Introduction: Anterior convex epiphysiodesis and posterior concave distraction has not been previously described in the literature for the treatment of thoracolumbar hemivertebrae. We describe our experience with long-term follow-up. Method: Six consecutive patients with a mean age of 3.4 years were operated on with this technique. Levels of fusion extended two levels above and below the hemi-vertebra, while the instrumentation span the full length of the curve. Further concave distraction was carried out when there was evidence of loosening of the hooks. Results: The average follow-up was 10.8 years (range 8 to 14). The mean Cobb angle before surgery was 49°, and at the latest follow-up was 26°. There was a mean 41% improvement in the scoliosis. In 5 of these cases, this correction was achieved immediately after surgery and did not significantly change despite repeated distraction. Conclusion: The addition of concave distraction provided better correction than convex epiphysiodesis alone. It is technically easier and safer than hemivertebra excision in the correction of such deformities. This method of treatment is recommended for patients with single fully segmented hemivertebrae located at the thoracolumbar junction that has a significant deformity

Aims: The purpose of this study is to compare the radiographic results of two different glenoid component designs by analyzing the radiolucent lines (RLL). Methods: Sixty-three shoulder arthroplasties with primary osteoarthritis were divided into two groups based on glenoid component type: thirty-five shoulders with flat back, and thirty-one shoulders with convex back, polyethylene glenoid implants. The radiolucenct lines were analyzed on fluoroscopically positioned, postoperative AP radiographs. The RLL Score (RLLS) was calculated using the technique of Molé. The RLLS was compared between the two groups. Results: On the immediate postoperative radiographs the average of total RLL score was 1.67 in Group 1 and 0.98 in Group 2 (p< 0.0005). There was a statistically significant association between the type of implant and the incidence of radiolucency behind the faceplate as well (p< 0.0005). On the 2-year postoperative radiographs the average RLL score was 4.19 in the Group1 (2.86 under the tray, and 1.33 around the keel), and 3.23 in Group2 (p=0.02) (2.09 under the tray, and 1.14 around the keel). The radiolucency behind the face-plate (p< 0.0005) was significantly greater in the flat back group, but not around the keel (p=0.427). There was no significant difference between the two groups regarding the degree of RLL score progression. Conclusions: The initial and mid-term RLLS is better with convex than fl at back glenoid component

Introduction: Anterior convex epiphysiodesis and posterior concave distraction has not been previously described in the literature for the treatment of thoracolumbar hemivertebrae. We describe our experience with long-term follow-up. Methods: Six consecutive patients with a mean age of 3.4 years were operated on using this technique. The levels of fusion extended two levels above and below the hemivertebra, while the instrumentation spanned the full length of the curve. Further concave distraction was carried out when there was evidence of loosening of the hooks. Results: The average follow-up was 10.8 years (range: eight to 14 years). The mean Cobb angle before surgery was 49 degrees, and at the latest follow-up was 26 degrees. There mean improvement in the scoliosis was 41%. In five of these cases, this correction was achieved immediately after surgery and did not significantly change despite repeated distraction. Conclusions: The addition of concave distraction provided better correction than convex epiphysiodesis alone. This method of treatment is recommended for patients with single fully segmented hemivertebrae located at the thoracolumbar junction associated with a significant deformity. This method is technically easier and safer than excision of the hemivertebra in the correction of such deformities

Objective: To report on the long-term follow-up (mean 14.2 years) of patients with early onset idiopathic scoliosis treated with convex epiphysiodesis (CE) and Luque trolley instrumentation (LTI) without fusion. To evaluate factors influencing curve progression during the adolescent growth spurt in such patients. Methods: Thirty-one cases of early onset idiopathic scoliosis with documented progression were surgically treated with CE and LTI without fusion between 1984 and 1992. Twenty-three (14 male, 9 female) of 31 cases had reached a minimum of 16 years of age at follow-up. These 23 cases were reviewed. The overlapped ‘L’ configuration of Luque trolley was used for the first 14 cases (prior to 1988), the overlapped ‘U’ configuration was used subsequently in the following 9 cases. Results: Mean age at operation was 4.3 years (range, 1.5 – 9 years). Mean pre-operative Cobb angle was 65° (range 30° – 95°), and immediate post-operative Cobb angle was 28° (range 10° – 60°). Mean follow-up was 14.2 years (range, 7–19 years). Four cases required insertion of longer Luque rods (mean age of 7.5 years). Definitive spinal fusion was required in thirteen cases at a mean age of 14.5 years (range 12–23 years), due to progression of scoliosis in 9 cases (mean Cobb angle 55°), and the development of junctional kyphosis in 4 cases. In ten cases the correction obtained was maintained through skeletal maturity (mean Cobb angle at final follow-up 33°). These cases did not require definitive spinal fusion. The mean growth within the instrumented segment was 3.2 cm (42% of the expected growth). Progression of scoliosis was predicted by pre-operative apical convex rib-vertebra angle (RVA) (p=0.002). Excessive growth within the instrumented segment was predictive of junctional kyphosis but not of scoliosis progression. Age at operation and initial curve magnitude were not found to be significant predictive factors. 72% of overlapped ‘L’ rod construct (10 cases), and 33% of overlapped ‘U’ rod construct (3 cases) had documented curve progression within the adolescent growth spurt and required definitive spinal fusion. Conclusions: CE and LTI was effective in controlling early onset idiopathic scoliosis, whilst still allowing significant growth. Pre-operative convex RVA was predictive of curve progression. The overlapped ‘U’ rod construct was more effective than the overlapped ‘L’ rod construct in preventing curve progression

To determine whether spinal facet osteoblasts at the curve apex display a different phenotype to osteoblasts from outside the curve in patients with adolescent idiopathic scoliosis (AIS). Intrinsic differences in the phenotype of spinal facet bone tissue and in spinal osteoblasts have been implicated in the pathogenesis of AIS. However, no study has compared the phenotype of facet osteoblasts at the curve apex with the facet osteoblasts from outside the curve in patients with AIS. Facet bone tissue was collected from three sites, the concave and convex side at the curve apex and from outside the curve from three female patients with AIS (aged 13–16 years). Micro-CT analysis was used to determine the density and trabecular structure. Osteoblasts were then cultured from the sampled bone. Osteoblast phenotype was investigated by assessing cellular proliferation (MTS assay), cellular metabolism (alkaline phosphatase and Seahorse Analyser), bone nodule mineralisation (Alizarin red assay), and the mRNA expression of Wnt signalling genes (quantitative RT-PCR). Convex bone showed greater bone mineral density and trabecular thickness than did concave bone. The convex side of the curve apex exhibited a significantly higher proliferative and metabolic phenotype and a greater capacity to form mineralised bone nodules than did concave osteoblasts. mRNA expression of SKP2 was significantly greater in both concave and convex osteoblasts than in non-curve osteoblasts. The expression of SFRP1 was significantly downregulated in convex osteoblasts compared with either concave or non-curve. Intrinsic differences that affect osteoblast function are exhibited by spinal facet osteoblasts at the curve apex in patients with AIS

Aims. Commonly performed unicompartmental knee arthroplasty (UKA) is not designed for the lateral compartment. Additionally, the anatomical medial and lateral tibial plateaus have asymmetrical geometries, with a slightly dished medial plateau and a convex lateral plateau. Therefore, this study aims to investigate the native knee kinematics with respect to the tibial insert design corresponding to the lateral femoral component. Methods. Subject-specific finite element models were developed with tibiofemoral (TF) and patellofemoral joints for one female and four male subjects. Three different TF conformity designs were applied. Flat, convex, and conforming tibial insert designs were applied to the identical femoral component. A deep knee bend was considered as the loading condition, and the kinematic preservation in the native knee was investigated. Results. The convex design, the femoral rollback, and internal rotation were similar to those of the native knee. However, the conforming design showed a significantly decreased femoral rollback and internal rotation compared with that of the native knee (p < 0.05). The flat design showed a significant difference in the femoral rollback; however, there was no difference in the tibial internal rotation compared with that of the native knee. Conclusion. The geometry of the surface of the lateral tibial plateau determined the ability to restore the rotational kinematics of the native knee. Surgeons and implant designers should consider the geometry of the anatomical lateral tibial plateau as an important factor in the restoration of native knee kinematics after lateral UKA. Cite this article: Bone Joint Res 2019;8:593–600

We previously reported that osteoblasts at the curve apex in adolescent idiopathic scoliosis (AIS) exhibit a differential phenotype, compared to non-curve osteoblasts(1). However, the Hueter-Volkmann principle on vertebral body growth in spinal deformities (2) suggests this could be secondary to altered biomechanics. This study examined whether non-curve osteoblasts subjected to mechanical strain resemble the transcriptomic phenotype of curve apex osteoblasts. Facet spinal tissue was collected perioperatively from three sites, (i) the concave and (ii) convex side at the curve apex and (iii) from outside the curve (non-curve) from six AIS female patients (age 13–18 years; NRES 19/WM/0083). Non-curve osteoblasts were subjected to strain using a 4-point bending device. Osteoblast phenotype was determined by RNA sequencing and bioinformatic pathway analysis. RNAseq revealed that curve apex osteoblasts exhibited a differential transcriptome, with 1014 and 1301 differentially expressed genes (DEGs; p<0.05, fold-change >1.5) between convex/non-curve and concave/non-curve sites respectively. Non-curve osteoblasts subjected to strain showed increased protein expression of the mechanoresponsive biomarkers COX2 and C-Fos. Comparing unstimulated vs strain-induced non-curve osteoblasts, 423 DEGs were identified (p<0.05, fold-change >1.5). Of these DEGs, only 5% and 6% were common to the DEGs found at either side of the curve apex, compared to non-curve cells. Bioinformatic analysis of these strain-induced DEGs revealed a different array of canonical signalling pathways and cellular processes, to those significantly affected in cells at the curve apex. Mechanical strain of AIS osteoblasts in vitro did not induce the differential transcriptomic phenotype of AIS osteoblasts at the curve apex

Aims. The aim of this study was to review the current evidence surrounding curve type and morphology on curve progression risk in adolescent idiopathic scoliosis (AIS). Methods. A comprehensive search was conducted by two independent reviewers on PubMed, Embase, Medline, and Web of Science to obtain all published information on morphological predictors of AIS progression. Search items included ‘adolescent idiopathic scoliosis’, ‘progression’, and ‘imaging’. The inclusion and exclusion criteria were carefully defined. Risk of bias of studies was assessed with the Quality in Prognostic Studies tool, and level of evidence for each predictor was rated with the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. In all, 6,286 publications were identified with 3,598 being subjected to secondary scrutiny. Ultimately, 26 publications (25 datasets) were included in this review. Results. For unbraced patients, high and moderate evidence was found for Cobb angle and curve type as predictors, respectively. Initial Cobb angle > 25° and thoracic curves were predictive of curve progression. For braced patients, flexibility < 28% and limited in-brace correction were factors predictive of progression with high and moderate evidence, respectively. Thoracic curves, high apical vertebral rotation, large rib vertebra angle difference, small rib vertebra angle on the convex side, and low pelvic tilt had weak evidence as predictors of curve progression. Conclusion. For curve progression, strong and consistent evidence is found for Cobb angle, curve type, flexibility, and correction rate. Cobb angle > 25° and flexibility < 28% are found to be important thresholds to guide clinical prognostication. Despite the low evidence, apical vertebral rotation, rib morphology, and pelvic tilt may be promising factors. Cite this article: Bone Joint J 2022;104-B(4):424–432

Introduction. Adolescent Idiopathic Scoliosis (AIS) is a three-dimensional deformity of the spine with unclear etiology. Due to the asymmetry of lateral curves, there are differences in the muscle activation between the convex and concave sides. This study utilized a comprehensive thoracic spine and ribcage musculoskeletal model to improve the biomechanical understanding of the development of AIS deformity and approach an explanation of the condition. Methods. In this study, we implemented a motion capture model using a generic rigid-body thoracic spine and ribcage model, which is kinematically determinate and controlled by spine posture obtained, for instance, from radiographs. This model is publicly accessible via a GitHub repository. We simulated gait and standing models of two AIS (averaging 15 years old, both with left lumbar curve and right thoracic curve averaging 25 degrees) and one control subject. The marker set included extra markers on the sternum and the thoracic and lumbar spine. The study was approved by the regional Research Ethics Committee (Journal number: H17034237). Results. We investigated the difference between the muscle activation on the right and left sides including erector spinae (ES), psoas major (PS), and multifidus (MF). Results of the AIS simulations indicated that, on average throughout the gait cycle, the right ES, left PS and left MF had 46%, 44%, and 23% higher activities compared to the other side, respectively. In standing, the ratios were 28%, 40%, and 19%, respectively. However, for the control subject, the differences were under 7%, except ES throughout the gait, which was 17%. Conclusion. The musculoskeletal model revealed distinct differences in force patterns of the right and left sides of the spine, indicating an instability phenomenon, where larger curves lead to higher muscle activations for stabilization. Acknowledgement. The project is funded by the European Union's Horizon 2020 program through Marie Skłodowska-Curie grant No. [764644]

This study aimed to describe the morphology of the coracoid process and determine the frequency of commonly observed patterns. The second purpose was to determine the location of inferior tunnel exit with superior based tunnel drilling and the superior tunnel exit with inferior based tunnel drilling. A sample of 100 dry scapulae for the morphology aspect and 52 cadaveric embalmed shoulders for tunnel drilling were used. The coracoid process was described qualitatively and categorized into 6 different shapes. A transcoracoid tunnel was drilled at the centre of the base. Twenty-six shoulders were used for the superior-inferior tunnel drilling approach and 26 for the inferior-superior tunnel drilling approach. The distances to the margins of the coracoid process, from both the entry and exit points of the tunnel, were measured. Eight coracoid processes were of convex shape, 31 of hooked shape, 18 of irregular shape, 18 of narrow shape, 25 of straight shape, and 13 of wide shape. The mean difference for the distances between superior entry and inferior exit from the apex was Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation 3.65+3.51mm (p=0.002); 1.57+2.27mm for the lateral border (p=0.40) and 5.53+3.45mm for the medial border (p=0.001). The mean difference for the distances between inferior entry and superior exit from the apex was 16.95+3.11mm (p=0.0001); 6.51+3.2mm for the lateral border (p=0.40) and 1.03+2.32 mm for the medial border (p=0.045). The most common coracoid process shape observed was a hooked pattern. Both superior to inferior and inferior to superior tunnel drilling directed the tunnel from a more anterior and medial entry to a posterior-lateral exit. Superior to inferior drilling resulted in a more posteriorly angled tunnel. With inferior to superior tunnel drilling cortical breaks were observed at the inferior and medial margin of the tunnel

Abstract. Aims. Vertebral body tethering (VBT) is a non-fusion technique to correct scoliosis allowing correction of scoliosis through growth modulation (GM) by tethering the convex side to allow concave unrestricted growth similar to the hemiepiphysiodesis concept. The other modality is anterior scoliosis correction (ASC) where the tether is able to perform most of the correction immediately where limited growth is expected. Methods. A retrospective analysis of 20 patients (M:F=19:1 – 9–17 years) between January 2014 to December 2016 with a mean five-year follow-up (4 to 7). Results. There were ten patients in each group with a total of 23 curves operated upon. VBT-GM mean age −12.5 years (9 to 14), mean Risser of 0.63 (0 to 2) and VBT-ASC was 14.9 years (13 to 17) and mean Risser of 3.66 (3 to 5). Mean preoperative VBT-GM Cobb was 47.4° (40°–58°) compared to VBT-ASC 56.5° (40°–79°). Postoperative VBT-GM Cobb was 20.3° and VBT-ASC was 11.2°. The early postoperative correction rate was 54.3% versus 81% whereas Fulcrum Bending Correction Index (FBCI) was 93.1% vs 146.6%. Latest Cobb angle at mean five years' follow-up was 19.4° (VBT-GM) and 16.5° (VBT-ASC). Overall, 5% of patients required fusion. Conclusion. We show a high success rate (95%) in helping children avoid fusion at five years post-surgery. VBT is a safe technique for scoliosis correction in the skeletally immature patient. This is the first report at five years showing two possible options of VBT depending on the skeletal maturity of the patient: GM and ASC

Cells typically respond to a variety of geometrical cues in their environment, ranging from nanoscale surface topography to mesoscale surface curvature. The ability to control cellular organisation and fate by engineering the shape of the extracellular milieu offers exciting opportunities within tissue engineering. Despite great progress, however, many questions regarding geometry-driven tissue growth remain unanswered. Here, we combine mathematical surface design, high-resolution microfabrication, in vitro cell culture, and image-based characterization to study spatiotemporal cell patterning and bone tissue formation in geometrically complex environments. Using concepts from differential geometry, we rationally designed a library of complex mesostructured substrates (10. 1. -10. 3. µm). These substrates were accurately fabricated using a combination of two-photon polymerisation and replica moulding, followed by surface functionalisation. Subsequently, different cell types (preosteoblasts, fibroblasts, mesenchymal stromal cells) were cultured on the substrates for varying times and under varying osteogenic conditions. Using imaging-based methods, such as fluorescent confocal microscopy and second harmonic generation imaging, as well as quantitative image processing, we were able to study early-stage spatiotemporal cell patterning and late-stage extracellular matrix organisation. Our results demonstrate clear geometry-dependent cell patterning, with cells generally avoiding convex regions in favour of concave domains. Moreover, the formation of multicellular bridges and collective curvature-dependent cell orientation could be observed. At longer time points, we found clear and robust geometry-driven orientation of the collagenous extracellular matrix, which became apparent with second harmonic generation imaging after ∼2 weeks of culture. Our results highlight a key role for geometry as a cue to guide spatiotemporal cell and tissue organisation, which is relevant for scaffold design in tissue engineering applications. Our ongoing work aims at understanding the underlying principles of geometry-driven tissue growth, with a focus on the interactions between substrate geometry and mechanical forces

Anterior vertebral body tethering (AVBT) is a growth modulating procedure used to manage idiopathic scoliosis by applying a flexible tether to the convex surface of the spine in skeletally immature patients. The purpose of this study is to determine the preliminary clinical outcomes for an adolescent patient cohort. 18 patients with scoliosis were selected using a narrow selection criteria to undergo AVBT. Of this cohort, 11 had reached a minimum follow up of 2 years, 4 had reached 18 months, and 3 had reached 6 months. These patients all demonstrated a primary thoracic deformity that was too severe for bracing, were skeletally immature, and were analysed in this preliminary study of coronal plane deformity correction. Using open-source image analysis software (ImageJ, NIH) PA radiographs taken pre-operatively and at regular follow-up visits post-operatively were used to measure the coronal plane deformity of the major and compensatory curves. Pre-operatively, the mean age was 12.0 years (S.D. 10.7 – 13.3), mean Sanders score 2.6 (S.D. 1.8-3.4), all Risser 0 and pre-menarchal, with mean main thoracic Cobb angle of 52° (S.D. 44.2-59.8°). Post-operatively the mean angle decreased to 26.4° (S.D. 18.4-32°) at 1 week, 30.4° (S.D. 21.3-39.6°) at 2 months, 25.7° (S.D. 18.7-32.8°) at 6 months, 27.9° (S.D. 16.2-39.6°) at 12 months, and 36.8° (S.D. 22.6– 51.0°) at 18 months and 38.2° (S.D. 27.6-48.7°) at 2 years. The change in curve at 2 years post-operative was statistically significant (P=0.004). There were 4 tether breakages identified that did not require return to theatre as yet, one patient underwent a posterior spinal instrumented fusion due to curve progression. AVBT is a promising new growth modulation technique for skeletally immature patients with progressive idiopathic scoliosis. This study has demonstrated a reduction in scoliosis severity

Aims. Mobile-bearing unicompartmental knee arthroplasty (UKA) with a flat tibial plateau has not performed well in the lateral compartment, leading to a high rate of dislocation. For this reason, the Domed Lateral UKA with a biconcave bearing was developed. However, medial and lateral tibial plateaus have asymmetric anatomical geometries, with a slightly dished medial and a convex lateral plateau. Therefore, the aim of this study was to evaluate the extent at which the normal knee kinematics were restored with different tibial insert designs using computational simulation. Methods. We developed three different tibial inserts having flat, conforming, and anatomy-mimetic superior surfaces, whereas the inferior surface in all was designed to be concave to prevent dislocation. Kinematics from four male subjects and one female subject were compared under deep knee bend activity. Results. The conforming design showed significantly different kinematics in femoral rollback and internal rotation compared to that of the intact knee. The flat design showed significantly different kinematics in femoral rotation during high flexion. The anatomy-mimetic design preserved normal knee kinematics in femoral rollback and internal rotation. Conclusion. The anatomy-mimetic design in lateral mobile UKA demonstrated restoration of normal knee kinematics. Such design may allow achievement of the long sought normal knee characteristics post-lateral mobile UKA. However, further in vivo and clinical studies are required to determine whether this design can truly achieve a more normal feeling of the knee and improved patient satisfaction. Cite this article: Bone Joint Res 2020;9(7):421–428

Tibial plateau fracture reduction involves restoration of alignment and articular congruity. Restorations of sagittal alignment (tibial slope) of medial and lateral condyles of the tibial plateau are independent of each other in the fracture setting. Limited independent assessment of medial and lateral tibial plateau sagittal alignment has been performed to date. Our objective was to characterize medial and lateral tibial slopes using fluoroscopy and to correlate X-ray and CT findings. Phase One: Eight cadaveric knees were mounted in extension. C-arm fluoroscopy was used to acquire an AP image and the C-arm was adjusted in the sagittal plane from 15° of cephalad tilt to 15 ° of caudad tilt with images captured at 0.5° increments. The “perfect AP” angle, defined as the angle that most accurately profiled the articular surface, was determined for medial and lateral condyles of each tibia by five surgeons. Given that it was agreed across surgeons that more than one angle provided an adequate profile of each compartment, a range of AP angles corresponding to adequate images was recorded. Phase Two: Perfect AP angles from Phase One were projected onto sagittal CT images in Horos software in the mid-medial compartment and mid-lateral compartment to determine the precise tangent subchondral anatomic structures seen on CT to serve as dominant bony landmarks in a protocol generated for calculating medial and lateral tibial slopes on CT. Phase Three: 46 additional cadaveric knees were imaged with CT. Tibial slopes were determined in all 54 specimens. Phase One: Based on the perfect AP angle on X-ray, the mean medial slope was 4.2°+/-2.6° posterior and mean lateral slope was 5.0°+/-3.8° posterior in eight knees. A range of AP angles was noted to adequately profile each compartment in all specimens and was noted to be wider in the lateral (3.9°+/-3.8°) than medial compartment (1.8°+/-0.7° p=0.002). Phase Two: In plateaus with a concave shape, the perfect AP angle on X-ray corresponded with a line between the superiormost edges of the anterior and posterior lips of the plateau on CT. In plateaus with a flat or convex shape, the perfect AP angle aligned with a tangent to the subchondral surface extending from center to posterior plateau on CT. Phase Three: Based on the CT protocol created in Phase Two, mean medial slope (5.2°+/-2.3° posterior) was significantly less than lateral slope (7.5°+/-3.0° posterior) in 54 knees (p<0.001). In individual specimens, the difference between medial and lateral slopes was variable, ranging from 6.8° more laterally to 3.1° more medially. In a paired comparison of right and left knees from the same cadaver, no differences were noted between sides (medial p=0.43; lateral p=0.62). On average there is slightly more tibial slope in the lateral plateau than medial plateau (2° greater). However, individual patients may have substantially more lateral slope (up to 6.8°) or even more medial slope (up to 3.1°). Since tibial slope was similar between contralateral limbs, evaluating slope on the uninjured side provides a template for sagittal plane reduction of tibial plateau fractures

Aims. Vertebral body tethering (VBT) is a non-fusion technique to correct scoliosis. It allows correction of scoliosis through growth modulation (GM) by tethering the convex side to allow concave unrestricted growth similar to the hemiepiphysiodesis concept. The other modality is anterior scoliosis correction (ASC) where the tether is able to perform most of the correction immediately where limited growth is expected. Methods. We conducted a retrospective analysis of clinical and radiological data of 20 patients aged between 9 and 17 years old, (with a 19 female: 1 male ratio) between January 2014 to December 2016 with a mean five-year follow-up (4 to 7). Results. There were ten patients in each group with a total of 23 curves operated on. VBT-GM mean age was 12.5 years (9 to 14) with a mean Risser classification of 0.63 (0 to 2) and VBT-ASC was 14.9 years (13 to 17) with a mean Risser classification of 3.66 (3 to 5). Mean preoperative VBT-GM Cobb was 47.4° (40° to 58°) with a Fulcrum unbend of 17.4 (1° to 41°), compared to VBT-ASC 56.5° (40° to 79°) with 30.6 (2° to 69°)unbend. Postoperative VBT-GM was 20.3° and VBT-ASC Cobb angle was 11.2°. The early postoperative correction rate was 54.3% versus 81% whereas Fulcrum Bending Correction Index (FBCI) was 93.1% vs 146.6%. The last Cobb angle on radiograph at mean five years’ follow-up was 19.4° (VBT-GM) and 16.5° (VBT-ASC). Patients with open triradiate cartilage (TRC) had three over-corrections. Overall, 5% of patients required fusion. This one patient alone had a over-correction, a second-stage tether release, and final conversion to fusion. Conclusion. We show a high success rate (95%) in helping children avoid fusion at five years post-surgery. VBT is a safe technique for correction of scoliosis in the skeletally immature patient. This is the first report at five years that shows two methods of VBT can be employed depending on the skeletal maturity of the patient: GM and ASC. Cite this article: Bone Jt Open 2022;3(2):123–129

Purpose of the study: The double-mobility concept was introduced for clinical applications for total hip arthroplasty in 1976. The concept preserves joint range of motion while increasing stability. In this study we evaluated the consequences of these advantages in terms of polyethylene wear, measuring wear both on the concave and convex surfaces and volumetrically. Material and methods: Forty polyethylene inserts were explanted and analyzed. Explantation had been performed for mechanical or septic failure after eight years implantation on average. Mean age of patients at implantation was 46 years. After examining the gross aspect of the insert, surface analysis was performed with direct measurement of changes in the curvature using a BHN 706 position sensor for the inner concave surface and lateral projection for the outer convex surface. Estimated measurement error was ±5μm for each method; the manufacturer's tolerance for production of the inserts was 50μm. Volumetric wear was determined by reference to the manufacturer’s data. Student’s t test for paired series was applied. Results: At gross inspection, all inserts had lost the strips originally present on the convex surface; 40% presented visible wear of the retaining ring. Mean annual wear (± standard deviation, SD) obtained with the measuring system was 9±9 μm/yr) for the convex surface and 73 ± 69 μm/yr for the concave surface. Total annual wear, the sum of inner and outer surface wear, was 82±72 μm/yr. The mean volumetric wear was 28±28 mm3/year for the convex surface and 25±23 mm3/year for the concave surface and 53.4±40 mm3/year for total wear. Discussion: Total wear for these 40 double-mobility inserts which had functioned in vivo was not greater than the values reported for the metal-polyethylene bearing with 22.2 mm femoral heads. The double mobility is not associated with greater wear. While there was no significant difference between the wear volume of the convex versus the concave surfaces, the differentials wear were widespread, which can be considered to result from functional differences

Introduction. Vertebral body tethering (VBT) is a non-fusion technique to correct scoliosis. It allows correction of scoliosis through Growth Modulation (GM) by tethering the convex side to allow concave unrestricted growth similar to the hemi-epiphysiodesis concept. The other modality is Anterior Scoliosis Correction (ASC) where the tether is able to perform most of the correction immediately where limited growth is expected. Methods. Retrospective analysis of clinical and radiographic data of 20 patients between 2014 to 2016 with a mean 5 year follow (range 4–6). Results. There were 10 patients in each group with a total of 23 curves operated on. VBT-GM mean age was 12.5y with mean Risser 0.63 and VBT-ASC was14.9y with a Risser of 3.66. Mean preop VBT-GM Cobb was 46° with a Fulcrum unbend of 13.6° compared to VBT-ASC 56.9° with 32.2° unbend. Postop VBT-GM was 21° and VBT-ASC Cobb was 10.8°. The early postop Correction Rate was 54.3% vs 81% whereas FBCI was 77.1% vs 186.6%. The last XR at mean 5y was 22.2° (VBT-GM) and 16.9° (VBT-ASC) 95% avoided fusion. Open TRC group had 3 over corrections. 1 patient alone had overcorrection, unplanned second stage and conversion to fusion. Discussion and Conclusion. We show a high success rate (95%) in helping children avoid fusion. Vertebral body tethering is a safe technique for correction of scoliosis in the skeletally immature patient. This is the first report at 5 years that shows two modalities of VBT can be employed depending on the skeletal maturity of the patient: Growth Modulation and Anterior Scoliosis Correction

Previous investigations have postulated that the asymmetry of the breasts in female adolescents may be linked with the development of right convex thoracic scoliosis, although there is no correlation between breast asymmetry and curve type or scoliosis magnitude. This breast asymmetry is supposed to be linked with anatomic and functional asymmetry of the internal mammary artery that is the main supplier to the mammary gland. However, no measurements of anatomic and haemodynamic parameters of internal mammary artery have been made to justify or to reject the hypothesis of asymmetric blood flow volume to the breasts and costosternal junction in female adolescent scoliotics. Twenty female adolescents with right thoracic scoliosis and 16 comparable female individuals without spine deformity were included in this study. Standing roentgenograms of the whole spine were made in all scoliotics to measure scoliosis curve, vertebral rotation and concave and convex rib-vertebra-angle at three vertebrae (apical, one level above and one below the apical vertebra). The Color Doppler Ultrasonography was used to measure at the origin of internal mammary artery its lumen diameter, cross sectional area, time average mean flow and flow volume per minute in scoliotics and controls and were compared each other. The roentgenographic parameters were compared with the ultrasonographic parameters in the scoliotics to disclose any relationship. The reliability of color Doppler ultrasonography was high and the intraobserver variability low (ANOVA, P=0.92–0.94). There was no statistically significant difference in the ultrasonographic parameters of the internal mammary artery between right and left side in each individual as well as between scoliotics and controls. In scoliotics the right mammary artery time average mean velocity increases with the convex and concave rib-vertebra-angle one level above the apical vertebrae (P< 0.01), convex rib-vertebra angle one level below the apical vertebra (P< 0.05), and concave apical rib-vertebra angle (P< 0.01). The left internal mammary artery time average increases with only the convex rib-vertebra angle one level above the apical vertebra (P< 0.05). The right and left internal mammary artery flow volume increases with the convex rib-vertebra-angle one level above the apical vertebra (P< 0.05), while the right internal mammary artery flow volume increases furthermore with the apical concave rib-vertebra-angle (P< 0.01) and concave rib-vertebra angle one level above the apical vertebra (P< 0.01). The concave apical rib-vertebra-angle (P< 0.01) and concave rib-vertebra-angle one level above the apical vertebra (P< 0.01) increases with left internal mammary artery cross sectional area. We concluded that anatomic and haemodynamic flow parameters measured at the origin of internal mammary artery are significantly correlated with apical rib-vertebra-angle in female adolescents suffering from right convex idiopathic thoracic scoliosis. This study did not find any evidence for side-difference in vascularity of the anterior thorax wall thus could not justify previous theories for development of right thoracic scoliosis in female adolescents

Costoplasty remains useful in the treatment of adolescent idiopathic scoliosis, rib hump and associated chest wall deformities. However traditional costoplasty increases morbidity and blood loss. We examine the feasibility and possible effectiveness of a more conservative costoplasty using an animal model. 4 fresh half Ovine rib cages from separate animals were obtained, stored at +4 °C and warmed to room temperature before testing. Each rib cage was randomly assigned to group 1, 2, 3 or 4. Ribs 2–10 were dissected out for testing. The ribs then underwent stepwise deconstruction according to their group. Beginning at the convexity, removing first the convex cortex, then the cancellous, then the cranial and caudal cortices to leave just the concave cortex. Testing for stiffness was by three-point bending on the concave side of each rib with the rib fixed at the head of the rib and 5 cm from the resected area. The ribs were deformed at a constant rate of 0.5 mm.sec . −. 1 up to a maximum load of 9.99 kg or until fracturing. Then stress was plotted against strain to find the Young's modulus of each group and statistics carried out with an ANOVA test. The ribs in each group were as follows: Group 1= control, group 2= 30 mm long convex side cortical bone removed 10 mm from lateral tubercle, group 3= convex, cortical and cancellous bone removal and group 4= removal of convex, caudal and cranial cortices with cancellous removal. The Young's Modulus of the groups were: 1= 3.38 N-m (+/− 0.84), 2= 2.65 N-m (+/− 1.58), 3= 1.55 N-m (+/− 0.55) and 4= 0.74 N-m (+/− 0.55). Groups 3 and 4 were significantly less stiff than group 1 (p< 0.01.) No ribs in groups 1, 2 and 4 fractured under the maximum load. 5/8 ribs in group 3 fractured before the maximum load was administered. By deconstructing the rib down to only the concave side it becomes significantly more flexible by approximately 4.5 times than the control Ribs. Coupled with its increase in flexibility it still retains its ability to withstand up to 10 kg of load without fracture. It may be possible to perform a costoplasty whilst preserving ventilatory integrity. This may improve rib hump correction, and curve correction due to increased flexibility of the stiff thoracic cage