in performing some tasks within both the clinical, cognitive and technical domains of revision knee arthroplasty. The high incidence of difficulty in tasks involving clinical decision-making and operative performance are characterized by a lack of accepted guidelines and the lack of a standard surgical practice. In general, our findings highlight the need for improvements in surgeon training to improve decision-making and procedural skills as part of the comprehensive management of patients undergoing revision knee arthroplasty. For any figures or tables, please contact authors directly

Introduction. The number of medial unicompartmental knee replacements (UKR) performed for arthritis has increased and as such, revisions to total knee replacement (TKR) is increasing. Previous studies have investigated survivorship of UKR to TKR revision and functional outcomes compared to TKR to TKR revision, but have failed to detail the surgical considerations involved in these revisions. Our objectives are to investigate the detailed surgical considerations involved in UKR to TKR revisions. Methods. This study is a retrospective comparative analysis of a prospectively collected database. From 2005 to 2017, 61 revisions of UKR to TKR were completed at a single center. Our inclusion criteria included: revision of UKR to TKR or TKR to TKR with minimum 1 year follow-up. Our exclusion criteria include: single component and liner revisions and revision for infection. The 61 UKR to TKR revisions were matched 2:1 with respect to age, ASA and BMI to a group of 122 TKR to TKR revisions. The following data was collected: indication for and time to revision, operative skin to skin surgical time, the use of specialized equipment (augment size/location, stem use), intraoperative and postoperative complications, re-operations and outcome scores (WOMAC, Oxford 12, SF 12, satisfaction score). Results. There were no statistical differences between the demographic data from either group (age, BMI, ASA, sex and follow-up range). Progression of arthritis was the most common reason for revision in the UKR to TKR group (30/61, 49%, p < 0.001). Aseptic loosening was the most common reason for revision in the TKR to TKR group (73/122, 60%,) and was encountered more often than aseptic loosening in the UKR to TKR group (21/61, 35%, p=0.002). The operative time was longer in the TKR to TKR group (77 vs 112 min, p< 0.001). Femoral augmentation was required for one 1/61 (1.64%) UNI and 92/122 (75%) TKR revisions, respectively (p <0.001). Medial tibial augments were required in 9/61 (14.8%) of the UKR to TKR group while 12/122 (10%) and 10/122 (8%) of the TKR to TKR group required medial and full tibial augments, respectively (p=0.7). UKR to TKR revisions never required femoral stems while 120/122 (98%) of the TKR to TKR group did (p<0.001). Tibial stems were required in 19/61 (31%) and 122/122 (100%) of UKR to TKR and TKR to TKR groups, respectively (p<0.001). There was no statistical difference in the overall complication rate of either group (15% in the UKR to TKR group and 13% in the TKR to TKR group, p = 0.9). Stiffness was a common complication of UKR to TKR and TKR to TKR re-revisions at 2/61 (3%), and 6/122 (5%), respectively (P = 0.6). Aseptic loosening was also a common complication of in both groups at 2/61 (3%) and 4/122 (3%) in the UKR to TKR and TKR to TKR groups, respectively (p = 0.7). There was no statistical difference in the re-operation rate of either group (10% in the UKR to TKR group and 7% in the TKR to TKR group, P = 1). Stiffness was the most common indication for re-operation in the UKR to TKR group (2/61, 3%, p = 0.11) while aseptic loosening was the most common in the TKR to TKR group (4/122, 3.2%, p = 0.7). The survivorship in the UKR to TKR was 93% and 90% at 5 and 9 years, respectively. The survivorship in the TKR to TKR group was 95% and 94% at 5 and 9 years, respectively, which was not statistically different from the UKR group. Discussion. The most common reason for revision was different between the two groups (p < 0.001) while the skin to skin time was longer in the TKR to TKR group. In terms of revision components, femoral stems were never required in the UKR to TKR group while tibial stems were only required in 31%. Similarly, medial tibial augments were only required in 15% of the UKR to TKR group. While the surgeon must be prepared to use augmentation and stems in UKR to TKR revisions, they can often be completed with primary components and therefor will have an overall lower cost to the health care system. Furthermore, the survivorship and re-operation between the two groups was similar which supports previous literature. The results of this study will allow for a more in-depth cost-effectiveness analysis of UKR to TKR vs TKR to TKR in arthroplasty decision making. Unicompartmental knee replacements should be considered in appropriate patients to decrease the lifetime cost of arthroplasty intervention and potentially decrease the burden on the health care system. For figures, tables, or references, please contact authors directly

The COVID-19 pandemic has led to unprecedented times worldwide. From lockdowns to masks now being part of our everyday routine, to the halting of elective surgeries, the virus has touched everyone and every part of our personal and professional lives. Perhaps, now more than ever, our ability to adapt, change and persevere is critical to our survival. This year's closed meeting of The Knee Society demonstrated exactly those characteristics. When it became evident that an in-person meeting would not be feasible, The Knee Society leadership, under the direction of President John Callaghan, MD and Program Chair Craig Della Valle, MD created a unique and engaging meeting held on September 10–12, 2020. Special recognition should be given to Olga Foley and Cynthia Garcia at The Knee Society for their flexibility and creativeness in putting together a world-class flawless virtual program. The Bone & Joint Journal is very pleased to partner with The Knee Society to once again publish the proceedings of the closed meeting of the Knee Society. The Knee Society is a United States based society of highly selected members who have shown leadership in education and research in knee surgery. It invites up to 15% international members; this includes some of the key opinion leaders in knee surgery from outside the USA. Each year, the top research papers from The Knee Society meeting will be published and made available to the wider orthopaedic community in The Bone & Joint Journal. The first such proceedings were published in BJJ in 2019. International dissemination should help to fulfil the mission and vision of the Knee Society of advancing the care of patients with knee disorders through leadership, education and research. The quality of dissemination that The Bone & Joint Journal provides should enhance the profile of this work and allow a larger body of surgeons, associated healthcare professionals and patients to benefit from the expertise of the members of The Knee Society. The meeting is one of the highlights of the annual academic calendar for knee surgeons. With nearly every member in attendance virtually throughout the 3 days, the top research papers from the membership were presented and discussed in a virtual format that allowed for lively interaction and discussion. There are 75 abstracts presented. More selective proceedings with full papers will be available after a robust peer review process in 2021, both online and in The Bone & Joint Journal. The meeting commenced with the first group of scientific papers focused on Periprosthetic Joint Infection. Dr Berry and colleagues from the Mayo Clinic further help to clarify the issue of serology and aspirate results to diagnose TKA PJI in the acute postoperative setting. 177 TKA's had an aspiration within 12 weeks and 22 were proven to have PJI. Their results demonstrated that acute PJI after TKA should be suspected within 6 weeks if CRP is ≥81 mg/L, synovial WBCs are ≥8500 cells/μL, and/or synovial neutrophils≥86%. Between 6– 12 weeks, concerning thresholds include a CRP ≥ 32 mg/L, synovial WBC ≥7450, and synovial neutrophils ≥ 84%. While historically the results of a DAIR procedure for PJI have been variable, Tom Fehring's study showed promise with the local delivery of vancomycin through the Intraosseous route improved early results. New member Simon Young contrasted the efficacy of the DAIR procedure when comparing early infections to late acute hematogenous PJI. DAIR failed in 63% of late hematogenous PJIs (implant age>1 year) compared to 36% of early (<1year) PJIs. Dr Masri demonstrated in a small group of patients that those with well-functioning articulating spacers can retain their spacers for over 12 months with no difference in infection from those that had a formal two stage exchange. The mental toll of PJI was demonstrated in a longitudinal study by Doug Dennis, where patient being treated with 2 stage exchange had 4x higher rates of depression compared to patient undergoing aseptic revision. The second session focused on both postoperative issues with regards to anticoagulation and manipulation. Steven Haas demonstrated high complication rates with utilization of anticoagulation for treatment of postoperative pulmonary embolism with modern therapeutic anticoagulation (warfarin, enoxaparin, Xa inhibitors) with the Xa inhibitors demonstrating lower complication rates. Two papers focused on the topic of manipulation. Mark Pagnano presented data on timing of manipulation under anesthesia up to even past 12 months. While gains were modest, a subset of patients did achieve substantial gains in ROM > 20degrees even after 3 months post op. Dr Westrich's study demonstrated no difference in MUA outcomes with either IV sedation or neuraxial anesthesia although the length of stay was shorter in the IV sedation group. Several studies in Session II focused on kinematics and femoral component position. Dr Li's in vivo kinematic study during weightbearing flexion and gait demonstrated that several knees rotated with a lateral pivot motion and not all knees can be described with a single motion character. Dr Mayman and his group utilized a computational knee model to demonstrate that additional distal femoral resection results in increasing levels of mid -flexion instability and cautioned against the use of additional bony resection as the first line for flexion contractures. Using computer navigation, Dr Huddleston's study nicely outlined the variability in femoral component rotation to achieve a rectangular flexion gap utilizing a gap balanced method. The third session opened the meeting on Friday morning. The focus was on unicompartmental knee arthroplasty and the increasing utilization of robotic assisted total knee arthroplasty. David Murray showed using registry data that for patient with higher comorbidities (ASA >3), UKA was safer and more cost effective than TKA while Dr Della Valle's group demonstrated overall lower average healthcare costs in UKA patients compared to TKA in the first 10 years after surgery. Dr Geller assessed UKA survivorship among 3 international registries. While survivorship varied by nation and designs, certain designs consistently had better overall performance. Dr Nunley and his group showed robotic navigation UKA significantly reduced outliers in alignment and overhang compared to manual UKA. Dr Catani's data demonstrated that full thickness cartilage loss should still be considered a requirement for UKA success even with robotic assistance. Despite a high dislocation rate of 4%, Mr Dodd demonstrated high survivorship for lateral UKA despite historical contraindications. The growing evidence for robotics TKA was demonstrated in two studies. Professor Haddad showed less soft tissue injury, reduced bone trauma and improved accuracy or rTKA compared to manual TKA while Dr Gustke single surgeon study showed his rTKA had improved forgotten joint scores and less ligament releasing required for balancing. Despite these finding, Dr Lee's study demonstrated that a robotic TKA could not guarantee excellent pain relief and other factors such a patient expectations and psychological factors play a role. Our fourth session was devoted to machine learning and smart tools and modeling. Dr Meneghini used machine learning algorithms to identify optimal alignment outcomes that correlated with patient outcomes. Several parameters such as native tibial slope, femoral sagittal position and coronal limb alignment correlated with outcomes. Along the same lines, Bozic and coauthors demonstrated that using AI algorithms incorporated with PROM's improved levels of shared decision making and patient satisfaction. Dr Lombardi demonstrated that a mobile patient engagement platform that provided smart phone-based exercise and education was comparable to traditional methods. Dr Mahfouz demonstrated the accuracy of using ultrasound to produce 3D models of the bone compared to conventional CT based strategies and Dr Mahoney showed the valued of a preop 3D model in reproducing more normal knee kinematics. The last two talks of the session focused on some of the positives of the COVID-19 pandemic, namely the embracing of telemedicine by patients and surgeons as demonstrated by Dr Slover and the increasing and far reaching educational opportunities made available to residents and fellows during the pandemic. Session five focused on risk stratification and optimization prior to TKA. Dr O'Connor demonstrated that that the implementation of an optimization program preoperatively reduced length of stay and ED visits, and Charles Nelson's study showed that risk stratification tool can lower complication rates in obese patients undergoing TKA comparable to those that are nonobese. Dr Markel's study demonstrated that those who have preoperative depression and anxiety are at higher risk of complications and readmissions after surgery and these issues should be addressed preoperatively. Interestingly, a study by Dr Callaghan demonstrated that care improvement pathways have not lowered the gap in complications for morbidly obese patients undergoing TKA, Dr Barsoum argued that the overall complication rates were low and this patient cohort had significant gains in PROMS after TKA that would not be experienced if arbitrary cutoff for limited surgery were established. The final session on Friday, Session six, had several well done and interesting studies. There continues to be mounting evidence that liposomal bupivacaine has little effect on managing post-operative pain to warrant its increased use. Bill Macaulay and colleagues showed no change in pain scores, opioid consumption and functional scores when liposomal bupivacaine was discontinued at a large academic medical center. Dr Bugbee importantly demonstrated that a supervised ambulation program reduced falls in the early postoperative period. Several paper on healthcare economics were presented. Rich Iorio showed that stratifying complexity of total joint cases between hospitals with a system can be efficient and cost savings while Dr Jiranek demonstrated in his study that complex TKAs can be identified preoperatively and are associated with prolonged operative time and cost of care and consideration should be given in future reimbursement models to a complexity modifier. Dr Springer, in their evaluation of Medicare bundled payment models, demonstrated that providers and hospitals in historical bundled models that became efficient were penalized in the new model, forcing many groups to drop out and return to a fee for service model. Ron Delanois important work showed that social determinants can have a major negative impact on outcomes following TKA. Our final day on Saturday opened with Session seven, and several interesting paper on metal ions/debris in TKA. Dr Whitesides simulator study showed the absence of scratches and material loss in a ceramic TKA compared with Co-Cr TKA and suggested an advantage to this material in patients with metal sensitivity. Conversely, in a histological study of failed TKA, perivascular lymphocytic infiltration was not associated with worse clinical outcomes or differences in revision in a series of 617 aseptic revisions, 19% of which had PVLI found on histology. The Mayo group and Dr Trousdale however, noted that serum metal ion levels can be helpful in identifying implant failure in a group of revision TKAs, especially those with metallic junctions. Dr Dalury demonstrated nicely that use of maximally conforming inserts did not have a negative effect on implant loosening in a series of 76 revision TKA's at an average follow up of 7 years, while Kevin Garvin and his group showed no difference in end of stem pain between cemented and cementless stems in revision TKA. The final two studies in the session by Bolognesi and Peters respectively showed that metaphyseal cones continue to demonstrate excelled survivorship in rTKA setting despite extensive bone loss. Session eight was highlighted by a large series of revision reported by new member Dr Schwarzkopf, who showed that revision TKA done by high volume surgeons demonstrated better outcomes and lower revision rates compared to surgeon who did less than 18 rTKA's per year. Dr Maniar importantly showed that preoperatively, patients with high activity level and low pain and indicated by a high preop forgotten joint score did poorly following TKA while David Ayers nicely demonstrated that KOOS scores that assess specific postoperative outcomes can predict patient dissatisfaction after TKA. The final paper in this session by Max Courtney showed that the majority of surgical cancellations are due to medical issues, yet a minority of these undergo any intervention specifically for that condition, but they resulted in a delay of 5 months. The first two studies of Session nine focused on polyethylene thickness. Dr Backstein demonstrated no difference in KSS scores, change in ROM and aseptic revision rates based on polyethylene thickness in a series of 195 TKA's. An interesting lab study by Dr Tim Wright showed a surprising consistency in liner thickness choice among varying levels of surgeon experience that did not correlate with applied forces or gap stability estimates. Two studies looked specifically at the issue of tibial loosening and implant design. Nam and colleagues were not able to demonstrate concerning findings for increasing tibial loosening in a tibial baseplate with a shortened tibial keel at short term follow up, while Lachiewicz demonstrated a 19% revision or revision pending rate in 223 cemented fixed bearing ATTUNE TKA at a mean of 30 months. Our final session of the meeting, began with encouraging news, that despite only currently capturing about 40% of TJA's done in the US, the American Joint Replacement Registry data is representative of data in other representative US databases. An interesting study presented by Robert Barrack looked at bone remodeling in the proximal tibia after cemented and cementless TKA of two different designs. No significant difference was noted among the groups with the exception of the cemented thicker cobalt chrome tray which demonstrated significantly more bone mineral density loss. Along the same lines, a study out of Dr Bostrom's lab demonstrated treatment of a murine tibial model with iPTH prevents fibrous tissue formation and enhances bone formation in cementless implants. New Member Jamie Howard showed no difference in implant migration and kinematics of a single radius cementless design using either a measured resection or gap balancing technique and Dr Cushner show no difference in blood loss with cemented or cementless TKA with the use of TKA. The final two studies looked at staging and bilateral TKA's. Peter Sharkey showed that simultaneous TKA's were associated with higher complication compared to staged TKA and that staged TKA with less than a 90-day interval was not associated with higher risk. However, Mark Figgie showed that patients undergoing simultaneous TKA compared to staged TKA, missed 17 fewer days of work. In spite of the virtual nature of the meeting, there were some outstanding scientific interactions and the material presented will continue to generate debate and to guide the direction of knee arthroplasty as we move forwards

Aims

Neither a surgeon’s intraoperative impression nor the parameters of computer navigation have been shown to be predictive of the outcomes following total knee arthroplasty (TKA). The aim of this study was to determine whether a surgeon, with robotic assistance, can predict the outcome as assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS) for pain (KPS), one year postoperatively, and establish what factors correlate with poor KOOS scores in a well-aligned and balanced TKA.

Aims

Arthrodesis is rarely used as a salvage procedure for patients with a chronically infected total knee arthroplasty (TKA), and little information is available about the outcome. The aim of this study was to assess the reliability, durability, and safety of this procedure as the definitive treatment for complex, chronically infected TKA, in a current series of patients.

Aims

The aim of the British Association for Surgery of the Knee (BASK) Meniscal Consensus Project was to develop an evidence-based treatment guideline for patients with meniscal lesions of the knee.

Aims

There is little information regarding the risk of a patient developing prosthetic joint infection (PJI) after primary total knee arthroplasty (TKA) when the patient has previously experienced PJI of a TKA or total hip arthroplasty (THA) in another joint. The goal of this study was to compare the risk of PJI of primary TKA in this patient population against matched controls.

Aims

The aim of this study was to determine whether closed suction drain (CSD) use influences recovery of quadriceps strength and to examine the effects of drain use on secondary outcomes: quadriceps activation, intra-articular effusion, bioelectrical measure of swelling, range of movement (ROM), pain, and wound healing complications.

Aims

The aim of this study was to characterize the factors leading to transfemoral amputation after total knee arthroplasty (TKA), as well as the rates of mortality and functional independence after this procedure in these patients.

Aims

Medial unicompartmental knee arthroplasty (UKA) is associated with successful outcomes in carefully selected patient cohorts. We hypothesised that severity and location of patellofemoral cartilage lesions significantly influences functional outcome after Oxford medial compartmental knee arthroplasty.

Objectives

The purpose of this study was to compare the joint space width between one-leg and both-legs standing radiographs in order to diagnose a primary osteoarthritis of the knee.