Prediction of Distal Femoral and Posterior Articular Surfaces in Total Knee Arthroplasty With Severe Bone Defects Using Computed Tomography-Based Templating Software.

Introduction Optimal repair of the joint line (JL) in total knee arthroplasty (TKA) is critical for knee joint motion reconstruction and ligament balance. Identification of JL may be difficult, particularly in revision or primary cases of severe femoral condylar bone loss. We aimed to define the relationship between the epicondyles and the articular surface (AS) of the femur using computed tomography-based three-dimensional digital templating software. Methods The study included 127 knees with osteoarthritis of the knee below grade 2 on the Kellgren-Lawrence index. A perpendicular line was drawn from the medial and lateral femoral epicondylar processes to the most distal point of the AS, and the distance was measured in the axial and coronal planes. Femoral width was measured as the distance between the medial and lateral epicondyles. All distances described above were converted to a ratio by division with femoral width. Results On the axial plane, the distance from epicondyles to the posterior ASs was 29.4 ± 2.2 mm medially and 21.3 ± 2.1 mm laterally. The width of the distal femur was 75.2 ± 4.2 mm. On the coronal plane, the distances from epicondyles to the distal ASs were 25.2 ± 2.9 mm on the medial side and 21.3 ± 2.5 mm on the lateral side. The ratio of the distance from epicondyles to the distal and posterior ASs divided by the width of the femur was 0.39 ± 0.02, 0.28 ± 0.03, 0.34 ± 0.03, and 0.28 ± 0.03. Conclusions The distance from the epicondyles to the distal and posterior JLs correlates with the distal femur width. These findings may be useful in determining an appropriate JL.

Comparison of bilateral cementless total knee arthroplasty results between patients in different BMI groups.

INTRODUCTION: The aim of this study was to compare the results of cementless bilateral total knee arthroplasty (TKA) between individuals in different obesity groups. MATERIALS AND METHODS: This was a retrospective cohort study. Patients with a body mass index (BMI) greater than 25 who underwent bilateral TKA for gonarthrosis between 2014 and 2020 and completed a minimum follow-up of 24 months were included. Age, sex, height, weight, BMI, operation time, length of stay, patient satisfaction, knee scores and complications were compared. Patients with missing data, who were followed for less than 24 months or had postoperative fractures around the knee were excluded. RESULTS: There was a significant difference between the groups in terms of operation time (Class III > overweight > Class II > Class I p < 0.001). There was a significant difference in complications between the groups (Class III > Class I > Class II > overweight p = 0.010). According to our pairwise comparison, complications were more common in the class III group than in the overweight group. Knee score (KS) and function score (FS) increased significantly after surgery in all groups (p < 0.001), with no difference in FS (p = 0.448). Knee score changes were greater in the overweight and class I groups (p < 0.001). There was a significant interaction between both KS and FS and person satisfaction (p < 0.001). CONCLUSION: Cementless TKA improved KS and FS in all obesity groups, yielded high patient satisfaction. Although the incidence of complications was higher in the morbidly obese patients than in the overweight patients, the difference was not significant. Patients with morbid obesity should be informed about related risks before planning cementless TKA.

Subtrochanteric fracture of the femur following knee replacement surgery: A case series and review of the literature.

INTRODUCTION AND IMPORTANCE: Knee arthroplasties as an effective intervention is primarily performed in patients with primary osteoarthritis and rheumatoid arthritis. Risk of hip fracture may be either decreased or increased in patients with Knee arthroplasties. There is conflicting evidence in this regard. Over the years, some studies have reported the occurrence of hip fractures following this operation as a rare but severe complication. The aim of the present case series was to report diagnosis and treatment of the mentioned five cases. CASE PRESENTATION: During a period of two years, five patients with a diagnosis of a subtrochanteric fracture and history of total knee arthroplasty who referred to hospital were selected to include in the present case series. CLINICAL DISCUSSION: the presence of RA and treatment with glucocorticoids, a reduction of BMD following knee replacement surgery, and ultimately, an increase in physical activity and movement after the arthroplasty due to the improvement of preoperational pain, may all contribute in a complex manner to the observed outcome of increased fracture risk in the hip following TKA. CONCLUSION: In summary, special care including using medications to improve BMD should be taken to minimize the risk of such an event.

Safety and outcomes of hip and knee replacement surgery in liver transplant recipients.

BACKGROUND: Liver transplant (LT) is becoming increasingly common with improved life expectancy. Joint replacement is usually a safe procedure; however, its safety in LT recipients remains understudied. AIM: To evaluate the mortality, outcome, and 90-d readmission rate in LT patients undergoing hip and knee replacement surgery. METHODS: Patients with history of LT who underwent hip and knee replacement surgery between 2016 and 2019 were identified using the National Readmission Database. RESULTS: A total of 5046119 hip and knee replacement surgeries were identified. 3219 patients had prior LT. Mean age of patients with no history of LT was 67.51 [95% confidence interval (CI): 67.44-67.58], while it was 64.05 (95%CI: 63.55-64.54) in patients with LT. Patients with history of LT were more likely to have prolonged length of hospital stay (17.1% vs 8.4%, P < 0.001). The mortality rate for patients with no history of LT was 0.22%, while it was 0.24% for patients with LT (P = 0.792). Patients with history of LT were more likely to have re-admissions within 90 d of initial hospitalization: 11.4% as compared to 6.2% in patients without history of LT (P < 0.001). The mortality rate between both groups during readmission was not statistically different (1.9% vs 2%, P = 0.871) respectively. CONCLUSION: Hip and knee replacements in patients with history of LT are not associated with increased mortality; increased re-admissions were more frequent in this cohort of patients. Chronic kidney disease and congestive heart failure appear to predict higher risk of readmission.

A 21-Day Individual Rehabilitation Exercise Training Program Changes Irisin, Chemerin, and BDNF Levels in Patients after Hip or Knee Replacement Surgery.

Osteoarthritis (OA) is the most frequent worldwide cause of adult population disabilities. The study evaluated the effects of a 21-day individual rehabilitation exercise training program focused on improving patients' functional capacity. The study analyzed the changes in irisin, chemerin, and BDNF serum levels in 36 OA patients subjected to an individually-adjusted rehabilitation program 90 days after surgical hip or knee replacement. The changes in irisin, chemerin, and BDNF serum levels were measured using enzyme-linked immunosorbent assay (ELISA) kits. A 21-day individual rehabilitation exercise training program significantly increased irisin and BDNF, and decreased chemerin serum levels. The presented study indicates that individually-adjusted exercise training is an important modulator influencing serum levels of anti- and pro-inflammatory factors, leading to positive clinical outcomes in osteoarthritis therapy. Selected factors are considered potential markers of various pathophysiological conditions. The presented study brings new details to the discussion.

Inertial-Sensor-Based Monitoring of Sample Entropy and Peak Frequency Changes in Treadmill Walking during Recovery after Total Knee Arthroplasty.

This study aimed to investigate whether sample entropy (SEn) and peak frequency values observed in treadmill walking could provide physical therapists valuable insights into gait rehabilitation following total knee arthroplasty (TKA). It was recognized that identifying movement strategies that during rehabilitation are initially adaptive but later start to hamper full recovery is critical to meet the clinical goals and minimize the risk of contralateral TKA. Eleven TKA patients were asked to perform clinical walking tests and a treadmill walking task at four different points in time (pre-TKA, 3, 6, and 12 months post-TKA). Eleven healthy peers served as the reference group. The movements of the legs were digitized with inertial sensors and SEn and peak frequency of the recorded rotational velocity-time functions were analyzed in the sagittal plane. SEn displayed a systematic increase during recovery in TKA patients (p < 0.001). Furthermore, lower peak frequency (p = 0.01) and sample entropy (p = 0.028) were found during recovery for the TKA leg. Movement strategies that initially are adaptive, and later hamper recovery, tend to diminish after 12 months post-TKA. It is concluded that inertial-sensor-based SEn and peak frequency analyses of treadmill walking enrich the assessment of movement rehabilitation after TKA.

A Comprehensive Research on the Prevalence and Evolution Trend of Orthopedic Surgeries in Romania.

Accurate knowledge of the prevalence and trends of orthopedic surgeries can facilitate the design of medical plans for effective treatments. The National Endoprosthetic Registry (NER) in Romania provides statistics on endoprosthetic activity (hip, knee), cases of fractures and bone tumors as a result of the legal obligations to report interventions performed by all orthopedic traumatology hospitals/wards in the country. The aim of this study is to describe the annual volumes of orthopedic surgeries between 2001 and 2022 in Romania and analyze the current and future evolution trends of the studied surgeries, gender differences and regional differences based on a complete survey carried out at a national level. For the period 2001-2022, we extracted from the NER the annual volumes of orthopedic interventions performed. With these data, we studied the prevalence and estimated, with the support of an original calculation methodology, the variation trends of orthopedic surgeries in two situations: over the entire 21-year period, respectively, and over the period 2001-2020, which does not include the pandemic period. For hip replacement surgery and knee replacement surgery, we showed the prevalence by subcategory of interventions, gender distribution, regional prevalence and regional density calculated by the annual averages of the total number of cases reported per 100,000 people in the 40 counties of the country and the capital, Bucharest. We also determined the variations in hip and knee arthroplasty revision burdens, calculated as a percentage between the number of revisions and the number of primary interventions in the same period. We determined the regional densities of revision burdens. The total number of orthopedic surgeries in the period 2001-2022 was 1,557,247, of which 189,881 were hip replacement surgeries; 51,035 were knee replacement surgeries; 11,085 were revision hip arthroplasty; 1497 were revision knee arthroplasty; 541,440 were operated fractures; and 16,418 were operated bone tumors. The growth rates of surgical interventions are hip replacement surgery, +8.19%; knee replacement surgery, +19.55%; revision hip arthroplasty, +9.43%; and revision knee arthroplasty, +28.57%. With these data, we have estimated a doubling of the volume of primary and revision interventions of the hip until 2034 and the knee until 2027, respectively. Operated bone tumors register an annual decrease of -4.52% thanks to modern treatments. There are clear gender differences; for primary hip interventions, the proportion of women is 58.82%, and for knee interventions, the proportion of women is 76.42%. This is the first research that, with the support of exhaustive data from the NER, analyzes for the period 2001-2022 the annual number of orthopedic surgeries in Romania. It allows knowledge of the large, anticipated increases in orthopedic surgery and provides a quantitative basis for future policy decisions related to the need for medical personnel and material resources.

Lateral epicondyle to the joint line distance is a precise landmark for determination of an accurate knee joint line: an observational retrospective study.

PURPOSE: To assess a quantitative and reproducible association between the position of the knee joint line and recognizable anatomical landmarks around it in order to help in restoring joint line in arthroplasty cases. METHODS: Magnetic resonance imaging (MRI) of 130 normal knees were investigated. Anatomical measurements of the knee joint distances on the obtained planes were performed manually by distance measurements using a ruler tool, followed by 6 anatomical bony landmarks determination about the knee to identify the joint line which included the joint line, medial epicondyle, lateral epicondyle, medial flare, lateral flare, and proximal tibiofibular joint. The entire process was examined twice by two independent fellowship trained musculoskeletal radiologists, with a 2-week interval between the first and second sets of readings. RESULTS: The lateral epicondyle to the joint line of the knee (LEJL) could be a reliable landmark for accurate distance measurements for the knee joint line level, with an absolute distance of 24.4 ± 2.8 mm. The analysis showed that the femorotibial ratio between the LEJL and proximal tibiofibular joint (PTFJ) was 1.0 (LEJL/PTFJJL = 1.0 ± 0.1), confirming the location of the knee joint at the midpoint between the lateral epicondyle and PTFJ, revealing two identifiable landmarks. CONCLUSIONS: LEJL is the most precise landmark for determination of an accurate knee joint line because the knee is located at the midline between the lateral epicondyle and PTFJ. These reproducible quantitative relationships can be widely employed in various imaging modalities to help restore the knee JL in arthroplasty surgeries.

Incidence, Etiology, and Risk Factors Associated with Foot Drop.

Background: Injury to the neurological pathway that enables ankle dorsiflexion is likely to cause foot drop. This pathway includes the motor cortex; lumbosacral plexus; and the sciatic, tibial, and peroneal nerves. Nerve damage typically occurs due to compression, entrapment, traction, or direct trauma to the nerve due to several etiologies. However, there are limited reports on the incidence, etiology, and factors associated with foot drop. Methods: The authors reviewed their clinic's data from 1022 patients with foot drop from 2004 to present to determine the incidence, causes, and risk factors of foot drop. Microsoft Excel was used for descriptive statistical data analysis and graphing. Results: A total of 21 causes of foot drop were found. Of 1022 patients, 142 (13.9%) had foot drop after lumbosacral (LS) spine surgery, while 131 patients (12.8%) with LS spine complications who had not undergone surgery also reported foot drop. The LS spine complications and surgeries were influenced by age (median age, 63 and 55 years, respectively) and were marginally higher in male patients (54%). A total of 79 patients (7.8%) with foot drop had previously undergone hip replacement surgery. Older age (median age, 60 years) and female sex (85%) were risk factors for hip replacement surgery resulting in foot drop. In contrast, younger age and male sex were the risk factors for gunshot and stab wounds, injection drug use, drug or medication overdoses, and motor vehicle accidents resulting in foot drop. Conclusions: Failed back surgery syndrome is the leading cause of foot drop after lumbosacral spine and hip replacement surgeries in both male and female older (median age, 60 years) patients. However, most (85%) of the foot drop patients in the present study who underwent hip replacement surgery were female patients. Sports and recreational activities, motor vehicle accidents, drug use, and violence are common causes of foot drop in younger male adults.

Thirty-Day Morbidity and Mortality After Total Knee Replacement in a Tertiary Care Hospital in Pakistan.

Background Total knee arthroplasty has become very popular globally as a safe surgical modality for relieving pain and improving functional outcomes in patients who fail to respond to conservative treatments; however, it may be associated with postoperative complications. The aim of this study is to determine the incidence of postoperative complications occurring within the first 30 days after total knee replacement (TKR). Materials and methods This is a prospective cross-sectional study. All consecutive patients who underwent primary unilateral or bilateral total knee arthroplasty between November 2020 and July 2021 were included in the study. Patients were followed for a period of 30 days, and postoperative complications (if any) were documented. Continuous variables were expressed as means ± standard deviations. Categorical variables were expressed as frequency and percentages, and chi-square test was used to compare the qualitative variables. Univariate and multiple logistic regression analyses were done to analyze the magnitude of associations of the complication with other predictor variables keeping a level of significance of <0.05. Results The overall complication rate within the 30-day window was 7.0%. Postoperative surgical site infections (SSI) were noted in three patients (2.6%). Thromboembolic complications were seen in only one patient (0.9%). One patient (0.9%) was readmitted within the one-month period after initial discharge, and one patient (0.9%) expired within 12 hours postoperatively. Conclusion TKR renders satisfactory results with a low incidence of complications in general; however, wound infections, thromboembolic complications, and cardiovascular complications do occur postoperatively. Male gender, obesity, and bilateral TKRs remain the notable risk factors for the development of complications post-procedure.

Comparison of postoperative analgesia with two different doses of dexmedetomidine as an adjuvant to ropivacaine in adductor canal block for unilateral total knee replacement surgery: A randomized double-blinded study.

Background and Aims: Multimodal analgesia is used to treat severe postoperative pain (POP) in total knee replacement (TKR) surgery. Adjuvants are used with local anesthetics to improve the quality and duration of pain relief. Studies comparing different doses of dexmedetomidine in adductor canal block (ACB) are sparse to date. This study compares postoperative analgesia with two different doses of dexmedetomidine as an adjuvant to 0.2% ropivacaine in ACB for unilateral TKR. Material and Methods: In this prospective, randomized, double-blinded comparative study, sixty patients were divided into two groups: A and B. Postoperatively perineural catheter was inserted and all patients received 0.2% ropivacaine 20 mL bolus followed by an infusion of 0.2% ropivacaine with dexmedetomidine (0.5 µg/Kg in Group A and 1 µg/Kg in Group B) at 8 mL/h. Postoperative pain, motor blockade, rescue analgesia, hemodynamic parameters, sedation, and adverse effects were recorded. Student t, Chi-square, and Mann-Whitney tests were used. Results: Most patients were elderly females (M:15, F:45). Postoperatively, from 2nd to 24th hour, pain score was less in Group B (P < 0.05). The requirement of rescue analgesic was also less in Group B (A:B 330 µg:60 µg; 23%:6%). Motor blockade assessed using modified Bromage scale and sedation using Richmond agitation sedation scale did not show any statistical difference. Conclusion: Dexmedetomidine infusion at 1 µg/Kg is a better adjuvant to 0.2% ropivacaine than 0.5 µg/Kg in ACB. It provides better analgesia without producing sedation, motor blockade, hemodynamic changes, or any adverse effects.

Wait time management strategies at centralized intake system for hip and knee replacement surgery: A need for a blended evidence-based and patient-centered approach.

Objectives: Delays in access to specialty care and elective hip and knee total joint replacement (TJR) surgery remain a major concern among patients with osteoarthritis (OA) in Canada. Centralized intake systems as a wait time management strategy in the face of resource constraints can increase access and patient flow through the system but are not standard practice. We examine how wait time management strategies for the assessment and triaging referrals in a centralized intake system can inform quality improvement initiatives. Design: We developed a discrete-event simulation model using all referrals to the Edmonton Bone and Joint Centre centralized intake system from 2012 to 2016 for the base case model. We assessed the combined effect of three wait time management strategies: improved prioritization, improved sorting through screening, and increased conservative management. Outcomes were measured in terms of patient flow and wait times. Results: The screener sees more patient referrals (7094 compared to 6922), and the number of patients who proceed to surgery is reduced by 282 patients (4%) in the wait time management scenario compared to the base case model. Wait times from referral to surgery are reduced by 54 days for surgical patients. Furthermore, urgent surgical patients experienced lower wait times in all stages of care than non-urgent patients, with wait times from referral to surgery reduced by 86 days. Conclusions: Triaging processes addressing prioritization, screening and conservative management of non-surgical patients can improve patient flow and significantly reduce patient wait times in a centralized intake process for TJR.

Opioid use among Danish patients with severe knee osteoarthritis: a drug utilization study.

PURPOSE: Knee osteoarthritis (OA) is one of the most common musculoskeletal diseases. Opioids have been increasingly used in the treatment of severe knee OA-related pain, particularly in the USA. Less is known about the patterns of use of opioids among Danish patients with severe knee OA. We investigated opioid use among Danish patients with severe knee OA in the 5 years preceding knee replacement surgery (KR). METHODS: We identified adults who had undergone KR from January 1st, 2005, to December 31st, 2018, using the Danish National Patient Register. These patients were considered to have severe knee OA in the 5-year period leading up to KR. Individual-level data on prescribed opioids were retrieved from the Danish National Prescription Registry. RESULTS: We identified 77,168 severe knee OA patients (mean age 66 years). The prevalence of opioid users increased from 21% 5 years before KR to 40% 1 year before. Total use of opioids increased each year and doubled from 3254 mg oral morphine equivalents (OMEQ)/1000 individuals/day 5 years before to 6396 mg OMEQ/1000 individuals/day the year before KR corresponding to an increase of 3141 mg OMEQ (95% confidence interval 3010 to 3273). Tramadol was the most frequently used opioid. About 10% of the population accounted for 90% of the total opioid use. CONCLUSION: Among patients with severe knee OA, the prevalence and total use of opioids doubled during the 5 years before KR. In addition, 10% of the study population was responsible for 90% of the opioids used.

Physician induced demand for knee replacement surgery in Iran.

BACKGROUND: The structure of the Iranian health system has raised this hypothesis that a part of the Knee Replacement Surgery (KRS) services are provided due to Physician-Induced Demand (PID). METHODS: This paper used an unbalanced individual panel data covering the steady-state 15,729 KRSs performed by 995 surgeons provided by the Armed Forces Insurance Organization at the provincial level over the 60 months (2014-2018). We use a generalized method of moment's system (GMM-SYS) to obtain consistent and asymptotically efficient estimates, which provide a vital instrument for our dynamic panel data. RESULTS: The outcomes show that with unequal increasing orthopedic surgeons to population ratio, both the number and size of KRS services were increased significantly at a 1 % level. Given that the positive elasticity obtained for the service size was significantly larger than the number of services, the findings give strong support for the existence of PID in the Iran system for KRS care. Also, the raw and population-adjusted number of KRS, cost, and the surgery per active physician increased significantly at the monthly province level. CONCLUSIONS: This is the first time that the existence of PID in the Iranian health system is investigated using approved econometric models. The findings indicate that the health system structure has been provided the conditions for aggressive, costly, and high-risk services such as KRS to be exposed to PID.

Evolución de la herida quirúrgica en pacientes intervenidos de artroplastia total de rodilla en los que se utilizaron cuatro tipos de apósitos distintos / Evolution of the surgical wound in patients undergoing total knee replacement surgery, using four different types of wound dressing

Objetivo: valorar la evolución de la herida quirúrgica en pacientes intervenidos de artroplastia total de rodilla en los que se utilizaron cuatro tipos de apósitos distintos.Método: estudio observacional a pacientes quirúrgicos de artroplastia de rodilla de la Unidad de Cirugía Ortopédica de Rodilla del Hospital Clínic (Barcelona). El primer día postcirugía, la enfermera curaba la herida quirúrgica (HQ) y colocaba un apósito, de los cuatro usados para el estudio. Los apósitos se distribuyeron en grupos de pacientes de 25. Se valoró el tiempo de permanencia del apósito, aparición de complicaciones (flictena, dehiscencia, exudado), confort por parte del paciente y facilidad en la colocación por parte de la enfermera. Las medidas de evaluación se tomaron a los siete días postcirugía en el momento de la cura en consultas externas. Se realizó un análisis descriptivo, con frecuencias, media y desviación estándar (DE).Resultados: se reclutaron 100 pacientes. El tiempo medio (DE) de permanencia fue superior en el Apósito 1 6,34 (1,56). Las complicaciones de HQ fueron menores en Apósito 4 (1 flictena, ninguna dehiscencia). El exudado moderado/abundante de HQ fue menor en Apósitos 1 y 4 (16% en ambos casos). La enfermera valoró facilidad en la colocación del Apósito 1, 2 y 4, en el 100% de pacientes. Los pacientes con mayor confort fueron los del grupo Apósito 1 (96%), aportando peor valoración los sujetos del grupo Apósito 4 (76%).Conclusiones: los apósitos 1 y 4 han mostrado un número mayor de ítems favorables (tiempo permanencia, facilidad colocación, menos complicaciones), con especial relevancia desde el punto de vista de la comodidad del paciente, superior en el Apósito 1 respecto al Apósito 4.(AU)

Objective: to assess the evolution of surgical wounds in patients undergoing total knee replacement surgery, using four different types of wound dressing.Method: an observational study on surgical patients with total knee replacement, from the Knee Orthopedic Surgery Unit of the Hospital Clínic (Barcelona). The first day after the procedure, the nurse treated the surgical wound (SW) and applied one dressing of the four used for the study. Each wound dressing was allocated to a 25-patient group. There was an assessment of time of permanence of the dressing, development of complications (phlyctena, dehiscence, exudate), comfort for the patient, and ease of application for the nurse. Evaluation measures were taken at seven days after the procedure, at the time of treatment in the outpatient unit. There was descriptive analysis, with frequencies, mean, and standard deviation (SD).Results: one hundred (100) patients were recruited. The mean time (SD) of permanence was higher for dressing 1: 6.34 (1.56). Surgical wound complications were lower with dressing 4 (1 phlyctena, no dehiscence). SW moderate/heavy exudate was lower with dressings 1 and 4 (16% in both cases). The nurse valued the ease of application for dressings 1, 2 and 4, in 100% of patients. The patients in the dressing 1 group reported higher comfort (96%), while the worse assessment was made by the subjects in the dressing 4 group (76%).Conclusions: wound dressings 1 and 4 have shown a higher number of favorable items (time of permanence, ease of application, lower number of complications), with special relevance from the point of view of patient comfort, superior with dressing 1 vs. dressing 4.(AU)

Assessment of the Effectiveness of Rehabilitation after Total Knee Replacement Surgery Using Sample Entropy and Classical Measures of Body Balance.

Exercises in virtual reality (VR) have recently become a popular form of rehabilitation and are reported to be more effective than a standard rehabilitation protocol alone. The aim of this study was to assess the efficacy of adjunct VR training in improving postural control in patients after total knee replacement surgery (TKR). Forty-two patients within 7-14 days of TKR were enrolled and divided into a VR group and a control group (C). The C group underwent standard postoperative rehabilitation. The VR group additionally attended twelve 30-min exercise sessions using the Virtual Balance Clinic prototype system. Balance was assessed on the AMTI plate in bipedal standing with and without visual feedback before and after the four-week rehabilitation. Linear measures and sample entropy of CoP data were analyzed. After four weeks of rehabilitation, a significant reduction in parameters in the sagittal plane and ellipse area was noted while the eyes remained open. Regression analysis showed that sample entropy depended on sex, body weight, visual feedback and age. Based on the sample entropy results, it was concluded that the complexity of the body reaction had not improved. The standing-with-eyes-closed test activates automatic balance mechanisms and offers better possibilities as a diagnostic tool.

A novel visualization system of using augmented reality in knee replacement surgery: Enhanced bidirectional maximum correntropy algorithm.

BACKGROUND AND AIM: Image registration and alignment are the main limitations of augmented reality (AR)-based knee replacement surgery. This research aims to decrease the registration error, eliminate outcomes that are trapped in local minima to improve the alignment problems, handle the occlusion and maximize the overlapping parts. METHODOLOGY: Markerless image registration method was used for AR-based knee replacement surgery to guide and visualize the surgical operation. While weight least square algorithm was used to enhance stereo camera-based tracking by filling border occlusion in right-to-left direction and non-border occlusion from left-to-right direction. RESULTS: This study has improved video precision to 0.57-0.61 mm alignment error. Furthermore, with the use of bidirectional points, that is, forward and backward directional cloud point, the iteration on image registration was decreased. This has led to improve the processing time as well. The processing time of video frames was improved to 7.4-11.74 frames per second. CONCLUSIONS: It seems clear that this proposed system has focused on overcoming the misalignment difficulty caused by the movement of patient and enhancing the AR visualization during knee replacement surgery. The proposed system was reliable and favourable which helps in eliminating alignment error by ascertaining the optimal rigid transformation between two cloud points and removing the outliers and non-Gaussian noise. The proposed AR system helps in accurate visualization and navigation of anatomy of knee such as femur, tibia, cartilage, blood vessels and so forth.

Efficacy of low-load blood flow restricted resistance EXercise in patients with Knee osteoarthritis scheduled for total knee replacement (EXKnee): protocol for a multicentre randomised controlled trial.

INTRODUCTION: Up to 20% of patients undergoing total knee replacement (TKR) surgery report no or suboptimal pain relief after TKR. Moreover, despite chances of recovering to preoperative functional levels, patients receiving TKR have demonstrated persistent deficits in quadriceps strength and functional performance compared with healthy age-matched adults. We intend to examine if low-load blood flow restricted exercise (BFRE) is an effective preoperative method to increase functional capacity, lower limb muscle strength and self-reported outcomes after TKR. In addition, the study aims to investigate to which extent preoperative BFRE will protect against surgery-related atrophy 3 months after TKR. METHODS: In this multicentre, randomised controlled and assessor blinded trial, 84 patients scheduled for TKR will be randomised to receive usual care and 8 weeks of preoperative BFRE or to follow usual care-only. Data will be collected before randomisation, 3-4 days prior to TKR, 6 weeks, 3 months and 12 months after TKR. Primary outcome will be the change in 30 s chair stand test from baseline to 3-month follow-up. Key secondary outcomes will be timed up and go, 40 me fast-paced walk test, isometric knee extensor and flexor strength, patient-reported outcome and selected myofiber properties.Intention-to-treat principle and per-protocol analyses will be conducted. A one-way analysis of variance model will be used to analyse between group mean changes. Preintervention-to-postintervention comparisons will be analysed using a mixed linear model. Also, paired Student's t-test will be performed to gain insight into the potential pretraining-to-post-training differences within the respective training or control groups and regression analysis will be used for analysation of associations between selected outcomes. ETHICAL APPROVAL: The trial has been accepted by the Central Denmark Region Committee on Biomedical Research Ethics (Journal No 10-72-19-19) and the Danish Data Protection Agency (Journal No 652164). All results will be published in international peer-reviewed scientific journals regardless of positive, negative or inconclusive results. TRIAL REGISTRATION NUMBER: NCT04081493.

A Novel Visualization System of Using Augmented Reality in Knee Replacement Surgery: Enhanced Bidirectional Maximum CorrentropyAlgorithm.

BACKGROUND AND AIM: Image registration and alignment are the main limitations of augmented reality-based knee replacement surgery. This research aims to decrease the registration error, eliminate outcomes that are trapped in local minima to improve the alignment problems, handle the occlusion and maximize the overlapping parts. METHODOLOGY: markerless image registration method was used for Augmented reality-based knee replacement surgery to guide and visualize the surgical operation. While weight least square algorithm was used to enhance stereo camera-based tracking by filling border occlusion in right to left direction and non-border occlusion from left to right direction. RESULTS: This study has improved video precision to 0.57 mm ∼ 0.61 mm alignment error. Furthermore, with the use of bidirectional points, i.e. Forwards and backwards directional cloud point, the iteration on image registration was decreased. This has led to improved the processing time as well. The processing time of video frames was improved to 7.4 ∼11.74 fps. CONCLUSIONS: It seems clear that this proposed system has focused on overcoming the misalignment difficulty caused by movement of patient and enhancing the AR visualization during knee replacement surgery. The proposed system was reliable and favourable which helps in eliminating alignment error by ascertaining the optimal rigid transformation between two cloud points and removing the outliers and non-Gaussian noise. The proposed augmented reality system helps in accurate visualization and navigation of anatomy of knee such as femur, tibia, cartilage, blood vessels, etc. This article is protected by copyright. All rights reserved.

Geographical and ethnic differences of osteoarthritis-associated hip and knee replacement surgeries in New Zealand: a population-based cross-sectional study.

OBJECTIVES: To (1) explore the regional and ethnic differences in rates of publicly funded osteoarthritis-associated hip and knee replacement surgeries and (2) investigate the mortality after surgery. DESIGN: Population-based, retrospective, cross-sectional study. SETTING: General population in New Zealand. PARTICIPANTS: Patients with osteoarthritis who underwent publicly funded primary hip and knee replacement surgeries in 2005-2017. Patients aged 14-99 years were included. PRIMARY AND SECONDARY OUTCOME MEASURES: Age-standardised rate, standardised mortality ratio (SMR) and 30 days, 90 days and 1 year mortality. RESULTS: We identified 53 439 primary hip replacements and 50 072 primary knee replacements with a diagnosis of osteoarthritis. The number and age-standardised rates of hip and knee replacements increased over time. Maori had the highest age-standardised rate of hip replacements, followed by European/others and Pacific, and Asian had the lowest rate. Pacific had the highest age-standardised rate of knee replacements, followed by Maori and European/others, and Asian had the lowest rate. The Northern Health Network had the lowest rate of hip surgeries, and the Southern Health Network had the lowest rate of knee surgeries. The SMRs of patients undergoing hip and knee replacements were lower than the general population: 0.92 (95% CI 0.89 to 0.95) for hip and 0.79 (95% CI 0.76 to 0.82) for knee. The SMRs were decreasing over time. The patterns of 30 days, 90 days and 1 year mortality were similar to the SMR. CONCLUSIONS: The numbers of publicly funded osteoarthritis-associated primary hip and knee replacements are steadily increasing. Maori people had the highest age-standardised rate of hip replacements and Pacific people had the highest rate of knee replacements. The Northern Health Network had the lowest rate of hip surgeries, and the Southern Health Network had the lowest rate of knee surgeries. Compared with the general population, patients who had hip and knee replacements have a better life expectancy.