Intelligent Reconfiguration-Promoted Cellular Internalization of Core-Shell DNA Nanoprobe Equipped with Successive Dual Stimuli-Responsive Protective Satellites for Amplification Fluorescence Imaging of Tumor Cells.

Although DNA probes have attracted increasing interest for precise tumor cell identification by imaging intracellular biomarkers, the requirement of commercial transfection reagents, limited targeting ligands, and/or non-biocompatible inorganic nanostructures has hampered the clinic translation. To circumvent these shortcomings, a reconfigurable ES-NC (Na+-dependent DNAzyme (E)-based substrate (S) cleavage core/shell DNA nanocluster (NC)) entirely from DNA strands is assembled for precise imaging of cancerous cells in a successive dual-stimuli-responsive manner. This nanoprobe is composed of a strung DNA tetrahedral satellites-based protective (DTP) shell, parallelly aligned target-responsive sensing (PTS) interlayer, and hydrophobic cholesterol-packed innermost layer (HCI core). Tetrahedral axial rotation-activated reconfiguration of DTP shell promotes the exposure of interior hydrophobic moieties, enabling cholesterol-mediated cellular internalization without auxiliary elements. Within cells, over-expressed glutathione triggers the disassembly of the DTP protective shell (first stimulus), facilitating target-stimulated signal transduction/amplification process (second stimuli). Target miRNA-21 is detected down to 10.6 fM without interference from coexisting miRNAs. Compared with transfection reagent-mediated counterpart, ES-NC displays a higher imaging ability, resists nuclease degradation, and has no detectable damage to healthy cells. The blind test demonstrates that the ES-NC is suitable for the identification of cancerous cells from healthy cells, indicating a promising tool for early diagnosis and prediction of cancer.

Comparison of Postoperative Axial Rotation of the Toric Intraocular Lens in Cataract Surgery Combined with Vitrectomy versus Cataract Surgery Alone.

INTRODUCTION: This study compared the postoperative axial rotation of the toric intraocular lens (T-IOL) after cataract surgery combined with vitrectomy versus cataract surgery alone. METHODS: This retrospective, non-randomized, observational study enrolled patients who underwent cataract surgery combined with vitrectomy in one eye and cataract surgery alone in the contralateral eye. AcrySof Toric IOLs (Alcon Laboratories) were implanted in both eyes of the same patient. The axial rotation of the T-IOL was analyzed 3 months postoperatively using photographs obtained during and after surgery. In the combined group, T-IOL axial alignment was performed before vitrectomy. Preoperative corneal astigmatism and postoperative residual astigmatism were also compared in both groups. RESULTS: This study examined 36 eyes of 18 patients (74.7 ± 6.8 years). The axial rotation was 2.94 ± 1.70° in the cataract group versus 3.06 ± 2.34° in the combined group 3 months postoperatively, and the difference lacked significance (p = 0.98). In the combined group, the mean axial rotation during surgery was 2.17 ± 1.80°. Axial rotation within 5° was observed in 17 of 18 eyes (94.4%) in the cataract group and 16 of 18 eyes (88.9%) in the combined group, with no significant difference (p = 0.54). The comparison of postoperative residual astigmatism with preoperative corneal astigmatism revealed a significant improvement from 1.49 ± 0.40 D to 0.39 ± 0.47 D in the cataract group (p < 0.0001) and from 1.61 ± 0.40 D to 0.42 ± 0.43 D in the combined group (p < 0.0001). CONCLUSIONS: The postoperative axial rotation of the T-IOL in eyes that underwent cataract surgery combined with vitrectomy was stable and comparable to that of eyes that underwent cataract surgery alone.

Effect of head rotation on two-dimensional cephalometric measurements using cone beam-computed tomography.

OBJECTIVE: The purpose of this study was to identify the variation of bi-dimensional cephalometric measurements following real head rotation. MATERIAL AND METHODS: Thirty cone beam-computed tomography (CBCT) head films were oriented according to three axes: horizontal Frankfort plane, transverse bi-orbital plane, and Opisthion-Nasion median plane. Axial rotation of 2°, 4°, 6°, and 8° from the Odontoïdale point were performed. Horizontal and vertical linear and angular measurements were studied on lateral cephalograms derived from each rotation T0, T2, T4, T6, and T8. A paired t-test was applied to compare the measurements between T0 and each rotational angle. RESULTS: Of the 18 measurements, 55% showed statistically significant differences (P < 0.05) and 22% showed clinically significant differences, mostly at T6 and T8. Horizontal linear measurements Ba-A and N-Ba decreased, and vertical linear measurement G-Sn increased gradually, as the angle of head rotation increased. Angular measurements studied did not vary. CONCLUSIONS: Head malpositions during X-ray acquisition should be avoided and rotated lateral CBCT cephalograms should be corrected and recentered to prevent any variation in linear measurements.

The relationship between pelvic tilt, frontal, and axial leg alignment in healthy subjects.

INTRODUCTION: The relationship between anterior pelvic tilt and overall sagittal alignment has been well-described previously. However, the relationship between pelvic tilt, frontal, and axial leg alignment remains unclear. The aim of the study was to analyze the relationship between pelvic tilt and frontal and axial leg alignment in healthy subjects. MATERIAL AND METHODS: Thirty healthy subjects (60 legs) without prior surgery underwent standing biplanar long leg radiograph. Pelvic parameters (pelvic tilt, pelvic incidence, sacral slope), hip-knee-ankle angle (HKA), femoral antetorsion and tibial torsion were measured using SterEOS (EOS Imaging) software. EOS was acquired with the feet directing straight anteriorly, which corresponds to a neutral foot progression angle (FPA). The influence of HKA, femoral antetorsion, tibial torsion and gender on pelvic tilt was analyzed in a univariate correlation and multiple regression model. RESULTS: Sixteen female subjects and 14 male subjects with a mean age of 27.1 years ± 10 (range 20-67) were included. HKA, femoral antetorsion, and tibial torsion correlated with anterior pelvic tilt in univariate analysis (all p < 0.05). Anterior pelvic tilt increased 1.1° (95% CI: 0.7 to 1.5) per 1° of knee valgus (p < 0.001) and 0.5° (95% CI: 0.3 to 0.7) per 1° of external tibial torsion (p < 0.001). Overall, linear regression model fit explained 39% of variance in pelvic tilt by the HKA, femoral antetorsion and tibial torsion (R2 = 0.385; p < 0.001). CONCLUSION: Valgus alignment and increasing tibial torsion demonstrated a weak correlation with an increase in anterior pelvic tilt in healthy subjects when placing their feet anteriorly. The relationship between frontal, axial leg alignment and pelvic tilt needs to be considered in patients with multiple joint disorders at the hip, knee and spine. Alteration of the frontal, or rotational profile after realignment surgery or by implant positioning might influence the pelvic tilt when the FPA is kept constant.

Axial rotation analysis in total ankle arthroplasty using weight-bearing computer tomography and three-dimensional modeling.

BACKGROUND: Post-operative alignment is the most critical indicator for a successful total ankle arthroplasty (TAA). Total ankle malrotation is associated with an increased risk for polyethylene wear and medial gutter pain. Currently, there is no consensus on the correct way to measure the alignment of the tibial and talar component rotations in the axial plane. In the current study, the post-operative analysis system was assessed using weight-bearing computer tomography and a three-dimensional (3D) model. The purpose of the study was to assess the inter-observer and intra-observer agreement of this system. MATERIAL AND METHOD: Four angles were measured by two raters independently in two separate readings: posterior tibial component rotation angle (PTIRA), posterior talar component rotation angle (PTARA), tibia talar component axial angle (TTAM), and tibial component to the second metatarsal angle (TMRA). Agreement analysis was quantified according to the interclass coefficient. RESULTS: Sixty TAAs across 60 patients were evaluated. A good inter-observer agreement and intra-observer agreement when measuring the PTIRA, PTARA, and TTAM angles was observed along with an excellent inter-observer agreement and intra-observer agreement when measuring the TMRA angle. CONCLUSION: In conclusion, the current 3D model-based measurement system demonstrates good to excellent inter and intra-agreement. According to these results, 3D modelling can be reliably used to measure and assess the axial rotation of TAA components. LEVEL OF EVIDENCE: Level 3 retrospective study.

Investigation of geometric deformations of the lumbar disc during axial body rotations.

BACKGROUND: Quantitative data on in vivo vertebral disc deformations are critical for enhancing our understanding of spinal pathology and improving the design of surgical materials. This study investigated in vivo lumbar intervertebral disc deformations during axial rotations under different load-bearing conditions. METHODS: Twelve healthy subjects (7 males and 5 females) between the ages of 25 and 39 were recruited. Using a combination of a dual fluoroscopic imaging system (DFIS) and CT, the images of L3-5 segments scanned by CT were transformed into three-dimensional models, which matched the instantaneous images of the lumbar spine taken by a double fluorescent X-ray system during axial rotations to reproduce motions. Then, the kinematic data of the compression and shear deformations of the lumbar disc and the coupled bending of the vertebral body were obtained. RESULTS: Relative to the supine position, the average compression deformation caused by rotation is between + 10% and - 40%, and the shear deformation is between 17 and 50%. Under physiological weightbearing loads, different levels of lumbar discs exhibit similar deformation patterns, and the deformation patterns of left and right rotations are approximately symmetrical. The deformation patterns change significantly under a 10 kg load, with the exception of the L3-4 disc during the right rotation. CONCLUSION: The deformation of the lumbar disc was direction-specific and level-specific during axial rotations and was affected by extra weight. These data can provide new insights into the biomechanics of the lumbar spine and optimize the parameters of artificial lumbar spine devices.

The short-term outcome of distal mesogastric fixation after laparoscopic sleeve gastrectomy: a randomized controlled trial.

PURPOSE: The proposed etiology of leakage after laparoscopic sleeve gastrectomy may be the axial rotation of the stomach owing to the loss of abdominal ligament fixation along the greater curvature of the stomach. The mechanism of increased intra-gastric pressure due to axial gastric rotation may place a great deal of stress on the staple lines, leading to an increased incidence of leakage. Other complications may occur, including vomiting, food intolerance or persistent reflux. METHODS: This study was registered in ClinicalTrials.gov (ID: NCT04834323). This study included patients who were admitted to our center to undergo laparoscopic sleeve gastrectomy. Cases were collected in the period from December 2019 to December 2020. The study population included 83 patients, who were divided into the following two groups: Group 1 included 42 patients who received distal mesogastric fixation after laparoscopic sleeve gastrectomy; Group 2 included 41 patients who received laparoscopic sleeve gastrectomy alone without distal mesogastric fixation. RESULTS: No leakage or axial rotation occurs after laparoscopic sleeve gastrectomy with distal fixation, while in patients without distal fixation, leakage and axial rotation occurred with no statistically significant differences between the two groups. Leakage and axial rotation occurred two times more frequently among patients who received laparoscopic sleeve gastrectomy without distal fixations. CONCLUSION: Distal mesogastric fixation after laparoscopic sleeve gastrectomy decreased the axial gastric rotation and subsequently decreased gastric leakage.

Strategies for controlling axial shoulder rotation change shoulder muscle activity during external rotation exercises.

BACKGROUND: The infraspinatus muscle has a crucial role in shoulder stability. Although axial shoulder rotation is useful for selective activation of the infraspinatus, no study has examined the influence of exercise position on axial shoulder rotation during shoulder external rotation (ER) exercises. Thus, this study investigated the muscle activity in the infraspinatus, posterior deltoid, and middle trapezius during shoulder ER exercises performed with and without controlled axial shoulder rotation in 2 different positions. METHODS: Twenty healthy subjects performed prone external rotation (PER) exercises with and without pressure biofeedback and seated external rotation (SITER) exercises with and without posterior humeral head gliding. Muscle activity during each ER exercise was measured using surface electromyography. RESULTS: Exercise strategy (P < .001) and position (P < .001) had a significant main effect on muscle activity in the infraspinatus and posterior deltoid. However, no significant interaction between strategy and position was observed. For muscle activity in the middle trapezius, strategy and position had a significant interaction effect (P = .014). Muscle activity in the infraspinatus increased significantly with the use of strategies to control axial shoulder rotation, whereas muscle activity in the posterior deltoid and middle trapezius decreased significantly. For all 3 muscles, greater activity was observed in the prone position than the seated position. CONCLUSION: We suggest that PER with pressure biofeedback can be useful to improve selective activation of the infraspinatus muscle while further eliciting infraspinatus muscle activity.

Outcome of proximal triple derotational metatarsal osteotomy for three-dimensional correction of hallux valgus deformity.

PURPOSE: To correct hallux valgus deformities in patients with a greater pronation of the first metatarsal, we designed a novel proximal triple derotational metatarsal osteotomy (PTDMO), which could be used to achieve three-dimensional correction of hallux valgus deformities at the proximal metatarsal level. METHODS: We prospectively evaluated the radiographic and clinical outcomes of 13 consecutive cases underwent PTDMO between November 2018 and May 2020. The minimum follow-up for inclusion was 12 months. The hallux valgus angle (HVA), first-to-second intermetatarsal angle (IMA), distal metatarsal articular angle (DMAA), relative length of the second metatarsal, and medial sesamoid position on the weight bearing foot anteroposterior radiographs, and the degree of the first metatarsal pronation on forefoot axial radiographs were measured pre-operatively, at six weeks post-operatively, and at the final follow-up. The American Orthopaedic Foot and Ankle Society (AOFAS) score and Foot Ankle Outcome Scores (FAOS) were measured. RESULTS: In the comparison of pre-operative and final follow-up parameters, HVA, IMA, and DMAA were significantly improved post-operatively (all, P < 0.001). The relative length of the second metatarsal did not differ significantly post-operatively (P = 0.724). The medial sesamoid was significantly reduced (P = 0.01), and the first metatarsal pronation decreased by 10.16° (P = 0.034). Regarding clinical parameters, the AOFAS score and FAOS in all categories significantly improved post-operatively (all, P < 0.001). CONCLUSION: PTDMO resulted in satisfactory radiographic and clinical outcomes with respect to deformity correction and pain relief, with significant post-operative reduced pronation of the first metatarsal.

Accuracy on the preoperative assessment of patients with adolescent idiopathic scoliosis using biplanar low-dose stereoradiography: a comparison with computed tomography.

BACKGROUND: Although computed tomography (CT) is commonly used to diagnose the scoliotic spine in patients with adolescent idiopathic scoliosis (AIS) preoperatively, it is limited by the high radiation and prone scanning position. Recently, a new biplanar stereoradiography (EOS) was used to image the scoliotic spine in an upright posture with significantly less radiation in non-severe AIS subjects. However, its reliability to assess preoperative AIS patients remains unreported. Hence, the purpose of this study is to compare the scoliotic curvature between prone (CT) and upright positions (EOS) in preoperative AIS patients. METHODS: Thirty-three pre-operative AIS patients (mean age:18.4 ± 4.2) were recruited. EOS was used to scan the whole thoracic spine at upright position. Whereas on the same day, a conventional CT scan was used to evaluate the spine in prone position. The three-dimensional reconstruction of EOS and CT of the spine were then generated. Using previous validated techniques, multiple scoliotic parameters in both modalities were determined. The agreement between the two modalities was compared using the Bland-Altman test, whereas the correlation was assessed by the intraclass correlation coefficient (ICC). RESULTS: The mean ICC (prone and upright) of intra-rater/inter-rater reliabilities for the measured parameters were 0.985,0.961/0.969,0.903, respectively. Thoracic Cobb angles, intervertebral wedging and lumbar lordosis correlated significantly between upright EOS imaging radiographs (62.9 ± 9.3°,6.4 ± 2.9° and 48.8 ± 12.4°) and prone CT (47.3 ± 10.0°,5.8 ± 2.7° and 27.9 ± 11.4°; P < 0.001). The apical vertebral wedging and apical intervertebral disc wedging showed a good correlation among the two modalities (upright, 6.5 ± 3.5° and 6.4 ± 2.9°; prone, 6.5 ± 3.6° and 5.8 ± 2.7°; R2 ≥ 0.94; P < 0.01). Similarly, there was significant correlation in apical intervertebral rotation (R2 = 0.834; P < 0.01) between the prone CT (3.4 ± 3.0°) and upright EOS (3.8 ± 3.2°). In addition, the Cobb angle was significantly larger in upright EOS (62.9 ± 9.3°) than in prone CT (47.3 ± 10.0°, P < 0.01) position. There was significant underestimation on scoliotic severity in the prone position when compared with upright position. CONCLUSIONS: Importantly, the image acquisition and reconstruction from EOS can better provide accurate three-dimensional spinal representations of the scoliotic curvature in preoperative AIS patients. Moreover, our findings suggested that scoliotic curvatures in preoperative AIS patients can be largely represented by both imaging modalities despite the difference in body positioning.

Interrater reliability of three-dimensional reconstruction of the spine : Low-dose stereoradiography for evaluating bracing in adolescent idiopathic scoliosis.

BACKGROUND: Bracing constitutes the mainstay treatment for mild scoliosis. The 3D reconstruction of the spine using low-dose stereoradiographic imaging (LSI) is increasingly being used to determine the true shape of the deformity and to assess the success of bracing. OBJECTIVE: The aim of the study was to validate the measurement of 3D spinopelvic parameters and vertebral rotation in the setting of bracing treatment via a reliability study conducted in adherence to the guidelines for reporting reliability and agreement studies (GRRAS). MATERIAL AND METHODS: Full spine stereoradiographs of patients with adolescent idiopathic scoliosis (AIS) who underwent Chêneau bracing were retrospectively analyzed. The 3D reconstruction was performed by two experienced operators in a blinded manner and randomized order. Rotation of every vertebra was computed in the coronal, sagittal and axial planes. Sagittal spinopelvic parameters were evaluated. All measurements were statistically compared to determine agreement of the measurement of brace correction using the intraclass correlation coefficient (ICC). RESULTS: In this study, 45 patients (81% females) aged 12.5 ± 2 years were included. The mean absolute difference was less than 3.5° for all measured angles, less than 4 mm for sagittal vertical axis (SVA) and less than 1.5 mm for lateral pelvic shift. The ICC was high for all parameters (ICC >0.81). Despite the overall high reliability, the reliability of axial rotation was lower in the upper and middle thoracic spine and the lower lumbar spine. CONCLUSION: Brace wearing during full spine LSI acquisition does not affect spinal measurements. The LSI under bracing treatment produces reliable measurements of spinopelvic parameters as well as vertebral rotation. These reproducible 3D data enable spine surgeons to assess the true shape of the deformity, to quantify rotation of each vertebra and enhance the understanding of the efficacy of bracing treatment.

The effects of rotation on radiological parameters in the spine.

BACKGROUND: Vertebral rotation in straight spines or in spines with small scoliosis may potentially affect measurement of radiological parameters in both the frontal and sagittal plane. This is important, since it could lead to potential misdiagnosis of scoliosis and other clinical consequences, and until now, this has not been examined. PURPOSE: To examine the effect of axial vertebral rotation of the spine on measurement of common radiological parameters. MATERIAL AND METHODS: Reconstructions from computed tomography scans of 40 consecutive included and anonymized patients with straight spines or small scoliosis. Fourteen sagittal and coronal reconstructions covering the whole pelvis and spine were executed. Radiographic parameters in both the frontal and sagittal plane were measured blinded and separately by three doctors. These parameters were evaluated for inter-rater reliability using intraclass correlation coefficient and mixed model analysis for the effects of rotation. The parameters were also analyzed sub-stratified according to "Lenke's classification" and 15 sub-categories of thoracic and lumbar Cobb's angle (CA). RESULTS: Vertebral rotation in general does not have any significant effects in both the frontal and sagittal plane. However, there are significant effects on CA and spinopelvic radiologic parameters in extreme rotation or for larger scoliosis. Inter-rater reliability was very good to good. CONCLUSION: In conclusion, axial spinal rotation does not influence common radiological parameters in the frontal and sagittal plane, except in cases of extreme rotation or large scoliosis for selected parameters; thus, this does not lead to potential misinterpretation in scoliosis diagnosis, treatment, or research.

CT-based study of vertebral and intravertebral rotation in right thoracic adolescent idiopathic scoliosis.

PURPOSE: To define the longitudinal rotation axis around which individual vertebrae rotate, and to establish the various extra- and intravertebral rotation patterns in thoracic adolescent idiopathic scoliosis (AIS) patients, for better understanding of the 3D development of the rotational deformity. METHODS: Seventy high-resolution CT scans from an existing database of thoracic AIS patients (Cobb angle: 46°-109°) were included to determine the vertebral axial rotation, rotation radius, intravertebral axial rotation, and local mechanical torsion for each spinal level, using previously validated image processing techniques. RESULTS: For all levels, the longitudinal rotation axis, from which the vertebrae rotate away from the midline, was localized posterior to the spine. The axis became closer to the spine at the apex: apex, r = 11.5 ± 5.1 cm versus two levels above (radius = 15.8 ± 8.5 cm; p < 0.001) and beneath (radius = 14.2 ± 8.2 cm; p < 0.001). The vertebral axial rotation, intravertebral axial rotation, and local mechanical torsion of the vertebral bodies were largest at the apex (21.9° ± 7.4°, 8.7° ± 13.5° and 3.0° ± 2.5°) and decreased toward the neutral, junctional zones (p < 0.001). CONCLUSION: In AIS, the vertebrae rotate away around an axis that is localized posterior to the spine. The distance between this axis and the spine is minimal at the apex and increases gradually to the neutral zones. The vertebral axial rotation is accompanied by smaller amounts of intravertebral rotation and local mechanical torsion, which increases toward the apical region. The altered morphology and alignment are important for a better understanding of the 3D pathoanatomical development of AIS and better therapeutic planning for bracing and surgical intervention. These slides can be retrieved under Electronic Supplementary Material.

Vertebral rotation estimation from frontal X-rays using a quasi-automated pedicle detection method.

PURPOSE: Measurement of vertebral axial rotation (VAR) is relevant for the assessment of scoliosis. Stokes method allows estimating VAR in frontal X-rays from the relative position of the pedicles and the vertebral body. This method requires identifying these landmarks for each vertebral level, which is time-consuming. In this work, a quasi-automated method for pedicle detection and VAR estimation was proposed. METHOD: A total of 149 healthy and adolescent idiopathic scoliotic (AIS) subjects were included in this retrospective study. Their frontal X-rays were collected from multiple sites and manually annotated to identify the spinal midline and pedicle positions. Then, an automated pedicle detector was developed based on image analysis, machine learning and fast manual identification of a few landmarks. VARs were calculated using the Stokes method in a validation dataset of 11 healthy (age 6-33 years) and 46 AIS subjects (age 6-16 years, Cobb 10°-46°), both from detected pedicles and those manually annotated to compare them. Sensitivity of pedicle location to the manual inputs was quantified on 20 scoliotic subjects, using 10 perturbed versions of the manual inputs. RESULTS: Pedicles centers were localized with a precision of 84% and mean difference of 1.2 ± 1.2 mm, when comparing with manual identification. Comparison of VAR values between automated and manual pedicle localization yielded a signed difference of - 0.2 ± 3.4°. The uncertainty on pedicle location was smaller than 2 mm along each image axis. CONCLUSION: The proposed method allowed calculating VAR values in frontal radiographs with minimal user intervention and robust quasi-automated pedicle localization. These slides can be retrieved under Electronic Supplementary Material.

The biomechanical effect of single-level laminectomy and posterior instrumentation on spinal stability in degenerative lumbar scoliosis: a human cadaveric study.

OBJECTIVEDegenerative lumbar scoliosis, or de novo degenerative lumbar scoliosis, can result in spinal canal stenosis, which is often accompanied by disabling symptoms. When surgically treated, a single-level laminectomy is performed and short-segment posterior instrumentation is placed to restore stability. However, the effects of laminectomy on spinal stability and the necessity of placing posterior instrumentation are unknown. Therefore, the aim of this study was to assess the stability of lumbar spines with degenerative scoliosis, characterized by the range of motion (ROM) and neutral zone (NZ) stiffness, after laminectomy and placement of posterior instrumentation.METHODSTen lumbar cadaveric spines (T12-L5) with a Cobb angle ≥ 10° and an apex on L3 were included. Three loading cycles were applied per direction, from -4 Nm to 4 Nm in flexion/extension (FE), lateral bending (LB), and axial rotation (AR). Biomechanical evaluation was performed on the native spines and after subsequent L3 laminectomy and the placement of posterior L2-4 titanium rods and pedicle screws. Nonparametric and parametric tests were used to analyze the effects of laminectomy and posterior instrumentation on NZ stiffness and ROM, respectively, both on an individual segment's motion and on the entire spine section. Spearman's rank correlation coefficient was used to study the correlation between disc degeneration and spinal stability.RESULTSThe laminectomy increased ROM by 9.5% in FE (p = 0.04) and 4.6% in LB (p = 0.01). For NZ stiffness, the laminectomy produced no significant effects. Posterior instrumentation resulted in a decrease in ROM in all loading directions (-22.2%, -24.4%, and -17.6% for FE, LB, and AR, respectively; all p < 0.05) and an increase in NZ stiffness (+44.7%, +51.7%, and +35.2% for FE, LB, and AR, respectively; all p < 0.05). The same changes were seen in the individual segments around the apex, while the adjacent, untreated segments were mostly unaffected. Intervertebral disc degeneration was found to be positively correlated to decreased ROM and increased NZ stiffness.CONCLUSIONSLaminectomy in lumbar spines with degenerative scoliosis did not result in severe spinal instability, whereas posterior instrumentation resulted in a rigid construct. Also, prior to surgery, the spines already had lower ROM and higher NZ stiffness in comparison to values shown in earlier studies on nonscoliotic spines of the same age. Hence, the authors question the clinical need for posterior instrumentation to avoid instability.

Influence of humeral abduction angle on axial rotation and contact area at the glenohumeral joint.

BACKGROUND: Although the elevation angle of the arm affects the range of rotation, it has not been evaluated up to the maximal abduction angle. In this study we conducted an evaluation up to maximal abduction and determined the contact patterns at the glenohumeral (GH) joint. METHODS: Fourteen healthy volunteers (12 men and 2 women; mean age, 26.9 years) with normal shoulders (14 right and 8 left) were instructed to rotate their shoulders at 0°, 90°, 135°, and maximal abduction for each shoulder at a time. Using 2-dimensional and 3-dimensional single-plane image registration, the internal rotation (IR), external rotation (ER), and range of motion (ROM; ie, axial rotations) at the thoracohumeral (TH) and GH joints, and the contribution ratio (%ROM = GH-ROM/TH-ROM) were calculated for each abduction. The glenoid position with respect to the humeral head was also analyzed. RESULTS: The TH-IR and TH-ER shifted toward an ER with increasing abduction angle, whereas the TH-ROM significantly decreased except at abduction between 0° and 90° (P < .001). The GH-IR and GH-ROM significantly decreased except at abduction between 0° and 90° (P < .001), but the GH-ER remained constant regardless of the abduction. The contribution ratio exceeded 80% for every abduction angle. The glenoid moved on the central and posterior areas of the humeral head at 0° and 90° abduction, respectively, and on the posterosuperior and anterosuperior areas at 135° and maximal abduction, respectively. CONCLUSION: Our results provide new knowledge about wide axial rotation up to maximal abduction and constant GH-ER at any abduction.

Total Knee Arthroplasty Kinematics.

Knee kinematics is an analysis of motion pattern that is utilized to assess a comparative, biomechanical performance of healthy nonimplanted knees, injured nonimplanted knees, and various prosthetic knee designs. Unfortunately, a consensus between implanted knee kinematics and outcomes has not been reached. One might hypothesize that the kinematic variances between the nonimplanted and implanted knee might play a role in patient dissatisfaction following TKA. There is a wide range of TKA designs available today. With such variety, it is important for surgeons and engineers to understand the various geometries and kinematic profiles of available prostheses. The purpose of this review is to provide readers with the pertinent information related to TKA kinematics.

Can Anatomic Measurements of Stem Anteversion Angle Be Considered as the Functional Anteversion Angle?

BACKGROUND: Stem anteversion angle is important in the combined anteversion theory to avoid implant impingement after total hip arthroplasty (THA). However, anatomic measurements of stem anteversion angle may not represent functional anteversion of the femur if the femur undergoes axial rotation. Herein, the femoral rotational angle (FRA) was measured in supine and standing positions before and after THA to evaluate the difference between anatomic and functional measurements. METHODS: A total of 191 hips (174 patients) treated with THA for osteoarthritis were analyzed in this retrospective, case-controlled study. The FRA was measured as the angle between the posterior condylar line and the line through the bilateral anterior superior iliac spines (positive for external rotation) and was measured preoperatively and postoperatively in supine and standing positions with computed tomography segmentation and landmark localization of the pelvis and the femur followed by intensity-based 2D-3D registration. The number of cases in which the absolute FRA remained <15° in both positions was also calculated. RESULTS: The average ± standard deviation preoperative FRA was 0.3° ± 8.3° in the supine position and -4.5° ± 8.8° during standing; the postoperative FRA was -3.8° ± 9.0° in supine and -14.3° ± 8.3° during standing. There were 134 cases (70%) in which the preoperative absolute FRA remained <15° in both positions while only 85 hips (45%) remained <15°, postoperatively. CONCLUSION: Substantial variability was seen in the FRA, especially during the postoperative period. These results suggest that the anatomic stem anteversion angle may not represent the functional anteversion of the femur.

Effect of increased functional residual capacity on the active range of thoracic axial rotation in healthy young men.

[Purpose] To understand the effect of increased functional residual capacity (FRC) on the active range of thoracic axial rotation (AROTAR) in healthy young men. [Subjects and Methods] Thirty-nine right-handed healthy male volunteers (age=20.1 ± 1.6 years) participated in this study. A standard plastic goniometer was used to measure the AROTAR in the supine position with both glenohumeral joints fully flexed. AROTAR was recorded at the resting expiration level (REL) and for 4 different FRC levels: 500, 1,000, 1,500, and 2,000 ml air inhaled at REL. FRC volumes and laterality were analyzed using a two-way repeated measure of ANOVA and post-hoc analysis. Relationships between the relative value (AROTAR for each increased FRC level / REL AROTAR × 100) and AROTAR for each increased FRC level were analyzed using Pearson's correlation coefficient. [Results] A significant main effect was found for only FRC factor. AROTAR had a positive moderate correlation with relative value. The correlation coefficient was higher than 0.5 for in 1,500 and 2,000 ml. [Conclusion] An increase in FRC might decrease AROTAR and if the REL AROTAR is high, the decrease in AROTAR due to increased FRC is lesser. It is suggested that maintaining the thoracic mobility could minimize a COPD patient's AROTAR limitation and maintain physical ability.

Posterior corrective surgery for moderate to severe focal kyphosis in the thoracolumbar spine: 57 cases with minimum 3 years follow-up.

PURPOSE: To evaluate the radiological and clinical outcomes of the corrective surgery for patients with moderate to severe focal kyphosis in thoracolumbar spine. METHODS: Fifty-seven patients with moderate to severe focal kyphosis of the thoracolumbar spine underwent apical segmental resection osteotomy with dual axial rotation correction at our hospital. There were 30 male and 27 female patients. The mean age was 34.3 years. The kyphosis level radiographs were obtained from each patient before surgery, immediately after surgery and at follow-up. Local kyphosis and scoliosis Cobb angles were measured. Full-spine standing radiographs were obtained before surgery and at follow-up, and the spine sagittal and coronal balance were evaluated. The height of patients, the Frankel grading system for neurological functions, the Oswestry disability index for life quality, the visual analogue score for back pain and the patient satisfactory index for satisfaction to surgery were applied before surgery and at follow-up. The radiological and clinical outcomes were further analyzed in different sub-groups of patients according to etiology, severity of kyphosis, age, level of kyphosis apex, Frankel grade before surgery, and complications. RESULTS: The average follow-up time of patients was 46.1 months. The average kyphosis angle reduced from 94.6° before surgery to 31.0° immediately after surgery, and remained at 34.4° at follow-up. The sagittal balance of the spine, height of patients, Frankel grading, Oswestry disability index and visual analogue score were improved. The patient satisfactory index (PSI) showed a satisfied rate of 91.2%. The correction rate was significantly higher in patients with kyphosis angle less than 95° and age less than 35 years. The clinical improvement rate was significantly higher in patient with kyphosis apex at lower thoracic spine or thoracolumbar segment, Frankel grade E before surgery and no complication group. The incidence of intra-operative and early stage complications was 38.6%, and the incidence of instrumentation failure was 10.5%. The most severe complication was transient spinal cord injury, and the incidence was 7.0%. All complications got good relief after appropriate intervention. CONCLUSIONS: Apical segmental resection osteotomy with dual axial rotation correction is an effective procedure to treat moderate to severe focal kyphosis, the prevention of serious neurological complications is fundamental to achieve the ideal clinical results.