Search

To study the direction and biomechanical consequences of hip center of rotation (HCOR) migration in Crowe type III and VI hips after total hip arthroplasty, post-operative radiographs and CT scans of several unilaterally affected hips were evaluated. Using a three-dimensional model of the human hip, the HCOR was moved in all directions, and joint reaction force (JRF) and abductor muscle force (AMF) were calculated for single-leg stance configuration. Comparing to the normal side, HCOR had displaced medially and inferiorly by an average of 23.4% and 20.8%, respectively, of the normal femoral head diameter. Significant decreases in JRF (13%) and AMF (46.13%) were observed in a presumptive case with that amount of displacement. Isolated inferior displacement had a small, increasing effect on these forces. In Crowe type III and IV hips, the HCOR migrates inferiorly and medially after THA, resulting in a decrease in JRF, AMF, and abductor muscle contraction force.

article i nfo Article history: Received 6 February 2013 Accepted 15 April 2013 A biomechanical computer-based model was developed to simulate the influence of patellar thickness on passive knee flexion after arthroplasty. Using the computer model of a single-radius, PCL-sacrificing knee prosthesis, a range of patella-implant composite thicknesses was simulated. The biomechanical model was then replicated using two cadaveric knees. A patellar-thickness range of 15 mm was applied to each of the knees. Knee flexion was found to decrease exponentially with increased patellar thickness in both the biomechanical and experimental studies. Importantly, this flexion loss followed an exponential pattern with higher patellar thicknesses in both studies. In order to avoid adverse biomechanical and functional consequences, it is recommended to restore patellar thickness to that of the native knee during total knee arthroplasty.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a pandemic since early 2020. The coronavirus disease 2019 (COVID-19) has already caused more than three million deaths worldwide and affected people's physical and mental health. COVID-19 patients with mild symptoms are generally required to self-isolate and monitor for symptoms at least for 14 days in the case the disease turns towards severe complications. In this work, we overviewed the impact of COVID-19 on the patients' general health with a focus on their cardiovascular, respiratory and mental health, and investigated several existing patient monitoring systems. We addressed the limitations of these systems and proposed a wearable telehealth solution for monitoring a set of physiological parameters that are critical for COVID-19 patients such as body temperature, heart rate, heart rate variability, blood oxygen saturation, respiratory rate, blood pressure, and cough. This physiological information can be further combined to potentially estimate the lung function using artificial intelligence (AI) and sensor fusion techniques. The prototype, which includes the hardware and a smartphone app, showed promising results with performance comparable to or better than similar commercial devices, thus potentially making the proposed system an ideal wearable solution for long-term monitoring of COVID-19 patients and other chronic diseases.

The aim of survival analysis in healthcare is to estimate the probability of occurrence of an event, such as a patient's death in an intensive care unit (ICU). Recent developments in deep neural networks (DNNs) for survival analysis show the superiority of these models in comparison with other well-known models in survival analysis applications. Ensuring the reliability and explainability of deep survival models deployed in healthcare is a necessity. Since DNN models often behave like a black box, their predictions might not be easily trusted by clinicians, especially when predictions are contrary to a physician's opinion. A deep survival model that explains and justifies its decision-making process could potentially gain the trust of clinicians. In this research, we propose the reverse survival model (RSM) framework that provides detailed insights into the decision-making process of survival models. For each patient of interest, RSM can extract similar patients from a dataset and rank them based on the most relevant features that deep survival models rely on for their predictions.

Background: Several pelvic osteotomy techniques are introduced for the treatment of Developmental Dysplasia of the Hip (DDH). However, there is no agreement on the optimal pelvic osteotomy in DDH. Thus, this study aimed to compare the outcomes of Pemberton Osteotomy (PO) and the Kalamchi Modification of Salter Osteotomy (KMSO). Objectives: Comparison of pemberton osteotomy and kalamchi modification of salter osteotomy in the treatment of developmental dysplasia of the hip. Methods: In a retrospective study, radiographic and clinical outcomes as well as surgical complications were compared between the patients who underwent unilateral DDH surgery using either KMSO or PO. The radiographic measures included the assessment of the acetabular index and the Shenton line. The clinical results of the osteotomies were evaluated by McKay’s criteria modified by Berkeley et al. Also, Kalamchi and MacEwen’s classification was used for the assessment of avascular necrosis. Results: The characteristic features of the patients, such as age and follow-up time, were statistically comparable between the two study groups. One year after the surgery, the Shenton line was intact in 55 patients (84.6%) of the KMSO group and 40 patients (88.9%) of the PO group (P=0.52). The Mean±SD value of the acetabular index was 21.1±5.1 and 20.7±3.9 in the KMSO and PO groups, respectively (P=0.13). Besides, the McKay’s clinical criteria were respectively excellent, good, and fair in 44, 16, and 5 patients (67.7%, 24.6%, and 7.7%, respectively) of the KMSO group, and 31, 12, and 2 patients (70%, 26.6%, and 4.4%, respectively) of the PO group (P=0.4). Moreover, the number of postoperative avascular necrosis did not significantly differ between the two study groups. Conclusion: The PO and KMSO techniques are equally safe and effective osteotomies in the treatment of DDH and can be used interchangeably.

In this study we present our experience with four generations of uncemented total knee arthroplasty (TKA) from SmithNephew: Tricon M, Tricon LS, Tricon II and Profix, focusing on the failure rates correlating with each design change. Beginning in 1984, 380 Tricon M, 435 Tricon LS, 305 Tricon 2 and 588 Profix were implanted by the senior author. The rate of revision for loosening was 1.1% for the Tricon M, 1.1% for the Tricon LS, 0.5% for the Tricon 2 with a HA coated tibial component, and 1.3% for the Profix TKA. No loosening of the femoral component was seen with the Tricon M, Tricon LS or Tricon 2, with no loosening seen of the tibial component with the Profix TKA. Regarding revision for wear, the incidence was 13.1% for the Tricon M, 6.6% for the Tricon LS, 2.3% for the Tricon 2, and 0% for the Profix. These results demonstrate that improvements in the design of uncemented components, including increased polyethylene thickness, improved polyethylene quality, and the introduction of hydroxyapatite coating, has improved the outcomes of uncemented TKA over time.

Background: Total hip arthroplasty (THA) is regarded as the most successful and common surgical approach in orthopedic surgeries. Several surgical approaches have been described for THA to introduce minimally invasive surgical exposures. Posterolateral and lateral approaches are traditional and still most commonly used approaches for primary THA. In deciding which approach to use, consideration of complications, and clinical and radiological outcomes, using one approach or another should be evaluated. Objectives: The purpose of this study was to compare the early postoperative outcomes of posterolateral and lateral surgical approaches. Patients and Methods: The current study was conducted on a group of 134 primary hip arthroplasty of 120 patients who had undergone THA surgery at Shafa Orthopedic Hospital in Tehran, Iran, from March 2011 to October 2014. The lateral approach was used in 79 hips and, posterolateral approach was used in 55 hip based on surgeon’s preference. Two groups were assessed considering the following outcomes: clinical evaluation including Harris hip score (HHS), blood loss, blood transfusion, hemoglobin level, infections, deep vein thrombosis (DVT) and dislocation, as well as radiological evaluation including the proximal femur fracture, limb length discrepancy and cup inclination angle. The follow-up for both groups was at 6, 12, 24, 36 and 48 weeks after the surgery. Results: There was no significant difference between the two approaches regarding demographic characteristics, HHS, blood loss, transfusion, hemoglobin level, dislocation and cup inclination angle. However, there was a significant difference in the incidences of infections, DVT, proximal femur fracture and discrepancy of limb length between the two approaches. Conclusions: The results of this study indicate that both lateral and posterolateral approaches offer similar early clinical outcomes and some different radiological outcomes.

The authors have reported on the prospective measurements of intraand post-operative blood loss of 96 total knee arthroplasty cases and have analyzed the relationship between these values and demographical factors of the series. Mean intraoperative blood loss and postoperative drainage were determined to be 147.1 ± 97.4 mL and 494.4 ± 188.1 mL, respectively. Male and obese patients had significantly higher intraoperative blood loss, whereas male sex and older age were associated with a greater drop in hemoglobin (Hb), on the first postoperative day. No predictors of the need for transfusion were found.

with the introduction of an illegal, steroid-containing opioid drug, Temgesic. The correlation of risk factors associated with the course of ONFH has yet to be determined. Objectives: The purpose of the present study was to assess the effects of etiologic factors on the course of ONFH after emergence of symptoms. Patients and Methods: We retrospectively assessed patients with untreated ONFH due to one of the four etiologies of steroid medication, Temgesic abuse, trauma and idiopathic. Patients with multiple risk factors and those without collapse at the last follow-up visit were excluded. The effect of age, gender, etiology of osteonecrosis, opium addiction and smoking on the time interval between pain onset and radiologic collapse were investigated. Results: In total, 110 patients (174 hips) were categorized into four etiologic groups. The average time between onset of pain to radiologic collapse in different etiologic groups was 12.8 months for all groups, 12.4 months for steroid, 8.7 months for Temgesic, 18.5 months for trauma and 16.6 months for idiopathic groups. Thirteen hips had collapse in less than six months. Patients who used steroid and Temgesic had shorter time interval to collapse, which was statistically significant (P Values < 0.001 and < 0.001, respectively). Smoking had a statistically significant association with the time to femoral head collapse (P Value = 0.003). Conclusions: Steroid medications and Temgesic abuse are associated with shorter time interval to femoral head collapse. Smoking is also a factor associated with shorter time interval to collapse. These factors should be considered in any joint preserving treatments for patients with FHON.

It is common practice in many centers to avoid performing a clean case in a room in which an infected procedure has just taken place. No studies of which we are aware speak to the necessity of this precaution.The purposes of this study were to identify (1) the risk of infection in a group of patients who underwent arthroplasties performed immediately after a first-stage arthroplasty for joint infection; and (2) the risk of superficial and deep infections in these patients compared with a matched group of patients who underwent arthroplasties not performed after an infected surgery.Eighty-three patients (85 arthroplasties) who underwent arthroplasties (primary or revision) immediately after patients with known infections underwent surgery in the same operating room (OR) were analyzed for 12 months after surgery to determine the incidence of infection. They were matched for demographic factors and surgery type with a control group of 321 patients (354 arthroplasties) who underwent surgery in an OR that had not just been used for surgery involving patients with infections. We compared the risk of superficial and deep infections between the groups.Patients in the study group were not more likely to have infections develop than those in the control group. One patient in the study group (1.17%) and three in the control group (0.84%) had deep infections develop; the infection in the patient in the study group was caused by a different organism than that of the patient with an infection whose surgery preceded in the OR. Two superficial infections (2.35%) were detected in the study group and 17 (4.8%) were detected in the control group.With the numbers available, we found that a deep infection was not more likely to occur in a patient without an infection after an arthroplasty that followed surgery on a patient with an infection than in one who had surgery after a clean case. Although sample size was a potential issue in this study, the results may serve as hypothesis generating for future studies.Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.