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Background: The rationale for advances in implant design is to improve performance in comparison to their predecessors. The purpose of this study was to compare a newer, self-pressurizing peripheral peg glenoid to a traditional polyethylene pegged glenoid through biomechanical evaluation and a retrospective radiographic and clinical review., Methods: Three testing conditions (uncemented, partially cemented, and fully cemented) were chosen to assess the 2 component designs in a foam block model. The number of hammer hits to seat the component, amount of time to seat the component, and resistance-to-seat were collected. The implants were then cyclically loaded following ASTM F2028-17 testing standard. Clinically, postoperative radiographs of patients with a self-pressurized glenoid component (n = 225 patients) and traditional glenoid component (n = 206 patients) were evaluated for radiolucent lines and glenoid seating at various timepoints. Clinical outcomes (American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form, Simple Shoulder Test, and visual analog scale pain scores) and complications were recorded. The presence of radiolucent lines at the bone-cement interface was evaluated using the Modified Franklin Grade and the Lazarus grade., Results: The self-pressurizing glenoid design required significantly more hammer hits than traditional glenoid designs in all groups tested (P < .029). Moreover, the self-pressurizing design had significantly more resistance-to-seat than traditional components in both the uncemented and partially cemented group (P < .002). No difference in resistance-to-seat was found between designs in the fully cemented group. The uncemented and partially cemented groups did not survive the full 50,000 cycles; however the self-pressurizing design had significantly less motion than the traditional design (P < .001). No differences between component designs were found in the fully cemented group at 50,000 cycles. The self-pressurizing glenoid component had 0.005% radiographic radiolucent lines, and the traditional glenoid component had 45% radiographic radiolucent lines, with 38% of the radiolucencies in the traditional glenoid component group being defined as grade E. There were no progressive radiolucencies, differences in clinical outcomes, or complications at 2 years postoperatively., Conclusion: In the fully cemented condition, the 2 component designs had comparable performance; however, the differences in designs could be better observed in the uncemented group. The self-pressurizing all-polyethylene design studied has superior biomechanical stability. Clinically, the improved stability of the glenoid component correlated with a reduction of radiolucent lines and will likely lead to a reduction in glenoid component loosening., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Preoperative planning for total shoulder arthroplasty (TSA) may change according to the measured degree of glenoid version. Both 2-dimensional (2D) and 3-dimensional (3D) computed tomographic (CT) scans are used to measure glenoid version, with no consensus on which method is more accurate. However, it is generally accepted that 3D measurements are more reliable, yet most 3D reconstruction software currently in clinical use have never been directly compared to 2D. The purpose of this study is to directly compare 2D and 3D glenoid version measurements and determine the differences between the two., Methods: CT scans were performed preoperatively on 315 shoulders undergoing either anatomic or reverse TSA. 2D measurements of glenoid version were obtained manually using the Friedman method, whereas 3D measurements were obtained using the Equinoxe Planning Application (Exactech Inc.) 3D-reconstruction software. Negative version values indicate retroversion, whereas positive values indicate anteversion. Two observers collected the 2D measurements 2 separate times, and intra- and interobserver measurements were calculated. Groups were compared for variability using intraclass correlation coefficients (ICCs), and for differences in sample means using Student t tests. Additionally, samples were stratified by version value in order to better understand the potential sources of error between measurement techniques., Results: For the 2D measurements, intraobserver variability indicated excellent reproducibility for both observer 1 (ICC = 0.928, 95% confidence interval [CI] 0.911-0.942) and observer 2 (ICC = 0.964, 95% CI 0.955-0.971). Interobserver variability measurements also indicated excellent reproducibility (ICC = 0.915, 95% CI 0.778-0.956). The overall 2D version measurement average (-4.9° ± 10.3°) was significantly less retroverted than the 3D measurement average (-8.4° ± 9.1°) (P < .001), with 3D measurements yielding a more retroverted value 73% of the time. When stratified on the basis of version value with outliers excluded, there was no significant difference in the distribution of high-error samples within the data., Discussion: There was excellent reproducibility between the 2 observers in terms of both intra- and interobserver variability. The 3D measurement techniques were significantly more likely to return a more retroverted measurement, and high-error samples were evenly distributed throughout the data, indicating that there were no discernable trends in the degree of error observed. Shoulder surgeons should be aware that different glenoid version measurement strategies can yield different version measurements, as these can affect preoperative planning and surgeon decision making., (Copyright © 2021 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Introduction: Preoperative 3D planning programs for anatomic (TSA) and reverse total shoulder arthroplasty (RSA) allow the analysis of glenohumeral joint pathoanatomy and templating for implant size selection and placement. The aim of this multicenter study was to compare the preoperative glenoid implant type and size planned to the final glenoid implant type and size used intraoperatively., Methods: Two hundred patients (100 TSA and 100 RSA) with a mean age of 72 years who had undergone preoperative planning and subsequent shoulder arthroplasty (100 TSA and 100 RSA) were included. All preoperative plans were saved and were analyzed for arthroplasty type (TSA vs. RSA), implant type (augment vs. nonaugment), and size (ie, polyethylene size, polyethylene radius of curvature, glenoid baseplate diameter, baseplate post length, and baseplate lateralization). The preoperative plan was available during surgery and was compared to the final implants inserted by the surgeon., Results: There were no intraoperative conversions of TSA to RSA or vice versa. In patients planned for a TSA, complete concordance between the preoperative plan and final implant selection was 85%. A complete mismatch for TSA glenoid size, backside radius of curvature, and augmentation occurred in 2%. For RSA, complete concordance was found in 90% of cases. A complete mismatch for implant type, size, post length, and glenosphere size occurred in 3%., Conclusion: A high concordance was found between preoperative 3D planning implant selection and the glenoid component inserted at surgery for TSA and RSA. This high concordance may assist with surgical preparedness, implant stocks, and possibly future implant production., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Total shoulder arthroplasty (TSA) is commonly performed for shoulder osteoarthritis (OA). Uncemented metal-backed (MB) glenoid components were introduced in an attempt to avoid glenoid loosening. New Zealand and Australian Joint Registry studies have shown significantly higher revision rates when uncemented MB glenoids are used. We used the New Zealand Joint Registry (NZJR) to compare all-cause revision rates and functional scores for TSA and investigated the trends of glenoid fixation used in New Zealand., Methods: The NZJR was accessed for all primary TSA undertaken for OA from January 2000 to December 2017. Patient demographics were collated. All-cause revision rates were reported as rate per 100 component-years. Analysis was repeated excluding the uncemented SMR L2 glenoid (LimaCorporate), as it was a potential confounder. Kaplan-Meier survival analysis was performed. Oxford Shoulder Scores at both 6 months and 5 years were analyzed., Results: A total of 2613 TSAs were performed for OA during the study period, representing 85.0% of all TSAs in New Zealand. Overall, 62.1% of the patients were female. In addition, 69.6% of glenoids were cemented and 30.4% uncemented. The most common uncemented MB glenoid was SMR 86.6% (LimaCorporate), and cemented was Global (DePuy) 49.8%. The revision rate for TSA with uncemented glenoids was significantly higher at 2.03 compared with cemented at 0.41 per 100 component-years (P < .001). Hazard ratio 5.0 for revision of uncemented glenoids. No significant difference was found in Oxford Scores at 6 months (39.7 vs. 40.3, P = .13) or 5 years (42.1 vs. 42.8, P = .22). The most common mode of failure was glenoid loosening in cemented glenoids (44.4%), and component failure in uncemented (34.8%). Revision for rotator cuff, deep infection, and instability were comparable between groups. When excluding SMR L2, uncemented MB glenoid all-cause revision rates remained significantly higher than cemented (1.42 vs. 0.41 per 100 component-years, P < .001). SMR L1 uncemented MB glenoids had a higher revision rate than the non-SMR uncemented glenoids (1.61 vs. 0.18 per 100 component-years, P = .009). Uncemented glenoid use peaked in New Zealand in 2011 at 46.7% of TSAs but declined to 20.1% in 2017., Conclusions: In the NZJR, primary TSAs undertaken for OA have a significantly higher all-cause revision rate when the glenoid component is uncemented. Uncemented glenoids have a 5.0 times higher revision rate. Excluding SMR L2 glenoids from the analysis, the significantly higher revision rate remained for uncemented glenoids. These data reaffirm that uncemented MB glenoids are associated with higher revision rates., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The purpose of this study was to compare long-term outcomes, complications, and reoperation rates of primary reverse total shoulder arthroplasty (RTSA) performed at a single institution using 2 implant designs: a Grammont medialized prosthesis (medialized [M] group) and a Frankle glenoid-based lateralized prosthesis (glenoid-lateralized [GL] group)., Methods: Between 2004 and 2008, 100 consecutive single-institution primary RTSAs were performed by reconstructive shoulder surgeons who were not design consultants, with the aim of obtaining 10-year follow-up: 56 in the M group and 44 in the GL group. Patients were followed up until death, until revision surgery, or for a minimum of 10 years., Results: Of 100 patients, 87 had more than 2 years' follow-up (mean, 77 months). A subset analysis of 41 patients with an average of 10.2 years' follow-up showed sustained long-term outcomes. RTSA provided clinical improvements without significant differences between the M and GL groups, except for improved active forward elevation in the M group (144° in M group vs. 115° in GL group, P = .002). Reoperation was required in 6 shoulders (10-year cumulative incidence of 3 [5%] in M group vs. 3 [8%] in GL group) for a total of 16 complications (10-year cumulative incidence of 8 [14%] in M group vs. 8 [20%] in GL group). Notching rates were significantly higher in the M group (77% in M group vs. 47% in GL group, P = .013); differences in severe notching (grade 3 or 4) were clinically relevant but did not reach statistical significance (23% in M group vs. 9% in GL group, P = .22)., Conclusion: Primary RTSA using these first 2 prosthesis designs was associated with good outcomes and low reoperation (5%-8%) and complication (14%-20%) rates at 10 years. The M group had higher rates of notching. These results may provide a benchmark for comparison with newer implants, especially considering that these results include the early RTSA implantation learning curve., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: This study presents the preliminary clinical results of arthroscopic glenoid labral lesion repair using all-suture anchors in the treatment of recurrent traumatic anterior shoulder instability., Methods: Seventy patients who underwent arthroscopic shoulder stabilization for traumatic anterior shoulder instability were evaluated in this single center-based retrospective study. Patients with a glenoid defect greater than 20%, off-track engaging Hills-Sachs lesion, multidirectional instability, and generalized ligamentous laxity were excluded. The 62 included patients treated with arthroscopic glenoid labral lesion repair using all-suture anchors were evaluated. The Rowe and Constant scores were used to assess the results., Results: We evaluated 62 patients with a mean age of 26.7 ± 12 years. The mean Rowe and Constant scores were 35 ± 7.2 and 65 ± 6.3, respectively, preoperatively and increased to 93.6 ± 5.3 and 92 ± 4.3, respectively, postoperatively at the mean follow-up of 28.8 months (range, 24-48 months) (P < .001). The redislocation rate was 8.1%. Of the patients, 91.9% had good to excellent clinical scores. Younger age and contact sports were associated with a higher risk of recurrent dislocation (P = .012 and P = .041, respectively). The postoperative functional results were not significantly correlated with the findings concerning the number of dislocations, time until surgery, degree of anterior translation, and number of anchors., Conclusion: The use of all-suture anchors for arthroscopic glenoid labral lesion repair for the treatment of recurrent traumatic anterior shoulder instability yields satisfactory clinical results and is a safe and effective option., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Wear of the polyethylene glenoid component and subsequent particle-induced osteolysis remains one of the most important modes of failure of total shoulder arthroplasty. Vitamin E is added to polyethylene to act as an antioxidant to stabilize free radicals that exist as a byproduct of irradiation used to induce cross-linking. This study was performed to assess the in vitro performance of vitamin E-enhanced polyethylene compared with conventional polyethylene in a shoulder simulator model., Methods: Vitamin E-enhanced, highly cross-linked glenoid components were compared with conventional ultrahigh-molecular-weight polyethylene glenoids, both articulating with a ceramic humeral head component using a shoulder joint simulator over 500,000 cycles. Unaged and artificially aged comparisons were performed. Volumetric wear was assessed by gravimetric measurement, and wear particle analysis was also subsequently performed., Results: Vitamin E-enhanced polyethylene glenoid components were found to have significantly reduced wear rates compared with conventional polyethylene in both unaged (36% reduction) and artificially aged (49% reduction) comparisons. There were no differences detected in wear particle analysis between the 2 groups., Conclusion: Vitamin E-enhanced polyethylene demonstrates improved wear compared with conventional polyethylene in both unaged and artificially aged comparisons and may have clinically relevant benefits., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Augmented glenoid implants to correct bone loss can possibly reconcile current prosthetic failures and improve long-term performance for total shoulder arthroplasty. Biomechanical implant studies have suggested benefits from augmented glenoid components, but limited evidence exists on optimal design., Methods: An integrated kinematic finite element analysis (FEA) model was used to evaluate optimal augmented glenoid design based on biomechanical performance in translation in the anteroposterior plane similar to clinical loading and failure mechanisms with osteoarthritis. Computer-aided design software models of 2 different commercially available augmented glenoid designs-wedge (Equinox; Exactech, Inc., Gainesville, FL, USA) and step (STEPTECH; DePuy Synthes, Warsaw, IN, USA) were created according to precise manufacturer's dimensions of the implants. Using FEA, they were virtually implanted to correct 20° of retroversion. Two glenohumeral radial mismatches, 3.5/4 mm and 10 mm, were evaluated for joint stability and implant fixation simulating high-risk conditions for failure., Results: The wedged and step designs showed similar glenohumeral joint stability under both radial mismatches. Surrogate for micromotion was a combination of distraction, translation, and compression. With similar behavior and measurements for distraction and translation, compression dictated micromotion (wedge: 3.5 mm = 0.18 mm and 10 mm = 0.10 mm; step: 3.5 mm = 0.19 mm and 10 mm = 0.25 mm). Stress levels on the backside of the implant and on the cement mantle were higher using a step design., Discussion: Greater radial mismatch has the advantage of providing higher glenohumeral stability with tradeoffs, such as higher implant and cement mantle stress levels, and micromotion worse when using a step design., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Reverse shoulder arthroplasty (RSA) is typically performed in patients with cuff tear arthropathy. A common type of RSA baseplate has a central peg and 4 peripheral screws inserting into the glenoid surface. Baseplate failure is a significant postoperative complication that reduces prosthetic longevity and usually requires revision surgery. This study evaluated the contribution of mechanical factors on initial baseplate fixation., Materials and Methods: This study simulated glenoid baseplate loading in a RSA. A half-fractional factorial design was used to test 5 factors: bone density (160 or 400 kg/m 3 ), screw length (18 or 36 mm), number of screws (2 or 4), screw angle (neutral or diverging), and central peg length (13.5 or 23.5 mm). Trials were cyclically loaded at a 60° angle with 500 N for 1000 cycles. Micromotion at 4 peripheral screw positions was analyzed using a multifactorial analysis of variance (P < .05)., Results: We found an increase in micromotion with 3 scenarios: (1) lower bone density at all screw positions; (2) shorter central peg length at the inferior, superior and anterior screws; and (3) shorter screw length at the inferior and anterior screws. There were interactions between bone density and screw length at the inferior and anterior screws and between bone density and central peg length at the inferior, superior, and anterior screws., Discussion: Greater bone density, a longer central peg, and longer screws provide improved initial glenoid fixation in an RSA, whereas the number of screws, and the angle of screw insertion do not. These findings may help minimize baseplate failure and revision operations., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The impending burden of revision shoulder arthroplasty has increased interest in outcomes of revision procedures. Painful glenoid arthrosis following hemiarthroplasty is a common cause of reoperation, and conversion to anatomic total shoulder arthroplasty is one option., Methods: We identified patients who underwent revision of painful hemiarthroplasty to total shoulder arthroplasty over a 15-year period in a single tertiary-care health system. Presurgical and operative data were analyzed for 28 patients who met the inclusion and exclusion criteria. Patients were contacted at a minimum of 2 years' follow-up after revision surgery for functional outcome scores, reoperations, and implant survival., Results: The 2- and 5-year implant survival rates were 93% and 86%, respectively. Functional outcomes were obtained from 21 patients with surviving implants. The mean American Shoulder and Elbow Surgeons score, visual analog scale score for pain, and Single Assessment Numerical Evaluation score were 78 ± 20, 2.3 ± 2.6, and 71 ± 24, respectively. The mean Short Form 12 mental and physical scores were 49 ± 10 and 43 ± 9, respectively. Of the patients, 17 (81%) were either satisfied or very satisfied with their outcome. Complications were seen in 10 patients (36%), and 6 patients (21%) required reoperation., Conclusions: Anatomic total shoulder arthroplasty following hemiarthroplasty can achieve successful outcomes and implant survival rates. Given our poor understanding of reverse shoulder arthroplasty longevity, this procedure should remain an option for patients with glenoid arthrosis and an intact rotator cuff., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: This study systematically reviewed the comparative studies in the literature to ascertain whether biceps tenodesis or labral repair results in superior clinical outcomes in the treatment of superior labrum anterior-to-posterior (SLAP) tears., Methods: A systematic search of articles in PubMed, EMBASE and The Cochrane Library databases was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Cohort studies of biceps tenodesis compared with labral repair of SLAP tears were included. Statistical analysis was performed using Review Manager software (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark). A P value of <.05 was considered to be statistically significant., Results: Included were 5 studies with 234 patients. Biceps tenodesis resulted in improved rates of patient satisfaction (95.6% vs. 76.2%, P = .01) and rate of return to sport (81.3% vs, 64.3%, P = .02), compared with SLAP repair. Although the difference in reoperation rates was not statistically significant, there was a trend toward higher reoperation rates in patients treated with SLAP repair (14.2% vs 6.5%, P = .09). In addition, there was no difference in complication rates or functional outcomes., Conclusion: Our study found that biceps tenodesis resulted in higher rates of patient satisfaction and return to sport in the studies published in the literature and that biceps tenodesis and SLAP repair resulted in similar functional outcome scores., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Glenoid loosening is a common mode of failure after total shoulder arthroplasty (TSA). Newer cementless glenoid components have been introduced to promote biological fixation with the aim to decrease glenoid loosening. Limited data are available comparing revision rates between cemented and cementless glenoid fixation in TSA. The study aim was to compare the revision rates of cemented and cementless design glenoid components used in conventional TSA performed for the diagnosis of osteoarthritis. The secondary aim was to compare various subclasses of glenoid components., Methods: Data were obtained between April 16, 2004, and December 31, 2016, from the Australian Orthopaedic Association National Joint Replacement Registry. Within the study period, 10,805 primary conventional TSAs were identified. The analysis was undertaken for the diagnosis of osteoarthritis, which represented 95.8% of all conventional TSA procedures., Results: At 5 years, in patients with primary TSA procedures, those with cemented glenoids had a lower revision rate than those with cementless glenoids: 3.7% versus 17.9% (hazard ratio for entire period, 4.77). The most common revision diagnosis for primary conventional TSA with cementless glenoid fixation was rotator cuff insufficiency (4.4% for cementless vs 0.4% for cemented), instability and/or dislocation (3.8% for cementless vs 0.8% for cemented), and loosening and/or lysis (1.1% for cementless vs 1.1% for cemented)., Conclusions: Cementless glenoid components in conventional TSA had a significantly higher revision rate than cemented glenoid components. The loosening rates between cemented and cementless glenoid components were similar. Glenoid design and fixation are important considerations when selecting a prosthesis for TSA., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Detection of postoperative component position and implant shift following total shoulder arthroplasty (TSA) can be challenging using routine imaging. The purpose of this study was to evaluate glenoid component position over time using 3-dimensional computed tomography (CT) analysis with minimum 2-year follow-up., Methods: Twenty patients underwent primary TSA with sequential CT scanning of the shoulder: a preoperative study, an immediate postoperative study within 2 weeks of surgery, and a postoperative study performed at minimum 2-year follow-up (CT3). Postoperative glenoid component position and central peg osteolysis were assessed across the immediate postoperative CT scan and CT3. Glenoids with evidence of component shift and/or grade 1 central peg osteolysis on CT3 were considered at risk of loosening., Results: Of the patients, 7 (35%) showed evidence of glenoid components at risk of loosening on CT3, 6 with component shift (3 with increased inclination alone, 1 with increased retroversion alone, and 2 with both increased inclination and retroversion). Significantly more patients with glenoid component shift had grade 1 central peg osteolysis on CT3 compared with those without shift (83% vs 7%, P = .002). One clinical failure occurred, with the patient undergoing revision to reverse TSA for rotator cuff deficiency., Conclusions: Three-dimensional CT imaging analysis following TSA identified changes in glenoid component position over time, with inclination being the most common direction of shift and grade 1 central peg osteolysis commonly associated with shift. These findings raise concern for glenoids at risk of loosening, but further follow-up is needed to determine the long-term clinical impact of these findings., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Hypothesis: The objective of this study was to determine the biomechanical function of the rotator cable when a partial-thickness (>50%) tear is present. We compared intact specimens with partial tears of the anterior cable followed by partial anterior and posterior tears in regard to glenohumeral kinematics and translation. The hypothesis was that partial-thickness tears will lead to abnormal glenohumeral biomechanics, including glenohumeral translation and path of glenohumeral articulation., Methods: Five fresh frozen cadaveric shoulders with intact labrum, rotator cuff, and humerus were tested using a custom shoulder testing system in the scapular plane. Glenohumeral translation was measured after applying an anterior load of 30 N at different angles of external rotation. The path of glenohumeral articulation was measured by calculating the humeral head center with respect to the glenoid articular surface at 30°, 60°, 90°, and 120° of external rotation., Results: With an anterior force of 30 N, there was a significant increase in anterior and total translation at 30° of external rotation after the anterior cable was cut (P < .05). When the tear was extended to the posterior cable, there was a significant increase in anterior, inferior, and total translation at 30° and 120° of external rotation (P < .05). With respect to the path of glenohumeral articulation , the humeral head apex was shifted superiorly at 90° and 120° of external rotation after the posterior cable was cut (P < .05)., Conclusion: Partial-thickness articular-sided rotator cuff tears with a thickness >50% involving the rotator cable increased glenohumeral translation and changed kinematics in our cadaveric biomechanical model., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Treatment of young, active patients with symptomatic glenohumeral osteoarthritis, excessive glenoid retroversion, and static posterior humeral subluxation is challenging. Correction of glenoid retroversion may lead to centric loading and perhaps recenter the humeral head. We describe the functional and radiologic outcomes after corrective osteotomy of the glenoid in this population of patients., Materials and Methods: In this retrospective study, we included 10 shoulders (8 patients) that were observed for a mean of 33.4 months (range, 24-52 months) after corrective osteotomy of the glenoid. The mean age at surgery was 41.5 years (range, 24-51 years). On standardized axial images, glenoid retroversion and posterior static humeral subluxation were measured preoperatively and postoperatively and at the final follow-up. At final follow-up, anterior and posterior axial radiographs were performed to determine humeral head position in different arm positions. Clinical follow-up included Constant-Murley score, subjective shoulder value, and patient satisfaction., Results: The mean Constant-Murley score improved significantly from 45.1 points (range, 24-71) to 64.1 points (range, 44-92; P < .001). The average degree of anterior flexion improved significantly from 117° (range, 50°-160°) to 143° (range, 110°-180°; P = .006). The mean glenoid retroversion changed from 16° (range, 11°-31°) preoperatively to 5° (range, 13° anteversion-16° retroversion; P = .003) at the final follow-up. The mean posterior static subluxation of the humeral head changed from 5 mm (range, 0-10 mm) preoperatively to 6 mm (range, 0-14 mm; P = .259) at the final follow-up., Conclusions: This study shows that posterior open wedge osteotomy of the glenoid neck provides excellent correction of glenoid retroversion., (Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The chondral print (CP) sign is a chondral change on the humeral head underneath the long head of the biceps (LHB) tendon. Several suggested causative links have been described, but the pathologic mechanism remains unclear., Methods: We designed this prospective cohort association study of 102 consecutive shoulder arthroscopies to investigate proposed associations of CP with LHB, rotator cuff, labral pathology, and other chondral lesions. Data collection was by a specifically designed pro forma, and statistical analysis was performed., Results: We identified 24 patients (23.5%) with the CP sign. Patients were a mean age of 58 years. Shoulders with positive CP sign had associated pathologies: 16 superior labral anteroposterior (SLAP) tears, 4 LHB instabilities, and 11 other LHB lesions. We also recorded other chondral lesions, 10 humeral head and 12 on the glenoid surface. The overall arthroscopic appearance of CP signs could be classified into 3 different types. Statistical analysis revealed that the CP sign is not statistically associated with LHB instability, any other LHB pathologies, rotator cuff tears, or instability. The CP sign was statistically positively associated with SLAP lesions (but only if type 1 were included). There was a weak association of CP sign with age and a positive association of SLAP lesions with other (non-CP) humeral chondral lesions., Conclusions: Our prospective association study cannot determine the cause of the CP sign. It does not seem to be a reliable sign of LHB instability or of other LHB pathology. There is an association with age and degenerative SLAP lesions., (Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.)

Background: Evidence suggests a relationship between glenoid retroversion and posterior instability, but no literature exists comparing glenoid version referencing the scapular body versus the endosteal vault. This study evaluated glenoid version and its relationship to unidirectional instability and labral tears., Methods: Glenoid version in patients with unidirectional instability or labral tears was measured with magnetic resonance imaging by either the Friedman method or the Poon and Ting method. Analyses of variance followed by independent t tests were used to compare 3 groups: anterior instability or labral tears (anterior pathology group, n = 33); posterior instability or labral tears (posterior pathology group, n = 34); and stable controls (n = 30). The referencing error for 2-dimensional axial images was evaluated for variance by imaging facility. Interobserver and intraobserver reliability scores were calculated., Results: With the Friedman method, the posterior pathology group (-9°) was more retroverted than the control group (-4°) (P = .0005) and the anterior pathology group (-5°) (P = .0104) but there was no difference between the control group and anterior pathology group (P = .38). The referencing error in the sagittal plane averaged 23° and varied by facility (P = .0365). The coronal-plane error averaged 1° and did not vary by facility (P = .7180). Intraclass correlation coefficient scores showed good to excellent intrarater and inter-rater reliability., Conclusion: The posterior pathology group had 5° more retroversion than controls using the Friedman method. Glenoid version using the Poon and Ting method or the Friedman method did not predict anterior instability or labral tears. Axial magnetic resonance images were constructed with a referencing error in the sagittal plane that varied by magnetic resonance imaging facility and has implications for improving 2-dimensional axial imaging protocols., (Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The "rocking horse" phenomenon is considered the main cause of glenoid component loosening by eccentric loading of the glenoid rim. This study aimed to investigate the influence of increasing glenohumeral implant mismatch on bone-implant interface micromotion in a cemented all-polyethylene pegged glenoid biomechanical model., Methods: Five glenoid sizes, 40 mm, 44 mm, 48 mm, 52 mm, and 56 mm, representing +2 mm, +6 mm, +10 mm, +14 mm, and +18 mm glenohumeral mismatch, respectively, were cyclically loaded according to ASTM Standard F2028-08 at a constant frequency of 2 Hz to a size-dependent humeral head subluxation translation. Additional glenoid components were cyclically loaded to their subluxation translations at a constant humeral head rate of 4.4 mm/s. Component micromotion was characterized as compression, distraction, and superior-inferior translation measured by differential variable reluctance transducers., Results: During constant frequency tests, 52-mm and 56-mm glenoids were unable to complete cyclic testing because of catastrophic failure of the glenoid-implant interface and permanent glenoid deformation, probably due to increasing severity of testing parameters. When tested at a constant humeral head speed, 48-mm, 52-mm, and 56-mm glenoids had significantly increased glenoid distraction and glenoid translation at cycle 50,000 compared with cycle 1. Distraction and translation measurements for 52-mm and 56-mm glenoids were significantly greater compared with 40-mm, 44-mm, and 48-mm glenoids at 50,000 cycles., Conclusions: In a biomechanical model, optimal glenohumeral mismatch in cemented pegged glenoid implants is multifactorial and has not been definitively established. However, our data suggest that a radial mismatch of less than +10 mm may decrease the risk of glenoid micromotion., (Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The purpose of this study was to examine the mid- to long-term functional outcome and implant survival of total shoulder arthroplasty (TSA) in adults aged 55 years or younger with primary glenohumeral arthritis. The hypothesis was that TSA would lead to improvement in functional outcome but that implant survival would decline between 5 years and 10 years postoperatively., Materials and Methods: Between 1992 and 2004, 52 TSAs were implanted in 8 centers for primary glenohumeral arthritis in patients aged 55 years or younger. Minimum follow-up of 5 years was available in 50 patients at a mean of 115.5 months postoperatively. Kaplan-Meier survivorship analysis was performed, and clinical outcome was assessed., Results: After TSA, adjusted Constant scores improved from 37.0% to 73.4% and forward flexion improved from 97° to 128° (P < .001). The adjusted Constant score was 80.0 in patients free of revision of the glenoid compared with 43.6 in the group requiring revision of the glenoid (P < .001). Survivorship of the glenoid component with revision surgery for glenoid loosening as the endpoint was 98% (95% confidence interval, 89.4%-100%) at 5 years and 62.5% (95% confidence interval, 40.6%-81.2%) at 10 years. Factors associated with survival of the glenoid included anatomic humeral component positioning and a compaction glenoid preparation technique., Conclusions: At 5 years' follow-up, TSA leads to improvement in functional outcome and a satisfactory implant survival rate of 98% in young adults with primary glenohumeral arthritis. However, the 10-year survival rate of TSA was only 62.5% in patients aged 55 years or younger at the time of surgery., (Copyright © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Background: Rugby is a collision sport with a high risk of shoulder injury. Although traumatic anterior shoulder instability is common, the long-term effects of rugby and joint instability on the shoulder have not been described; thus, this study assessed the effects of rugby itself, and joint instability, on the glenoid cavity., Materials and Methods: Both sides of the shoulders from 25 rugby players and 17 control patients with unilateral shoulder instability were prospectively evaluated by means of computed tomography osteoabsorptiometry, which represents the distribution of mineralization in subchondral bone plate (DMSB) as a marker of the long-term loading history of a joint. For the quantitative analysis, intergroup differences of maximum Hounsfield unit (HU) values in 7 areas on the glenoid were assessed in the uninjured intact shoulder to characterize the influence of rugby. Side-to-side differences of the HUs in each area were assessed in each participant to characterize the effects of shoulder instability. For the qualitative analysis, associations between the patterns of each DMSB and each group were assessed by means of correspondence analysis., Results: All examined areas on the glenoid had a significantly higher HUs in rugby players. Shoulder instability affected the HUs in both groups. A qualitative analysis demonstrated that the maximum HU tended to be shifted more inferiorly in rugby players and in the unstable shoulders., Conclusions: Rugby affects the shoulder joint, regardless of any history of instability, suggesting that "rugby shoulder" tends to involve degenerative changes, such as osteoarthritis or labral tears., (Copyright © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)