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Background: In recent years, there has been considerable interest in prosthetic alignment techniques for total knee arthroplasty (TKA), particularly in the so-called kinematic alignment, which aims to restore the knee's native alignment. However, implementing this technique requires specialized instruments and procedural steps that can be laborious. This study introduces the bisector of the trochlear groove as a reliable landmark for performing the distal femoral cut while maintaining parallelism with the native femoral joint line. Methods: Three orthopedic specialists assessed 110 X-ray images of full-leg, weight-bearing lower limbs obtained from healthy individuals between January 2021 and December 2022. The bisector of the trochlear groove was identified on the X-ray images, and the angle between this bisector and the femoral joint line was measured. The consistency of these measurements across repeated assessments and different examiners was evaluated. Results: The bisector of the trochlear groove was found to be perpendicular to the femoral joint line, with a mean angle of 89.4°. The inter-rater reliability was 68% within ±1.3° from the mean, while the intra-rater reliability was 82% within ±1.5° from the mean. Conclusions: These results suggest that by performing a femoral cut perpendicular to the bisector of the trochlear groove, surgeons can inherently restore the femoral joint line of the native knee in patients where the native joint line is no longer identifiable due to the effect of osteoarthritis. This method may offer a viable and straightforward alternative to the standard surgical technique currently practiced for kinematic alignment in TKA. [ABSTRACT FROM AUTHOR]

Background: Distal junctional kyphosis (DJK) is a concerning complication for surgeons performing cervical deformity (CD) surgery. Patients sustaining such complications may demonstrate worse recovery profiles compared to their unaffected peers. Methods: DJK was defined as a >10° change in kyphosis between LIV and LIV-2, and a >10° index angle. CD patients were grouped according to the development of DJK by 3M vs. no DJK development. Means comparison tests and regression analyses used to analyze differences between groups and arelevant associations. Results: A total of 113 patients were included (17 DJK, 96 non-DJK). DJK patients were more sagittally malaligned preop, and underwent more osteotomies and combined approaches. Postop, DJK patients experienced more dysphagia (17.7% vs. 4.2%; p = 0.034). DJK patients remained more malaligned in cSVA through the 2-year follow-up. DJK patients exhibited worse patient-reported outcomes from 3M to 1Y, but these differences subsided when following patients through to 2Y; they also exhibited worse NDI (65.3 vs. 35.3) and EQ5D (0.68 vs. 0.79) scores at 1Y (both p < 0.05), but these differences had subsided by 2Y. Conclusions: Despite patients exhibiting similar preoperative health-related quality of life metrics, patients who developed early DJK exhibited worse postoperative neck disability following the development of their DJK. These differences subsided by the 2-year follow-up, highlighting the prolonged but eventually successful course of many DJK patients after CD surgery. [ABSTRACT FROM AUTHOR]

Background: In recent years, there has been considerable interest in prosthetic alignment techniques for total knee arthroplasty (TKA), particularly in the so-called kinematic alignment, which aims to restore the knee’s native alignment. However, implementing this technique requires specialized instruments and procedural steps that can be laborious. This study introduces the bisector of the trochlear groove as a reliable landmark for performing the distal femoral cut while maintaining parallelism with the native femoral joint line. Methods: Three orthopedic specialists assessed 110 X-ray images of full-leg, weight-bearing lower limbs obtained from healthy individuals between January 2021 and December 2022. The bisector of the trochlear groove was identified on the X-ray images, and the angle between this bisector and the femoral joint line was measured. The consistency of these measurements across repeated assessments and different examiners was evaluated. Results: The bisector of the trochlear groove was found to be perpendicular to the femoral joint line, with a mean angle of 89.4°. The inter-rater reliability was 68% within ±1.3° from the mean, while the intra-rater reliability was 82% within ±1.5° from the mean. Conclusions: These results suggest that by performing a femoral cut perpendicular to the bisector of the trochlear groove, surgeons can inherently restore the femoral joint line of the native knee in patients where the native joint line is no longer identifiable due to the effect of osteoarthritis. This method may offer a viable and straightforward alternative to the standard surgical technique currently practiced for kinematic alignment in TKA.

Background: Distal junctional kyphosis (DJK) is a concerning complication for surgeons performing cervical deformity (CD) surgery. Patients sustaining such complications may demonstrate worse recovery profiles compared to their unaffected peers. Methods: DJK was defined as a >10° change in kyphosis between LIV and LIV-2, and a >10° index angle. CD patients were grouped according to the development of DJK by 3M vs. no DJK development. Means comparison tests and regression analyses used to analyze differences between groups and arelevant associations. Results: A total of 113 patients were included (17 DJK, 96 non-DJK). DJK patients were more sagittally malaligned preop, and underwent more osteotomies and combined approaches. Postop, DJK patients experienced more dysphagia (17.7% vs. 4.2%; p = 0.034). DJK patients remained more malaligned in cSVA through the 2-year follow-up. DJK patients exhibited worse patient-reported outcomes from 3M to 1Y, but these differences subsided when following patients through to 2Y; they also exhibited worse NDI (65.3 vs. 35.3) and EQ5D (0.68 vs. 0.79) scores at 1Y (both p < 0.05), but these differences had subsided by 2Y. Conclusions: Despite patients exhibiting similar preoperative health-related quality of life metrics, patients who developed early DJK exhibited worse postoperative neck disability following the development of their DJK. These differences subsided by the 2-year follow-up, highlighting the prolonged but eventually successful course of many DJK patients after CD surgery.

An electronic survey was administered to multidisciplinary neurocritical care providers at 365 hospitals in 32 countries to describe intrahospital transport (IHT) practices of neurocritically ill patients at their institutions. The reported IHT practices were stratified by World Bank country income level. Variability between high-income (HIC) and low/middle-income (LMIC) groups, as well as variability between hospitals within countries, were expressed as counts/percentages and intracluster correlation coefficients (ICCs) with a 95% confidence interval (CI). A total of 246 hospitals (67% response rate; n = 103, 42% HIC and n = 143, 58% LMIC) participated. LMIC hospitals were less likely to report a portable CT scanner (RR 0.39, 95% CI [0.23; 0.67]), more likely to report a pre-IHT checklist (RR 2.18, 95% CI [1.53; 3.11]), and more likely to report that intensive care unit (ICU) physicians routinely participated in IHTs (RR 1.33, 95% CI [1.02; 1.72]). Between- and across-country variation were highest for pre-IHT external ventricular drain clamp tolerance (reported by 40% of the hospitals, ICC 0.22, 95% CI 0.00–0.46) and end-tidal carbon dioxide monitoring during IHT (reported by 29% of the hospitals, ICC 0.46, 95% CI 0.07–0.71). Brain tissue oxygenation monitoring during IHT was reported by only 9% of the participating hospitals. An IHT standard operating procedure (SOP)/hospital policy (HP) was reported by 37% (n = 90); HIC: 43% (n= 44) vs. LMIC: 32% (n = 46), p = 0.56. Amongst the IHT SOP/HPs reviewed (n = 13), 90% did not address the continuation of hemodynamic and neurophysiological monitoring during IHT. In conclusion, the development of a neurocritical-care-specific IHT SOP/HP as well as the alignment of practices related to the IHT of neurocritically ill patients are urgent unmet needs. Inconsistent standards related to neurophysiological monitoring during IHT warrant in-depth scrutiny across hospitals and suggest a need for international guidelines for neurocritical care IHT. [ABSTRACT FROM AUTHOR]

Background. The inaccurate maxillomandibular relationship of virtual casts following alignment by the vestibular scan may result in intersection (intermesh penetration) between opposing dental arch surfaces. Intersection occurs at short interocclusal distances in the occlusal contact area (OCA) and may result in infra-occluded definitive restorations. The purpose of this clinical study was to compare initial (by the proprietary scanner software) and new alignments (by a standalone 3D software) of virtual casts regarding OCA and intersection failure. New alignments aimed to rectify intersections by refinement of occlusal contacts. Material and Methods. The virtual casts of 30 patients following digital and conventional impression-taking were analyzed, which were acquired for single implant restoration in the posterior site. Digital impressions were performed by both IOS 1 (3M True Definition) and IOS 2 (TRIOS 3), either as complete- or partial-arch scans, respectively. Mounted gypsum casts were digitized as complete-arch by a laboratory scanner (LS) in enabled and disabled mode to avoid intersection [LS (+)/LS (−)]. All virtual casts were newly aligned by a 3D software. The difference of the OCA and the area of intersection were calculated for initial and new alignments, using interocclusal distance ranges of 0–100 μm, 0–10 μm or <0 μm (=intersection). The difference of the OCA was compared using a linear mixed model. The distribution of occlusal contact points per modality and alignment was assessed independently by three observers and estimated by inter- and intraclass correlation (ICC) coefficients. Results. Virtual casts following initial alignment demonstrated intersections irrespective of the modality. The mean area of the intersection was most for IOS 2 (79.23 mm2), followed by IOS 1 (48.28 mm2), LS (−) (2.77 mm2), and LS (+) (2.01 mm2) in partial-arch scans. Complete-arch scans demonstrated an area of intersection of 70.63 mm2 for IOS 1 followed by 65.52 mm2 (IOS 2), 6.13 mm2 [LS (−)] and 2.76 mm2 [LS (+)]. Newly aligned scans showed no intersections. The overall distribution of occlusal contact points demonstrated moderate reliability (ICC 0.63). Good reliability could be observed (ICC 0.9) for LS (−) scans. Conclusions. Intersections in the area of occlusal contact points are a phenomenon restricted to virtual casts, which should be considered in CAD/CAM. Initial alignments of LS are less affected by this virtual phenomenon, and contact points may be more distinct according to their anatomic region compared to IOS. Furthermore, intersections can be rectified in a 3D software by adjustment of the maxillomandibular relationship. [ABSTRACT FROM AUTHOR]

Background: A convincing association between the foot and ankle alignment (FAA) and patellofemoral pain syndrome (PFPS) remains debatable in the literature. Therefore, all studies investigating the role of FAA in patients with PFPS were systematically reviewed. Methods: A systematic literature search was performed on the databases PubMed, Embase, Cochrane Library, and Web of Science. Inclusion criteria were all studies investigating static and/or dynamic FAA factors and PFPS. Studies with less than 20 patients or with patellofemoral osteoarthritis were excluded. The quality assessment was based on Cochrane study criteria, and the maximum score was set at eight. Results: Of 2246 articles, only 13 case-control studies were eligible. Considering static FAA factors, two studies found an association with rearfoot eversion and one with rearfoot inversion. While examining dynamic FAA characteristics, one study found an association with rearfoot eversion range of motion and three with gait kinematics. No further associations were reported. The quality assessment mean score was 5.5 (SD = 0.97) corresponding to moderate quality. Conclusions: In contrast to our expectations, a limited number of studies were founded supporting an association between FAA and PFPS. At present, the quality of the literature is still poor and conflicting, thus the need for further studies to determine any association between FAA and PFPS. [ABSTRACT FROM AUTHOR]

Background. The inaccurate maxillomandibular relationship of virtual casts following alignment by the vestibular scan may result in intersection (intermesh penetration) between opposing dental arch surfaces. Intersection occurs at short interocclusal distances in the occlusal contact area (OCA) and may result in infra-occluded definitive restorations. The purpose of this clinical study was to compare initial (by the proprietary scanner software) and new alignments (by a standalone 3D software) of virtual casts regarding OCA and intersection failure. New alignments aimed to rectify intersections by refinement of occlusal contacts. Material and Methods. The virtual casts of 30 patients following digital and conventional impression-taking were analyzed, which were acquired for single implant restoration in the posterior site. Digital impressions were performed by both IOS 1 (3M True Definition) and IOS 2 (TRIOS 3), either as complete- or partial-arch scans, respectively. Mounted gypsum casts were digitized as complete-arch by a laboratory scanner (LS) in enabled and disabled mode to avoid intersection [LS (+)/LS (−)]. All virtual casts were newly aligned by a 3D software. The difference of the OCA and the area of intersection were calculated for initial and new alignments, using interocclusal distance ranges of 0–100 μm, 0–10 μm or 2), followed by IOS 1 (48.28 mm2), LS (−) (2.77 mm2), and LS (+) (2.01 mm2) in partial-arch scans. Complete-arch scans demonstrated an area of intersection of 70.63 mm2 for IOS 1 followed by 65.52 mm2 (IOS 2), 6.13 mm2 [LS (−)] and 2.76 mm2 [LS (+)]. Newly aligned scans showed no intersections. The overall distribution of occlusal contact points demonstrated moderate reliability (ICC 0.63). Good reliability could be observed (ICC 0.9) for LS (−) scans. Conclusions. Intersections in the area of occlusal contact points are a phenomenon restricted to virtual casts, which should be considered in CAD/CAM. Initial alignments of LS are less affected by this virtual phenomenon, and contact points may be more distinct according to their anatomic region compared to IOS. Furthermore, intersections can be rectified in a 3D software by adjustment of the maxillomandibular relationship.

Although osteoporotic vertebral fractures (OVFs) are the most common type of osteoporotic fracture, few reports have investigated the factors contributing to residual low back pain in the chronic phase after OVFs by using radiographic evaluation. We examined the contribution of nonunion, vertebral deformity, and thoracolumbar alignment to the severity of residual low back pain post-OVF. This post hoc analysis of a prospective randomized study included 195 patients with a 48-week follow-up period. We investigated the associations between radiographic variables with the visual analog scale (VAS) scores for low back pain at 48 weeks post-OVF using a multiple linear regression model. Univariate analysis revealed that analgesic use, the local angle on magnetic resonance imaging, anterior vertebral body compression percentage on X-ray, and nonunion showed a significant association with VAS scores for low back pain. Multiple regression analysis produced the following equation: VAS for low back pain at 48 weeks = 15.49 + 0.29 × VAS for low back pain at 0 weeks + (with analgesics: +8.84, without analgesics: −8.84) + (union: −5.72, nonunion: −5.72). Among local alignment, thoracolumbar alignment, and nonunion, nonunion independently contributed to residual low back pain at 48 weeks post-OVF. A treatment strategy that reduces the occurrence of nonunion is desirable. [ABSTRACT FROM AUTHOR]

Background: A convincing association between the foot and ankle alignment (FAA) and patellofemoral pain syndrome (PFPS) remains debatable in the literature. Therefore, all studies investigating the role of FAA in patients with PFPS were systematically reviewed. Methods: A systematic literature search was performed on the databases PubMed, Embase, Cochrane Library, and Web of Science. Inclusion criteria were all studies investigating static and/or dynamic FAA factors and PFPS. Studies with less than 20 patients or with patellofemoral osteoarthritis were excluded. The quality assessment was based on Cochrane study criteria, and the maximum score was set at eight. Results: Of 2246 articles, only 13 case-control studies were eligible. Considering static FAA factors, two studies found an association with rearfoot eversion and one with rearfoot inversion. While examining dynamic FAA characteristics, one study found an association with rearfoot eversion range of motion and three with gait kinematics. No further associations were reported. The quality assessment mean score was 5.5 (SD = 0.97) corresponding to moderate quality. Conclusions: In contrast to our expectations, a limited number of studies were founded supporting an association between FAA and PFPS. At present, the quality of the literature is still poor and conflicting, thus the need for further studies to determine any association between FAA and PFPS.

Worldwide tendencies to perform large numbers of total hip arthroplasties in the treatment of osteoarthritis are observable over a long period of time. Every year, there is an observable increase in the number of these procedures performed. The outcomes are good but not ideal, especially in groups of patients with spine problems. In recent years, a growing interest in this field may be observed, since spinopelvic alignment seems to have a significant impact on total hip replacement (THR) results. The aim of this study is to describe relations between spine and pelvic alignment and provide practical information about its impact on total hip replacement. The authors performed a literature review based on PubMed, Embase, and Medline and provide practical guidelines based on them and their own experience.

There have been remarkable advances in knee replacement surgery over the last few decades. One of the concerns continues to be the accuracy in achieving the desired alignment. Patient-specific instrumentation (PSI) was developed to increase component placement accuracy, but the available evidence is not conclusive. Our study aimed to determine a PSI system’s three-dimensional accuracy on 3D virtual models obtained by post-operative computed tomography. We compared the angular placement values of 35 total knee arthroplasties (TKAs) operated within a year obtained with the planned ones, and we analyzed the possible relationships between alignment and patient-reported outcomes. The mean (SD) discrepancies measured by two experienced engineers to the planned values observed were 1.64° (1.3°) for the hip–knee–ankle angle, 1.45° (1.06°) for the supplementary angle of the femoral lateral distal angle, 1.44° (0.97°) for the proximal medial tibial angle, 2.28° (1.78°) for tibial slope, 0.64° (1.09°) for femoral sagittal flexion, and 1.42° (1.06°) for femoral rotation. Neither variables related to post-operative alignment nor the proportion of change between pre-and post-operative alignment influenced the patient-reported outcomes. The evaluated PSI system’s three-dimensional alignment analysis showed a statistically significant difference between the angular values planned and those obtained. However, we did not find a relevant effect size, and this slight discrepancy did not impact the clinical outcome.

Weight bearing whole-leg radiograph (WLR) is essential to assess lower limb alignment such as weight bearing line (WBL) ratio. The purpose of this study was to develop a deep learning (DL) model that predicts the WBL ratio using knee standing AP alone. Total of 3997 knee AP & WLRs were used. WBL ratio was used for labeling and analysis of prediction accuracy. The WBL ratio was divided into seven categories (0, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6). After training, performance of the DL model was evaluated. Final performance was evaluated using 386 subjects as a test set. Cumulative score (CS) within error range 0.1 was set with showing maximum CS in the validation set (95% CI, 0.924–0.970). In the test set, mean absolute error was 0.054 (95% CI, 0.048–0.061) and CS was 0.951 (95% CI, 0.924–0.970). Developed DL algorithm could predict the WBL ratio on knee standing AP alone with comparable accuracy as the degree primary physician can assess the alignment. It can be the basis for developing an automated lower limb alignment assessment tool that can be used easily and cost-effectively in primary clinics.

The aim of this study was to construct a novel, repeatable, reproducible, and accurate measurement protocol for the area and volume of the remaining cement after removal of fixed multibracket appliances, the area and volume of remaining cement after cement removal, the area and volume of enamel removed after cement removal, and the volume of cement used to adhere fixed multibracket appliances. A total of 30 brackets were cemented and removed with over 30 extracted teeth embedded into three experimental models of epoxy resin. The models were scanned before and after bracket placement, bracket debonding, and polishing the remaining cement. The brackets were submitted to micro-computed tomography. The standard tessellation language digital files were aligned, segmented, and re-aligned using geomorphometric software. The digital measurement technique accuracy, repeatability, and reproducibility were analyzed using Gage R&R statistical analysis. The variability attributable to the area and volume measurement techniques of the total variability of the samples was 0.70% and 0.11% for repeatability, respectively, and 0.79% and 0.01% for reproducibility, respectively. The re-alignment procedure is a repeatable, reproducible, and accurate technique that can be used to measure the area and volume of the remaining cement after removal of fixed multibracket appliances, the area and volume of remaining cement after cement removal, the area and volume of enamel removed after cement removal, and the volume of cement used to adhere the fixed multibracket appliance.

Worldwide tendencies to perform large numbers of total hip arthroplasties in the treatment of osteoarthritis are observable over a long period of time. Every year, there is an observable increase in the number of these procedures performed. The outcomes are good but not ideal, especially in groups of patients with spine problems. In recent years, a growing interest in this field may be observed, since spinopelvic alignment seems to have a significant impact on total hip replacement (THR) results. The aim of this study is to describe relations between spine and pelvic alignment and provide practical information about its impact on total hip replacement. The authors performed a literature review based on PubMed, Embase, and Medline and provide practical guidelines based on them and their own experience. [ABSTRACT FROM AUTHOR]

Weight bearing whole-leg radiograph (WLR) is essential to assess lower limb alignment such as weight bearing line (WBL) ratio. The purpose of this study was to develop a deep learning (DL) model that predicts the WBL ratio using knee standing AP alone. Total of 3997 knee AP & WLRs were used. WBL ratio was used for labeling and analysis of prediction accuracy. The WBL ratio was divided into seven categories (0, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6). After training, performance of the DL model was evaluated. Final performance was evaluated using 386 subjects as a test set. Cumulative score (CS) within error range 0.1 was set with showing maximum CS in the validation set (95% CI, 0.924–0.970). In the test set, mean absolute error was 0.054 (95% CI, 0.048–0.061) and CS was 0.951 (95% CI, 0.924–0.970). Developed DL algorithm could predict the WBL ratio on knee standing AP alone with comparable accuracy as the degree primary physician can assess the alignment. It can be the basis for developing an automated lower limb alignment assessment tool that can be used easily and cost-effectively in primary clinics. [ABSTRACT FROM AUTHOR]

There have been remarkable advances in knee replacement surgery over the last few decades. One of the concerns continues to be the accuracy in achieving the desired alignment. Patient-specific instrumentation (PSI) was developed to increase component placement accuracy, but the available evidence is not conclusive. Our study aimed to determine a PSI system's three-dimensional accuracy on 3D virtual models obtained by post-operative computed tomography. We compared the angular placement values of 35 total knee arthroplasties (TKAs) operated within a year obtained with the planned ones, and we analyzed the possible relationships between alignment and patient-reported outcomes. The mean (SD) discrepancies measured by two experienced engineers to the planned values observed were 1.64° (1.3°) for the hip–knee–ankle angle, 1.45° (1.06°) for the supplementary angle of the femoral lateral distal angle, 1.44° (0.97°) for the proximal medial tibial angle, 2.28° (1.78°) for tibial slope, 0.64° (1.09°) for femoral sagittal flexion, and 1.42° (1.06°) for femoral rotation. Neither variables related to post-operative alignment nor the proportion of change between pre-and post-operative alignment influenced the patient-reported outcomes. The evaluated PSI system's three-dimensional alignment analysis showed a statistically significant difference between the angular values planned and those obtained. However, we did not find a relevant effect size, and this slight discrepancy did not impact the clinical outcome. [ABSTRACT FROM AUTHOR]

The aim of this study was to construct a novel, repeatable, reproducible, and accurate measurement protocol for the area and volume of the remaining cement after removal of fixed multibracket appliances, the area and volume of remaining cement after cement removal, the area and volume of enamel removed after cement removal, and the volume of cement used to adhere fixed multibracket appliances. A total of 30 brackets were cemented and removed with over 30 extracted teeth embedded into three experimental models of epoxy resin. The models were scanned before and after bracket placement, bracket debonding, and polishing the remaining cement. The brackets were submitted to micro-computed tomography. The standard tessellation language digital files were aligned, segmented, and re-aligned using geomorphometric software. The digital measurement technique accuracy, repeatability, and reproducibility were analyzed using Gage R&R statistical analysis. The variability attributable to the area and volume measurement techniques of the total variability of the samples was 0.70% and 0.11% for repeatability, respectively, and 0.79% and 0.01% for reproducibility, respectively. The re-alignment procedure is a repeatable, reproducible, and accurate technique that can be used to measure the area and volume of the remaining cement after removal of fixed multibracket appliances, the area and volume of remaining cement after cement removal, the area and volume of enamel removed after cement removal, and the volume of cement used to adhere the fixed multibracket appliance. [ABSTRACT FROM AUTHOR]