A Morphometric Study of Glenoid Cavity of Scapula in Bangladeshi Population.

This cross-sectional descriptive purposive study was conducted among 150 (70 right and 80 left) fully ossified dry human scapulae of Bangladeshi people from January 2019 to December 2019 in the Department of Anatomy, Mymensingh Medical College, Mymensingh. Shape of the glenoid cavity was observed as pear, oval or inverted comma shape. Morphometric parameters such as length and breadth of glenoid cavity were measured by digital Vernier slide calipers. In this study, 19.13% cases were found inverted comma shaped, 35.65% cases were oval and 45.22% cases were pear shaped. The mean±SD length of glenoid cavity was 37.5±3.61 mm and 36.19±3.68 mm on right and left sided scapulae respectively and mean±SD breadth was 23.6±2.73 mm on right and 23.42±2.75 mm on left side respectively. Mean±SD glenoid cavity index was 62.89±4.39 on right and 64.61±4.74 on left sided scapulae. Morphometric analysis of glenoid fossa of scapula might help clinicians in shoulder and its associated diseases.

Posterior deltoid-sparing approach for displaced inferior or posterior glenoid fossa fractures: technical note and case series.

Scapular surgery has usually been performed through the posterior Judet approach. This approach allows access to the entire posterior scapular body, but causes significant soft tissue damage and detaches the deltoid muscle. To date, there has been no clinical study of a deltoid-preserving approach to access the joint for displaced postero-inferior glenoid fractures (Ideberg type II or Ib). We describe an easy and less invasive approach to the postero-inferior glenoid fossa.

A formula for instability-related bone loss: estimating glenoid width and redefining bare spot.

PURPOSE: The aim of the study reveals a new intuitive method for preoperatively assessing defect ratio in glenoid deficiency based on the native glenoid width and the bare spot. METHODS: A linear relationship, i.e. the rh formula, between the native glenoid width (2r) and height (h) was revealed by a cadaver cohort (n = 204). To validate the reliability of the rh formula, 280 3D-CT images of intact glenoids were recruited. To evaluate the accuracy of rh formula in estimating glenoid defect, the 65 anterior-inferior defect models were artificially established based on the 3D-CT images of intact glenoids. Moreover, a clinically common anterior-posterior (AP) method was compared with the rh formula, to verify the technical superiority of rh formula. RESULTS: The regression analysis indicated a linear relationship between the width and height of intact glenoid: 2r = 0.768 × h - 1.222 mm (R2 = 0.820, p < 0.001). An excellent reliability was found between the formula prediction and model width (ICC = 0.911, p = 0.266). An excellent agreement was found between the predicted values and model parameters (glenoid width, ICCrh = 0.967, prh = 0.778; defect ratio, prh = 0.572, ICCrh = 0.997). And, it is of higher accuracy compared to the AP method (glenoid width, ICCAP = 0.933, pAP = 0.001; defect ratio, ICCAP = 0.911, pAP = 0.033). CONCLUSION: Applying the cadaver-based formula on 3D-CT scans accurately predicts native glenoid width and redefines bare spot for preoperatively determining glenoid bone loss.

Femoral head allograft for glenoid bone loss in primary reverse shoulder arthroplasty: functional and radiologic outcomes.

BACKGROUND: Several techniques have been adopted during primary reverse shoulder arthroplasty (RSA) to manage glenoid bone defect. Among bone grafts, humeral head autograft is currently the mainstream option. However, autologous humeral heads may be unavailable or inadequate, and allografts may be a viable alternative. The aim of the present study was to evaluate the functional and radiologic outcomes of femoral head allografts for glenoid bone defects in primary RSA. METHODS: We conducted a retrospective study with prospective data collection enrolling 20 consecutive patients who underwent RSA with femoral head allografts for glenoid bone defects. Indications for surgery were eccentric cuff tear arthropathy in 10 cases (50%), concentric osteoarthritis in 9 cases (45%), and fracture sequelae in 1 case (5%). Each patient was evaluated preoperatively and at follow-up by radiologic and computed tomography (CT) and by assessing the range of motion (ROM) and the Constant-Murley score (CMS). A CT-based software, a patient-specific 3D model of the scapula, and patient-specific instrumentation were used to shape the graft and to assess the position of K-wire for the central peg. Postoperatively, CT scans were used to identify graft incorporation and resorption. RESULTS: After a median follow-up of 26.5 months (24-38), ROM and CMS showed a statistically significant improvement (all P = .001). The median measures of the graft were as follows: 28 mm (28-29) for diameter, 22° (10°-31°) for angle, 4 mm (2-8 mm) for minimum thickness, and 15 mm (11-21 mm) for maximum thickness. Before the surgery, the median glenoid version was 21.8° (16.5°-33.5°) for the retroverted glenoids and -13.5° (-23° to -12°) for the anteverted glenoids. At the follow-up, the median postoperative baseplate retroversion was 5.7° (2.2°-1.5°) (P = .001), and this value was close to the 4° retroversion planned on the preoperative CT-based software. Postoperative major complications were noted in 4 patients: 2 dislocations, 1 baseplate failure following a high-energy trauma, and 1 septic baseplate failure. Partial graft resorption without glenoid component failure was observed in 3 cases that did not require revision surgery. CONCLUSION: The femoral head allograft for glenoid bone loss in primary RSA restores shoulder function, with CMS values comparable to those of sex- and age-matched healthy individuals. A high rate of incorporation of the graft and satisfactory correction of the glenoid version can be expected after surgery. The management of glenoid bone defects remains a challenging procedure, and a 15% risk of major complication must be considered.

3-dimensionally printed patient-specific glenoid drill guides vs. standard nonspecific instrumentation: a randomized controlled trial comparing the accuracy of glenoid component placement in anatomic total shoulder arthroplasty.

BACKGROUND: Traditional, commercially sourced patient-specific instrumentation (PSI) systems for shoulder arthroplasty improve glenoid component placement but can involve considerable cost and outsourcing delays. The purpose of this randomized controlled trial was to compare the accuracy of glenoid component positioning in anatomic total shoulder arthroplasty (aTSA) using an in-house, point-of-care, 3-dimensionally (3D) printed patient-specific glenoid drill guide vs. standard nonspecific instrumentation. METHODS: This single-center randomized controlled trial included 36 adult patients undergoing primary aTSA. Patients were blinded and randomized 1:1 to either the PSI or the standard aTSA guide groups. The primary endpoint was the accuracy of glenoid component placement (version and inclination), which was determined using a metal-suppression computed tomography scan taken between 6 weeks and 1 year postoperatively. Deviation from the preoperative 3D templating plan was calculated for each patient. Blinded postoperative computed tomography measurements were performed by a fellowship-trained shoulder surgeon and a musculoskeletal radiologist. RESULTS: Nineteen patients were randomized to the patient-specific glenoid drill guide group, and 17 patients were allocated to the standard instrumentation control group. There were no significant differences between the 2 groups for native version (P = .527) or inclination (P = .415). The version correction was similar between the 2 groups (P = .551), and the PSI group was significantly more accurate when correcting version than the control group (P = .042). The PSI group required a significantly greater inclination correction than the control group (P = .002); however, the 2 groups still had similar accuracy when correcting inclination (P = .851). For the PSI group, there was no correlation between the accuracy of component placement and native version, native inclination, or the Walch classification of glenoid wear (P > .05). For the control group, accuracy when correcting version was inversely correlated with native version (P = .033), but accuracy was not correlated with native inclination or the Walch classification of glenoid wear (P > .05). The intraclass correlation coefficient was 0.703 and 0.848 when measuring version and inclination accuracy, respectively. CONCLUSION: When compared with standard instrumentation, the use of in-house, 3D printed, patient-specific glenoid drill guides during aTSA led to more accurate glenoid component version correction and similarly accurate inclination correction. Additional research should examine the influence of proper component position and use of PSI on clinical outcomes.

Treatment of Glenoid Wear with the Use of Augmented Glenoid Components in Total Shoulder Arthroplasty: A Scoping Review.

¼ Treatment of glenoid bone loss continues to be a challenge in total shoulder arthroplasty (TSA). Although correcting glenoid wear to patient's native anatomy is desirable in TSA, there is lack of consensus regarding how much glenoid wear correction is acceptable and necessary in both anatomic and reverse TSA.¼ Use of augmented glenoid components is a relatively new treatment strategy for addressing moderate-to-severe glenoid wear in TSA. Augmented glenoid components allow for predictable and easy correction of glenoid wear in the coronal and/or axial planes while at the same time maximizing implant seating, improving rotator cuff biomechanics, and preserving glenoid bone stock because of off-axis glenoid reaming.¼ Augmented glenoid components have distinct advantages over glenoid bone grafting. Glenoid bone grafting is technically demanding, adds to the surgical time, and carries a risk of nonunion and graft resorption with subsequent failure of the glenoid component.¼ The use of augmented glenoid components in TSA is steadily increasing with easy availability of computed tomography-based preoperative planning software and guidance technology (patient-specific instrumentation and computer navigation).¼ Although different augment designs (full wedge, half wedge, and step cut) are available and a particular design may provide advantages in specific glenoid wear patterns to minimize bone removal (i.e. a half wedge in B2 glenoids), there is no evidence to demonstrate the superiority of 1 design over others.

Comparison of long-term clinical and radiological outcomes for cemented keel, cemented peg, and hybrid cage glenoids with anatomical total shoulder arthroplasty using the same humeral component.

Aims: The aim of this study was to longitudinally compare the clinical and radiological outcomes of anatomical total shoulder arthroplasty (aTSA) up to long-term follow-up, when using cemented keel, cemented peg, and hybrid cage peg glenoid components and the same humeral system. Methods: We retrospectively analyzed a multicentre, international clinical database of a single platform shoulder system to compare the short-, mid-, and long-term clinical outcomes associated with three designs of aTSA glenoid components: 294 cemented keel, 527 cemented peg, and 981 hybrid cage glenoids. Outcomes were evaluated at 4,746 postoperative timepoints for 1,802 primary aTSA, with a mean follow-up of 65 months (24 to 217). Results: Relative to their preoperative condition, each glenoid cohort had significant improvements in clinical outcomes from two years to ten years after surgery. Patients with cage glenoids had significantly better clinical outcomes, with higher patient-reported outcome scores and significantly increased active range of motion, compared with those with keel and peg glenoids. Those with cage glenoids also had significantly fewer complications (keel: 13.3%, peg: 13.1%, cage: 7.4%), revisions (keel: 7.1%, peg 9.7%, cage 3.5%), and aseptic glenoid loosening and failure (keel: 4.7%, peg: 5.8%, cage: 2.5%). Regarding radiological outcomes, 70 patients (11.2%) with cage glenoids had glenoid radiolucent lines (RLLs). The cage glenoid RLL rate was 3.3-times (p < 0.001) less than those with keel glenoids (37.3%) and 4.6-times (p < 0.001) less than those with peg glenoids (51.2%). Conclusion: These findings show that good long-term clinical and radiological outcomes can be achieved with each of the three aTSA designs of glenoid component analyzed in this study. However, there were some differences in clinical and radiological outcomes: generally, cage glenoids performed best, followed by cemented keel glenoids, and finally cemented peg glenoids.

Clinical and radiologic outcomes of Lima ProMade custom 3D-printed glenoid components in primary and revision reverse total shoulder arthroplasty with severe glenoid bone loss: a minimum 2-year follow-up.

BACKGROUND: The purpose of this study is to report the clinical and radiologic outcomes of patients undergoing primary or revision reverse total shoulder arthroplasty using custom 3D-printed components to manage severe glenoid bone loss with a minimum of 2-year follow-up. METHODS: Following ethical approval, patients were identified and invited to participate. Inclusion criteria were (1) severe glenoid bone loss necessitating the need for custom implants and (2) patients with definitive glenoid and humeral components implanted more than 2 years prior. Included patients underwent clinical assessment using the Oxford Shoulder Score (OSS), Constant-Murley score, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), and the quick Disabilities of the Arm, Shoulder, and Hand questionnaire (QuickDASH). Radiographic assessment included anteroposterior and axial projections. Patients were invited to attend a computed tomography (CT) scan to confirm osseointegration. Statistical analysis used descriptive statistics (mean and standard deviation [SD]) and paired t test for parametric data. RESULTS: Eleven patients declined to participate. Five patients were deceased prior to study commencement, leaving 42 remaining patients in this analysis. Three patients had revision surgery before the 2-year follow-up; of these, 2 retained their custom glenoid components. Mean follow-up was 31.6 months from surgery (range 24-52 months). All 4 scores improved: OSS from a mean 15 (SD 8.4) to 36 (SD 12) (P < .001), Constant-Murley score from a mean 15 (SD 11.2) to 52 (SD 20.1) (P < .001), QuickDASH from a mean 70 (SD 21) to 31 (SD 24.8) (P = .004), and the ASES score from a mean 22 (SD 17.8) to 71 (SD 23.3) (P = .007). Radiologic evaluation demonstrated good osseointegration in all but 1 included patient. CONCLUSION: The utility of custom 3D-printed components for managing severe glenoid bone loss in primary and revision reverse total shoulder arthroplasty yields significant clinical improvements in this complex cohort. Large complex glenoid bone defects can be managed successfully with custom 3D-printed glenoid components.

Editorial Commentary: High Variability Exists Among Different Techniques for Measuring Glenoid Bone Loss.

Glenoid bone loss is a predominant factor in determining proper surgical management for glenohumeral instability. Precise measurements of glenoid (and humeral) bone defects are fundamental, and millimeters matter. Three-dimensional computed tomography scans may provide the highest interobserver reliability for making these measurements. Yet, because imprecision in the range of millimeters is observed with even the most precise glenoid bone loss measurement techniques, it could be a mistake to over-rely, let alone solely rely, on glenoid bone loss measurement as the primary determinant for selecting one surgical procedure over another. Surgeons must measure glenoid bone loss but also thoughtfully consider patient age, associated soft-tissue injuries, and activity level, including throwing and participation in collision sports. When choosing the proper surgical procedure for a shoulder instability patient, we should not focus on only one variably measured parameter but, instead, on a comprehensive assessment of the patient.

Osseous variations associated with physiological thinning of the glenoid articular cartilage: an osteological study with CT, MRI and arthroscopic correlations.

OBJECTIVE: To investigate the relationship between osseous variations of the glenoid fossa and thinning of the overlaying articular cartilage. MATERIALS AND METHODS: In total, 360 dry scapulae, comprising adult, children and fetal specimens, were observed for potential presence of osseous variants inside the glenoid fossa. Subsequently, the appearance of the observed variants was evaluated using CT and MRI (each 300 scans), and in-time arthroscopic findings (20 procedures). New terminology of the observed variants was proposed by an expert panel formed by orthopaedic surgeons, anatomists and radiologists. RESULTS: Tubercle of Assaky was observed in 140 (46.7%) adult scapulae, and an innominate osseous depression was identified in 27 (9.0%) adult scapulae. Upon radiological imaging, the tubercle of Assaky was found in 128 (42.7%) CTs and 118 (39.3%) MRIs, while the depression was identified in 12 (4.0%) CTs and 14 (4.7%) MRIs. Articular cartilage above the osseous variations appeared relatively thinner and in several young individuals was found completely absent. Moreover, the tubercle of Assaky featured an increasing prevalence with aging, while the osseous depression develops in the second decade. Macroscopic articular cartilage thinning was identified in 11 (55.0%) arthroscopies. Consequently, four new terms were invented to describe the presented findings. CONCLUSION: Physiological articular cartilage thinning occurs due to the presence of the intraglenoid tubercle or the glenoid fovea. In teenagers, the cartilage above the glenoid fovea may be naturally absent. Screening for these variations increases the diagnostic accuracy of glenoid defects. In addition, implementing the proposed terminological updates would optimize communication accuracy.

Glenoid component placement accuracy in total shoulder arthroplasty with preoperative planning and standard instrumentation is not influenced by supero-inferior glenoid erosion.

PURPOSE: Accurate glenoid component placement in total shoulder arthroplasty (TSA) remains challenging even with preoperative planning, especially for variable glenoid erosion patterns in the coronal plane. METHODS: We retrospectively reviewed 170 primary TSAs in which preoperative planning software was used. After registration of intraoperative bony landmarks, surgeons were blinded to the navigation screen and attempted to implement their plan by simulating placement of a central-axis guide pin: 230 screenshots of simulated guide pin placement were included (aTSA = 66, rTSA = 164). Displacement, error in version and inclination, and overall malposition from the preoperatively-planned target point were stratified by the Favard classification describing superior-inferior glenoid wear: E0 (n = 89); E1 (n = 81); E2 (n = 29); E3(n = 29); E4(n = 2). Malposition was considered > 10° for version/inclination errors or > 4 mm displacement from the starting point. RESULTS: Mean displacement error was 3.5 ± 2.7 mm (aTSA = 2.7 ± 2.3 mm, rTSA = 3.8 ± 2.9 mm), version error was 5.7 ± 4.7° (aTSA = 5.8 ± 4.4°, rTSA = 5.7 ± 4.8°), inclination error was 7.1 ± 5.6 (aTSA = 4.8 ± 4.8°, rTSA = 8.1 ± 5.7°), and malposition rate was 53% (aTSA = 38%, rTSA = 59%). When compared by Favard classification, there were no differences in any measure; when stratified by TSA type, version error differed for rTSAs (P = .038), with E1 having the greatest version error (6.9 ± 5.2°) and E3 the least (4.2 ± 3.4°). When comparing glenoids without wear (E0) and glenoids with superior wear (E2 and E3), the only difference was greater version error in glenoids without wear (6.0 ± 4.9° vs. 4.6 ± 3.7°, P = .041). CONCLUSIONS: Glenoid malposition did not differ based on coronal glenoid morphology. Although, malposition was relatively high, suggesting surgeons should consider alternate techniques beyond preoperative planning and standard instrumentation in TSA. LEVEL OF EVIDENCE III: Retrospective Cohort Study.

The morphofunctional implications of the glenoid labrum of the glenohumeral joint in hominoids.

OBJECTIVES: A morphocline of the glenoid cavity has been used to infer differences in locomotor behaviors; however, the glenoid cavity is surrounded by the glenoid labrum, a fibrocartilaginous structure that could influence the functionality of the glenoid. The objectives of this study are to explore the effects of the glenoid labrum on the area, depth, and morphology of the glenoid cavity in primates. MATERIALS AND METHODS: Photogrammetry was used to build 3D models of the glenoid, with and without the labrum, and three- (3D) and two-dimensional (2D) geometric morphometrics (GM) was applied. 2D areas were collected from zenithal images for glenoids with and without labrum to evaluate the availability of articular surface area. RESULTS: In the 2D GM the morphocline is present in the dry-bone sample but not with the presence of the glenoid labrum. In the 3D GM there are differences between species mainly concerning the depth of the glenoid cavity. 2D areas reveal that the amount of articular area of the glenoid cavity increases with the presence of the labrum, particularly in humans. DISCUSSION: The glenoid labrum changes the shape, increases the depth and the surface area of the glenoid cavity, particularly in humans. Therefore, the glenoid labrum might hold a functional role, increasing the stability of the glenohumeral joint of primates in general, and especially in humans.

Glenoid reconstruction bone loss with a pediculated coracoid autograft during shoulder arthroplasty. A technical note.

Reconstruction of glenoid bone loss is a difficult but often required component of shoulder arthroplasty. A variety of free autografts or allografts have been proposed for reconstruction. While Latarjet is well accepted for the management of anterior instability, the use of a coracoid graft has not been described in conjunction with shoulder arthroplasty. We propose that anterior and central glenoid bone defects can be reconstructed with the coracoid process. to provide a vascularized local structural autograft. Level of evidence: IV.

Analysis and 3D correction of glenoid dysplasia with metal hemi-wedge base plate augment: short-term radiographic outcomes.

BACKGROUND: Glenoid defects can be addressed traditionally by asymmetric reaming or by bone-preserving correction to a more lateral joint line by bone or metal augmented baseplates in reverse shoulder arthroplasties. While there is more evidence in literature regarding the outcome and complications of Bony Increased Offset Reversed Shoulder Arthroplasty (BIO-RSA), there is minimal reported experience with the outcome after metal glenoid augments. The aim of this study was to determine whether a metal augment can correct the glenoid deformity in an anatomic manner. METHODS: Glenoid morphology and deformity were determined in 50 patients with Walch type B1, B2, D and Favard type E0-E3 glenoid defects using preoperative radiographic and computed tomography (CT) analysis. All patients received a preoperative planning CT with 3D planning, and measurements of glenoid inclination (in 3 planes proximal, middle, distal), reversed shoulder arthroplasty angle (RSA) and glenoid version were obtained. All patients had a pathologic inclination in the coronal or frontal planes of > 10°. Above the threshold of 10° pathological glenoid version or inclination metal hemi-augments of 10°, 20°, or 30° were used which allow an individual 360° augment positioning according to the patient glenoid deformity. RESULTS: The mean preoperative numbers of the glenoid version demonstrate that most glenoids were in retroversion and superior inclination. In total 2410° wedges, 1820° wedges and 8 30° wedges were used. In the majority of cases, the wedge was positioned posteriorly and/or cranially between 10:00 and 12:00 o'clock, which allows a correction in a 3D manner of the glenoid inclination and version. The mean RSA angle could be corrected from 22.76 ± 6.06 to 0.19° ± 2.7 (p < 0.0001). The highest retroversion of the glenoid is evidenced in the proximal section and it could be corrected from - 23.32° ± 4.56 to - 6.74° ± 7.75 (p < 0.0001) and in the middle section from - 18.93° ± 3.35 to - 7.66° ± 5.28 (p < 0.0001). A mean sphere bone overhang distance (SBOD) of 5.70 ± 2.04 mm was found in order to avoid or minimize relevant scapular notching. CONCLUSION: By using a new 360° metal-augmented baseplate, the preoperative pathological inclination and retroversion can be corrected without medialization of the joint line. Future clinical results will show whether this bone-preserving procedure improves also the clinical outcomes as compared to asymmetric medialized reaming or wedged BIO-RSA. LEVEL OF EVIDENCE: Level IV, Case series.

Total shoulder arthroplasty in patients with a B2 glenoid addressed with corrective reaming: mean 8-year follow-up.

BACKGROUND: The management of Walch B2 glenoid deformities in primary glenohumeral osteoarthritis is frequently debated. Previous literature has shown that the treatment of B2 glenoids with high-side reaming and anatomic total shoulder arthroplasty (aTSA) perform well in the short-term but is associated with an increased glenoid component failure rate in severe deformities. Therefore, many have explored alternative options, including augmented anatomic glenoid components and reverse shoulder arthroplasty. Our goal in this study is to provide mid-term radiographic and clinical outcomes after high-side reaming and aTSA for B2 glenoids. METHODS: Patients were followed both clinically and radiographically. Preoperative computed tomography scans were used for retrospective analysis of deformity. Both preoperative and postoperative visual analog scale pain, American Shoulder and Elbow Surgeons score, and Simple Shoulder Test scores were collected. Radiographs were analyzed preoperatively and postoperatively for humeral head decentering relative to the glenoid vault, immediate glenoid seating, and final glenoid peg radiolucency. RESULTS: Of the original cohort of 59 patients (6 now deceased) reported at a mean radiographic follow-up of 3.4 years, 34 shoulders in 33 patients with B2 glenoids (mean retroversion 18.9°, range 4°-32°) were available for follow-up at a mean of 8.6 years (range 5.5-11.2) after high-side glenoid reaming with aTSA. Three (5.1%) of the original 59 shoulder were revised. At final follow-up, 3 of 30 (10.0%) shoulders had radiographic glenoid component failure, but were unrevised. Glenoid component failure was associated with worse initial glenoid component seating (mean Lazarus score 1.2 vs. 2.0, P = .002). Glenoid failure was also associated with increased posterior humeral head subluxation at 2-4 year follow-up (mean 5.6% vs. 12.6%, P = .045) and at final follow-up (mean 7.0% vs. 21%, P = .002). There was no association between glenoid component failure and preoperative retroversion, inclination, or humeral head subluxation (all P > .05). Glenoid component failure was associated with worse American Shoulder and Elbow Surgeons (88 vs. 73) and visual analog scale pain (0.8 vs. 2.1) scores (both P = .03). CONCLUSIONS: At a mean of 8.6 years, 88% of shoulders available for follow-up had well-fixed glenoid components. Glenoid component failure was associated with poor initial glenoid component seating, with failed components having an average of 25% of the glenoid component not seated. Preoperative deformity such as glenoid retroversion, inclination, or humeral head subluxation did not predict glenoid component failure. This study supports that initial glenoid component seating and recurrence of posterior humeral head subluxation may be the most important factors for mid-term glenoid component survival in aTSA in patients with B2 glenoids.

Computed tomography revealed the correlation between radiolucency and alignment of all-polyethylene pegged glenoid component more than 10 years after total shoulder arthroplasty in the Japanese population.

BACKGROUND: Anatomical total shoulder arthroplasty (TSA) provides successful long-term outcomes but complications can occur after 10 years that require revision. Computed tomography (CT) is a useful tool for assessing radiolucent lines around the glenoid component of TSA; however, the merits of long-term post-TSA follow up with CT are unclear. The purpose of this study was to evaluate the long-term outcomes after TSA of Japanese population and to identify factors related to radiolucency around the glenoid component using CT. METHODS: A retrospective review was conducted of TSA patients who had completed at least 10 years of clinical follow up. Radiographs and CT images of the affected shoulder obtained at the last follow up were evaluated for radiolucent lines around the stem and each peg, superior inclination and retroversion of the glenoid component, subluxation index, and critical shoulder angle (CSA). Shoulder ROM, Constant-Murley score and UCLA score were compared between the preoperative and last follow up period. RESULTS: Eighteen shoulders in 16 patients met the inclusion criteria. Mean patient age was 61 years, mean follow up period was 137 months, and mean Yian CT score was 19%. CT score was significantly highest in pegs located inferiorly (p < 0.05). Mean glenoid superior inclination was 12.6°, retroversion was -0.3°, subluxation index was 46%, and CSA was 33.7°. Glenoid superior inclination was significantly lower (p = 0.007) in shoulders with possible loosening than in cases with no loosening (5.0° vs 15.6°). Mean Constant score and UCLA score improved significantly after TSA, from 25.8 to 10.7 points preoperatively to 70.1 and 28.9 points postoperatively, respectively. Mean shoulder flexion, internal rotation, and external rotation also showed improvement postoperatively. CONCLUSION: TSA provides good long-term outcomes. Radiolucency was present most frequently around the inferior pegs of the glenoid component. Glenoid superior inclination may affect the formation of radiolucent lines around glenoid pegs. LEVEL OF EVIDENCE: Level IV; Case Series; Treatment study.

High correlation between inner and outer glenoid circle diameters and its clinical relevance.

PURPOSE: The majority of methods for measuring glenoid bone loss in shoulder instability use the best-fit circle following the inferior glenoid rim. However, there is no precise method on how to draw this circle, particularly in case of a missing rim segment. Defining the radius is a source of substantial error. It was hypothesized that there is a relationship between the best-fit inferior circle (inner circle), defined by Sugaya, and the circle tangent to the supra- and infra-glenoid tubercles (outer circle), defined by Itoi, thus allowing a more consistent appreciation of the paleo-glenoid. METHODS: Ninety-five normal dry scapulae were examined. The specimens were digitally photographed obtaining perpendicular images of the glenoid cavity. Using HOROS® imaging software, a best-fit inferior circle (inner circle) and a second circle fitting the most inferior and superior points of the glenoid (outer circle) were drawn by two investigators. The diameters and areas of the circles were recorded. Two-way random-effects intra-class correlation coefficients (ICC) were used to measure intra- and inter-observer agreement. A Bayesian measurement-error regression model was used to determine the relationship between outer and inner circle measurements. RESULTS: The mean glenoid height was 35.1 mm and the glenoid width 25.6 mm. The mean diameter of the outer circle was 35.7 ± 4.2 mm and the mean diameter of the inner circle was 26.8 ± 3.2 mm. ICC showed excellent inter- and intra-observer agreement for both the outer circle diameter (ICC ≥ 0.95) and inner circle diameter (ICC ≥ 0.93). The two diameters demonstrated a very strong significant Pearson correlation (0.92, p < 0.001) and the regression showed excellent model fit R2 = 0.87. The areas of the two circles were also highly and significantly correlated (r = 0.94; p < 0.001). The ratio of inner circle to outer diameters was 0.74. CONCLUSION: There is a strong correlation between the inner and outer glenoid circle diameters. This study sets the base for the use the combined outer and inner circle and its ratio to better appreciate the paleo-glenoid morphology and thus obtain a more reliable bone loss estimation. Application of this method aids in a more reliable estimation bone loss with potential benefit in surgical decision-making.

Correlation between glenoid bone structure and recurrent anterior dislocation of the shoulder joint.

BACKGROUND: The aim of the study was to investigate the anatomical characteristics and symmetry of the bilateral glenoid structures of Chinese people and to explore the relationship between the glenoid bone structure and recurrent anterior dislocation. MATERIALS AND METHODS: The control group included 131 individuals with no history of shoulder dislocation. The dislocation group consisted of 131 patients with a history of unilateral shoulder dislocation. All subjects underwent computed tomography scans. Glenoid shape (pear-shaped, inverted comma-shaped, oval-shaped), width, height, depth, version angle, area, maximum fitting circle area and volume were measured. RESULTS: There was no significant difference in normal bilateral glenoid of Chinese people (p > 0.05). There were statistically significant differences in depth, height to width ratio, maximum fitting circle area and shape between the dislocation and control groups (p < 0.05). Regression analyses showed that the glenoid depth (odds ratio [OR] 0.48; p < 0.01), the glenoid height to width ratio (OR 28.61; p < 0.01), the glenoid maximum fitting circle area (OR 1.01; p < 0.01) and the glenoid shape (p <0.05; pear-shaped OR 0.432; inverted comma-shaped OR 0.954) were associated with anterior shoulder instability. Pear-shaped and inverted comma-shaped glenoid had lower risk of recurrent anterior shoulder dislocation compared to oval glenoid. Receiver operating characteristic curve analysis showed that individuals with anterior shoulder instability had smaller glenoid depth and larger height to width ratio and the glenoid maximum fitting circle area compared with the control group. CONCLUSIONS: The normal bilateral glenoids of Chinese people are basically symmetrical. The glenoid shape, depth, height to width ratio and maximum fitting circle area are risk factors for recurrent anterior shoulder dislocation. Evaluation of the glenoid bone structure enables more accurate prediction of the risk of recurrent shoulder dislocation.

Accuracy of reverse shoulder arthroplasty angle according to the size of the baseplate.

BACKGROUND: Glenoid inclination must be assessed precisely during preoperative planning for reverse shoulder arthroplasty (RSA) to position the glenoid baseplate correctly. We hypothesized that a more dynamic measurement method would better match the diversity of glenoid heights in the population and the variety of commercialized glenoid baseplates. Our purpose was to describe a new method to measure the RSA angle accounting for the baseplate size. METHODS: Computed tomography scans of 50 shoulders that underwent RSA for primary osteoarthritis or cuff tear arthropathy between June 2019 and February 2020 were included (mean age, 76 years). Three variants of the RSA angle were measured: the RSA angle as originally described by Boileau et al, the relative RSA 25 angle (which simulates the implantation of a 25-mm baseplate), and the relative RSA 29 angle (which simulates the implantation of a 29-mm baseplate). Measurements in the 2-dimensional true reformatted scapular plane were made by 3 independent operators. RESULTS: The mean R-S distance (ie, distance between point R [intersection of supraspinatus fossa line with glenoid surface] and point S [inferior border of glenoid]) was 24.2 ± 4.0 mm. The mean RSA angle was 20.3° ± 8.4°, whereas the mean relative RSA 25 angle was 19.3° ± 7.8° and the mean relative RSA 29 angle was 15.6° ± 7.6°. The mean difference between the RSA angle and the relative RSA 25 angle was 1.0° ± 4.1° (P = .16). The mean difference between the RSA angle and the relative RSA 29 angle was 4.7° ± 3.8° (P < .0001). In half of the shoulders in our series, the difference between the RSA angle and the RSA 29 angle exceeded 5°. CONCLUSION: The RSA angle is a reproducible measure of the inclination of the inferior part of the glenoid that is reliable in most cases for glenoid baseplates of 24-25 mm in height. However, surgeons should be aware that the RSA angle may overestimate the superior orientation of the inferior glenoid for baseplates of different sizes or for small- or large-stature patients. In these cases, the relative RSA angle adapted to the size of the baseplate more accurately evaluates the inclination of the inferior glenoid.

How to Fashion the Bone Block for Reconstruction of the Glenoid in Anterior and Posterior Instability.

BACKGROUND: Glenoid restoration techniques to address glenohumeral instability-induced anterior and posterior glenoid bone loss (AGBL and PGBL) often require reconstruction, but best-fit bone block (BFBB) modeling has not been developed. PURPOSE: To provide glenoid bony reconstruction models for anterior and posterior instability of the shoulder using a bone loss instability cohort with high-fidelity 3-dimensional (3D) imaging. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: We reviewed consecutive patients indicated for operative stabilization who had posterior glenohumeral instability and suspected GBL who underwent 2-dimensional (2D) computed tomography (CT). Patients were matched by sex, laterality, and age to patients who underwent operative stabilization of anterior glenohumeral instability. Mimics software was used to convert all 2D CT scans into 3D models of the scapula. A BFBB model was designed to digitally reconstruct GBL and was used to predict the amount, anatomic configuration, and fixation configuration of bony reconstruction required in AGBL and PGBL. RESULTS: The study included 30 patients with posterior instability and 30 patients with anterior instability; the participants' mean ± SD age was 28.8 ± 8.15 years (range, 16.0-51.0 years). Mean surface area of AGBL was 24.9% ± 7.7% (range, 14.7%-39.1%). Mean BFBB dimensions to reconstruct the anterior glenoid were determined to be a superior-inferior length of 23.9 ± 4.2 mm, anterior-posterior width of 6.4 ± 2.4 mm, and height of 1 cm. Mean angle of AGBL bone block interface relative to glenoid to reconstruct the native concavity was 79.4°± 5.9°. For PGBL, the mean surface area was 9.2% ± 5.6% (range, 3.0%-26.3%). Mean BFBB dimensions to reconstruct the posterior glenoid were a superior-inferior length of 21.9 ± 3.4 mm, width of 4.5 ± 2.3 mm, and height of 1 cm. The mean angle of PGBL bone block interface relative to the glenoid to reconstruct the native concavity was 38.6°± 14.3°. Orientation relative to the vertical glenoid axis was 77.2°± 13.8° in anterior reconstructions versus 105.9°± 10.9° in posterior reconstructions. CONCLUSION: Patients with anterior instability required a more rectangular BFBB with a bone block-glenoid interface angle of 79°, whereas patients with posterior instability required a more trapezoidal, obtusely oriented BFBB with a bone block-glenoid interface angle of 39°. BFBBs for either AGBL or PGBL can be effectively designed, and their size and/or shape can be predicted based on approximate percentage of GBL.