Increase in the Posterior Tibial Slope Provides Better Joint Awareness and Patient Satisfaction in Cruciate-Retaining Total Knee Arthroplasty.

The effect of the posterior tibial slope (PTS) in cruciate-retaining total knee arthroplasty (CR-TKA) on clinical outcomes remains unclear. We aimed to investigate (1) the effect of alteration of the PTS on clinical outcomes, including patient satisfaction and joint awareness, and (2) the relationship between the patient-reported outcomes, the PTS, and compartment loading. Based on the alteration of the PTS after CR-TKA, 39 and 16 patients were stratified into increased and decreased PTS groups, respectively. Clinical evaluation was performed by the Knee Society Score (KSS) 2011 and the Forgotten Joint Score-12 (FJS-12). Compartment loading was intraoperatively assessed. KSS 2011 (symptoms, satisfaction, and total score) was significantly higher (p = 0.018, 0.023, and 0.040, respectively), and FJS ("climbing stairs?") was significantly lower (p = 0.025) in the increased PTS group compared with the decreased PTS group. The decrease in both medial and lateral compartment loading of Δ45°, Δ90°, and ΔFull was significantly greater in the increased PTS group than in the decreased PTS group (p< 0.01 for both comparisons). Medial compartment loading of Δ45°, Δ90°, and ΔFull significantly correlated with KSS 2011 for "symptom" (r = - 0.4042, -0.4164, and -0.4010, respectively; p = 0.0267, 0.0246, and 0.0311, respectively). ΔPTS significantly correlated with medial compartment loading differentials of Δ45°, Δ90°, and ΔFull (r = - 0.3288, -0.3792, and -0.4424, respectively; p = 0.0358, 0.01558, and 0.0043, respectively). Patients with increased PTS showed better symptoms and higher patient satisfaction compared with those with decreased PTS following CR-TKA, possibly due to a greater decrease in compartment loading during knee flexion.Level of evidence:level IV, therapeutic case series.

A new magnetic resonance imaging grading system for anterior cruciate ligament myxoid degeneration in osteoarthritis of the knee.

BACKGROUND: This study aimed to investigate association between magnetic resonance imaging (MRI) and histological findings of degenerated anterior cruciate ligament (ACL) in knee osteoarthritis (OA), and based on this result, to develop a new ACL degeneration grading system by MRI that corresponds to histological findings of degenerated ACL. HYPOTHESIS: MRI signal intensity of the ACL could correspond to histological findings of collagen degeneration. PATIENTS AND METHODS: A collection of 106 ACL specimens from 85 patients who underwent primary total knee arthroplasty was investigated for signal intensity of the ACL and muscle on axial Fat-saturated proton density-weighted MRI and MRI signal intensity ratio (ACL/muscle) was calculated. The correlation between ACL histological degeneration and MRI ACL/muscle signal intensity ratio was analyzed. The ACL was stratified into 3 grades based on signal intensity relative to muscle intensity (grade 1, low; grade 2, iso; and grade 3, high), and the extent to ACL degeneration in each MRI ACL degeneration grade was evaluated. RESULTS: Collagen degeneration (53.5±24.0%) and myxoid change (25.2±18.8%) in degenerated ACL significantly correlated with MRI signal intensity ratio of the ACL/muscle (r=0.62, p<0.0001; r=0.67, p<0.0001). ACL were assigned to grade 1 (n=22 [20.8%]), grade 2 (n=56 [52.8%]), and grade 3 (n=28 [26.4%]). ACL collagen degeneration was 34.8±18.4% in grade 1, 49.3±21.7% in grade 2, and 76.6±12.0% in grade 3. ACL myxoid change was 10.0±11.3% in grade 1, 21.3±14.1% in grade 2, and 45.0±15.3% in grade 3. DISCUSSION: The ACL/muscle signal intensity ratio on MRI correlated with the extent to ACL myxoid degeneration. The new MRI ACL degeneration grade is helpful to estimate the extent to ACL myxoid degeneration in knee OA. LEVEL OF EVIDENCE: III; retrospective cohort study.

Age-related learning difficulty through trial-and-error method associated with decreased default mode network integration in healthy middle-aged adults.

INTRODUCTION: Efficient learning is critical to adapting to different environments. There are well-known learning principles in cognitive rehabilitation, including errorless (EL) and trial-and-error (T&E) learning; however, little is known about their underlying neural mechanisms. In the current study, to understand the age-related changes in learning benefits and neural mechanisms applying EL and T&E learning methods in healthy middle-aged adults, we conducted a graph theoretical analysis using functional magnetic resonance imaging data and analyzed the relationship between learning benefits and age, as well as functional network connectivity and age, with both learning principles. METHOD: A total of 43 participants performed a color-name association task through EL and T&E learning methods. We focused on the functional connectivity patterns of the default mode network (DMN) since previous studies demonstrated this network to be more distinctive and important for the T&E learning method than EL. Within-network functional connectivity was used as the graph metric. RESULTS: Age showed significant moderate negative correlations with T&E scores and within-DMN functional connectivity in the test state following T&E learning. Conversely, age was not significantly correlated with EL scores or within-DMN functional connectivity in either the EL learning or test states. CONCLUSIONS: Our findings demonstrate the age-related learning decline associated with decreased DMN integration with aging, when applying the T&E method but not the EL method, even in healthy middle-aged adults. Relationships between the underlying neural network and age are different depending on the learning method. This suggests the need to take into consideration the remaining learning ability through the T&E learning method compared to normal aging and to utilize residual DMN functioning, in addition to the comparison between score differences between EL and T&E methods, when tailoring an individual learning approach.

Cooperation and competition between the default mode network and frontal parietal network in the elderly.

Recent research has shown that the Default Mode Network (DMN) typically exhibits increased activation during processing of social and personal information but shows deactivation during working memory (WM) tasks. Previously, we reported the Frontal Parietal Network (FPN) and DMN showed coactivation during task preparation whereas the DMN exhibited deactivation during task execution in working memory tasks. Aging research has shown that older adults exhibited decreased functional connectivity in the DMN relative to younger adults. Here, we investigated whether age-related cognitive decline is related to a reduced relationship between the FPN and DMN using a working memory task during the execution period. First, we replicated our previous finding that the FPN and DMN showed coactivation during the preparation period, whereas the DMN showed deactivation during the execution period. The older adults showed reduced DMN activity during task preparation and reduced deactivation during task execution; however, they exhibited a higher magnitude of activation in the FPN than the young individuals during task execution. Functional connectivity analyses showed that the elderly group, compared to the young group, showed weaker correlations within the FPN and the DMN, weaker positive correlations between the FPN and DMN during task preparation, and weaker negative correlations between the FPN and DMN during execution. The results suggest that cognitive decline in the older adults might be related to reduced connectivity within the DMN as well as between the FPN and DMN.

Effect of medial opening wedge distal tibial tuberosity osteotomy on possible neuropathic pain in patients with osteoarthritis of the knee.

BACKGROUND: There is a paucity of literature regarding the changes and features of neuropathic pain (NP) in knee osteoarthritis (OA) following medial opening wedge distal tibial tuberosity osteotomy (OWDTO). This study aimed to investigate the effect of OWDTO on NP in knee OA; we hypothesized that OWDTO improves knee symptoms and functions and also meets patient satisfaction in those with knee OA with possible NP or without NP. METHODS: Fifty-two consecutive patients who underwent OWDTO were categorized into the unlikely NP and possible NP groups using the painDETECT questionnaire. The Western Ontario and McMaster Universities Arthritis Index (WOMAC) score and the Knee Society Score 2011 (KSS 2011) were compared between the groups preoperatively and at the 1-year follow-up. RESULTS: The number of patients having possible NP significantly decreased from 12 (23.1%) preoperatively to one (1.9%) postoperatively (p < 0.001). The patient with postoperative possible NP also had possible NP preoperatively. All preoperative sub-scores of WOMAC were significantly higher in the possible NP group than in the unlikely NP group (p = 0.018, 0.013, 0.004, and 0.005, respectively); however, the postoperative scores did not differ between the two groups. Regarding the KSS 2011, the preoperative scores for symptom and functional activities were significantly lower in the possible NP group than in the unlikely NP group (p = 0.031 and 0.024, respectively). CONCLUSIONS: OWDTO is an effective surgery for patients with possible NP; it improves symptoms and knee function as well as meets patient satisfaction. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Administration of prosaposin-derived neurotrophic factor to neural tube defects facilitates regeneration and restores neurological functions.

Neural tube defects (NTDs) cause fetal and pediatric deaths or lifelong neurological disabilities. No effective treatment is currently available for NTDs. We attempted to elucidate the pathogenesis of NTDs and propose a therapeutic strategy. Intra-amniotic treatment with prosaposin-derived 18-mer peptide (PS18) protected the spinal cord from secondary damage and rescued neurological function in an established chicken model of spina bifida aperta (SBA), the severe type of NTDs. PS18 promoted the formation of a neuroectodermal covering over the defective neural tube within 24-h after treatment, enhanced the regeneration/restoration process, and decreased apoptotic activity in the developing spinal cord. PS18 reduced the SBA wound and almost completely formed the spinal cord. SBA chicks that received PS18 exhibited relatively normal walking and sensorimotor responses, and reduced pain-associated behavior in postnatal life. In conclusion, PS18 is a promising therapeutic agent for NTDs and may be useful for treating other types of spinal cord injuries.

Can radiological findings detect neuropathic pain in patients with osteoarthritis of the knee undergoing surgery?

OBJECTIVES: The mechanism underlying neuropathic pain (NP) in osteoarthritis (OA) of the knee is not completely understood. This study aimed to investigate whether possible NP in patients with knee OA undergoing knee surgery is associated with specific radiological findings. METHODS: This study included 197 patients who underwent knee surgery for symptomatic knee OA. Clinical evaluation was performed using the Central Sensitization Inventory (CSI), Western Ontario and McMaster Universities Arthritis Index (WOMAC), and PainDETECT questionnaire. Radiological evaluation was performed using the hip-knee-ankle (HKA) angle, posterior tibial slope (PTS), varus and valgus laxities, and magnetic resonance imaging OA Knee Score (MOAKS). Radiological findings were compared between patients with possible and unlikely NP. Logistic regression analysis was performed to identify the predictive factors for NP. RESULTS: There were 163 and 34 patients with unlikely NP and with possible NP, respectively. The percentage of patients with CSI score ≥ 40 was significantly higher in the possible NP group than in the unlikely NP group (17.6% vs. 6.1%). Patients with possible NP had worse WOMAC scores than patients with unlikely NP. There were no significant positive associations between the possible NP and radiological findings in knee OA. Regression analysis showed no predictive factors for possible NP. CONCLUSIONS: Possible NP is not associated with specific radiological findings in knee OA. Patients with possible NP may mediate CS and experience more severe symptoms, including decreased knee function and lower quality of life, than patients with unlikely NP.

Cadaveric and CT angiography study of vessels around the transverse colon mesentery.

BACKGROUND: Laparoscopic and robotic surgery for transverse colon cancer are difficult due to complex fusion of the foregut and midgut and variation of the vessels of the transverse colon. Although the vessels of the right colon have been investigated, middle colic artery (MCA) variation and the relationship with vessels around the transvers colon are unknown. We investigated variation of the MCA using computed tomography angiography (CTA) and cadaver specimen and the relationship between the superior mesenteric vein (SMV) and MCA using CTA. The classification of vessels around the transverse colon may lead to safer and reliable surgery. METHODS: This study included 505 consecutive patients who underwent CTA in our institution from 2014 to 2020 and 44 cadaver specimens. Vascular anatomical classifications and relationships were analyzed using CT images. RESULTS: The MCA was defined as the arteries arising from the superior mesenteric artery (SMA) that flowed into the transverse colon at the distal ends. The classifications were as follows: type I, branching right and left from common trunk; type II, the right and left branches bifurcated separately from the SMA; and type III, the MCA branched from a vessel other than the SMA. Type II was subclassified into two subtypes, type IIa with one left branch and type IIb with two or more left branches from SMA. In the CTA and cadaver studies, respectively, the classifications were as follows: type I, n = 290 and n = 31; type IIa, n = 211 and n = 13; type IIb, n = 3 and n = 0; and type III, n = 1 and n = 0. We classified the relationship between the MCA and left side of the SMV into three types: type A, a common trunk runs along the left edge of the SMV (n = 173; 59.7%); type B, a right branch of the MCA runs along the left edge of the SMV (n = 116; 40.0%); and type C, the MCA runs dorsal of the SMV (n = 1; 0.3%). CONCLUSIONS: This study revealed that The MCA branching classifications and relationship between the SMV and MCA. Preoperative CT angiography may be able to reliably identify vessel variation, which may be useful in clinical practice.

Joint gap produced by manual stress is dependent on the surgeon's experience and is smaller in flexion in robotic-assisted total knee arthroplasty.

PURPOSE: This study aimed to retrospectively investigate (1) the reproducibility of gap measurements by manual stress using the Z-shaped retractor depending on the surgeon's experience with this maneuver and (2) the consistency of the gap distraction force produced by manual stress throughout the range of motion (ROM) in the robotic-assisted total knee arthroplasty (TKA). It was hypothesized that the joint gap produced by manual stress is not reproducible depending on the surgeon's experience, and the distraction force applied by manual stress throughout the ROM is not constant. METHODS: Medial and lateral joint gaps were obtained throughout the ROM by manual stress or a tensioner by two surgeons with different levels of experience in robotic-assisted TKA. The association between the differences in gap measurement by the two surgeons and the preoperative radiographic parameters, including the hip-knee-ankle (HKA) angle and absolute and relative varus/valgus laxities were analyzed. RESULTS: The experienced surgeon produced significantly greater gaps than the inexperienced surgeon from 0° to 100° flexion, with a mean difference of 0.35 ± 0.12 mm in the medial gap (p < 0.0001), and from 10° to 120° flexion with a mean difference of 0.57 ± 0.13 mm in the lateral gap (p < 0.0001). The tensioner produced a significantly greater medial gap from 70° to 110° flexion with a mean difference of 0.32 ± 0.01 mm in the medial gap (p < 0.0001) and from 0° to 110° flexion with a mean difference of 1.12 ± 0.26 mm in the lateral gap (p < 0.0001). The differences in gap distance by manual stress between experienced and inexperienced surgeons were moderately correlated with the HKA angle in the lateral gap (r = 0.40, p = 0.01). The gap differences due to manual stress and a tensioner showed moderate negative correlation with the HKA angle in the medial gap (r = - 0.50, p = 0.001) and weak negative correlation with the absolute valgus laxity in the lateral gap (r = - 0.35, p = 0.03). CONCLUSIONS: The joint distraction force by manual stress may differ depending on the surgeon's experience and tended to be smaller in deep flexion; therefore, the flexion gap may be underestimated. Surgeons should determine implant positioning considering gap balance by manual stress, taking into account these characteristics of the manual stress maneuver. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

A neural basis of rational inattention models: consistency of cognitive cost with the mutual information criterion.

The rational inattention model has recently attracted much attention as a promising candidate to model bounded rationality in the research field of decision-making and game theory. However, in contrast to this energetic promotion of the theoretical works, empirical verification of the validity of the RI model has not progressed much. Furthermore, to our knowledge, the central assumption of the RI model, that the amount of mutual information obtained from signals adequately represents the cognitive cost of information, has not been tested from a neuroscientific perspective. The purpose of the present study was to test whether the amount of mutual information adequately represents the cognitive cost of information from a neuroscientific perspective. We proposed a sequential investment task, in which the two main models of RI can be treated simultaneously in a more realistic experimental environment. We used a model-fitting approach to analyze the subjective information cost, and compared the model parameters representing the information cost with the concentration of oxidized hemoglobin in the brain blood. Our results showed that the cost parameter λ of the stochastic choice type model, which fits the behavioral data of the present experiment better than the Kalman filter type model, was significantly positively correlated with the activation status of the rostral prefrontal cortex and dorsolateral prefrontal cortex. The cognitive cost represented by the amount of mutual information employed in the RI model is consistent with the activation of brain regions associated with cognitive cost, and, thus, indirectly supports the assumption of the RI model.

A comprehensive design for prevention and management of COVID-19 in a tertiary medical institution in Bangladesh.

INTRODUCTION: Containment of the further spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and reducing fatality due to coronavirus disease 19 (COVID-19) represent a pressing challenge to global health services. Here, we present a management blueprint for both the containment of SARS-CoV-2 and treatment of COVID-19 through a comprehensive approach. METHODOLOGY: A cohort of 130 consecutive patients identified as positive for SARS-CoV-2 by testing of nasal swab by polymerase chain reaction were managed at a peripheral city of Bangladesh between 1 April and 31 May, 2020. Based on their clinical status, 64 of them were initially selected for isolation (Isolation Group) and 66 recommended for hospitalization (Hospital Group) as per the direction of the "Central COVID-19 Control" Center. Both groups of patients were allocated to receive standard of care management and oxygen inhalation, and intensive care unit management as and when necessary. Based on the conditions of the COVID-19 patients, there was an active system of patients being transferred from the "Isolation Group" to "Hospital Group" and vice versa. RESULTS: Twelve patients of the "Isolation Group" were transferred to the hospital, as they exhibited symptoms of deterioration. Four patients of the "Hospital Group" died during the observation period of two months in the intensive care unit. However, there has been no fatality among the patients of the "Isolation Group". CONCLUSIONS: The concept of "Isolation" and "Hospital Management" with the participation of the community seems to be an effective management strategy for COVID-19 in developing countries.

Default mode network-associated intrinsic connectivity relates to individual learnability differences in errorless and trial-and-error learning.

The intrinsic functional network architecture accounts for task-evoked brain activity changes and variabilities in cognitive performance. Relationships between the intrinsic functional network architecture and task performance or learning ability have been previously reported. However, the relationships between learning benefits and the characteristics of intrinsic functional network architecture for different types of learning methods remain unclear. In this study, we used graph theoretical analysis to examine the relationships between intrinsic functional network connectivity and learning benefits in two well-known learning methods in the field of cognitive rehabilitation-errorless learning (EL learning) and trial-and-error learning (T&E learning). We focused on the default mode network (DMN) as a task-relevant network, which can differentiate between EL and T&E learning and was found to be more important for T&E learning in a previous study. Participants performed a color-name association task with both learning methods. The graph metrics used were within-network connectivity and efficiency for the DMN. Within-DMN connectivity and DMN efficiency showed a significantly weak positive correlation with T&E scores but not with EL scores. These findings show that the intrinsic integration strength within the DMN relates to individuals' learnability through the T&E method.

Thinner tuberosity osteotomy is more resistant to axial load in medial open-wedge distal tuberosity proximal tibial osteotomy: A biomechanical study.

BACKGROUND: The purpose of this study was to investigate axial load resistance of the tibia depending on the thickness of tibial tuberosity osteotomy in medial open-wedge distal tuberosity proximal tibial osteotomy (OWDTO). The hypothesis is that a thin tibial tuberosity osteotomy shows high axial load resistance of the tibia. METHODS: The OWDTO model was constructed from imitation bones of the tibia. Distal tibial tuberosity osteotomy was performed with thicknesses of 7, 14, and 21 mm (n = 5 for each group). Cyclic axial-load fatigue tests were performed to investigate the strain at five measurement points on the OWDTO model. An axial-load failure test was also performed to investigate the maximum strain for failure. RESULTS: The 7-mm OWDTO model showed a significantly lower stain range than the 14-mm model at the middle part of the lateral hinge (P = 0.0263, mean difference: -852.6 µÎµ), posterior part (P = 0.0465, mean difference: -1040.0 µÎµ), posterior tibial cortex (P < 0.0001, mean difference: -583.4 µÎµ), and plate (P = 0.0029, mean difference: -121.6 µÎµ). There were no significant differences in the strain at the tibial tuberosity between the groups. The axial load for complete failure was significantly higher in the 7-mm model than in the 21-mm model (P = 0.0010, mean difference: 2577.0 N). The failure points were at the lateral hinges. CONCLUSIONS: Thinner distal tibial tuberosity osteotomy is more resistant to axial load and may be recommended for the prevention of tibial and lateral hinge fractures after OWDTO.

Hippocampal Connectivity of the Presubiculum in the Common Marmoset (Callithrix jacchus).

The marmoset (a New World monkey) has recently received much attention as an experimental animal model; however, little is known about the connectivity of limbic regions, including cortical and hippocampal memory circuits, in the marmoset. Here, we investigated the neuronal connectivity of the marmoset, especially focusing on the connectivity between the hippocampal formation and the presubiculum, using retrograde and anterograde tracers (cholera toxin-B subunit and biotin dextran amine). We demonstrated the presence of a direct projection from the CA1 pyramidal cell layer to the deep layers of the presubiculum in the marmoset, which was previously identified in the rabbit brain, but not in the rat. We also found that the cells of origin of the subiculo-presubicular projections were localized in the middle part along the superficial-to-deep axis of the pyramidal cell layer of the distal subiculum in the marmoset, which was similar to that in both rats and rabbits. Our results suggest that, compared to the rat and rabbit brains, connections between the hippocampal formation and presubiculum are highly organized and characteristic in the marmoset brain.

Impact of Gestational Haloperidol Exposure on miR-137-3p and Nr3c1 mRNA Expression in Hippocampus of Offspring Mice.

BACKGROUND: Schizophrenia is a mental disorder caused by both environmental and genetic factors. Prenatal exposure to antipsychotics, an environmental factor for the fetal brain, induces apoptotic neurodegeneration and cognitive impairment of offspring similar to schizophrenia. The aim was to investigate molecular biological changes in the fetal hippocampus exposed to haloperidol (HAL) by RNA expression as a model of the disorder. METHODS: HAL (1 mg/kg/d) was administered to pregnant mice. Upregulated and downregulated gene expressions in the hippocampus of offspring were studied with RNA-sequencing and validated with the qPCR method, and micro-RNA (miR) regulating mRNA expressional changes was predicted by in silico analysis. An in vitro experiment was used to identify the miRNA using a dual-luciferase assay. RESULTS: There were significant gene expressional changes (1370 upregulated and 1260 downregulated genes) in the HAL group compared with the control group on RNA-sequencing analysis (P < .05 and q < 0.05). Of them, the increase of Nr3c1 mRNA expression was successfully validated, and in silico analysis predicted that microRNA-137-3p (miR-137-3p) possibly regulates that gene's expression. The expression of miR-137-3p in the hippocampus of offspring was significantly decreased in the first generation, but it increased in the second generation. In vitro experiments with Neuro2a cells showed that miR-137-3p inversely regulated Nr3c1 mRNA expression, which was upregulated in the HAL group. CONCLUSIONS: These findings will be key for understanding the impact of the molecular biological effects of antipsychotics on the fetal brain.

Relationship between histological changes of the anterior cruciate ligament and knee function in osteoarthritis patients.

BACKGROUND: The function of the anterior cruciate ligament (ACL) in osteoarthritis (OA) of the knee remains to be elucidated. The purpose of this study is to evaluate histological changes of the ACL in end-stage knee OA and to clarify the relationship between histological changes in the ACL and knee function. HYPOTHESIS: The hypothesis in this study was that ACL degeneration in knee OA is associated with decreased knee function. PATIENTS AND METHODS: Eighty-two ACL specimens from 65 patients who underwent primary total knee arthroplasty (TKA) were investigated. The correlation between histological changes of the ACL (myxoid changes, chondroid metaplasia, total collagen degeneration, microcyst formation, vascular proliferation, and inflammatory cell infiltration) and knee function (range of motion, anterior tibial translation test, knee extension muscle strength, one-leg standing time, and functional reach test) were investigated. Age, body mass index, joint space narrowing, osteophyte formation, lower extremity alignment, and knee medial/lateral instability were also evaluated. RESULTS: Myxoid change in the ACLs was significantly negatively correlated with one-leg standing time. Chondroid metaplasia was not correlated with knee function. Collagen degeneration in the ACL was significantly negatively correlated with knee flexion angle and one-leg standing time. In addition, a negative correlation between microcyst formation and knee flexion angle was noted. Osteophyte formation, particularly lateral femoral intercondylar osteophytes, was correlated with myxoid changes. The other parameters did not correlate with ACL histological changes. DISCUSSION: Myxoid changes in the ACL were shown to correlate with knee function. The osteophyte score, particularly as related to lateral femoral intercondylar osteophytes, correlated with the severity of myxoid changes in the ACL in knee OA. Precise ACL evaluation should be included in the indications for ACL-retaining surgeries because ACL degeneration may be related to decreased knee function after surgery. LEVEL OF EVIDENCE: IV, Diagnostic case series.

Extra-articular factors of the femur and tibia affecting knee balance in mechanically aligned total knee arthroplasty.

PURPOSE: Although the joint gap distance and compartment loading of the knee are different parameters for obtaining balanced knees in patients with total knee arthroplasty (TKA), the extent to which a balanced knee is achieved in patients with mechanically aligned TKA (MA-TKA) is unclear. This study aimed to investigate the anatomical factors that affect the ligament balancing in MA-TKA according to a gap balancing technique by measured resection technique. METHODS: The relationship between compartment loading, gap distance, and lower limb alignment was analysed in forty-three patients who underwent navigation-assisted MA-TKA with the minimum soft-tissue release. Radiographic parameters included hip-knee-ankle (HKA) angle, femorotibial angle, mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle, posterior tibial slope, varus and valgus joint line convergence angle, femoral valgus angle, femoral shaft curve, and tibial shaft curve (TSC). RESULTS: The postoperative HKA angle was 0.4±1.5°, with one coronal alignment outlier (2.3%). The gap distance showed four unbalanced knees for extension (9.3%) and flexion (9.3%), whereas the compartment loading identified 17 unbalanced knees (39.5%) at extension, 8 (18.6%) at 45° flexion, 7 (16.2%) at 90° flexion, and 10 (23.2%) at full flexion in MA-TKA. Mediolateral differentials of compartment loading correlated with femoral valgus angle (0°, 45°, and 90° flexion), mLDFA (45° and 90° flexion), and TSC (45° and 90° flexion). Femoral valgus angle and TSC were risk factors of the mediolateral differentials of compartment loading. CONCLUSION: Extra-articular factors of femoral valgus angle, mLDFA, and TSC were associated with the mediolateral imbalance of compartmental loading, suggesting there is a limit to obtaining balanced knees in MA-TKA due to these unadjustable extra-articular factors. LEVEL OF EVIDENCE: IV, therapeutic case series.

Medial proximal tibial angle at the posterior tibial plateau represents the pre-arthritic constitutional medial proximal tibial angle in anterior cruciate ligament-intact, advanced osteoarthritis of the knee.

PURPOSE: In kinematically aligned total knee arthroplasty (TKA), it is necessary to infer the pre-arthritic constitutional medial proximal tibial angle (MPTA) in advanced osteoarthritis (OA) of the knee with bone loss. The aim of this study was to investigate whether MPTA at the posterior tibial plateau represents the pre-arthritic constitutional MPTA in anterior cruciate ligament (ACL)-intact, advanced OA knees. It was hypothesized that MPTA at the posterior tibial plateau represents the pre-arthritic constitutional MPTA of ACL-intact, advanced knee OA. METHODS: One hundred varus, anterior cruciate ligament (ACL)-intact, advanced OA knees were analysed. The hip-knee-ankle (HKA) angle and MPTA were assessed on computed radiography (CR) and MPTAs at the anterior, middle, and posterior part of the tibial plateau were assessed on computed tomography (CT) images. The association between these parameters was also analysed. RESULTS: CR images showed an HKA angle of 172.4 ± 4.1° and MPTA of 84.3 ± 2.5°. CT images showed different MPTAs in the three regions, ranging from 83.9 ± 2.4° to 85.9 ± 2.8°. The middle MPTA was the lowest at 83.9 ± 2.4°. HKA angle correlated with the middle MPTA (r = 0.3355, 95% confidence interval [CI] 0.1489-0.4991, p = 0.0006) and ΔMPTA (Middle-Posterior) (r = 0.5128, 95% CI 0.3518-0.6443, p < 0.0001). CONCLUSION: The MPTA at the posterior tibial plateau represents the pre-arthritic constitutional MPTA in ACL-intact, advanced OA knees. LEVEL OF EVIDENCE: III, retrospective cohort study.

Compensatory Pelvic Retro-Rotation Associated with a Decreased Quality of Life in Patients with Normal Sagittal Balance.

STUDY DESIGN: Cross-sectional observational study. PURPOSE: To examine whether pelvic rotation as a compensatory mechanism for sagittal imbalance is related to quality of life (QOL). OVERVIEW OF LITERATURE: Poor sagittal alignment is associated with compensatory pelvic retroversion and decreased QOL. Whether the compensatory pelvic tilt (PT) influences QOL is unclear. METHODS: Overall, 134 subjects aged ≥20 years with lower back pain were included (104 females; mean age, 70±9.8 years). Sagittal vertical alignment (SVA) and PT were analyzed radiographically. Patients were stratified into three groups based on SVA values: good alignment (group G), intermediate alignment (group I), and poor sagittal alignment (group P). Patients in group I were further categorized into two groups: low PT and high PT. The Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) was used for clinical assessment, and the scores were compared between groups. RESULTS: As SVA increased, PT and lumbar lordosis (LL) increased and decreased, respectively. PT and LL differed significantly between groups G and P (p<0.01 for each comparison). Within group I, there was no significant difference in SVA between the high PT and low PT groups, suggesting that the high PT group had acquired a compensated sagittal balance. Importantly, all domains in the JOABPEQ (except for lower back pain) were significantly lower in the high PT group than in the low PT group (p<0.05 for every comparison). CONCLUSIONS: This study showed that focusing solely on SVA as a single indicator can cause important losses in QOL to be overlooked in patients with lumbar disorders. Although pelvic retroversion can compensate for sagittal balance, it is associated with a significant decrease in QOL. To improve the assessment of patients with lumbar disorders, PT should be considered besides SVA.

Cognitive functions relating to aberrant interactions between task-positive and task-negative networks: Resting fMRI study of patients with schizophrenia.

Brain functional connectivity in the resting-state represents intrinsic functional states and correlates with cognitive performance. In patients with schizophrenia, reports on the relationships between forms of functional disconnectivity in local areas and cognitive disability have used resting-state functional magnetic resonance imaging data. Meanwhile, cognitive deficits in relation to inter-network forms of functional connectivity on a large scale are not well understood. This study examines cognitive functions in relation to the number of resting-state inter-network forms of functional connectivity focusing on task-positive networks (fronto-parietal network [FPN] and cingulo-opercular network [CON]) and task-negative network (default mode network [DMN]). We compare patients with schizophrenia (SCH group) and healthy controls (HC group). We conducted a functional network analysis by applying graph theory and evaluated cognitive functions using the Brief Assessment of Cognition in Schizophrenia. The number of forms of functional connectivity between FPN and DMN and between CON and DMN were significantly higher in SCH group than in HC group, and those in SCH group were also weakly correlated with their attention scores. It is suggested that fewer than typical functional segregations between task-positive and task-negative networks in SCH group relate to inefficient distribution of cognitive resources and low attentional abilities.