BACKGROUND. Stability of the glenoid component is essential to ensure successful long-term outcomes following Total shoulder arthroplasty (TSA), and may be improved through better glenoid component design. As such, this study assessed identical all-polyethylene glenoid components stability, having various fixation types, using component micromotion under simulated joint loading in an osteoarthritic patient cohort. METHODS. Five all-polyethylene glenoid component designs were compared (Keel, Central-Finned 4-Peg, Peripheral 4-Peg, Cross-Keel, and Inverted-Y). A cement mantle surrounded each fixation type, except the Central-Finned 4-Peg which was surrounded by bone. The humeral component had a non-conforming radius of curvature. Scapular models of six type A1 osteoarthritic male patients (mean: 61 years old, range: 48 to 76 years old) were assigned heterogeneous bone properties based on CT intensity. Each of the 30 scapula models were truncated and fully constrained on the medial scapular border. The bone/cement interface was fully bonded, and the fixation feature/cement interface was frictionally constrained. A ‘worst case’ load magnitude of 125% BW of a 50th percentile male was used. A purely compressive load was applied to the center of the glenoid component, followed by superior, superior-posterior, posterior, inferior-posterior, and inferior loads. Stability of the glenoid component based solely on the fixation type was determined using the mean and maximum normal (liftoff) and tangential (sliding) micromotion in six regions of the glenoid component. RESULTS. The greatest mean normal micromotion occurred for the Inverted-Y (90 ± 36 μm) in the anterior- inferior region of the component under a posterior-superior directed load. The mean normal micromotions were significantly less for the same region and loading direction in the Peripheral 4-peg (48 ± 16 μm; p < .001) and Central-Finned 4-Peg (35 ± 13 μm; p < .001), but not significantly different for the Keel (78 ± 37 μm; p = .029), or Cross-Keel (82 ± 32 μm; p = .143). The same region and loading direction produced the maximum normal micromotion in the Inverted-Y (109 ± 43 μm), which was significantly greater than the other four components (Peripheral 4-peg, 61 ± 25 μm; p < .001, Keel, 89 ± 36 μm; p < .001, Central-Finned 4-Peg, 47 ± 19 μm; p < .001, and Cross-Keel, 92 ± 37 μm; p = .002). The greatest mean tangential micromotion occurred for the Cross-Keel (100 ± 36 μm) in the posterior-superior region of the glenoid component under a posterior-superior directed load. The mean tangential micromotions for all other components were significantly less (p < .001) for the same region and loading direction (Peripheral 4-peg, 73 ± 19 μm, Keel, 73 ± 22 μm, Central-Finned 4-Peg, 73 ± 26 μm, and Inverted-Y, 83 ± 24 μm). The same region and loading direction for the maximum tangential micromotion was also in the Cross-Keel (146 ± 46 μm), which was significantly greater (p < .001) from the other four components (Peripheral 4-peg, 111 ± 21 μm, Keel, 115 ± 34 μm, Central-Finned 4-Peg, 111 ± 39 μm, and Inverted-Y, 117 ± 34 μm). DISCUSSION. This study addressed the contribution of all-polyethylene glenoid component fixation types on component stability under simulated joint loading. Pegged components were significantly more stable than keeled components. An inverse relationship between normal and tangential micromotion was observed, with the greatest sliding (tangential micromotion) occurring in the direction of the applied load, and the greatest liftoff (normal micromotion) occurring opposite the applied load. This likely occurs due to polyethylene deformation of both the fixation features and the component as a whole

Total shoulder arthroplasty (TSA) is an excellent surgical solution for patients with shoulder arthritis, providing good to excellent results in the vast majority of patients. Complications are rare, however, when they occur, can be devastating for both the patient and surgeon. An increasingly recognised complication of TSA is glenoid component failure. In a recent review of nearly 4000 shoulder arthroplasties, symptomatic glenoid component loosening occurs at a rate of 1.2% per year, while asymptomatic radiolucent lines occur at a rate of 7.3% per year. In addition, keeled glenoid components have been found to have an increased incidence of radiolucent lines compared to pegged glenoid components at both short and longer-term follow-up. Further, pegged glenoid components are associated with a lower risk of revision arthroplasty compared to keeled glenoid components. In a separate study of approximately 4600 shoulder arthroplasties, metal-backed glenoid components were found to have significantly lower rates of radiolucent lines, radiographic loosening, and component failure compared to all-polyethylene glenoid components. Despite these findings, however, metal-backed components are significantly more likely to require revision surgery (3:1) compared to all-polyethylene components. For the failed TSA due to glenoid component failure, revision with glenoid reimplantation may be considered, but is associated with a high rate of recurrent glenoid loosening. Alternatively, revision to a reverse shoulder arthroplasty, is feasible, but is technically demanding with high complication and reoperation rates. This paper will discuss the etiology, work-up, and treatment of patients with glenoid component failure following TSA

BACKGROUND. Abnormal glenoid version positioning has been recognized as a cause of glenoid component failure caused by the rocking horse phenomenon. In contrast, the importance of the glenoid inclination has not been investigated. MATERIALS AND METHODS. The computed tomography scans of 152 healthy shoulders were evaluated. A virtual glenoid component was positioned in 2 different planes: the maximum circular plane (MCP) and the inferior circle plane (ICP). The MCP was defined by the best fitting circle of the most superior point of the glenoid and 2 points at the lower glenoid rim. The ICP was defined by the best fitting circle on the rim of the inferior quadrants. The inclination of both planes was measured as the intersection with the scapular plane. We defined the force vector of the rotator force couple and calculated the magnitude of the shear force vector on a virtual glenoid component in both planes during glenohumeral abduction. RESULTS. The inclination of the component positioned in the MCP averaged 95° (range, 84°–108°) and for the ICP averaged 111° (range, 94°–126°). A significant reduction in shear forces was calculated for the glenoid component in the ICP vs the MCP: 98% reduction in 60° of abduction to 49% reduction in 90° of abduction. CONCLUSION. Shear forces are significantly higher when the glenoid component is positioned in the MCP compared with the ICP, and this is more pronounced in early abduction. Positioning the glenoid component in the inferior circle might reduce the risk of a rocking horse phenomenon. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved

Aims. We evaluated clinical and radiographic outcomes of total shoulder arthroplasty (TSA) using the second-generation Trabecular Metal (TM) Glenoid component. The first generation component was withdrawn in 2005 after a series of failures were reported. Between 2009 and 2012, 40 consecutive patients with unilateral TSA using the second-generation component were enrolled in this clinical study. The mean age of the patients was 63.8 years (40 to 75) and the mean follow-up was 38 months (24 to 42). Methods. Patients were evaluated using the Constant score (CS), the American Shoulder and Elbow Surgeons (ASES) score and routine radiographs. Results. Significant differences were found between the pre- and post-operative CS (p = 0.003), ASES (p = 0.009) scores and CS subscores of pain (p < 0.001), strength (p < 0.001) and mobility items (p < 0.05). No glenoid or humeral components migrated. Posterior thinning of the keel and slight wear at the polyethylene-TM interface was observed in one patient but was asymptomatic. Radiolucent lines were found around three humeral (< 1.5 mm) and two glenoid components (< 1 mm) and all were asymptomatic. Discussion. TSA with the second-generation TM Glenoid component results in satisfactory to excellent clinical performance, function, and subjective satisfaction at a mean follow-up of about three years. Radiographic changes were few and did not affect the outcome. Take home message: This paper highlights that the second generation Trabecular Metal Glenoid has better outcomes than those reported with the first-generation component.  . Cite this article: Bone Joint J 2016;98-B:75–80

The incidence of loosening of a cemented glenoid component in total shoulder arthroplasty, detected by means of radiolucent lines or positional shift of the component on true antero-posterior radiographs, has been reported to be between 0% to 44%. These numbers depend on the criteria used for loosening and on the length of follow-up. Radiolucent lines are however difficult to detect and to interpret, because of the mobility of the shoulder girdle and the obliquity of the glenoid, which hinder standardisation of radiographs. After review of radiolucencies around cemented glenoid components with a mean follow-up of 5. 3 years in 48 patients we found progressive changes to be present predominantly at the inferior pole of the component. This may hold a clue for the mechanism behind loosening of this implant. Since loosening is generally defined as a complete radiolucent line around the glenoid component and is difficult to assess as a result of the oblique orientation of the glenoid, an underestimation of the loosening rate using radiological data was suspected. Therefore a pilot study using Roentgen Stereophotogrammatric Analysis (RSA) was performed. In five patients an additional analysis of glenoid component loosening using digital Roentgen Stereophotogrammetric Analysis (RSA) was performed. The relative motion of the glenoid component with respect to the scapula was assessed and the length of this translation vector was used to represent migration. Loosening was defined as a migration of the component, exceeding the pessimistic estimate of the accuracy of RSA 0. 3 mm for this study. After three years of follow-up, three out of five glenoid components had loosened (1. 2 – 5. 5 mm migration). In only one patient with a gross loosened glenoid, the radiological signs were consistent with the RSA findings. It was concluded that when traditional radiographs are used for assessment of early loosening, the loosening rate is underestimated. We recommend that RSA be used for this

Total shoulder replacement is a successful procedure for degenerative or some inflammatory diseases of the shoulder. However, fixation of the glenoid seems to be the main weakness with a high rate of loosening. The results using all-polyethylene components have been better than those using metal-backed components. We describe our experience with 35 consecutive total shoulder replacements using a new metal-backed glenoid component with a mean follow-up of 75.4 months (48 to 154). Our implant differs from others because of its mechanism of fixation. It has a convex metal-backed bone interface and the main stabilising factor is a large hollow central peg. The patients were evaulated with standard radiographs and with the Constant Score, the Simple Shoulder Test and a visual analogue scale. All the scores improved and there was no loosening, no polyethylene-glenoid disassembly and no other implant-related complications. We conclude that a metal-backed glenoid component is a good option in total shoulder replacement with no worse results than of those using a cemented all-polyethylene prosthesis

Aims. To report early (two-year) postoperative findings from a randomized controlled trial (RCT) investigating disease-specific quality of life (QOL), clinical, patient-reported, and radiological outcomes in patients undergoing a total shoulder arthroplasty (TSA) with a second-generation uncemented trabecular metal (TM) glenoid versus a cemented polyethylene glenoid (POLY) component. Methods. Five fellowship-trained surgeons from three centres participated. Patients aged between 18 and 79 years with a primary diagnosis of glenohumeral osteoarthritis were screened for eligibility. Patients were randomized intraoperatively to either a TM or POLY glenoid component. Study intervals were: baseline, six weeks, six-, 12-, and 24 months postoperatively. The primary outcome was the Western Ontario Osteoarthritis Shoulder QOL score. Radiological images were reviewed for metal debris. Mixed effects repeated measures analysis of variance for within and between group comparisons were performed. Results. A total of 93 patients were randomized (46 TM; 47 POLY). No significant or clinically important differences were found with patient-reported outcomes at 24-month follow-up. Regarding the glenoid components, there were no complications or revision surgeries in either group. Grade 1 metal debris was observed in three (6.5%) patients with TM glenoids at 24 months but outcomes were not negatively impacted. Conclusion. Early results from this RCT showed no differences in disease-specific QOL, radiographs, complication rates, or shoulder function between uncemented second-generation TM and cemented POLY glenoids at 24 months postoperatively. Revision surgeries and reoperations were reported in both groups, but none attributed to glenoid implant failure. At 24 months postoperatively, Grade 1 metal debris was found in 6.5% of patients with a TM glenoid but did not negatively influence patient-reported outcomes. Longer-term follow-up is needed and is underway. Cite this article: Bone Jt Open 2021;2(9):728–736

Introduction The aim of this study was to investigate the potential of impaction bone grafting for the restoration of glenoid bone stock in revision shoulder arthroplasty. Methods There was significant osteolysis around the glenoid component in four rheumatoid patients who underwent revision shoulder arthroplasty using this technique. The criteria was a contained or containable defect. Femoral head allograft and iliac crest autograft harvested at the time of revision were used. Pre and post-operative radiographs, tomograms and fluoroscopic views aided in bone-stock analysis. Images were analysed for osteolysis, graft survival, incorporation and component loosening. Patients were followed using Constant-Murley scoring pre-operatively, and at a minimum of 12 months. The average patient age was 56 years (range 42 to 76), with three females and one male patient. Results Glenoid component survivorship pre-revision averaged 9.5 years (range 8 to 12). The pre-operative Constant-Murley average was 11 (range 4 to 20) versus 64 post-operatively, a significant improvement over an average follow-up of 19.5 months (range 12 to 40). Radiological assessment demonstrated all grafts had incorporated with minimal subsidence and no radio-lucency at the graft-bone interface. Two of the glenoid components demonstrated static lucency at the component-graft interface, but no component movement on serial x-rays. In both patients the significant improvement in functional was maintained. Conclusions To our knowledge this technique has not been described in glenoid component revision. It successfully provided bone for glenoid component insertion. This would not have been possible using standard techniques. The early results for this technique are encouraging and justify the continued application and follow-up of glenoid impaction grafting

The incidence of total shoulder arthroplasty continues to increase. The most common reason for failure of a total shoulder arthroplasty is the glenoid component. Two styles of cemented all-polyethylene components are commonly implanted. These two styles are pegged glenoid and keel glenoid components. Data regarding the superiority of the styles has focused on radiolucent lines, complete loosening and need for revision procedures. Several retrospective and randomised controlled trials have been published to examine these endpoints. There is a trend in the literature to demonstrate decreased rates of radiolucent lines with pegged glenoid components, but a recent systematic review of available trials did not demonstrate a significant difference in the rate of radiolucent lines between the two styles. A slightly increased rate of revision was noted for the keel components. Overall pegged and keel glenoids both still represent good options in total shoulder arthroplasty

In a prospective study between 2000 and 2005, 22 patients with primary osteoarthritis of the shoulder had a total shoulder arthroplasty with a standard five-pegged glenoid component, 12 with non-offset humeral head and ten with offset humeral head components. Over a period of 24 months the relative movement of the glenoid component with respect to the scapula was measured using radiostereometric analysis. Nine glenoids needed reaming for erosion. There was a significant increase in rotation about all three axes with time (p < 0.001), the largest occurring about the longitudinal axis (anteversion-retroversion), with mean values of 3.8° and 1.9° for the non-offset and offset humeral head eroded subgroups, respectively. There was also a significant difference in rotation about the anteversion-retroversion axis (p = 0.01) and the varus-valgus (p < 0.001) z-axis between the two groups. The offset humeral head group reached a plateau at early follow-up with rotation about the z-axis, whereas the mean of the non-offset humeral head group at 24 months was three times greater than that of the offset group accounting for the highly significant difference between them

Aims. Radiostereometric analysis (RSA) allows an extremely accurate measurement of early micromotion of components following arthroplasty. . Patients and Methods. In this study, RSA was used to measure the migration of 11 partially cemented fluted pegged glenoid components in patients with osteoarthritis who underwent total shoulder arthroplasty using an improved surgical technique (seven men, four women, mean age 68). Patients were evaluated clinically using the American Shoulder and Elbow Surgeons (ASES) and Constant-Murley scores and by CT scans two years post-operatively. . Results. There were two patterns of migration, the first showing little, if any, migration and the second showing rotation by > 6° as early as three months post-operatively. At two years, these two groups could be confirmed on CT scans, one with osseointegration around the central peg, and the second with cystic changes. Patients with osteolysis around the central peg were those with early migration and those with osseointegration had minimal early migration. Both groups,however,had similar clinical results. . Conclusion. Rapid early migration associated with focal lucency and absence of osseointegration was observed in three of 11 glenoid components, suggesting that lack of initial stability leads to early movement and failure of osseointegration. Cite this article: Bone Joint J 2017;99-B:674–9

Background. Use of a baseplate with a smaller diameter in reverse shoulder arthroplasty has been recommended, especially in patients with a small glenoid or insufficient bony stock due to severe glenoid wear. However, effect of a smaller baseplate on stability of the glenoid component has not been evaluated. The purpose of this study was to determine whether a smaller baseplate (25 mm) is beneficial to the initial primary stability of the glenoid component compared to that with a baseplate of a commonly used size (29 mm) by finite element analysis. Methods. Computed tomography (CT) scans of fourteen scapulae were acquired from cadavers with no apparent deformity or degenerative change. Glenoid diameter corresponding to the diameter of the inferior circle of glenoid was measured using a caliper and classified into the small and large glenoid groups based on 25mm diameter. CT slices were used to construct 3-dimensional models with Mimics (Materialise, Leuven, Belgium). A corresponding 3D Tornier Aequalis® Reversed Shoulder prosthesis model was generated by laser scanning (Rexcan 3D Laser Scanner, Solutionix, Seoul, Korea). Glenoid components with 25mm and 28mm diameter of the baseplate were implanted into the scapular of small and large glenoid group, respectively. Finite element models were constructed using Hypermesh 11.0 (Altair Engineering, Troy, MI, USA) and a reverse engineering program (Rapidform 3D Systems, Inc., Rock Hill, SC, USA). Abaqus 6.10 (Dassault Systemes, Waltham, MA) was used to simulate 30. o. , 60. o. , and 90. o. glenohumeral abduction in the scapular plane. Single axial loads of 686N (1 BW) at angles of 30. o. , 60. o. , and 90. o. abduction were applied to the center of the glenosphere parallel to the long axis of the humeral stem. Relative micromotion at the middle and inferior thirds bone–glenoid component interface, and distribution of bone stress under the glenoid component and around the screws were analyzed. Wilcoxon's rank-sum test was used for statistical comparison and p < 0.05 was considered as a minimum level of statistical significance. Results. In small glenoid group, micromotion at the middle and inferior thirds of the glenoid-glenosphere interface at angles of 30. o. and 60. o. abduction were significantly greater in the 29mm baseplate than in the 25mm baseplate. There was no significant difference in micromotion at angle of 90. o. abduction between 25mm and 29mm baseplate. In large glenoid group, there was no statistically significant difference in micromotion between 25mm and 29mm baseplate at all angles of abduction. In small glenoid group, maximum bone stress was measured at the point of cortical engagement of the inferior screw and was statistically greater in the 29mm baseplate than in the 25mm baseplate. In large glenoid group, there was no statistically significant difference of maximum bone stress around the inferior screw between 25mm and 29mm baseplates. Conclusions. Use of a baseplate with a smaller diameter (25 mm) in reverse shoulder arthroplasty is suitable for improving the primary stability of the glenoid component, especially in small glenoid

Glenoid component loosening is a concern in long term outcome of total shoulder arthroplasty. Unfortunately revision of glenoid loosening remains very challenging regarding bone reconstruction and reimplantation of a glenoid component. A new design metal-back component (Arrow™) seems to get the procedure easier and lead to higly best clinical and radiological results than prior technics. It is a retrospective study of 34 patients operated on for isolated aseptic glenoid component loosening between 1997 and 2007. Glenoid bone loss based on a new classification was rated in 5 degrees. All patients were reviewed at a mean follow up of 34 months (from 12 to 89). Pre and post operatively Constant score and SST have been evaluated. Fluoroscopic views and CT scan have been performed for radiologic assesment. Mean delay for revision surgery was 58 months (from 28 to 134 months). 16 patients underwent only bone graft reconstruction. 18 patients underwent both bone reconstruction and glenoid implant reimplantation. Autolog bone graft (iliac crest) was used in 19 cases, allograft bone in 5 cases, and both autolog and dried bone substitutes in 10 cases. The glenoid component was an uncemented metal-backed in 11 cases, and a polyethylene cemented in 2 cases. The new metal-backed bone ingrowth component is composed with a keel and a winglet securing bone graft fixation and implant stability. For the all cohort Constant score improves of 21 points (from 35 to 56). Gain of pain and active motion is statiscally significative (p< 0.005).Patients who underwent reimplantation of a new glenoid component had a higher clinical result (Constant score: 66) than those who underwent only a bone graft reconstruction (Constant score: 52) in term of pain and active forward elevation as well (p< 0.001). At maximum follow up (32 months) no radiolucent lines or loosening of the new glenoid component was noted. Patients who underwent only bone reconstruction showed a mild glenoid erosion due to subsidence and resorption of cancellous auto or allograft bone. Revision of glenoid component depends on the glenoid bone stock specially about posterior defect. The use of cortical autolog bone graft and new metalback component allows better glenoid reconstruction, secure the stabiliy of the new gle and yields to goods clinical results restoring painless shoulder and function. Reimplantation of a glenoid component becomes an adequate procedure for total shoulder arthroplasty revision

Glenoid replacement is technically challenging. Removal of a cemented glenoid component often results in a large osseous defect which makes the immediate introduction of a revision prosthesis almost impossible. We describe a two-stage revision procedure using a reversed shoulder prosthesis. Freeze-dried allograft with platelet-derived growth factor was used to fill the glenoid defect. Radiological incorporation of the allograft was seen and its consistency allowed the placement of a screwed glenoid component. There were no signs of new mature bone formation on histological examination. The addition of platelet-derived growth factor to the allograft seems to contribute to an increase in incorporation and hardness, but does not promote the growth of new bone

The incidence of loosening of a cemented glenoid componentin total shoulder arthroplasty, detected by means of radiolucent lines or positional shift of the component on true anteroposterior radiographs, has been reported to be between 0% and 44%. Radiolucent lines are, however, difficult to detect and to interpret because of the mobility of the shoulder girdle and the obliquity of the glenoid which hinder standardisation of radiographs. We examined radiolucencies around cemented glenoid components in 48 patients, with a mean follow-up of 5.3 years, and found progressive changes to be present predominantly at the inferior pole of the component. This may hold a clue for the mechanism of loosening of this implant. In five patients we performed an additional analysis of loosening of the glenoid component using digital roentgen stereophotogrammetric analysis (RSA). After three years, three of the five implants had loosened (migration 1.2 to 5.5 mm). In only one, with gross loosening, were the radiological signs consistent with the RSA findings. When traditional radiographs are used for assessment, the rate of early loosening is underestimated. We recommend that RSA be used for this

Glenoid baseplate positioning for reverse total shoulder replacements (rTSR) is key for stability and longevity. 3D planning and image-derived instrumentation (IDI) are techniques for improving implant placement accuracy. This is a single-blinded randomised controlled trial comparing 3D planning with IDI jigs versus 3D planning with conventional instrumentation. Eligible patients were enrolled and had 3D pre-operative planning. They were randomised to either IDI or conventional instrumentation; then underwent their rTSR. 6 weeks post operatively, a CT scan was performed and blinded assessors measured the accuracy of glenoid baseplate position relative to the pre-operative plan. 47 patients were included: 24 with IDI and 23 with conventional instrumentation. The IDI group were more likely to have a guidewire placement within 2mm of the preoperative plan in the superior/inferior plane when compared to the conventional group (p=0.01). The IDI group had a smaller degree of error when the native glenoid retroversion was >10° (p=0.047) when compared to the conventional group. All other parameters (inclination, anterior/posterior plane, glenoids with retroversion <10°) showed no significant difference between the two groups. Both IDI and conventional methods for rTSA placement are very accurate. However, IDI is more accurate for complex glenoid morphology and placement in the superior-inferior plane. Clinically, these two parameters are important and may prevent long term complications of scapular notching or glenoid baseplate loosening. Image-derived instrumentation (IDI) is significantly more accurate in glenoid component placement in the superior/inferior plane compared to conventional instrumentation when using 3D pre-operative planning. Additionally, in complex glenoid morphologies where the native retroversion is >10°, IDI has improved accuracy in glenoid placement compared to conventional instrumentation. IDI is an accurate method for glenoid guidewire and component placement in rTSA

We report the long-term clinical and radiological outcomes of the Aequalis total shoulder replacement with a cemented all-polyethylene flat-back keeled glenoid component implanted for primary osteoarthritis between 1991 and 2003 in nine European centres. A total of 226 shoulders in 210 patients were retrospectively reviewed at a mean of 122.7 months (61 to 219) or at revision. Clinical outcome was assessed using the Constant score, patient satisfaction score and range of movement. Kaplan-Meier survivorship analysis was performed with glenoid revision for loosening and radiological glenoid loosening (. sd. ) as endpoints. The Constant score was found to improve from a mean of 26.8 (. sd. 10.3) pre-operatively to 57.6 (. sd. 20.0) post-operatively (p < 0.001). Active forward flexion improved from a mean of 85.3° (. sd. 27.4) pre-operatively to 125° (. sd. 37.3) postoperatively (p < 0.001). External rotation improved from a mean of 7° (. sd. 6.5) pre-operatively to 30.3° (. sd. 21.8°) post-operatively (p < 0.001). Survivorship with revision of the glenoid component as the endpoint was 99.1% at five years, 94.5% at ten years and 79.4% at 15 years. Survivorship with radiological loosening as the endpoint was 99.1% at five years, 80.3% at ten years and 33.6% at 15 years. Younger patient age and the curettage technique for glenoid preparation correlated with loosening. The rate of glenoid revision and radiological loosening increased with duration of follow-up, but not until a follow-up of five years. Therefore, we recommend that future studies reporting radiological outcomes of new glenoid designs should report follow-up of at least five to ten years

We studied the stability of cemented all-polyethylene keeled glenoid components by radiostereometric analysis (RSA) in 16 shoulders which had received a total shoulder replacement. There were 14 women (one bilateral) and one man with a mean age of 64 years. The diagnosis was osteoarthritis in eight and rheumatoid arthritis in seven. Two of the shoulders were excluded from the RSA study because of loosening of the tantalum markers. Three tantalum markers were inserted in the glenoid socket, two in the coracoid process and two in the acromion. The polyethylene keeled glenoid component was marked with three to five tantalum markers. Conventional radiological and RSA examinations were carried out at five to seven days, at four months and at one and two years after operation. Radiolucent lines were found in all except three shoulders. Migration was most pronounced in the distal direction and exceeded 1 mm in four shoulders. In ten shoulders rotation exceeded 2° in one or more axes with retroversion/anteversion being most common. No correlation was found between migration and the presence of radiolucencies on conventional radiographs

Purpose of study:. Reverse shoulder arthroplasty is effective in the management of symptomatic arthritic shoulders with a non-reconstructable rotator cuff. Optimal orientation and initial fixation of the glenoid component is correlated with improved outcomes. This may be difficult to achieve with distorted glenoid morphology. The authors present a previously undescribed system for accurate, consistent and reliable screw placement for fixation of the glenoid component with the desired version during reverse shoulder arthroplasty. Description of methods:. The pre-operative CT scan images are used to construct a scapula model (Medical Image Processing software, CustomMed Orthopaedics)allowing the surgeon to determine the optimal position for screw placement based on available bone stock. A custom drill guide is made from polyamide, which is sterilized in an autoclave and fitted to the glenoid intra-operatively prior to reaming. The system minimizes the likelihood of malposition of glenoid components and is compatible with all arthroplasty systems. Summary of results:. The technique has been performed on 5 patients after informed consent. Post-operative CT images demonstrate intended component version and screw position in all cases. Patients are being recruited for a multicenter prospective trial. Conclusion:. The authors present a new technique for achieving optimal screw position in fixation of glenoid components. A prospective trial is underway which aims to prove through post-operative imaging that intended glenoid version and screw placement was achieved and show improved long term results

Introduction: Concern remains in loosening of glenoid component reversed prostheses. This study is to analyze glenoid location of stem and 4 screws of glenoid component. Material and method: 34 reversed prostheses included. Mean age 74,10, 33 females/1 male. Preoperative CT study : glenoid version; measure of anterior-posterior osteophytes. Postoperative CT study: central stem location and superior, inferior, anterior, posterior screws location. Study of influence of glenoid version and presence of osteophytes in location of glenoid implant. Results: 27 retroverted glenoids (mean 6,5°); 7 ante-verted (mean 5,3°). 17 cases with anterior osteophyte and 12 of posterior. In 52% the central stem was centered inside glenoid, 33% anterior end was outside glenoid and 14% the posterior end. When central stem was anteriorly outside 85% presented retroverted glenoid (mean 8,33°). When the central stem was posteriorly outside 66% presented anteverted glenoid (mean 9,5°). Inferior screw was fully in place in 38%, ¾ part inside in 19%, 2/4 part in 23%, ¼ part in 19%. Superior screw was fully in place in 47%, ¾ part inside in 23%, 2/4 part in 19%, ¼ part in 9%. Anterior screw was fully in place in 66%, ¾ part in 23% and 2/4 part in 9%. Posterior screw was fully in place in 38%, ¾ part in 42%, 2/4 part in 14%, ¼ part in 4%. The correct positioning of superior screw correlates with less coverture of inferior screw. Anterior and posterior osteophytes did not correlated with stem nor screw positioning. Conclusions: Positoning of central stem correlates with glenoid version. Anteriorly extruded stems correlate with higher retroverted glenoids and posteriorly extruded stems correlate with higher anteversion. Positioning the inferior screw fully inside the lateral border of the scapula correlates with lower bony coverture of superior screw