Stability of Three-Dimensional Printed Custom-Made Metaphyseal Cone for Tibial Bone Defects Reconstruction: A Finite Element Analysis and Biomechanical Study.

OBJECTIVES: The reconstruction of bone defects in tibial revision knee arthroplasty is challenging. In this study, we evaluated the primary stability of a novel three-dimensional (3D)-printed custom-made metaphyseal cone for Anderson Orthopedic Research Institute (AORI) IIb or III bone defect reconstruction in tibial revision knee arthroplasty using the combination of finite-element analysis and biomechanical experiments. METHODS: In the finite-element analysis, AORI II b and III medial tibial bone defects were designed at varying depths. A novel 3D-printed custom-made metaphyseal cone was designed and used to reconstruct the bone defect with or without a stem in simulated revision total knee arthroplasty (RTKA). A no-stem group and a stem group were established (based on whether a stem was used or not). Von Mises stress and micromotion were calculated with varying depths of bone defects, ranging from 5 mm to 35 mm, and then micromotions at the bone-implant interface were calculated and compared with the critical value of 150 µm. In the biomechanical experiment, the no-stem group was used, and the same bone defects were made in four synthetic tibias using patient-specific instruments. Micromotions at the bone-implant interface were investigated using a non-contact optical digital image correlation system and compared with the critical value of 150 µm. RESULTS: When the bone defect was <30 mm, micromotions at the bone-implant interface in the finite-element analysis were all below 150 µm both in the stem groups and no-stem groups, whereas those in the biomechanical experiment were also below 150 µm in the no-stem group. CONCLUSIONS: The 3D-printed custom-made metaphyseal cone in RTKA has excellent primary stability and does not require stems in reconstructing tibial AORI type IIb or III bone defects with a depth of <30 mm.

Bacteriosynthetic Degradable Tranexamic Acid-Functionalized Short Fibers for Inhibiting Invisible Hemorrhage.

Current research on hemostatic materials have focused on the inhibition of visible hemorrhage, however, invisible hemorrhage is the unavoidable internal bleeding that occurs after trauma or surgery, leading directly to a dramatic drop in hemoglobin and then to anemia and even death. In this study, bacterial nanocellulose (BNC) was synthesized and oxidized from the primary alcohols to carboxyl groups, and then grafted with tranexamic acid through amide bonds to construct degradable nanoscale short fibers (OBNC-TXA), which rapidly activated the coagulation response. The hemostatic material is made up of nanoscale short fibers that can be constructed into different forms such as emulsions, gels, powders, and sponges to meet different clinical applications. In the hemostatic experiments in vitro, the composites had significantly superior pro-coagulant properties due to the rapid aggregation of blood cells. In the coagulation experiments with rat tail amputation and liver trauma hemorrhage models, the group treated with OBNC-TXA1 sponge showed low hemorrhage and inhibited invisible hemorrhage in rectus abdominis muscle defect hemorrhage models, with a rapid recovery of hemoglobin values from 128±5.5 to 165±2.6 g L-1 within 4 days. In conclusion, the degradable short fibers constructed from bacterial nano-cellulose achieved inhibition of invisible hemorrhage in vivo.

Study on the association of the microstructure and bone metabolism in the osteoporotic femoral head.

BACKGROUND: We compared the bone microstructure and metabolism of the femoral heads in patients with osteoporosis (OP) and non-OP patients to investigate the pathologic mechanism of OP and guide clinical treatment. METHODS AND RESULTS: From January 2020 to June 2021, we obtained femoral head samples from 30 patients undergoing hip replacement due to femoral neck fracture. All patients were women aged approximately 67 to 80 years (mean age, 74 years). According to the dual-energy X-ray results, the femoral head samples were divided into the OP (T< - 2.5) and non-OP (T > - 1.5) groups. Microcomputed tomography scanning, bone metrology analysis, hematoxylin and eosin staining, and Masson's trichrome staining were used to compare the local bone trabecular microstructure changes. Quantitative reverse transcription PCR was performed to identify changes in the osteogenesis-related genes and the osteoclast-related genes in specific regions to reflect osteogenic and osteoclastic activities. Femoral heads with OP showed significant changes in the local bone microstructure. Bone density, bone volume fraction, and the number and thickness of the bone trabeculae decreased. Local bone metabolism was imbalanced in the areas with microstructural changes in femoral heads with OP, with increased osteoclast activity and decreased osteoblast activity. CONCLUSIONS: Deterioration of bone microstructure is closely related to abnormal bone metabolism associated with the activity of osteoblasts and osteoclasts in osteoporotic femoral heads. Promoting bone formation by improving local bone metabolism, enhancing osteogenic activity and inhibiting osteoclast activity may be a promising way of preventing local OP and osteoporotic fractures.

Demographic and radiographic factors for knee symptoms and range of motion in patients with knee osteoarthritis: a cross-sectional study in Beijing, China.

BACKGROUND: Knee osteoarthritis (KOA) causes not only pain, stiffness, and dysfunction of the knee, but also the reduction of the joint range of motion (ROM). This study explored the demographic and radiographic factors for knee symptoms and ROM in patients with symptomatic KOA. METHODS: The demographic variables, Kellgren-Lawrence (KL) grade, and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) of patients with symptomatic KOA recruited in Beijing were collected. The knee ROM of all patients were also measured. We analyzed the influencing factors for WOMAC and ROM using a generalize linear model, respectively. RESULTS: This study included a total of 2034 patients with symptomatic KOA, including 530 males (26.1%) and 1504 females (73.0%), with a mean age of 59.17 (± 10.22) years. Patients with advanced age, overweight or obesity, a family history of KOA, a moderate-to-heavy manual labor job and use of nonsteroidal anti-inflammatory drugs (NSAIDs) had significantly higher WOMAC and lower ROM (all P < 0.05). The more the comorbidities, the higher the WOMAC (all P < 0.05). Patients with higher education had better ROM than those with only an elementary education(ß = 4.905, P < 0.05). Compared with those KL = 0/1, the WOMAC of patients whose KL = 4 were higher (ß = 0.069, P < 0.05), but the WOMAC of those KL = 2 were lower (ß = -0.068, P < 0.05). ROM decreased with the increase of KL grade (all P < 0.05). CONCLUSIONS: KOA patients with advanced age, overweight or obesity, a family history of KOA in first-degree relatives, a moderate-to-heavy manual labor job tended to have more severe clinical symptoms and worse ROM. Patients with more severe imaging lesions tend to have poorer ROM. Symptom management measures and regular ROM screening should be taken early to these people.

Adenovirus-associated anti-miRNA-214 regulates bone metabolism and prevents local osteoporosis in rats.

Objective: We investigated the expression of miRNA-214 in human osteoporotic bone tissue and tested the utility of adeno-associated virus (AAV) expressing a miRNA-214 inhibitor in terms of preventing local osteoporosis of the femoral condyle in a rat model of osteoporosis. Methods: (1) Femoral heads of patients who underwent hip replacements at our hospital because of femoral neck fractures were collected and divided into osteoporosis and non-osteoporosis groups based on preoperative bone mineral density data. MiRNA-214 expression was detected in bone tissues exhibiting obvious bone microstructural changes in the two groups. (2) A total of 144 SD female rats were divided into four groups: the Control, Model, Negative control (Model + AAV), and Experimental (Model + anti-miRNA-214) groups. AAV-anti-miRNA-214 was injected locally into the rat femoral condyles; we explored whether this prevented or treated local osteoporosis. Results: (1) MiRNA-214 expression in the human femoral head was significantly increased in the osteoporosis group. (2) Compared to the Model and Model + AAV groups, the bone mineral density (BMD) and femoral condyle bone volume/tissue volume (BV/TV) ratio in the Model + anti-miRNA-214 group were significantly higher; in addition, the number (TB.N) and thickness (TB.Th) of the trabecular bones were increased (all p < 0.05). MiRNA-214 expression in the femoral condyles of the Model + anti-miRNA-214 group was significantly higher than that in the other groups. The expression levels of the osteogenesis-related genes Alp, Bglap, and Col1α1 increased, while those of the osteoclast-related genes NFATc1, Acp5, Ctsk, Mmp9, and Clcn7 decreased. Conclusion: AAV-anti-miRNA-214 promoted osteoblast activity and inhibited osteoclast activity in the femoral condyles of osteoporotic rats, improving bone metabolism and slowing osteoporosis progression.

Artificial Intelligence-Based Prediction of Lower Extremity Deep Vein Thrombosis Risk After Knee/Hip Arthroplasty.

Deep vein thrombosis (DVT) is a common postoperative complication of knee/hip arthroplasty. There is a continued need for artificial intelligence-based methods of predicting lower extremity DVT risk after knee/hip arthroplasty. In this study, we performed a retrospective study to analyse the data from patients who underwent primary knee/hip arthroplasty between January 2017 and December 2021 with postoperative bilateral lower extremity venous ultrasonography. Patients' features were extracted from electronic health records (EHRs) and assigned to the training (80%) and test (20%) datasets using six models: eXtreme gradient boosting, random forest, support vector machines, logistic regression, ensemble, and backpropagation neural network. The Caprini score was calculated according to the Caprini score measurement scale, and the corresponding optimal cut-off Caprini score was calculated according to the largest Youden index. In total, 6897 cases of knee/hip arthroplasty were included (average age, 65.5 ± 8.9 years; 1702 men), among which 1161 (16.8%) were positive and 5736 (83.2%) were negative for deep vein thrombosis. Among the six models, the ensemble model had the highest area under the curve [0.9206 (0.8956, 0.9364)], with a sensitivity, specificity, positive predictive value, negative predictive value, and F1 score of 0.8027, 0.9059, 0.6100, 0.9573 and 0.7003, respectively. The corresponding optimal cut-off Caprini score was 10, with an area under the curve, sensitivity, specificity, positive predictive value, and negative predictive values of 0.5703, 0.8915, 0.2491, 0.1937, 0.9191, and 0.3183, respectively. In conclusion, machine learning models based on EHRs can help predict the risk of deep vein thrombosis after knee/hip arthroplasty.

Cistanche Deserticola for Regulation of Bone Metabolism: Therapeutic Potential and Molecular Mechanisms on Postmenopausal Osteoporosis.

Osteoporosis is a generalized disease of bone that leads to a loss of bone density and bone mass, destruction of bone microstructure, increased brittleness and therefore fracture. At present, the main treatment of Western medicine is drug therapy such as bisphosphonates, calcitriol, vitamin D, etc. However, long-term use of these drugs may bring some adverse reactions. Chinese herbal medicine Cistanche deserticola could regulate bone metabolism by promoting osteoblast activity and inhibiting osteoclast activity with low toxicity and adverse reactions. Therefore, Cistanche deserticola has attracted increasing attention for its efficacy in the prevention and treatment of osteoporosis in recent years. Here we present a literature review of the molecular pathways involved in osteoporosis and the effects of Cistanche deserticola on bone metabolism. Our objective is to clarify the mechanism of Cistanche deserticola in the treatment of osteoporosis.

An artificial neural network model based on standing lateral radiographs for predicting sitting pelvic tilt in healthy adults.

Background: Spinopelvic motion, the cornerstone of the sagittal balance of the human body, is pivotal in patient-specific total hip arthroplasty. Purpose: This study aims to develop a novel model using back propagation neural network (BPNN) to predict pelvic changes when one sits down, based on standing lateral spinopelvic radiographs. Methods: Young healthy volunteers were included in the study, 18 spinopelvic parameters were taken, such as pelvic incidence (PI) and so on. First, standing parameters correlated with sitting pelvic tilt (PT) and sacral slope (SS) were identified via Pearson correlation. Then, with these parameters as inputs and sitting PT and SS as outputs, the BPNN prediction network was established. Finally, the prediction results were evaluated by relative error (RE), prediction accuracy (PA), and normalized root mean squared error (NRMSE). Results: The study included 145 volunteers of 23.1 ± 2.3 years old (M:F = 51:94). Pearson analysis revealed sitting PT was correlated with six standing measurements and sitting SS with five. The best BPNN model achieved 78.48% and 77.54% accuracy in predicting PT and SS, respectively; As for PI, a constant for pelvic morphology, it was 95.99%. Discussion: In this study, the BPNN model yielded desirable accuracy in predicting sitting spinopelvic parameters, which provides new insights and tools for characterizing spinopelvic changes throughout the motion cycle.

Prediction of Knee Prosthesis Using Patient Gender and BMI With Non-marked X-Ray by Deep Learning.

Background: Total knee arthroplasty (TKA) is effective for severe osteoarthritis and other related diseases. Accurate prosthesis prediction is a crucial factor for improving clinical outcomes and patient satisfaction after TKA. Current studies mainly focus on conventional manual template measurements, which are inconvenient and inefficient. Methods: In this article, we utilize convolutional neural networks to analyze a multimodal patient data and design a system that helps doctors choose prostheses for TKA. To alleviate the problems of insufficient data and uneven distribution of labels, research on model structure, loss function and transfer learning is carried out. Algorithm optimization based on error correct output coding (ECOC) is implemented to further boost the performance. Results: The experimental results show the ECOC-based model reaches prediction accuracies of 88.23% and 86.27% for femoral components and tibial components, respectively. Conclusions: The results verify that the ECOC-based model for prosthesis prediction in TKA is feasible and outperforms existing methods, which is of great significance for templating.

Modified Medial Collateral Ligament Indentation Technique in Total Knee Arthroplasty with Severe Type II Valgus Deformity.

OBJECTIVE: To explore the feasibility and clinical efficacy of a modified medial collateral ligament indentation technique in total knee arthroplasty (TKA) with severe type II valgus deformity. METHODS: Consecutive patients with Krackow type II valgus deformity >20° who underwent a primary unilateral TKA between May 2008 and June 2017 were studied retrospectively. A medial collateral ligament indentation technique was performed in 20 patients (MCLI group), and 23 patients received the routine lateral structures release technique (LSR group). Radiological parameters, such as the valgus angle (VA), and functional outcomes including the use of constraint implants, Knee Society Score (KSS), Knee Society Function score (KSF), and thickness of the polyethylene insert were compared between the two groups. RESULTS: A total of 43 consecutive patients had a minimum 2-year follow-up. The preoperative VA was comparable between the MCLI (23.5° ± 5.8°) and LSR groups (21.3° ± 3.2°, P = 0.134), as was the postoperative VA (1.1° ± 2.1° and 2.5° ± 3.0°, respectively, P = 0.084). The mean KSS and KSF scores in the MCLI group were 30.2 ± 4.8 and 38.8 ± 4.8, respectively, before surgery, and they increased to 91.3 ± 2.6 and 86.5 ± 2.4 at the last follow-up. The scores in the LSR group were 31.5 ± 7.5 and 36.5 ± 7.8 before surgery and 92.4 ± 3.5 and 88.5 ± 3.6 at the last follow-up. While no statistically significant differences in pre- or postoperative functional scores were found between the two groups, the MCLI group had thinner polyethylene inserts (9.5 ± 1.1 mm vs 12.9 ± 1.5 mm) and less use of constrained condylar inserts (15% vs 69.6%). During follow-up, the MCLI group had fewer complications. CONCLUSION: A modified MCLI technique can achieve good outcomes in TKA with type II valgus deformity of >20°. It can maintain a normal joint line level, reduce the use of constrained condylar knee prostheses, and is a reliable choice for severe genu valgum.

Novel cross LSTM for predicting the changes of complementary pelvic angles between standing and sitting.

Sagittal spino-pelvic balance has been increasingly emphasized in hip surgery. The conversion between standing and sitting, characterized by complementary pelvic angles (pelvic tilt, pt and sacral slope, ss), involves a congruent sagittal spino-pelvic relationship. Hence, the changes of complementary pelvic angles pt, ss between standing and sitting could reflect the mechanism of sagittal spino-pelvic balance, and should be analyzed in evidence-based hip surgery planning. To this end, we propose a novel cross LSTM (C-LSTM) framework embedding the conversion between standing and sitting by cross-mapping, to predict the changes of complementary pelvic pt, ss between standing and sitting. Furthermore, to introduce the prior knowledge of the invariance of pelvic incidence, pi, two dual C-LSTMs are integrated to construct a much more powerful Fused C-LSTM. We have conducted extensive experiments on the sagittal standing-sitting dataset for the comprehensive evaluation of the proposed framework. Even in a small samples, Fused C-LSTM can achieve low prediction errors and high correlation between predicted and actual values. Notably, just based on static standing or sitting X-ray, Fused C-LSTM can obtain the change of complementary pt, ss between standing and sitting to assist in formulating a surgical hip plan that conforms to the sagittal spino-pelvic balance.

A Randomized Controlled Trial of Psychological Intervention to Improve Satisfaction for Patients with Depression Undergoing TKA: A 2-Year Follow-up.

BACKGROUND: The overall satisfaction of patients after total knee arthroplasty (TKA) is approximately 80%, and current studies have demonstrated that patients with depression may have lower patient satisfaction. The purpose of this study was to determine whether perioperative psychological intervention in patients with depression improves the clinical outcomes and patient satisfaction in patients undergoing TKA. METHODS: Six hundred patients who underwent primary TKA from May 2016 to January 2018 were prospectively screened for eligibility. A preoperative psychological evaluation was conducted by a psychiatrist to evaluate each patient's psychological status. Patients who were diagnosed with depression were randomly divided into 2 groups: the intervention group (patients received psychological interventions that were administered by a psychiatrist at the first visit before surgery and from then on) and the control group (patients received routine TKA care without psychological interventions). The primary outcome was patient satisfaction at 6 months postoperatively. The secondary outcomes were patient satisfaction at 2 years postoperatively as well as the Hospital for Special Surgery (HSS) scores, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, and range of motion at 6 months and 2 years postoperatively. RESULTS: Fifty-three patients with depression were identified. Fifty-one patients were enrolled in the randomized controlled trial. Two patients were lost to follow-up at 6 months after surgery. Therefore, 49 patients (25 in the intervention group and 24 in the control group) remained in the final analysis. At 6 months postoperatively, statistical differences in patient satisfaction were identified between the 2 groups (88.0% in the intervention group compared with 62.5% in the control group; odds ratio = 4.40; 95% confidence interval, 1.02 to 18.99). There was a significant improvement in the Self-Rating Depression Scale (SDS) score (the reduction rate was 51.97% in the intervention group compared with 17.35% in the control group) and the Symptom Checklist 90 Revised (SCL-90-R) subscore for depression (the reduction rate was 44.66% in the intervention group compared with 15.73% in the control group). The clinical outcomes, including the WOMAC scores, the HSS scores, and maximal range of motion, in the intervention group had improved significantly more compared with those in the control group. CONCLUSIONS: Psychological interventions during the perioperative period can improve patient satisfaction in patients with depression who undergo TKA. Therefore, psychological intervention and management may be beneficial for patients with depression who are planning to undergo TKA. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Chinese primary knee osteoarthritis progression cohort (CPKOPC) to evaluate the progression of knee osteoarthritis in the Beijing population: a prospective cohort study protocol.

INTRODUCTION: Millions of patients are currently suffering from pain and dysfunction caused by osteoarthritis (OA), and billions of dollars have been invested into treatment. Because there is no effective treatment that can reverse the progression of knee OA, it is important to determine the risk factors that may influence the progression. However, although there are many studies that examine risk factors for progression, there are only a few that specifically focus on the impact of each risk factor for predicting progression of knee OA. This study aimed to develop a cohort of patients with primary knee OA in the Beijing area to establish models that identify the influence of each risk factor on the prediction of knee OA progression. METHODS AND ANALYSIS: This is a prospective, multicentre, hospital-based cohort study. The study population comprises 2000 patients with primary knee OA from the Beijing area. The recruitment and baseline visits started in December 2017 and will finish in November 2018. After baseline visits, the patients will be followed for 3 years or until the occurrence of primary outcomes. Demographic variables will be collected during the baseline visit. Influencing factors including occupational exposures, family history and treatment will be collected at baseline and each follow-up visit. The primary outcome measure is a comprehensive index which will be combined with clinical WOMAC score, imaging K-L grade and clinical outcomes. These data will also be collected at baseline and each follow-up visit. ETHICS AND DISSEMINATION: This study protocol has been approved by Peking University Third Hospital Medical Science Research Ethics Committee. All the eligible participants will give written informed consent. The findings will be published in peer-reviewed journals and presented at national or international conferences. Besides, the results will be disseminated to all participants via the social software 'WeChat'. TRIAL REGISTRATION NUMBER: ChiCTR-ROC-17013790; preresults.

The value of tranexamic acid for patients with preoperative anemia in primary total knee arthroplasty.

BACKGROUND: Preoperative anemia is relatively common in patients undergoing primary total knee arthroplasty (TKA), and is associated with higher medical costs due to blood transfusions. METHODS: We aimed to discuss the efficiency of tranexamic acid (TXA) administration for blood loss control in preoperatively anemic patients undergoing primary TKA. We retrospectively reviewed the clinical data regarding a consecutive series of primary unilateral TKA patients with preoperative anemia. Patients were divided into TXA group (received TXA peri-operatively) and control group (did not receive TXA). Outcome measures included drainage volume; hemoglobin, and hematocrit levels recorded preoperatively and over the first 5 days postoperatively; amount of allogeneic blood transfusion; and prevalence of thrombosis. RESULTS: Ninety-six patients from 996 cases were included in the study. Demographics, general health condition, and preoperative conditions were comparable between the two groups. However, significantly lower drainage volume (P < 0.001), hidden blood loss (P < 0.001), and allogeneic blood transfusion volume (χ = 4.00, P = 0.046) were noted in TXA group. The hemoglobin and hematocrit levels were significantly higher in TXA group on the first postoperative day (P = 0.006), but overall the drop in hemoglobin and hematocrit levels over the first 5 days postoperatively was similar between the groups (P = 0.763), as was the incidence of thromboembolism events (P = 0.794). CONCLUSION: TXA has a positive role for patients with preoperative anemia in primary total knee arthroplasty. In patients with mild preoperative anemia, TXA decreases hidden blood loss and the need for allogeneic blood transfusion, which mainly appears effective on the first postoperative day of TKA.

Additional Dose of Intravenous Tranexamic Acid after Primary Total Knee Arthroplasty Further Reduces Hidden Blood Loss.

BACKGROUND: Total knee arthroplasty (TKA) is the most frequently performed procedure in treating advanced knee osteoarthritis. Excessive perioperative blood loss can sometimes lead to postoperative anemia. Tranexamic acid (TXA) is a potent fibrinolysis inhibitor which has been extensively used at the surgical incision and closure to lower overall blood loss in adult reconstruction surgery. Our previous study suggested that about two-thirds of the total blood loss (TBL) came from hidden blood loss (HBL) on postoperative days 1 and 2. The role of reducing HBL with TXA administration in postoperative TKA patients is unknown. The current study was designed to evaluate the efficiency and safety of supplemental intravenous (IV) TXA in further reducing HBL after primary TKA. METHODS: A prospective pilot study was conducted at a single institution on 43 consecutive patients who underwent unilateral TKA from September 2014 to February 2015. All patients were given 1 g of IV TXA 10-15 min before operation and another 1 g of IV TXA at the time of wound closure on the day of surgery. On postoperative days 1 and 2, the supplemental group (n = 21) was given additional 1 g of TXA intravenously twice a day, whereas the control group (n = 22) received an equal volume of saline. Drain output, hemoglobin (Hb), and hematocrit (HCT) were recorded preoperatively and 5 consecutive days postoperatively in both groups. HBL was calculated with the Gross formula. Pre- and post-operative lower extremity Doppler venous ultrasound was performed in all patients to detect deep vein thrombosis (DVT). The indexes were compared using the Mann-Whitney test, whereas the results of Hb and HCT were analyzed by repeated-measures analysis of variance. The difference was considered statistically significant if P < 0.05. RESULTS: The demographics and surgical characteristics of the two groups were comparable. Supplemental group had higher Hb level on postoperative days 1-5 compared to the control; however, the difference was not significant (F = 2.732, P = 0.106). The HCT of the supplemental group was significantly higher than that of the control group on postoperative day 5 (F = 5.254, P = 0.027). No significant difference was found in drainage volume and TBL, but the HBL was reduced in the supplemental group (supplemental 133.1 [71.8, 287.3] ml and control 296.0 [185.3, 421.4] ml, Z = 2.478, P = 0.013, median [interquartile range]). There was one DVT in the control group and none in the supplemental group. All patients were followed at 1 year after surgery, and no further complications were reported. CONCLUSION: Based on the current study, additional doses of IV TXA could potentially further reduce HBL after primary TKA without increasing the risk of venous thromboembolism.

Patient-Specific Instruments Based on Knee Joint Computed Tomography and Full-Length Lower Extremity Radiography in Total Knee Replacement.

BACKGROUND: Restoring good alignment after total knee replacement (TKR) is still a challenge globally, and the clinical efficiency of patient-specific instruments (PSIs) remains controversial. In this study, we aimed to explore the value and significance of three-dimensional printing PSIs based on knee joint computed tomography (CT) and full-length lower extremity radiography in TKR. METHODS: Between June 2013 and October 2014, 31 TKRs were performed using PSIs based on knee joint CT and full-length lower extremity radiography in 31 patients (5 males and 26 females; mean age: 67.6 ± 7.9 years; body mass index [BMI]: 27.4 ± 3.5 kg/m2). Thirty-one matched patients (4 males and 27 females; mean age: 67.4 ± 7.2 years; mean BMI: 28.1 ± 4.6 kg/m2) who underwent TKR using conventional instruments in the same period served as the control group. The mean follow-up period was 38 months (31-47 months). Knee Society Score (KSS), surgical time, and postoperative drainage volume were recorded. Coronal alignment was measured on full-length radiography. RESULTS: Twenty-three (74.2%) and 20 (64.5%) patients showed good postoperative alignment in the PSI and control groups, respectively, without significant difference between the two groups (χ2 = 0.68, P = 0.409). The mean surgical time was 81.48 ± 16.40 min and 72.90 ± 18.10 min for the PSI and control groups, respectively, without significant difference between the two groups (t = 0.41, P = 0.055). The postoperative drainage volume was 250.9 ± 148.8 ml in the PSI group, which was significantly less than that in the control group (602.1 ± 230.6 ml, t = 6.83, P < 0.001). No significant difference in the KSS at the final follow-up was found between the PSI and control groups (91.06 ± 3.26 vs. 90.19 ± 3.84, t = 0.95, P = 0.870). CONCLUSIONS: The use of PSIs based on knee joint CT and standing full-length lower extremity radiography in TKR resulted in acceptable alignment compared with the use of conventional instruments, although the marginal advantage was not statistically different. Surgical time and clinical results were also similar between the two groups. However, the PSI group had less postoperative drainage.

Global scientific production in the field of knee arthroplasty: A cross-sectional survey of research activities.

Objective To determine the quantity and quality of articles in the field of knee arthroplasty worldwide and elucidate the characteristics of global scientific production. Methods Web of Science was used to identify articles in the field of knee arthroplasty from 2011 to 2015. The total number of papers, number of papers per capita, total number of citations, and mean number of citations were collected. Results In total, 11,590 papers were identified. The number of publications significantly increased from 2011 to 2015. Most originated from North America, East Asia, and West Europe. Most (88.51%) were from high-income countries, 11.48% were from middle-income countries, and only 0.01% were from lower-income countries. The United States had the most articles and total citations. Sweden had the highest mean citations, followed by Denmark and Canada. However, when adjusted by population size, Denmark had the most articles per million population, followed by Switzerland and the Netherlands. Conclusions The number of knee arthroplasty publications has rapidly increased in recent years. The United States is the most prolific, but some European countries are more productive relative to their population.

Effect of Femoral Resection on Coronal Overall Alignment after Conventional Total Knee Arthroplasty.

BACKGROUND: A good postoperative alignment in total knee arthroplasty (TKA) is the key to achieving satisfactory results. We assessed the effect of femoral and tibial resection on the overall alignment after conventional TKA. METHODS: We conducted a retrospective analysis of 212 primary TKAs in 188 patients. Intramedullary (IM)-guided resection was applied on the femoral side while extramedullary (EM)-guided resection was used on the tibial side. Using full-length X-ray, the preoperative femoral valgus angle and lower extremity alignment, as well as 2-week postoperative femoral and tibial prosthetic coronal alignment and overall lower extremity alignment, were measured. RESULTS: Postoperatively, good prosthetic alignment was achieved in 191 cases (90.1%) on the tibial side and in 144 cases (67.9%) on the femoral side (χ2 = 5.441, P = 0.02). Multiple linear regression analysis was used to assess the effect of different alignment sides on the overall alignment in the coronal plane. Data were divided into five subgroups based on the valgus or varus status of the prostheses. The standardized regression coefficients of the femoral and tibial prosthetic alignment on the overall alignment were 0.666 and 0.414, respectively; in varus on both sides were 0.658 and 0.377, respectively; in valgus, 0.555 and 0.030; femoral side varus and tibial side valgus, 0.702 and 0.211; femoral side valgus and tibial side varus, -0.416 and 0.287. The study showed that the overall low extremity alignment was statistically influenced by the prosthetic alignment, except for the tibial prosthetic alignment when femoral prosthesis was in valgus (P = 0.153). CONCLUSIONS: In conventional TKA, tibial side EM-guided resection may offer satisfactory postoperative alignment, and femoral resection relying on IM guide may lead to more undesirable results. Postoperative coronal alignment is mainly affected by the femoral resection. Therefore, femoral side operation should receive adequate attention from the surgeons.