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B-type glenoids are characterized by posterior humeral head migration and/or bony-erosion-induced glenoid retroversion. Patients with this type of osteoarthritic glenoids are known to be at increased risk of glenoid component loosening after anatomic total shoulder arthroplasty (aTSA). One of the main challenges in B glenoid surgical planning is to find a balance between correcting the bony shape and maintaining the quality of the bone support. This study aims to systematically quantify variabilities in terms of scapular morphology and bone mineral density in patients with B glenoids and to identify patterns of covariation between these two features. Using computed tomography scan images of 62 patients, three-dimensional scapular surface models were constructed. Rigid and nonrigid surface registration of the scapular surfaces, followed by volumetric registration and material mapping, enabled us to develop statistical shape model (SSM) and statistical density model (SDM). Partial least square correlation (PLSC) was used to identify patterns of covariation. The developed SSM and SDM represented 85.9% and 56.6% of variabilities in terms of scapular morphology and bone density, respectively. PLSC identified four modes of covariation, explaining 66.0% of the correlation between these two variations. Covariation of posterior-inferior glenoid erosion with posterior sclerotic bone formation in association with reduction of bone density in the anterior and central part of the glenoid was detected as the primary mode of covariation. Identification of these asymmetrical distribution of bone density can inform us about possible reasons behind glenoid component loosening in B glenoids and surgical guidelines in terms of the compromise between bony shape correction and bone support quality., (© 2023 Orthopaedic Research Society.)

Objectives: The idea to aim for an "individualized" alignment, whereby the constitutional alignment is restored, has gained much interest among knee surgeons. This requires insight into the prediseased, natural alignment of our patients' knees. The aim of this study is (1) to determine how the hip-knee-ankle (HKA) angle is influenced during the arthritic process and (2) to investigate the correlation between joint line changes and the progression of osteoarthritis (OA). It is our hypothesis that the most pronounced coronal parameter changes appear at the proximal tibia and at the joint line., Methods: One hundred sequential full-length X-rays with a minimum follow-up of 1 year were retrospectively reviewed from a radiographic joint database. Patients had to be at least 50 years of age needed to have an HKA angle of more than 1.3° varus to be included. Patients with ipsilateral total hip arthroplasty, femoral or tibial fracture, osteotomy, or ligamentous repair were excluded. Fifteen alignment parameters were investigated on the sequential full-length X-rays. Moreover, the relationship between the alignment parameters and the Kellgren-Lawrence grade (KL grade) was determined by using linear mixed models., Results: A progressive KL grade is associated with an increase of the HKA (p < 0.001). Mostly, HKA differs due to decrease of the medial tibial plateau (MPTA) angle (0.93°) and an increase of the joint line angle (JLCA) (0.86°). The mLDFA demonstrated the most pronounced changes in the beginning of OA (KL grade 1-2) (p = 0.049). In particular, the MPTA becomes considerably smaller (p = 0.004) in the later stage of OA (KL grade 3). Also, a progressive increase of the JLCA (p < 0.001) is observed upwards of KL grade 3., Conclusion: By comparing consecutive full-length X-rays in the same patients, it is possible to define the coronal alignment changes during the arthritic process. The HKA angle increases according the arthritic progression, whereby the most pronounced changes appear at the proximal tibia (MPTA) and at the joint line (JLCA).The alignment changes in varus OA knees can be divided in three stadia: (1) erosion of the distal medial femoral condyle, (2) erosion of the medial tibial plateau, and (3) a progressive increase of the joint line angle., Level of Evidence: Therapeutic Study, Level III., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Hypothesis and Background: Shoulder osteoarthritis can be divided into different glenoid types (A, B, C, and D) and subtypes. The aim of this study was to investigate if there is an association between the prearthropathy scapular anatomy, shoulder osteoarthritis, and different glenoid types and subtypes., Methods: Using principal components analysis, a statistical shape model (SSM) of the scapula was constructed from a data set of 110 computed tomographic (CT) scans. These subjects formed the control group. Next, CT scan images of 117 patients with osteoarthritis were classified according to the modified Walch classification. A complete 3-dimensional (3D) scapular bone model was created for every patient, and using the SSM, a reconstruction of their prearthropathy scapular anatomy was performed. Automated 3D measurements were performed in both the patient and control group to obtain glenoid version and inclination, critical shoulder angle (CSA), posterior acromial slope (PAS), lateral acromion angle, scapular offset, and the rotational alignment of the coracoacromial complex. These parameters were compared between controls, patients with osteoarthritis, and glenoid types and subtypes., Results: Mean version and inclination for the control group was 6° retroversion and 8° superior inclination (both SD 4°). The mean CSA, PAS, coracoid-posterior acromion angle, posterior acromion-scapular plane angle, and fulcrum axis ratio were 30° (SD 4°), 64° (SD 8°), 116° (SD 9°), 55° (SD 7°), and 46% (SD 4%), respectively. Patients with osteoarthritis had a significant lower CSA, posterior acromion-scapular plane angle, coracoid-posterior acromion angle, and fulcrum axis ratio (27°, 50°, 111°, and 44%, all P < .001). We found a significant difference between the control group and the respective glenoid types for the following parameters: mean CSA and coracoid-posterior acromion angle for A glenoids (27°, P = .001, and 111°, P = .007); mean version, CSA, PAS, coracoid-posterior acromion angle, posterior acromion-scapular plane angle, and fulcrum axis ratio for B glenoids (11°, 27°, 71°, 111°, 49°, and 43%, all P < .001); and mean version, CSA, and posterior acromion-scapular plane angle for D glenoids (2°, P = .002, 26°, P = .003, and 48°, P = .007)., Discussion: There seems to be an association between prearthropathy scapular anatomy and shoulder osteoarthritis. A small lateral extension and less posterior rotation of the acromion is associated with shoulder osteoarthritis and is present in almost all types and subtypes of glenoid morphology. Furthermore, B and D glenoids are associated with, respectively, a more and less pronounced prearthropathy glenoid retroversion., (Copyright © 2021 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Hypothesis and Background: Rotator cuff tear arthropathy (RCTA) is a pathology characterized by a massive rotator cuff tear combined with acromiohumeral and/or glenohumeral arthritis. The severity of RCTA can be staged according to the Hamada classification. Why RCTA develops in some patients is unknown. Furthermore, in RCTA patients, distinctly different articular damage patterns can develop on the glenoid side as categorized by the Sirveaux classification (glenoid erosion). The goal of this study was to determine whether an association exists between scapular anatomy and RCTA and different severity stages of RCTA, as well as the associated glenoid erosion types., Methods: A statistical shape model of the scapula was constructed from a data set of 110 computed tomography scans using principal component analysis. Sixty-six patients with degenerative rotator cuff pathology formed the control group. The computed tomography scan images of 89 patients with RCTA were included and grouped according to the Hamada and Sirveaux classifications. A complete 3-dimensional scapular bone model was created, and statistical shape model reconstruction was performed. Next, automated 3-dimensional measurements of glenoid version and inclination, scapular offset, the critical shoulder angle (CSA), the posterior acromial slope (PAS), and the lateral acromial angle (LAA) were performed. All measurements were then compared between controls and RCTA patients., Results: The control group had a median of 7° of retroversion (variance, 16°), 8° of superior inclination (variance, 19°), and 106 mm of scapular offset (variance, 58 mm). The median CSA, PAS, and LAA were 30° (variance, 14°), 65° (variance, 60°), and 90° (variance, 17°), respectively. In terms of inclination, version, scapular offset, and the PAS, we found no statistically significant differences between the RCTA and control groups. For RCTA patients, the median CSA and median LAA were 32° (P ≤ .01) and 86° (P ≤ .01), respectively. For all investigated parameters, we did not find any significant difference between the different stages of RCTA. Patients with type E3 erosion had a different pre-arthropathy anatomy with increased retroversion (12°, P = .006), an increased CSA (40°, P ≤ .001), and a reduced LAA (79°, P ≤ .001)., Discussion: Our results seem to indicate that a 4° more inferiorly tilted and 2° more laterally extended acromion is associated with RCTA. RCTA patients in whom type E3 erosion develops have a distinct pre-arthropathy scapular anatomy with a more laterally extended and more inferiorly tilted acromion and a more retroverted glenoid in comparison with RCTA patients with no erosion. The pre-arthropathy scapular anatomy does not seem to differ between patients with different stages of RCTA., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Recent studies highlighted the crucial contribution of subchondral bone to OA development. Yet, only limited data have been reported on the relation between alteration to cartilage morphology, structural properties of the subchondral bone plate (SBP) and underlying subchondral trabecular bone (STB). Furthermore, the relationship between the morphometry of the cartilage and bone in the tibial plateau and the OA-induced changes in the joint’s mechanical axis remains unexplored. Therefore, a visualisation and quantification of cartilage and subchondral bone microstructure in the medial tibial plateau was performed. End stage knee-OA patients with varus alignment and scheduled for total knee arthroplasty (TKA) underwent preoperative fulllength radiography to measure the hip-knee-ankle angle (HKA) and the mechanical-axis deviation (MAD). 18 tibial plateaux were μ-CT scanned (20.1 μm/voxel). Cartilage thickness, SBP, and STB microarchitecture were quantified in 10 volumes of interest (VOIs) in each medial tibial plateau. Significant differences (p < 0.001) were found for cartilage thickness, SBP, and STB microarchitecture parameters among the VOIs. Closer to the mechanical axis, cartilage thickness was consistently smaller, while SBP thickness and STB bone volume fraction (BV/TV) were higher. Moreover, trabeculae were also more superior-inferiorly oriented, i.e. perpendicular to the transverse plane of the tibial plateau. As cartilage and subchondral bone changes reflect responses to local mechanical loading patterns in the joint, the results suggested that region-specific subchondral bone adaptations were related to the degree of varus deformity. More specifically, subchondral sclerosis appeared to be most pronounced closer to the mechanical axis of the knee.