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Background: Preoperative traditional software planning (TSP) is a method used to assist surgeons with implant selection and glenoid guide-pin insertion in shoulder arthroplasty. Mixed-Reality (MR) is a new technology that uses digital holograms of the preoperative plan and guide-pin trajectory projected into the operative field. The purpose of this study was to compare TSP to MR in a simulated surgical environment involving insertion of guide-pins into models of severely deformed glenoids., Methods: Eight surgeons inserted guide-pins into eight randomized three-dimensional-printed severely eroded glenoid models in a simulated surgical environment using either TSP or MR. In total, 128 glenoid models were used and statistically compared. The outcomes compared between techniques included procedural time, difference in guide-pin start point, difference in version and inclination, and surgeon confidence via a confidence rating scale., Results: When comparing traditional preoperative software planning to MR visualization as techniques to assist surgeons in glenoid guide pin insertion, there were no statistically significant differences in terms of mean procedure time (P=0.634), glenoid start-point (TSP = 2.2 ± 0.2 mm , MR = 2.1 ± 0.1 mm; P=0.760), guide-pin orientation (P=0.586), or confidence rating score (P=0.850)., Conclusions: The results demonstrate that there were no significant differences between traditional preoperative software planning and MR visualization for guide-pin placement into models of eroded glenoids. A perceived benefit of MR is the real-time intraoperative visibility of the surgical plan and the patient's anatomy; however, this did not translate into decreased procedural time or improved guide-pin position. Level of evidence: Basic Science Study; Biomechanics.

This study compares standard procurement methodology (SPM) with total cost of ownership (TCO) methodology for the procurement of orthopaedic-powered instruments. The authors conducted semi-structured standardized interviews with key hospital procurement stakeholders following consolidated criteria for reporting qualitative research. Of the 33 hospital procurement stakeholders interviewed, all (100%) reported that SPM would be easier to use than TCO. However, only six (18%) preferred SPM over TCO. Barriers to the adoption of TCO emerged as a theme. Creating TCO frameworks can help to simplify the process for procurement agents and facilitate its adoption in the healthcare sector., (Copyright © 2023 Longwoods Publishing.)

Background: The longevity of a reverse total shoulder arthroplasty prosthesis can be compromised by glenoid baseplate loosening. Circular baseplate designs can be secured with superoinferior (SI) locking screws and anteroposterior (AP) compression screws or vice versa (AP-locking and SI-compression screws). This biomechanical cadaveric study investigated screw position (locking screws SI vs. AP and compression screws AP and SI) and screw orientation (parallel vs. divergent) to determine quantitative differences in baseplate micromotion., Methods: Ten paired fresh-frozen cadaveric scapulae (n = 20) were implanted with a standard circular baseplate (∅ = 29 mm). The specimens were randomized into SI-locking or AP-locking screw configurations with the screw orientation directed either parallel or angled divergently at 15°. This yielded a total of 4 groups for statistical comparison: SI-locking parallel , SI-locking divergent , AP-locking parallel , and AP-locking divergent , which were subjected to axial eccentric loading on the implanted baseplates, similar to the American Standard of Testing of Materials standard for shoulder joint arthroplasty., Results: In both static and cyclic testing, there were no statistically significant differences (P = .6) in micromotion between SI-locking (2.9 ± 0.8 μm) and AP-locking (3.5 ± 1.5 μm) configurations. In addition, there were no statistically significant differences (P = .2) in the divergent screw orientation group (2.0 ± 0.7 μm) vs. the parallel group (4.0 ± 1.5 μm)., Conclusion: All configurations of screw position and screw orientation tested in a circular reverse baseplate have similar time-zero fixation in an intact glenoid bone model. In addition, the resultant micromotions for all configurations tested fell far below the 150 μm threshold for bone ongrowth., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Introduction: Shorter humeral reverse total shoulder arthroplasty (RTSA) stems may reduce stress shielding, however, potentially carry the risk of varus/valgus malalignment. This radiographic study's purpose was to measure the incidence of stem malalignment and thus the realized neck-shaft angle (NSA). The hypothesis was that malalignment of the stem is a frequent postoperative radiographic finding., Methods: Radiographs of an uncemented curved short stem RTSA with a 145° NSA were reviewed. The study group included 124 cases at a mean age of 74 (range 48-91) years. The humeral stem axis was measured and defined as neutral if the value fell within ± 5° of the longitudinal humeral axis. Angular values > 5° were defined as malaligned in valgus or varus. The filling ratio of the implant within the humeral shaft was measured at the level of the metaphysis (FR met ) and diaphysis (FR dia )., Results: The average humeral stem axis angle was 4 ± 3° valgus, corresponding to a true mean NSA of 149 ± 3°. Stem axis was neutral in 73% (n = 90) of implants. Of the 34 malaligned implants, 82% (n = 28) were in valgus (NSA = 153 ± 2°) and 18% (n = 6) in varus (NSA = 139 ± 1°). The average FR met  and FR dia were 0.68 ± 0.11 and 0.72 ± 0.11, respectively. A low positive association was found between stem diameter and filling ratios (r = 0.39; p < 0.001); indicating smaller stem sizes were more likely to be misaligned., Conclusion: Uncemented short stem implants may decrease stress shielding; however, approximately one quarter were implanted > 5° malaligned. The majority of malaligned components (86%) were implanted in valgus, corresponding to an NSA of > 150°. As such, surgeons must be aware that shorter and smaller stems may lead to axial malalignment influencing the true SA., Level of Evidence: Level IV, retrospective study.

Background: The purpose of this study was 2-fold: (1) to quantify type E2 bone loss orientation and its association with rotator cuff fatty infiltration and (2) to examine reverse baseplate designs used to manage type E2 glenoids., Methods: Computed tomography scans of 40 patients with type E2 glenoids were examined for pathoanatomic features and erosion orientation. The rotator cuff fatty infiltration grade was compared with the erosion orientation angle. To compare reconstructive options in light of the pathoanatomic findings, virtual implantation of 4 glenoid baseplate designs (standard, half wedge, full wedge, and patient-matched) was conducted to determine the volume of bone removal for seating and impingement-free range of motion., Results: The mean type E2 erosion orientation angle was 47° ± 17° from the 0° superoinferior glenoid axis, resulting in the average erosion being located in the posterosuperior quadrant directed toward the 10:30 clock-face position. The type E2 neoglenoid, on average, involved 67% of the total glenoid surface (total surface area, 946 ± 209 mm 2 ; neoglenoid surface area, 636 ± 247 mm 2 ). The patient-matched baseplate design resulted in significantly (P ≤ .01) less bone removal (200 ± 297 mm 3 ) for implantation, followed by the full-wedge design (1228 ± 753 mm 3 ), half-wedge design (1763 ± 969 mm 3 ), and standard (non-augmented) design (4009 ± 1210 mm 3 ). We noted a marked difference in erosion orientation toward a more superior direction as the subscapularis fatty infiltration grade increased from grade 3 to grade 4 (P < .001)., Conclusion: The average type E2 erosion orientation was directed toward the 10:30 clock-face position in the posterosuperior glenoid quadrant. This orientation resulted in the patient-matched glenoid augmentation requiring the least amount of bone removal for seating, followed by the full-wedge, half-wedge, and standard designs. Implant selection also substantially affected computationally derived range of motion in external rotation, flexion, extension, and adduction., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Little is known about the cortical-like and cancellous bone density variations in superiorly eroded glenoids due to cuff tear arthropathy. The purpose of this study was to analyze regional bone density in type E2 glenoids., Methods: Clinical shoulder computed tomography scans were obtained from 32 patients with a type E2 superior erosion (10 men and 22 women; mean age, 73 years). Measurement regions were organized into quadrants (superior, inferior, anterior, and posterior) and depth regions. The depth regions were incremented by 2 mm from 0 to 10 mm. A repeated-measures multiple analysis of variance was performed to assess differences and interactions between mean densities (cortical-like and cancellous bone) in each depth, in each quadrant, and between sexes., Results: The lowest cancellous bone density was found in the inferior glenoid quadrant compared with all other quadrants (307 ± 50 Hounsfield units [HU], P < .001). At the glenoid surface, the superior quadrant contained the highest mean density for cortical-like bone (895 ± 97 HU); this differed significantly from the posterior, anterior, and inferior quadrants (P ≤ .033). As for depth of measurement, cortical-like bone was most dense at the glenoid surface (0-2 mm, 892 ± 91 HU), and density decreased significantly at depths greater than 2 mm (P ≤ .019)., Conclusion: In patients with type E2 glenoids due to cuff tear arthropathy, the densest bone was found in the superior quadrant in the area of erosion. The inferior quadrant, which tends to be unloaded as the humeral head migrates superiorly, had the lowest density bone. In addition, the best-quality bone was located at the glenoid surface as compared with deeper in the vault., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The implant-free, autologous, iliac crest bone graft procedure (J-bone graft) for the treatment of anterior shoulder instability shows low rates of recurrent dislocations and moderate progression of instability arthropathy in the midterm follow-up., Purpose: To analyze the clinical and radiological long-term results of the J-bone graft procedure., Study Design: Case series; Level of evidence, 4., Methods: A total of 46 patients (47 shoulders) with anterior shoulder instability and a relevant bony glenoid defect who received a J-bone graft between 1993 and 2000 and who were previously subjected to a midterm follow-up (mean, 8 years) were included. In total, 34 patients and 35 shoulders (74%) were clinically and radiologically assessed after a mean follow-up of 18 years (range, 15-23 years). Patients were assessed in terms of pain, bilateral active range of motion, and strength; in addition, the Western Ontario Shoulder Instability Index (WOSI), the Rowe Score, and the Subjective Shoulder Value (SSV) were obtained. Both an apprehension test and a relocation test were performed. Radiological imaging included bilateral radiographs (true anteroposterior and axillary view) to determine the grade of instability arthropathy., Results: At final follow-up, a mean WOSI score of 295 (range, 0-1765), Rowe Score of 94 (range, 55-100), SSV of 90% (range, 20%-100%), and pain level of 0.5 (range, 0-4) were noted. Slight differences were detected in active range of motion between the affected and the contralateral side: flexion 178° vs 179° ( P = .325), abduction 177° vs 179° ( P = .225), external rotation 63° vs 67° ( P = .048), high external rotation 77° vs 82° ( P = .007), internal rotation 8.8 vs 9.4 points ( P = .017), and high internal rotation 70° vs 74° ( P = .026). No significant strength deficit of the affected side was noticed. In 1 patient, a traumatic redislocation with fracture of the bone graft was observed 6 weeks after index surgery. No further recurrences were found during the follow-up period. Negative apprehension and relocation tests were confirmed in 77% of the shoulders, while 23% were positive. At final follow-up, 9 shoulders showed no signs of instability arthropathy (26%), mild arthropathy was revealed in 22 shoulders (63%), moderate arthropathy was noted in 3 shoulders (9%), and signs of severe arthropathy were found in 1 shoulder (3%) (collective instability arthropathy score, 0.9). The collective instability arthropathy score on the contralateral side was 0.4 ± 0.8 with no instability arthropathy in 24 shoulders (69%), mild arthropathy in 8 shoulders (23%), moderate signs of arthropathy in 2 shoulders (6%), and severe arthropathy in 1 shoulder (3%) at the time of follow-up examination (collective instability arthropathy score, 0.4). The overall difference between affected shoulders and contralateral shoulders was significant ( P = .005)., Conclusion: The J-bone graft procedure for the treatment of recurrent anterior shoulder instability shows excellent results regarding stability and function after a mean follow-up period of 18 years. However, the development of instability arthropathy of the affected shoulder is not prevented by this procedure.

In the field of traumatic shoulder dislocations, this report of a 61-year-old female patient discusses the case of an acute locked superior shoulder dislocation in conjunction with a chronic rotator cuff arthropathy resulting from a low-energy fall on the outstretched and abducted arm. Radiological assessment revealed a complex combination of associated bony injuries including a fracture of the upper part of the glenoid and an impaction fracture of the inferior articular surface of the humeral head. Closed reduction and immobilisation were not successful in obtaining joint stability. This unique report highlights the clinical importance of accurate management of bony injuries in traumatic shoulder dislocation., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)