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. Previous studies have demonstrated that higher volume hospitals have better outcomes following revision total knee arthroplasty (rTKA), in current literature there are no reports investigating the effect of surgeon volume. The purpose of this study is to investigate if patients of high-volume revision surgeons have better outcomes following rTKA as compared to patients of low volume surgeons. Methods. This retrospective observational analysis examined the rTKA database at a large urban academic medical center for aseptic, unilateral rTKA between January 2016 and March 2019 with at least 1-year of follow-up. Surgeon operative volume during the same time period was evaluated. Surgeons who performed at least 18 aseptic rTKA per year were considered high volume (HV), whereas surgeons who performed fewer than 18 aseptic rTKA per year were considered low volume (LV). Demographics, surgical factors, and post-operative outcomes were collected and compared between the two cohorts. A post-hoc power analysis was conducted for full revisions (1-ß=0.909, α=0.05). Results. 307 cases were identified: 177 performed by LV surgeons and 130 performed by HV surgeons. The only demographic difference was a greater proportion of non-smokers in the LV cohort (59.4% vs. 50.0%; p=0.031). Patients of HV surgeons were more likely to receive a full revision (64.6% vs. 47.5%; p<0.001). For all revisions, HV surgeons had shorter surgical times by about 17 minutes (p=0.010). For the 168 full revisions (84 HV, 84 LV), patients of HV surgeons had shorter hospital stays (2.92±1.62 vs. 3.57±2.69 days; p=0.048), shorter surgical times (131.42±33.86 vs. 171.65±49.88 minutes; p<0.001), lower re-revision rates (7.1% vs. 19.0%; p=0.038), and fewer re-revisions (0.07±0.26 vs. 0.29±0.74 re-revisions; p=0.018). Conclusions. Patients of HV revision surgeons have better outcomes following full rTKA. These findings support the development of revision teams within arthroplasty centers of excellence to offer patients the best possible outcomes following rTKA

Abstract

Introduction

The use of stem cell and platelet-rich plasma (PRP) injections for knee osteoarthritis (OA) is extremely controversial and at best experimental. These treatments are being given to patients across the nation for “cash only payments”. Our objectives were (1) to determine the proportion of board certified orthopedic surgeons who offer stem cell or PRP treatment for knee OA, (2) how much the practices charge for those treatments and (3) if members of the knee society use these therapies.

Aims. To identify variables independently associated with same-day discharge (SDD) of patients following revision total knee arthroplasty (rTKA) and to develop machine learning algorithms to predict suitable candidates for outpatient rTKA. Methods. Data were obtained from the American College of Surgeons National Quality Improvement Programme (ACS-NSQIP) database from the years 2018 to 2020. Patients with elective, unilateral rTKA procedures and a total hospital length of stay between zero and four days were included. Demographic, preoperative, and intraoperative variables were analyzed. A multivariable logistic regression (MLR) model and various machine learning techniques were compared using area under the curve (AUC), calibration, and decision curve analysis. Important and significant variables were identified from the models. Results. Of the 5,600 patients included in this study, 342 (6.1%) underwent SDD. The random forest (RF) model performed the best overall, with an internally validated AUC of 0.810. The ten crucial factors favoring SDD in the RF model include operating time, anaesthesia type, age, BMI, American Society of Anesthesiologists grade, race, history of diabetes, rTKA type, sex, and smoking status. Eight of these variables were also found to be significant in the MLR model. Conclusion. The RF model displayed excellent accuracy and identified clinically important variables for determining candidates for SDD following rTKA. Machine learning techniques such as RF will allow clinicians to accurately risk-stratify their patients preoperatively, in order to optimize resources and improve patient outcomes. Cite this article: Bone Jt Open 2023;4(6):399–407

Aims. The transepicondylar axis is a well-established reference for the determination of femoral component rotation in total knee arthroplasty (TKA). However, when severe bone loss is present in the femoral condyles, rotational alignment can be more complicated. There is a lack of validated landmarks in the supracondylar region of the distal femur. Therefore, the aim of this study was to analyze the correlation between the surgical transepicondylar axis (sTEA) and the suggested dorsal cortex line (DCL) in the coronal plane and the inter- and intraobserver reliability of its CT scan measurement. Methods. A total of 75 randomly selected CT scans were measured by three experienced surgeons independently. The DCL was defined in the coronal plane as a tangent to the dorsal femoral cortex located 75 mm above the joint line in the frontal plane. The difference between sTEA and DCL was calculated. Descriptive statistics and angulation correlations were generated for the sTEA and DCL, as well as for the distribution of measurement error for intra- and inter-rater reliability. Results. The external rotation of the DCL to the sTEA was a mean of 9.47° (SD 3.06°), and a median of 9.2° (IQR 7.45° to 11.60°), with a minimum value of 1.7° and maximum of 16.3°. The measurements of the DCL demonstrated very good to excellent test-retest and inter-rater reliability coefficients (intraclass correlation coefficient 0.80 to 0.99). Conclusion. This study reveals a correlation between the sTEA and the DCL. Overall, 10° of external rotation of the dorsal femoral cortical bone to the sTEA may serve as a reliable landmark for initial position of the femoral component. Surgeons should be aware that there are outliers in this study in up to 17% of the measurements, which potentially could result in deviations of femoral component rotation. Cite this article: Bone Jt Open 2024;5(12):1067–1071

Aims. Unicompartmental knee arthroplasty (UKA) is the preferred treatment for anterior medial knee osteoarthritis (OA) owing to the rapid postoperative recovery. However, the risk factors for UKA failure remain controversial. Methods. The clinical data of Oxford mobile-bearing UKAs performed between 2011 and 2017 with a minimum follow-up of five years were retrospectively analyzed. Demographic, surgical, and follow-up data were collected. The Cox proportional hazards model was used to identify the risk factors that contribute to UKA failure. Kaplan-Meier survival was used to compare the effect of the prosthesis position on UKA survival. Results. A total of 407 patients who underwent UKA were included in the study. The mean age of patients was 61.8 years, and the mean follow-up period of the patients was 91.7 months. The mean Knee Society Score (KSS) preoperatively and at the last follow-up were 64.2 and 89.7, respectively (p = 0.001). Overall, 28 patients (6.9%) with UKA underwent revision due to prosthesis loosening (16 patients), dislocation (eight patients), and persistent pain (four patients). Cox proportional hazards model analysis identified malposition of the prostheses as a high-risk factor for UKA failure (p = 0.007). Kaplan-Meier analysis revealed that the five-year survival rate of the group with malposition was 85.1%, which was significantly lower than that of the group with normal position (96.2%; p < 0.001). Conclusion. UKA constitutes an effective method for treating anteromedial knee OA, with an excellent five-year survival rate. Aseptic loosening caused by prosthesis malposition was identified as the main cause of UKA failure. Surgeons should pay close attention to prevent the potential occurrence of this problem. Cite this article: Bone Jt Open 2023;4(12):914–922

Abstract. Introduction. There is currently very little evidence which can be used to guide surgeons treating skeletally immature patients with suspected meniscal injury. The aim of our modified Delphi study was to develop comprehensive recommendations for the management of isolated meniscal tears in skeletally immature children. Methodology. An international, two round, modified Delphi consensus was completed. Included ‘experts’ were identified as having an established adult and/or paediatric knee practice and either: 1) Faculty at the international kid's knee meeting, 2) Active member of the complex national paediatric MDT group, or 3) faculty on recognised national course aimed at teaching knee surgeons regarding the management of meniscal lesions. A threshold of 70% was used to identify consensus. Results. A total of 43 experts (Round 1) and 41 experts (Round 2) took part in the Delphi study. Surgeons from the UK, Europe, USA and South America took part. 34 statements were identified exploring 4 main domains – clinical diagnosis, investigation, management and specialist tears. Following round 1 consensus was reached on 17 (50%) statements, subsequently after completion of round 2 consensus was reached on 28 (82%) statements, leaving 6 (18%) with no consensus. Conclusions. This is the first modified delphi consensus which provides evidence for surgeons treating skeletally immature children with isolated meniscal tears. Further studies are required to provide evidence for the areas where no consensus was reached

Aims. Surgeons commonly resect additional distal femur during primary total knee arthroplasty (TKA) to correct a flexion contracture, which leads to femoral joint line elevation. There is a paucity of data describing the effect of joint line elevation on mid-flexion stability and knee kinematics. Thus, the goal of this study was to quantify the effect of joint line elevation on mid-flexion laxity. Methods. Six computational knee models with cadaver-specific capsular and collateral ligament properties were implanted with a posterior-stabilized (PS) TKA. A 10° flexion contracture was created in each model to simulate a capsular contracture. Distal femoral resections of + 2 mm and + 4 mm were then simulated for each knee. The knee models were then extended under a standard moment. Subsequently, varus and valgus moments of 10 Nm were applied as the knee was flexed from 0° to 90° at baseline and repeated after each of the two distal resections. Coronal laxity (the sum of varus and valgus angulation with respective maximum moments) was measured throughout flexion. Results. With + 2 mm resection at 30° and 45° of flexion, mean coronal laxity increased by a mean of 3.1° (SD 0.18°) (p < 0.001) and 2.7° (SD 0.30°) (p < 0.001), respectively. With + 4 mm resection at 30° and 45° of flexion, mean coronal laxity increased by 6.5° (SD 0.56°) (p < 0.001) and 5.5° (SD 0.72°) (p < 0.001), respectively. Maximum increased coronal laxity for a + 4 mm resection occurred at a mean 15.7° (11° to 33°) of flexion with a mean increase of 7.8° (SD 0.2°) from baseline. Conclusion. With joint line elevation in primary PS TKA, coronal laxity peaks early (about 16°) with a maximum laxity of 8°. Surgeons should restore the joint line if possible; however, if joint line elevation is necessary, we recommend assessment of coronal laxity at 15° to 30° of knee flexion to assess for mid-flexion instability. Further in vivo studies are warranted to understand if this mid-flexion coronal laxity has negative clinical implications. Cite this article: Bone Joint J 2021;103-B(6 Supple A):87–93

Aims. The COVID-19 pandemic led to a swift adoption of telehealth in orthopaedic surgery. This study aimed to analyze the satisfaction of patients and surgeons with the rapid expansion of telehealth at this time within the division of adult reconstructive surgery at a major urban academic tertiary hospital. Methods. A total of 334 patients underging arthroplasty of the hip or knee who completed a telemedicine visit between 30 March and 30 April 2020 were sent a 14-question survey, scored on a five-point Likert scale. Eight adult reconstructive surgeons who used telemedicine during this time were sent a separate 14-question survey at the end of the study period. Factors influencing patient satisfaction were determined using univariate and multivariate ordinal logistic regression modelling. Results. A total of 68 patients (20.4%) and 100% of the surgeons completed the surveys. Patients were “Satisfied” with their telemedicine visits (4.10/5.00 (SD 0.98)) and 19 (27.9%) would prefer telemedicine to in-person visits in the absence of COVID-19. Multivariate ordinal logistic regression modelling revealed that patients were more likely to be satisfied if their surgeon effectively responded to their questions or concerns (odds ratio (OR) 3.977; 95% confidence interval (CI) 1.260 to 13.190; p = 0.019) and if their visit had a high audiovisual quality (OR 2.46; 95% CI 1.052 to 6.219; p = 0.042). Surgeons were “Satisfied” with their telemedicine experience (3.63/5.00 (SD 0.92)) and were “Fairly Confident” (4.00/5.00 (SD 0.53)) in their diagnostic accuracy despite finding the physical examinations to be only “Slightly Effective” (1.88/5.00 (SD 0.99)). Most adult reconstructive surgeons, seven of eight (87.5%) would continue to use telemedicine in the future. Conclusion. Telemedicine emerged as a valuable tool during the COVID-19 pandemic. Patients undergoing arthroplasty and their surgeons were satisfied with telemedicine and see a role for its use after the pandemic. The audiovisual quality and the responsiveness of physicians to the concerns of patients determine their satisfaction. Future investigations should focus on improving the physical examination of patients through telemedicine and strategies for its widespread implementation. Cite this article: Bone Joint J 2021;103-B(6 Supple A):196–204

Aims. The purpose of this study was to assess total knee arthroplasty (TKA) volume and rates of early complications in morbidly obese patients over the last decade, where the introduction of quality models influencing perioperative care pathways occurred. Methods. Patients undergoing TKA between 2011 to 2018 were identified in the American College of Surgeons National Surgical Quality Improvement Program database. Patients were stratified by BMI < 40 kg/m. 2. and ≥ 40 kg/m. 2. and evaluated by the number of cases per year. The 30-day rates of any complication, wound complications, readmissions, and reoperation were assessed. Trends in these endpoints over the study period were compared between groups using odds ratios (ORs) and multivariate analyses. Results. In total, 314,695 patients underwent TKA and 46,362 (15%) had BMI ≥ 40 kg/m. 2. The prevalence of morbid obesity among TKA patients did not change greatly, ranging between 14% and 16%. Reoperation rate decreased from 1.16% to 0.96% (odds ratio (OR) 0.81 (95% confidence interval (CI) 0.66 to 0.99)) for patients with BMI < 40 kg/m. 2. , as did rates of readmission (4.46% to 2.87%; OR 0.61 (0.55 to 0.69)). Patients with BMI ≥ 40 kg/m. 2. also had fewer readmissions over the study period (4.87% to 3.34%; OR 0.64 (0.49 to 0.83)); however, the rate of reoperation did not change (1.37% to 1.41%; OR 0.99 (0.62 to 1.56)). Significant improvements were not observed for infective complications over time for either group; patients with BMI ≥ 40 kg/m. 2. had increased risk of both deep infection and wound complications compared to non-morbidly obese patients. Rate of any complication decreased for all patients. Conclusion. The proportion of TKAs in morbidly obese patients has not significantly changed over the past decade. Although readmission rates improved for all patients, reductions in reoperation in non-morbidly obese patients were not experienced by the morbidly obese, resulting in a widening of the complication gap between these cohorts. Care improvements have not lowered the differential risk of infective complications in the morbidly obese. Cite this article: Bone Joint J 2021;103-B(6 Supple A):38–44

Aims. It has previously been shown that higher-volume hospitals have better outcomes following revision total knee arthroplasty (rTKA). We were unable to identify any studies which investigated the effect of surgeon volume on the outcome of rTKA. We sought to investigate whether patients of high-volume (HV) rTKA surgeons have better outcomes following this procedure compared with those of low-volume (LV) surgeons. Methods. This retrospective study involved patients who underwent aseptic unilateral rTKA between January 2016 and March 2019, using the database of a large urban academic medical centre. Surgeons who performed ≥ 19 aseptic rTKAs per year during the study period were considered HV and those who performed < 19 per year were considered LV. Demographic characteristics, surgical factors, and postoperative outcomes were compared between the two groups. Results. A total of 308 rTKAs were identified, 132 performed by HV surgeons and 176 by 22 LV surgeons. The LV group had a significantly greater proportion of non-smokers (59.8% vs 49.2%; p = 0.029). For all types of revision, HV surgeons had significantly shorter mean operating times by 17.75 minutes (p = 0.007). For the 169 full revisions (85 HV, 84 LV), HV surgeons had significantly shorter operating times (131.12 (SD 33.78) vs 171.65 (SD 49.88) minutes; p < 0.001), significantly lower re-revision rates (7.1% vs 19.0%; p = 0.023) and significantly fewer re-revisions (0.07 (SD 0.26) vs 0.29 (SD 0.74); p = 0.017). Conclusion. Patients of HV rTKA surgeons have better outcomes following full rTKA. These findings support the development of revision teams within arthroplasty centres of excellence to offer patients the best possible outcomes following rTKA. Cite this article: Bone Joint J 2021;103-B(6 Supple A):131–136

Aims. Manipulation under anaesthesia (MUA) remains an effective intervention to address restricted range of motion (ROM) after total knee arthroplasty (TKA) and occurs in 2% to 3% of primary TKAs at our institution. Since there are few data on the outcomes of MUA with different anaesthetic methods, we sought to compare the outcomes of patients undergoing MUA with intravenous (IV) sedation and neuraxial anaesthesia. Methods. We identified 548 MUAs after primary TKA (136 IV sedation, 412 neuraxial anaesthesia plus IV sedation) from March 2016 to July 2019. The mean age of this cohort was 62 years (35 to 88) with a mean body mass index of 31 kg/m. 2. (18 to 49). The mean time from primary TKA to MUA was 10.2 weeks (6.2 to 24.3). Pre-MUA ROM was similar between groups; overall mean pre-MUA extension was 4.2° (p = 0.452) and mean pre-MUA flexion was 77° (p = 0.372). We compared orthopaedic complications, visual analogue scale (VAS) pain scores, length of stay (LOS), and immediate and three-month follow-up knee ROM between these groups. Results. Following MUA, patients with IV sedation had higher mean VAS pain scores of 5.2 (SD 1.8) compared to 4.1 (SD = 1.5) in the neuraxial group (p < 0.001). The mean LOS was shorter in patients that received IV sedation (9.5 hours (4 to 31)) compared to neuraxial anaesthesia (11.9 hours (4 to 51)) (p = 0.009), but an unexpected overnight stay was similar in each group (8.6%). Immediate-post MUA ROM was 1° to 121° in the IV sedation group and 0.9° to 123° in the neuraxial group (p = 0.313). Three-month follow-up ROM was 2° to 108° in the IV sedation group and 1.9° to 110° in the neuraxial anaesthesia group (p = 0.325) with a mean loss of 13° (ranging from 5° gain to 60° loss), in both groups by three months. No patients in either group sustained a complication. Conclusion. IV sedation alone and neuraxial anaesthesia are both effective anaesthetic methods for MUA after primary TKA. Surgeons and anaesthetists should offer these anaesthetic techniques to match patient-specific needs as the orthopaedic outcomes are similar. Also, patients should be counselled that ROM following MUA may decrease over time. Cite this article: Bone Joint J 2021;103-B(6 Supple A):126–130

Introduction. Patient satisfaction is an important outcome measure after total knee arthroplasty (TKA) and is the ultimate goal of surgery. However, patient satisfaction reflects a complex construct of the patient's personal expectations and preferences in addition to subjective evaluation of outcome after TKA. Multiple studies have found a patient dissatisfaction rate of approximately 20% at 1 year after TKA. The purpose of this study is to determine whether there is an association between a single-item validated TKA satisfaction score and patient-reported outcome measures (PROMs) at 3 time points (1, 2, and 5 years after TKA) and to determine if dissatisfaction rate after TKA varies over time. Methods. A multi-center, prospective cohort of 12,952 patients (8,078 patients were assessed at 1-year, 702 patients at 2-year, and 4,172 patients at 5-year) undergoing primary TKA were enrolled by 230 surgeons in 28 states between 2012–2015. Surgeons practices varied in size, reimbursement models, and geographic setting ensuring that the cohort included diverse patient populations and delivery models. Surgeons agreed to invite all TKA patients to participate and sporadic audits of surgical logs validated that all patients were invited and > 90% of patients were included. Demographic and clinical data [age, gender, body mass index (BMI), and modified Charlson co-morbidity index (CCI)] were collected. Patient-reported outcome measures (PROMs) were collected pre-op and post-op at 1, 2, and 5 years using an internet-based platform including the KOOS (total score, and pain, ADL, QoL sub scores), KOOS Jr, SF-36 (PCS and MCS). We used the single-item satisfaction scale which was tested and validated by the Swedish Knee Arthroplasty Registry. The patients' responses were made on 5-point Likert scale (very satisfied, somewhat satisfied, neutral, somewhat dissatisfied, very dissatisfied). Patients were classified into 2 categories: satisfied group for patients who answered satisfied or very satisfied and dissatisfied group for patients answered neutral, somewhat dissatisfied, or very dissatisfied. Univariate analysis of the difference between the satisfied and dissatisfied patients' groups was performed using Mann-Whitney U test for continuous variables and chi-square test for categorical variables. Logistic regression model was performed to study the correlation between the satisfaction and PROMs with 95% confidence interval. Results. Mean age was 66.6 years, 62.7% were female, and mean BMI was 31.6. The CCI was 0 in 55.1%, 1 in 22%, 2–5 in 12.6% and ≥ 6 in 10.3%. Cumulative revision rate was 1.29% at 2 years. The 30-day adverse events incidence was 2.5% while the 90-day adverse events incidence was 4.7%. The dissatisfaction rate was 18.1% at 1-year, 11.5% at 2-year, and 8.5% at 5-year (P<0.001, Chi-square). Dissatisfaction significantly affects younger patients (<55 years) (P=0.04, Chi-square) and patients with high Charlson comorbidity index >1 (P=0.001, Chi-square). Low post-operative KOOS Pain, KOOS ADL, KOOS total score, KOOS JR, SF-36 PCS, and SP-36 MCS scores were significantly associated with dissatisfaction (P<0.001). At 5 years follow-up, in patients with KOOS scores greater than 70, 1.3% of patients were dissatisfied; with KOOS 50–70, 16.3% were dissatisfied and when KOOS < 50, 62.2% are dissatisfied. Logistic regression showed significant correlation of satisfaction with postoperative KOOS pain, KOOS ADL, KOOS QoL, KOOS total score, KOOS JR, and SF-36 PCS (P< 0.001) at 1-year, 2-year, and at 5-year. The MCS was correlated with patient satisfaction only at 1-year (P< 0.001). Conclusion. The patient dissatisfaction rate 5 years after TKA is 8.1% in FORCE-TJR patients which is significantly lower than 18.1% at 1-year. Less improvement of PROM scores after TKA are significantly associated with patient dissatisfaction. Postoperative PROM scores are associated with patient satisfaction at 1-year, 2-years, and 5-years. When the 5-year post- op KOOS total score is >70, 98.7% of patients are satisfied and only 1.3% are dissatisfied. Patient satisfaction is an important outcome measure after TKA that can be determined by asking a single question. However, in order to understand why a patient is dissatisfied, KOOS scores (KOOS pain, KOOS ADL, KOOS QoL) that assess specific postoperative outcomes can assist in determining the reason for patient dissatisfaction after TKA

Aims. Rates of readmission and reoperation following primary total knee arthroplasty (TKA) are under scrutiny due to new payment models, which penalize these negative outcomes. Some risk factors are more modifiable than others, and some conditions considered modifiable such as obesity may not be as modifiable in the setting of advanced arthritis as many propose. We sought to determine whether controlling for hypoalbuminaemia would mitigate the effect that prior authors had identified in patients with obesity. Methods. We reviewed the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database for the period of January 2008 to December 2016 to evaluate the rates of reoperation and readmission within 30 days following primary TKA. Multivariate logistic regression modelling controlled for preoperative albumin, age, sex, and comorbidity status. Results. Readmission rates only differed significantly between patients with Normal Weight and Obesity Class II, with a decreased rate of readmission in this group (odds ratio (OR) 0.82; 95% confidence interval (CI) 0.71 to 0.96; p = 0.010). The only group demonstrating association with increased risk of reoperation within 30 days was the Obesity Class III group (OR 1.38; 95% CI 1.05 to 1.82; p = 0.022). Hypoalbuminaemia (preoperative albumin < 35 g/L) was significantly associated with readmission (OR 1.62; 95% CI 1.41 to 1.86; p < 0.001) and reoperation (OR 1.52; 95% CI 1.18 to 1.96; p = 0.001) within 30 days. Conclusion. In this study, hypoalbuminaemia appears to be a more significant risk factor for readmission and reoperation than even the highest obesity categories. Future studies may assess whether preoperative albumin restoration or weight loss may improve outcomes for patients with hypoalbuminaemia. The implications of this study may allow surgeons to discuss risk of surgery with obese patients planning to undergo primary TKA procedures if other comorbidities are adequately controlled. Cite this article: Bone Joint J 2020;102-B(6 Supple A):31–35

Aims. Commonly performed unicompartmental knee arthroplasty (UKA) is not designed for the lateral compartment. Additionally, the anatomical medial and lateral tibial plateaus have asymmetrical geometries, with a slightly dished medial plateau and a convex lateral plateau. Therefore, this study aims to investigate the native knee kinematics with respect to the tibial insert design corresponding to the lateral femoral component. Methods. Subject-specific finite element models were developed with tibiofemoral (TF) and patellofemoral joints for one female and four male subjects. Three different TF conformity designs were applied. Flat, convex, and conforming tibial insert designs were applied to the identical femoral component. A deep knee bend was considered as the loading condition, and the kinematic preservation in the native knee was investigated. Results. The convex design, the femoral rollback, and internal rotation were similar to those of the native knee. However, the conforming design showed a significantly decreased femoral rollback and internal rotation compared with that of the native knee (p < 0.05). The flat design showed a significant difference in the femoral rollback; however, there was no difference in the tibial internal rotation compared with that of the native knee. Conclusion. The geometry of the surface of the lateral tibial plateau determined the ability to restore the rotational kinematics of the native knee. Surgeons and implant designers should consider the geometry of the anatomical lateral tibial plateau as an important factor in the restoration of native knee kinematics after lateral UKA. Cite this article: Bone Joint Res 2019;8:593–600

Introduction. Surgeons commonly resect additional distal femur during primary total knee arthroplasty (TKA) to correct a flexion contracture. However, the effect of joint line proximalization on TKA kinematics is unclear. Thus, our goal was to quantify the effect of additional distal femoral resection on knee extension and mid-flexion laxity. Methods. Six computational knee models with TKA-specific capsular and collateral ligament properties were implanted with a contemporary posterior-stabilized TKA. A 10° flexion contracture was modeled to simulate a capsular contracture. Distal femoral resections of +2 mm and +4 mm were simulated for each model. The knees were then extended under standardized torque to quantify additional knee extension achieved. Subsequently, varus and valgus torques of ±10 Nm were applied as the knee was flexed from 0° to 90° at the baseline, +2 mm, and +4 mm distal resections. Coronal laxity, defined as the sum of varus and valgus angulation with respective torques, was measured at mid-flexion. Results. With +2 mm and +4 mm of distal femoral resection, the knee extended an additional 4°±0.5° and 8°±0.75°, respectively. At 30° and 45°of flexion, baseline laxity averaged 4.8° and 5.0°, respectively. At +2 mm resection, mean coronal laxity increased by 3.1° and 2.7° at 30° and 45°of flexion, respectively. At +4 mm resection, mean coronal laxity increased by 6.5° and 5.5° at 30° and 45° of flexion, respectively. Maximal increased coronal laxity for a +4 mm resection occurred at a mean 16° (range, 11–27°) of flexion with a mean increased laxity of 7.8° from baseline. Conclusion. While additional distal femoral resection in primary TKA increases knee extension, the consequent joint line elevation induces up to 8° of coronal laxity in mid-flexion in this computational model. As such, posterior capsular release prior to resecting additional distal femur to correct a flexion contracture should be considered

Aims. Tranexamic acid (TXA) is proven to reduce blood loss following total knee arthroplasty (TKA), but there are limited data on the impact of similar dosing regimens in revision TKA. The purpose of this multicentre randomized clinical trial was to determine the optimal regimen to maximize the blood-sparing properties of TXA in revision TKA. Patients and Methods. From six-centres, 233 revision TKAs were randomized to one of four regimens: 1 g of intravenous (IV) TXA given prior to the skin incision, a double-dose regimen of 1 g IV TXA given both prior to skin incision and at time of wound closure, a combination of 1 g IV TXA given prior to skin incision and 1 g of intraoperative topical TXA, or three doses of 1950 mg oral TXA given two hours preoperatively, six hours postoperatively, and on the morning of postoperative day one. Randomization was performed based on the type of revision procedure to ensure equivalent distribution among groups. Power analysis determined that 40 patients per group were necessary to identify a 1 g/dl difference in the reduction of haemoglobin postoperatively between groups with an alpha of 0.05 and power of 0.80. Per-protocol analysis involved regression analysis and two one-sided t-tests for equivalence. Results. In total, one patient withdrew, five did not undergo surgery, 16 were screening failures, and 25 did not receive the assigned treatment, leaving 186 patients for analysis. There was no significant difference in haemoglobin reduction among treatments (2.8 g/dl for single-dose IV TXA, 2.6 g/dl for double-dose IV TXA, 2.6 g/dl for combined IV/topical TXA, 2.9 g/dl for oral TXA; p = 0.38). Similarly, calculated blood loss (p = 0.65) and transfusion rates (p = 0.95) were not significantly different between groups. Equivalence testing assuming a 1 g/dl difference in haemoglobin change as clinically relevant showed that all possible pairings were statistically equivalent. Conclusion. Despite the higher risk of blood loss in revision TKA, all TXA regimens tested had equivalent blood-sparing properties. Surgeons should consider using the lowest effective dose and least costly TXA regimen in revision TKA. Cite this article: Bone Joint J 2019;101-B(Supple 7):10–16

Introduction. The COVID-19 pandemic led to a swift adoption of telehealth in orthopedic surgery. The purpose of this study was to analyze patient and surgeon satisfaction with a rapid expansion of telehealth use during COVID-19 pandemic within the division of adult reconstructive surgery at a major urban academic hospital. Methods. 334 hip and knee arthroplasty patients who completed a telemedicine visit from March 30th, 2020 through April 30th, 2020 were sent a 14-question survey. Eight adult reconstructive surgeons who used telemedicine were sent a separate 14-question survey at the end of the study period. Factors influencing patient satisfaction were determined using univariate and multivariate ordinal logistic regression modeling. Results. 20.4% of patients (68/334) and 100% of surgeons (8/8) completed the surveys. Patients were on average “Satisfied” with their telemedicine visits (4.10/5.00 ± 0.98), 54.4% considered themselves high-risk for COVID-19 complications, and 27.9% reported that they preferred future visits to be conducted using telemedicine for reasons unrelated to COVID-19. Multivariate ordinal logistic regression modeling revealed that patients reported higher satisfaction if their surgeon effectively responded to their questions/concerns (OR 3.977; 95% CI 1.260 to 13.190, p=0.019) and if their visit had higher audiovisual quality (OR 2.46; 95% CI 1.052 to 6.219, p=0.042). Surgeons were “Satisfied” with their telemedicine experience (3.63/5.00 ± 0.92), felt that physical exams conducted via telemedicine were “Slightly Effective” (1.88/5.00 ± 0.99), and believed that 43.5% of visits required an in-person component. Most adult reconstructive surgeons would continue to use telemedicine in the future (87.5%). Conclusion. Telehealth emerged as a valuable tool during the COVID-19 pandemic. Arthroplasty patients and surgeons were generally satisfied with telehealth and see a role for telehealth after the pandemic. Future investigations should explore how to improve telehealth physical examinations and identify which types of visits and patient concerns are reliably addressed using telehealth

Introduction. Manipulation under anesthesia (MUA) remains the gold standard to address restricted range of motion (ROM) within 3–6 months after primary total knee arthroplasty (TKA). However, there is little data on the outcomes of MUA with different types of anesthesia. We sought to compare the outcomes of patients undergoing MUA with intravenous (IV) sedation and neuraxial anesthesia. Methods. We identified 548 MUAs after primary TKA (136 IV sedation, 413 neuraxial anesthesia) at a single institution from 2016–2019. Mean age was 62 years and 349 patients (64%) were female. Mean body mass index was 32 kg/m. 2. The mean time from primary TKA to MUA was 10 weeks. Mean pre-MUA ROM was similar between each group; mean pre-MUA extension was 4.2° (p=0.35) and mean pre-MUA flexion was 77° (p=0.56). Patient demographics were statistically similar between both groups. We compared immediate complications, including fracture, extensor mechanism disruptions, and wound complications, Visual analogue pain scores (VAS), length of stay (LOS), and immediate and 3 month follow-up ROM between these groups. Results. No patients in either group sustained an immediate post-MUA complication. Patients undergoing MUA with IV sedation had significantly higher day of MUA average VAS of 5.1 compared to 4.1 in the neuraxial group (p<0.001). The average LOS was shorter in patients that received IV sedation (9 hours) compared to neuraxial anesthesia (12 hours) (p=0.009). Immediate-post MUA ROM was 1° – 121° in the IV sedation group and 0.9° – 123° in the neuraxial anesthesia group (p=0.21). Three month follow-up ROM was 2° – 108° in the IV sedation group and 1.9° – 110° in the neuraxial anesthesia group. Conclusion. IV sedation and neuraxial anesthesia are both effective anesthetic methods for patients undergoing MUA after primary TKA with minimal perioperative differences. Surgeons and anesthesiologists should cater anesthetic technique to patient specific needs as the orthopedic outcomes are similar for both methods; however, IV sedation resulted in a shorter LOS