Knowledge of the premorbid glenoid shape and the morphological changes the bone undergoes in patients with glenohumeral arthritis can improve surgical outcomes in total and reverse shoulder arthroplasty. Several studies have previously used scapular statistical shape models (SSMs) to predict premorbid glenoid shape and evaluate glenoid erosion properties. However, current literature suggests no studies have used scapular SSMs to examine the changes in glenoid surface area in patients with glenohumeral arthritis. Therefore, the purpose of this study was to compare the glenoid articular surface area between pathologic glenoid cavities from patients with glenohumeral arthritis and their predicted premorbid shape using a scapular SSM. Furthermore, this study compared pathologic glenoid surface area with that from virtually eroded glenoid models created without influence from internal bone remodelling activity and osteophyte formation. It was hypothesized that the pathologic glenoid cavities would exhibit the greatest glenoid surface area despite the eroded nature of the glenoid and the medialization, which in a vault shape, should logically result in less surface area. Computer tomography (CT) scans from 20 patients exhibiting type A2 glenoid erosion according to the Walch classification [Walch et al., 1999] were obtained. A scapular SSM was used to predict the premorbid glenoid shape for each scapula. The scapula and humerus from each patient were automatically segmented and exported as 3D object files along with the scapular SSM from a pre-operative planning software. Each scapula and a copy of its corresponding SSM were aligned using the coracoid, lateral edge of the acromion, inferior glenoid tubercule, scapular notch, and the trigonum spinae. Points were then digitized on both the pathologic humeral and glenoid surfaces and were used in an iterative closest point (ICP) algorithm in MATLAB (MathWorks, Natick, MA, USA) to align the humerus with the glenoid surface. A Boolean subtraction was then performed between the scapular SSM and the humerus to create a virtual erosion in the scapular SSM that matched the erosion orientation of the pathologic glenoid. This led to the development of three distinct glenoid models for each patient: premorbid, pathologic, and virtually eroded (Fig. 1). The glenoid surface area from each model was then determined using 3-Matic (Materialise, Leuven, Belgium). Figure 1. (A) Premorbid glenoid model, (B) pathologic glenoid model, and (C) virtually eroded glenoid model. The average glenoid surface area for the pathologic scapular models was 70% greater compared to the premorbid glenoid models (P < 0 .001). Furthermore, the surface area of the virtual glenoid erosions was 6.4% lower on average compared to the premorbid glenoid surface area (P=0.361). The larger surface area values observed in the pathologic glenoid cavities suggests that sufficient bone remodelling exists at the periphery of the glenoid bone in patients exhibiting A2 type glenohumeral arthritis. This is further supported by the large difference in glenoid surface area between the pathologic and virtually eroded glenoid cavities as the virtually eroded models only considered humeral anatomy when creating the erosion. For any figures or tables, please contact the authors directly

Aims. The survival of humeral hemiarthroplasties in patients with relatively intact glenoid cartilage could theoretically be extended by minimizing the associated postoperative glenoid erosion. Ceramic has gained attention as an alternative to metal as a material for hemiarthroplasties because of its superior tribological properties. The aim of this study was to assess the in vitro wear performance of ceramic and metal humeral hemiarthroplasties on natural glenoids. Methods. Intact right cadaveric shoulders from donors aged between 50 and 65 years were assigned to a ceramic group (n = 8, four male cadavers) and a metal group (n = 9, four male cadavers). A dedicated shoulder wear simulator was used to simulate daily activity by replicating the relevant joint motion and loading profiles. During testing, the joint was kept lubricated with diluted calf serum at room temperature. Each test of wear was performed for 500,000 cycles at 1.2 Hz. At intervals of 125,000 cycles, micro-CT scans of each glenoid were taken to characterize and quantify glenoid wear by calculating the change in the thickness of its articular cartilage. Results. At the completion of the wear test, the total thickness of the cartilage had significantly decreased in both the ceramic and metal groups, by 27% (p = 0.019) and 29% (p = 0.008), respectively. However, the differences between the two were not significant (p = 0.606) and the patterns of wear in the specimens were unpredictable. No significant correlation was found between cartilage wear and various factors, including age, sex, the size of the humeral head, joint mismatch, the thickness of the native cartilage, and the surface roughness (all p > 0.05). Conclusion. Although ceramic has better tribological properties than metal, we did not find evidence that its use in hemiarthroplasty of the shoulder in patients with healthy cartilage is a better alternative than conventional metal humeral heads. Cite this article: Bone Joint J 2024;106-B(11):1273–1283

Patients receiving reverse total shoulder arthroplasty (RTSA) often have osseous erosions because of glenohumeral arthritis, leading to increased surgical complexity. Glenoid implant fixation is a primary predictor of the success of RTSA and affects micromotion at the bone-implant interface. Augmented implants which incorporate specific geometry to address superior erosion are currently available, but the clinical outcomes of these implants are still considered short-term. The objective of this study was to investigate micromotion at the glenoid-baseplate interface for a standard, 3 mm and 6 mm lateralized baseplates, half-wedge, and full-wedge baseplates. It was hypothesized that the mechanism of load distribution from the baseplate to the glenoid will differ between implants, and these varying mechanisms will affect overall baseplate micromotion. Clinical CT scans of seven shoulders (mean age 69 years, 10°-19° glenoid inclinations) that were classified as having E2-type glenoid erosions were used to generate 3D scapula models using MIMICS image processing software (Materialise, Belgium) with a 0.75 mm mesh size. Each scapula was then repeatedly virtually reconstructed with the five implant types (standard,3mm,6mm lateralized, and half/full wedge; Fig.1) positioned in neutral version and inclination with full backside contact. The reconstructed scapulae were then imported into ABAQUS (SIMULIA, U.S.) finite element software and loads were applied simulating 15°,30°,45°,60°,75°, and 90° of abduction based on published instrumented in-vivo implant data. The micromotion normal and tangential to the bone surface, and effective load transfer area were recorded for each implant and abduction angle. A repeated measures ANOVA was used to perform statistical analysis. Maximum normal micromotion was found to be significantly less when using the standard baseplate (5±4 μm), as opposed to the full-wedge (16±7 μm, p=0.004), 3 mm lateralized (10±6 μm, p=0.017), and 6 mm lateralized (16±8 μm, p=0.007) baseplates (Fig.2). The half-wedge baseplate (11±7 μm) also produced significantly less micromotion than the full-wedge (p=0.003), and the 3 mm lateralized produced less micromotion than the full wedge (p=0.026) and 6 mm lateralized (p=0.003). Similarly, maximum tangential micromotion was found to be significantly less when using the standard baseplate (7±4 μm), as opposed to the half-wedge (12±5 μm, p=0.014), 3 mm lateralized (10±5 μm, p=0.003), and 6 mm lateralized (13±6 μm, p=0.003) baseplates (Fig.2). The full wedge (11±3 μm), half-wedge, and 3 mm lateralized baseplate also produced significantly less micromotion than the 6 mm lateralized (p=0.027, p=012, p=0.02, respectively). Both normal and tangential micromotion were highest at the 30° and 45° abduction angles (Fig.2). The effective load transfer area (ELTA) was lowest for the full wedge, followed by the half wedge, 6mm, 3mm, and standard baseplates (Fig.3) and increased with abduction angle. Glenoid baseplates with reduced lateralization and flat backside geometries resulted in the best outcomes with regards to normal and tangential micromotion. However, these types of implants are not always feasible due to the required amount of bone removal, and medialization of the bone-implant interface. Future work should study the acceptable levels of bone removal for patients with E-type glenoid erosion and the corresponding best implant selections for such cases. For any figures or tables, please contact the authors directly

Reverse total shoulder arthroplasty (RTSA) has a proven track record as an effective treatment for a variety of rotator cuff deficient conditions. However, glenoid erosion associated with the arthritic component of these conditions can present a challenge for the shoulder arthroplasty surgeon. Options for treatment of glenoid wear include partial reaming with incomplete baseplate seating, bony augmentation using structural or impaction grafting techniques, and augmented baseplates. Augmented components have the advantage of accommodating glenoid deformity with a durable material and also ream less subchondral bone; both of which may offer an advantage over traditional bone grafting. Biomechanical and early clinical studies of augmented glenoid baseplates suggest they are a reasonable treatment option, though posteriorly augmented baseplates have shown better performance than superiorly augmented implants. However, there are no mid- or late-term studies comparing augmented baseplates to bone grafting or partial reaming. We present a live surgical demonstration of RTSA for a patient with advanced glenoid erosion being treated with an augmented glenoid baseplate that can be dialed in the direction of any deformity (superior, posterior, etc.). This versatility allows the surgeon to place the augment in any direction and is not confined to the traditional concepts of glenoid wear in a single vector. Clearly, longer term follow up studies are needed to determine the ultimate effectiveness of these devices in treating glenoid deformity in RTSA

Aims. Controversy about the use of an anatomical total shoulder arthroplasty (aTSA) in young arthritic patients relates to which is the ideal form of fixation for the glenoid component: cemented or cementless. This study aimed to evaluate implant survival of aTSA when used in patients aged < 60 years with primary glenohumeral osteoarthritis (OA), and to compare the survival of cemented all-polyethylene and cementless metal-backed glenoid components. Materials and Methods. A total of 69 consecutive aTSAs were performed in 67 patients aged < 60 years with primary glenohumeral OA. Their mean age at the time of surgery was 54 years (35 to 60). Of these aTSAs, 46 were undertaken using a cemented polyethylene component and 23 were undertaken using a cementless metal-backed component. The age, gender, preoperative function, mobility, premorbid glenoid erosion, and length of follow-up were comparable in the two groups. The patients were reviewed clinically and radiographically at a mean of 10.3 years (5 to 12, . sd. 26) postoperatively. Kaplan–Meier survivorship analysis was performed with revision as the endpoint. Results. A total of 26 shoulders (38%) underwent revision surgery: ten (22%) in the polyethylene group and 16 (70%) in the metal-backed group (p < 0.0001). At 12 years’ follow-up, the rate of implant survival was 74% (. sd.  0.09) for polyethylene components and 24% (. sd.  0.10) for metal-backed components (p < 0.0002). Glenoid loosening or failure was the indication for revision in the polyethylene group, whereas polyethylene wear with metal-on-metal contact, instability, and insufficiency of the rotator cuff were the indications for revision in the metal-backed group. Preoperative posterior subluxation of the humeral head with a biconcave/retroverted glenoid (Walch B2) had an adverse effect on the survival of a metal-backed component. Conclusion. The survival of a cemented polyethylene glenoid component is three times higher than that of a cementless metal-backed glenoid component ten years after aTSA in patients aged < 60 years with primary glenohumeral OA. Patients with a biconcave (B2) glenoid have the highest risk of failure. Cite this article: Bone Joint J 2018;100-B:485–92

Superiorly eroded glenoids in cuff tear arthropathy represent a surgical challenge for reconstruction. The bone loss orientation and severity may influence glenoid component fixation. This computed-tomography study quantifies both the degree of erosion and orientation in superiorly eroded Favard E2 glenoids. We hypothesized that the erosion in E2 glenoids does not occur purely superiorly, rather, it is oriented in a predictable posterosuperior orientation with a largely semicircular line of erosion. Three-dimensional reconstructions of 40 shoulders with E2 glenoids (28 female, 12 male patients) at a mean age of 74 years (range, 56–88 years) were created from computed-tomography images. Point coordinates were extracted from each construct to analyze the morphologic structure. The anatomical location of the supra- and infraglenoid tubercle guided the creation of a superoinferior axis, against which the orientation angle of the erosion was measured. The direction and, thus, orientation of erosion was calculated as a vector. By placing ten point coordinates along the line of erosion and creating a circle of best fit, the radius of the circle was placed orthogonally against a chord that resulted by connecting the two outermost points along the line of erosion. To quantify the extent of curvature of the line of erosion between the paleo- and neoglenoid, the length of the radius of the circle of best fit was calculated. Individual values were compared against the mean of circle radii. The area of bony erosion (neoglenoid), was calculated as a percentage of the total glenoid area (neoglenoid + paleoglenoid). The severity of the erosion was categorized as mild (0% to 33%), moderate (34% to 66%), and severe erosion (>66%). The mean orientation angle between the vector of bony erosion and the superoinferior axis of the glenoid was 47° ± 17° (range, 14° – 74°) located in the posterosuperior quadrant of the glenoid, resulting in the average erosion being directed between the 10 and 11 o'clock position (right shoulder). In 63% of E2 cases, the line of erosion separating the paleo- and neoglenoids was more curved than the average of all bony erosions in the cohort. The mean surface area of the neoglenoid was 636 ± 247 mm2(range, 233 – 1,333 mm2) and of the paleoglenoid 311 ± 165 mm2(range, 123 – 820 mm2), revealing that, on average, the neoglenoids consume 67% of the total glenoid surface. The extent of erosion of the total cohort was subdivided into one mild (2%), 14 moderate (35%) and 25 severe (62%) cases. Using a clock-face for orientation, the average orientation of type E2 glenoid defects was directed between the 10 and 11 o'clock position in a right shoulder, corresponding to the posterosuperior glenoid quadrant. Surgeons managing patients with E2 type glenoids should be aware that a superiorly described glenoid erosion is oriented in the posterosuperior quadrant on the glenoid clock-face when viewed intra-operatively. Additionally, the line of erosion in 63% of E2 glenoids is substantially curved, having a significant effect on bone removal techniques when using commercially available augments for defect reconstruction

Biologic resurfacing of the glenoid combined with surface replacement hemiarthroplasty for relatively young patients suffering from advanced glenohumeral arthritis has the advantages of both humeral head and glenoid bone preservation. The longer term results of this procedure are reported. Twenty two shoulders in 21 patients had a surface replacement hemiarthroplasty with resurfacing of the glenoid with the anterior capsule. At follow up one had died, and another was not contactable. The prosthesis was removed in one for deep infection, and the fourth patient had undergone revision to a total shoulder arthroplasty for ongoing pain. Therefore, 17 patients with 18 operated shoulders were available for clinical assessment. The average age of the patients was 54.8 years (35–78) at the time of surgery. The average length of follow-up was 4.8 years (2–10.6). The average Constant Score was 71.4 points (41–95), and the sex- and age-adjusted Constant Score was 83.9%. The mean ASES score was 74.4 points (35–100). The average arc of forward flexion was 130 degrees (100–160), and external rotation was 39 degrees (20–60). On a VAS scale of 0 to 10, the average pain score at rest was 0.5 (0–3), while pain with activity was 2.4 (0–6). Sixteen of the 17 patients (94%) had a satisfactory result, and would have the operation again. Eight of the 17 patients (47%) were able to return to their previous sporting activities. Radiographic follow-up demonstrated there were 2 mild and 2 moderate cases of superior subluxation of the humeral head. There was no subsidence or signs of loosening of any humeral prosthesis. The average glenohumeral joint space was 0.13mm (0–2). Glenoid erosion was none in one case, mild in 6 cases, moderate in 6 cases, and severe in 3 shoulders. Although the results of this procedure compare favourably with other series, the extent of glenoid erosion is concerning. A more robust tissue for interposition may give better results

This study examined the regional variations of cortical and cancellous bone density present in superiorly eroded glenoids. It is hypothesized that eroded regions will contain denser bone in response to localized stress. The shift in natural joint articulation may also cause bone resorption in areas opposite the erosion site. Clinical CT scans were obtained for 32 shoulders (10m/22f, mean age 72.9yrs, 56–88yrs) classified as having E2-type glenoid erosion. The glenoid was divided into four measurement regions - anterior, inferior, posterior, and superior - as well as five depth regions. Depth regions were segmented in two-millimeter increments from zero to 10 millimeters, beginning at the center of the glenoid surface. A repeated-measures multiple analysis of variance (RM-MANOVA) was performed using SPSS statistical software to look for differences and interactions between mean densities in each depth, quadrant, and between genders. A second RM-MANOVA was performed to examine effects of gender and quadrant on cortical to cancellous bone volume ratios. Significance was set at p < 0 .05. Quadrant and depth variables showed significant multivariate main effects (p 0.147 respectively). Quadrant, depth, and their interaction showed significant univariate main effects for cortical bone (p≤0.001) and cancellous bone (p < 0 .001). The lowest bone density was found to be in the inferior quadrant for cancellous bone (307±50 HU, p < 0 .001). The superior quadrant contained the highest mean density for cortical bone (895±97 HU), however it was only significantly different than in the posterior quadrant (865±97 HU, p=0.022). As for depth, it was found that cortical bone is most dense at the glenoid surface (zero to two millimeters, 892±91 HU) when compared to bone at two to eight millimeters in depth (p < 0 .02). Cancellous bone was also most dense at the surface (352±51 HU), but only compared to the eight to 10 millimeters depth (p=0.005). Cancellous bone density was found to decrease with increasing depth. For cortical-to-cancellous bone volume ratios, the inferior quadrant (0.37±0.28) had a significantly lower ratio than all other quadrants (p < 0 .001). The superoposterior region of the glenoid was found to have denser cancellous bone and a high ratio of cortical to cancellous bone, likely due to decreased formation of cancellous bone and increased formation of cortical bone, in response to localized stresses. The inferior quadrant was found to have the least dense cortical and cancellous bone, and the lowest volume of cortical bone relative to cancellous bone. Once again, this is likely due to reduction in microstrain responsible for bone adaptation via Wolff's law. The density values found in this study generally agree with the range of values found in previous studies of normal and arthritic glenoids. An important limitation of this study is the sizing of measurement regions. For a patient with a smaller glenoid, a depth measurement of two millimeters may represent a larger portion of the overall glenoid vault. Segments could be scaled for each patient based on a percentage of each individual's glenoid size

We prospectively compared hemiarthroplasty (HA) and total shoulder replacement (TSR) in cuff intact osteoarthritis. The 2 years postoperative review, which has been presented previously, showed an advantage of TSR over HA. This study reviewed the longer term outcome in the same patients at a minimum of 10 years to assess the longer term durability of the glenoid components. Patients with Osteoarthritis and an intact rotator cuff were intraoperatively randomisation to HA or TSR using the Global. ™. Shoulder Arthroplasty system after glenoid exposure. Post-operative mobilisation for the two groups was identical, and up until two years, patients were assessed using the UCLA and Constant Score, as well as analog pain scales and functional questionnaire. At the 10 year review patients were assessed using a similar range of subjective evaluations by telephone, or reviewed in the clinic as was possible. Thirty-three shoulders in thirty-two patients were entered into the trial (14 HA and 19 TSR). At six months and one year, function scores and motion were similar, but the TSR group had less pain than the HA patients (p < 0.05) and this became more apparent at two years postoperatively (p< 0.02). Apart from those who died, no patients were lost to follow-up. At the two year mark postoperatively one patient in the HA group had undergone revision to TSR due to severe pain secondary to glenoid erosion, and three further HA were subsequently revised (2 at 3 years, and one at 4 years). Two shoulders in the TSR group have been revised (at 5 years and 7 years). At 10 years from the initial arthroplasty, 5 of the 14 HA and 6 of the 19 TSR had died. 10 of the 14 HA (71%) and 17 of the 19 TSR (89%) remained in situ at the time of death or at the 10 year review. Overall outcomes in each group were similar with respect to pain, function, daily activities. Based on this longer term review, our recommendation remains that TSR has advantages over HA with respect to pain and function at two years, and there has not been a reversal of the outcomes on prolonged follow-up. Revision from HA to TSR is made difficult due to glenoid erosion. Overall 89% of TSR remain insitu at death or 10 year, whereas 71% of HA were intact at the same times. The contention that HA will avoid later arthroplasty complications and, in particular, an unacceptable rate of late glenoid failure is not supported by this longer term review

Background. Degeneration of the shoulder joint is a frequent problem. There are two main types of shoulder degeneration: Osteoarthritis and cuff tear arthropathy (CTA) which is characterized by a large rotator cuff tear and progressive articular damage. It is largely unknown why only some patients with large rotator cuff tears develop CTA. In this project, we investigated CT data from ‘healthy’ persons and patients with CTA with the help of 3D imaging technology and statistical shape models (SSM). We tried to define a native scapular anatomy that predesignate patients to develop CTA. Methods. Statistical shape modeling and reconstruction:. A collection of 110 CT images from patients without glenohumeral arthropathy or large cuff tears was segmented and meshed uniformly to construct a SSM. Point-to-point correspondence between the shapes in the dataset was obtained using non-rigid template registration. Principal component analysis was used to obtain the mean shape and shape variation of the scapula model. Bias towards the template shape was minimized by repeating the non-rigid template registration with the resulting mean shape of the first iteration. Eighty-six CT images from patients with different severities of CTA were analyzed by an experienced shoulder surgeon and classified. CT images were segmented and inspected for signs of glenoid erosion. Remaining healthy parts of the eroded scapulae were partitioned and used as input of the iterative reconstruction algorithm. During an iteration of this algorithm, 30 shape components of the shape model are optimized and the reconstructed shape is aligned with the healthy parts. The algorithm stops when convergence is reached. Measurements. Automatic 3D measurements were performed for both the healthy and reconstructed shapes, including glenoid version, inclination, offset and critical shoulder angle. These measurements were manually performed on the mean shape of the shape model by a surgeon, after which the point-to-point correspondence was used to transfer the measurements to each shape. Results. The critical shoulder angle was found to be significantly larger for the CTA scapulae compared to the references (P<0.01). When analyzing the classified scapulae significant differences were found for the version angle in the scapulae of group 4a/4b and the critical shoulder angle of group 3 when compared to the references (P<0.05). Conclusion. Patients with CTA have a larger critical shoulder angle compared with reference patients. Some significant differences are found between the scapulae from patients in different stages of CTA and healthy references, however the differences are smaller than the accuracy of the SSM reconstruction. Therefore, we are unable to conclude that there is a predisposing anatomy in terms of glenoid version, inclination or offset for CTA

Introduction. The Walch Type B2 glenoid has the hallmark features of posteroinferior glenoid erosion, retroversion, and posterior humeral head subluxation. Although our understanding of the pathoanatomy of bone loss and its evolution in Type B's has improved, the etiology remains unclear. Furthermore, the morphology of the humerus in Walch B types has not been studied. The purpose of this imaging based anthropometric study was to examine the humeral torsion in Walch Type B2 shoulders. We hypothesized that there would be a compensatory decrease in humeral retroversion in Walch B2 glenoids. Methods. Three-dimensional models of the full length humerus were generated from computed tomography data of normal cadaveric (n = 59) and Walch Type B shoulders (n = 59). An anatomical coordinate system referencing the medial and lateral epicondyles was created for each model. A simulated humeral head osteotomy plane was created and used to determine humeral version relative to the epicondylar axis and the head-neck angle. Measurements were repeated by two experienced fellowship-trained shoulder surgeons to determine inter-rater reliability. Glenoid parameters (version, inclination and 2D critical shoulder angle) and posterior humeral head subluxation were calculated in the Type B group to determine the pathologic glenohumeral relationship. Two-way ANOVAs compared group and sex within humeral version and head-neck angle, and intra-class correlation coefficients (ICCs) with a 2-way random effects model and absolute agreement were used for inter-rater reliability. Results. There were statistically significant differences in humeral version between normal and Type B shoulders (p < .001) and between males and females within the normal group (p = .043). Normal shoulders had a humeral retroversion of 36±12°, while the Walch Type B group had a humeral retroversion of 14±9° relative to the epicondylar axis. For head-neck angle, there were no significant differences between sexes (p = .854), or between normal and Type B shoulders when grouped by sex (p = .433). In the Type B group, the mean glenoid version was 22±7°, glenoid inclination was 8±6°, 2D critical shoulder angle was 30±5° and humeral head subluxation was 80±9%. Inter-rater reliability showed fair agreement between the two experienced observers for head-neck angle (ICC = .562; 95% CI: -.28 to .809) and excellent agreement for humeral version (ICC = .962;.913 to .983). Although only fair agreement was found between observers in head-neck angle ICC, the difference in mean angle was only 2°. Discussion. Although much time and effort has been spent understanding and managing Type B2 glenoids, little attention has been paid to investigating associated humeral contributions to the Type B shoulder. Our results indicate that the humeral retroversion in Type B shoulders is significantly lower than in normals. These findings have several implications, including, helping to understanding the etiology of the B2, the unknown effects of arbitrarily selecting higher version angles for the humeral component, and the unknown effects of altered version on glenohumeral joint stability, loading and implant survivorship post-arthroplasty. Our results also raise an important question, whether it is best to reconstruct Type B humeral component version to pathologic version or to non-pathologic population means

Introduction. Modern prostheses of the 3rd and 4th generation facilitate a precise adjustment to various humeral anatomies. This provides major advantages regarding soft tissue balancing and the reconstruction of the rotational center. Thus, high expectations are linked to the use of modern shoulder prostheses compared to conventional designs. Methods. Out of a prospective multicenter study, 108 cases (72 females, 36 males) were reviewed. All patients were treated with the same type of double eccentric shoulder prosthesis. The mean age at surgery was 71.5 years (range, 44.6 to 97.3). The Constant Score (CS), ASES Score, X-rays and complications were evaluated at 3, 6, 12 and 24 months as well as 4, 7 and 10 years follow-up. Results. At a mean follow-up time of 93.3 months, the mean CS improved from preoperative 25.6 (±8.8) to 63.8 (±19.1) points at 7 years. In the same period, the mean ASES Score improved from 24.5 (±12.5) to 79.6 (±19.1). Pain according to the CS was rated preoperatively as high (mean 1.8 points). After 7 years patients suffered from mild to no pain (mean 12.0 points). A total of 7 prostheses were revised, leading to an overall survival rate of 91.5% at 10 years. In 4 cases secondary glenoid erosion was the reason for revision. Conclusion. The clinical results of the investigated prosthesis system are convincing and comparable to other modern shaft prostheses. To achieve an anatomical reconstruction of the rotational center of the humeral head, the use of a double eccentric shoulder prosthesis is recommended

Hemi shoulder arthroplasty is a rather successful procedure although revision surgery due to secondary glenoid erosion is reported in more than 25%. The downside of common shoulder arthroplasty is that in a deltopectoral approach the subscapularis tendon needs to be detached for exposure of the humeral head. Refixation of subscapularis tendon is associated with a retear rate of 4%, furthermore with progressing fatty muscle infiltration and loss of function. In case of revision surgery a second subscapularis tendon detachment is even more associated with worse function. Thus, arthroscopic humeral head resurfacing is an expedient alternative for minimal invasive humeral head arthroplasty without compromising subscapularis function. The purpose of this study was to report first clinical and subjective results after arthroscopic-assisted resurfacing of the humeral head. For this prospective case series, 24 patients (7 females, 17 males; mean age 59 years, range 42–73 years) undergoing arthroscopic-assisted partial shoulder resurfacing with the partial eclipse prosthesis were included in the study. Clinical conditions and subjective assessments were evaluated before surgery and annually thereafter using the Constant score (CS), active range of motion (ROM), visual analog scale (VAS) for pain, and the American Shoulder and Elbow Surgeons scale (ASES). Radiological outcomes and major complications were monitored. The mean CS for all patients improved significantly from 51 points preoperatively to 83 points 12 months after surgery (p=0.005). Trends towards increasing ROMs were detected. Subjective scores significantly improved from baseline to the 1-year follow-up (VAS: from 6.4 to 2.5, p=0.010; ASES: from 47 to 76, p=0.026). The majority of patients (88%) stated that they would undergo the procedure again. Revisions were indicated in 17% due to progression of osteoarthritis. Arthroscopic-assisted partial humeral head resurfacing as a minimal invasive procedure with the advantages of bone stock preservation and intact subscapularis tendon allowed immediate postoperative active mobilization and provided significant improvements in subjective outcome. In case of revision surgery a primary situation was encountered with postoperative results comparable to primary arthroplasty

Aims

The aim of this study is to evaluate the change in incidence rate of shoulder arthroplasty, indications, and surgeon volume trends associated with these procedures between January 2003 and April 2021 in the province of Nova Scotia, Canada.

Arthroplasty of the shoulder is a common procedure. Although there are many studies of the results of individual arthroplasty concepts, there is little published on the results of all shoulder replacements (with no exclusions) from a single centre. We analysed 120 elective shoulder replacements in 106 patients performed over a 5 year period in our unit. 77 were female and average age was 70 years. 85 procedures were for osteoarthritis, 10 cuff arthropathy, 8 post-traumatic arthritis. 65 patients underwent a resurfacing hemiarthroplasty, 25 stemmed hemiarthroplasty and 30 had total shoulder replacements (5 reverse polarity). Mean follow up was 1.6 years. There was a move away from resurfacing hemiarthroplasty towards stemmed total shoulder replacement over the study period. The overall incidence of complications was 25.8%, 19.2% occurring within 12 months of surgery: 4 replacements dislocated, there were 5 periprosthetic fractures, 2 patients developed deep infection (treated by debridement), 2 patients aseptic loosening, 11 developed subacromial/biceps pain and 2 had glenoid erosions. The overall revision rate was 5.8%, the re-operation rate 10%. The complication and re-operation rate in our unit is comparable with individual arthroplasty studies and may be useful as a reference for audits in centres across the UK

Aims

Optimal glenoid positioning in reverse shoulder arthroplasty (RSA) is crucial to provide impingement-free range of motion (ROM). Lateralization and inclination correction are not yet systematically used. Using planning software, we simulated the most used glenoid implant positions. The primary goal was to determine the configuration that delivers the best theoretical impingement-free ROM.

Aims

The aim of this study was to determine whether there is a correlation between the grade of humeral osteoarthritis (OA) and the severity of glenoid morphology according to Walch. We hypothesized that there would be a correlation.

Background. The use of reverse total shoulder arthroplasty considerably increased since first introduced by Paul Grammont in the late 1980s. Over the past few years, results from several mid- and long-term clinical studies have demonstrated good functional outcomes and pain relief. However, several complications, especially inferior glenoid notching, and high revision rates were reported in the literature. Improvements in prosthesis design should contribute to a lower complication rate and lesser amount of glenoid erosion. Few studies have reported the clinical outcome andcomplications of Anatomical Shoulder Inverse/ Reverse Prosthesis. This study documents 2- and 6-year clinical and radiological results following reversed shoulder arthroplasty using this novel prosthesis. Methods. We report the results for sixty-eight consecutive patients (seventy shoulders) with cuff tear arthropathy (CTA) treated with Anatomical Shoulder Inverse/Reverse Prosthesis between 2006 and 2008. Two groups were defined: (A) primary treatment and (B) revision. Clinical evaluation tools comprised Constant-Murley score (CS), range of motion, and a visual analog scale to assess pain. Radiographs (anteroposterior view in neutral position) were evaluated for notching and radiolucent lines. Any complications were recorded. Results. In total, 66 shoulders (94%) with a mean follow-up of 30.0 months were initially analysed. CS increased from preoperatively 20.2 to postoperatively 53.6 points. Inferior scapular notching was identified in 58% of patients, primarily grade 1 and 2 (low-graded). 16% of patients experienced a complication, including instability, infection or periprosthetic fracture. 58 patients (83%) were re-evaluated 69.0 months after implantation. CS decreased to 50.2 points (n.s.). 16 patients (23%) had postoperative complication at final follow-up. We observed progressive radiographic changes in 75% and an increased frequency of large notches (grade 3 and 4). No significant difference regarding clinical outcome was detected between group A and B after both 2 and 6 years. Conclusion. Total shoulder arthroplasty with the Anatomical Shoulder Inverse/Reverse Prosthesis is a reliable treatment option in patients with cuff tear arthropathy. Primary and revision arthropathies result in similar improvements in range of motion and pain. Constant-Murley score and radiographic changes deteriorated with time. Inferior scapular notching appeared rapidly after implantation. A change of prosthesis design and prosthetic overhang intraoperatively seems to be the most effective way to prevent scapular conflict. The complication rate in our series is equally to previously reported rates

Bone defects are frequently observed in anterior shoulder instability. Over the last decade, knowledge of the association of bone loss with increased failure rates of soft-tissue repair has shifted the surgical management of chronic shoulder instability. On the glenoid side, there is no controversy about the critical glenoid bone loss being 20%. However, poor outcomes have been described even with a subcritical glenoid bone defect as low as 13.5%. On the humeral side, the Hill-Sachs lesion should be evaluated concomitantly with the glenoid defect as the two sides of the same bipolar lesion which interact in the instability process, as described by the glenoid track concept. We advocate adding remplissage to every Bankart repair in patients with a Hill-Sachs lesion, regardless of the glenoid bone loss. When critical or subcritical glenoid bone loss occurs in active patients (> 15%) or bipolar off-track lesions, we should consider anterior glenoid bone reconstructions. The techniques have evolved significantly over the last two decades, moving from open procedures to arthroscopic, and from screw fixation to metal-free fixation. The new arthroscopic techniques of glenoid bone reconstruction procedures allow precise positioning of the graft, identification, and treatment of concomitant injuries with low morbidity and faster recovery. Given the problems associated with bone resorption and metal hardware protrusion, the new metal-free techniques for Latarjet or free bone block procedures seem a good solution to avoid these complications, although no long-term data are yet available.

Cite this article: Bone Joint J 2024;106-B(10):1100–1110.

The acromion is a bony process that juts out from the lateral end of the scapular spine. It is continuous with the blade and the spinous process. The process is rectangular, and carries a facet for the clavicle. Inferiorly is sited the subacromial bursa. Inferior encroachment or displacement of the acromion can result in impingement. The aim of this osteological study was to assess the presence of acromial displacement and variations predisposing to compaction of the subacromial space. Using the method described by Morrison and Bigliana, we assessed the scapulae of 128 men and women ranging from 35 to 92 years of age. We found a flat acromion in 30%, no hook in 48%, a small hook in 18% and a large hook in 4%. The presence of a hook was associated with a subacromial facet and a large hook with glenoid erosion. This study confirms the presence of four types of acromion