Gender-specific factors influencing the glenoid version and reference values for it.

BACKGROUND: Glenoid version is an important factor in the evaluation of shoulder stability and shoulder pathologies. However, there are neither established reference values nor known factors that influence the glenoid version, even though valid reference values are needed for diagnostic and orthopaedic surgery like corrective osteotomy and total or reverse shoulder arthroplasty (TSA/RSA). The aim of our population-based study was to identify factors influencing the glenoid version and to establish reference values from a large-scale population cohort. RESULTS: Our study explored the glenoid versions in a large sample representing the general adult population. We investigated 3004 participants in the population-based Study of Health in Pomerania (SHIP). Glenoid version was measured for both shoulders via magnetic resonance imaging (MRI). Associations with the glenoid version were calculated for sex, age, body height, body weight and BMI. The reference values for glenoid version in the central European population range between -9° and 7.5°, while multiple factors are associated with the glenoid version. CONCLUSION: To achieve a reliable interpretation prior to orthopaedic surgery, sex- and age-adjusted reference values are proposed.

The Scapular Skiver Screw: A Useful Fixation Technique for Inferior Glenoid and Scapular Neck Fractures.

SUMMARY: The inferior glenoid and scapular neck are common locations for scapular fractures. Operative exposures for reduction and fixation can be challenging, and frequently, the proximal fracture planes are not conducive to optimal fixation with a plate alone. The purpose of this article was to describe a new technique for enhancing fixation in specific inferior glenoid fractures using a single cortical lag screw.

Experimental guide wire placement for total shoulder arthroplasty in glenoid models: higher precision for patient-specific aiming guides compared to standard technique without learning curve.

BACKGROUND: Patient-specific aiming devices (PSAD) may improve precision and accuracy of glenoid component positioning in total shoulder arthroplasty, especially in degenerative glenoids. The aim of this study was to compare precision and accuracy of guide wire positioning into different glenoid models using a PSAD versus a standard guide. METHODS: Three experienced shoulder surgeons inserted 2.5 mm K-wires into polyurethane cast glenoid models of type Walch A, B and C (in total 180 models). Every surgeon placed guide wires into 10 glenoids of each type with a standard guide by DePuy Synthes in group (I) and with a PSAD in group (II). Deviation from planned version, inclination and entry point was measured, as well as investigation of a possible learning curve. RESULTS: Maximal deviation in version in B- and C-glenoids in (I) was 20.3° versus 4.8° in (II) (p < 0.001) and in inclination was 20.0° in (I) versus 3.7° in (II) (p < 0.001). For B-glenoid, more than 50% of the guide wires in (I) had a version deviation between 11.9° and 20.3° compared to ≤ 2.2° in (II) (p < 0.001). 50% of B- and C-glenoids in (I) showed a median inclination deviation of 4.6° (0.0°-20.0°; p < 0.001) versus 1.8° (0.0°-4.0°; p < 0.001) in (II). Deviation from the entry point was always less than 5.0 mm when using PSAD compared to a maximum of 7.7 mm with the standard guide and was most pronounced in type C (p < 0.001). CONCLUSION: PSAD enhance precision and accuracy of guide wire placement particularly for deformed B and C type glenoids compared to a standard guide in vitro. There was no learning curve for PSAD. However, findings of this study cannot be directly translated to the clinical reality and require further corroboration.

Reliability of glenoid measurements performed using Multiplanar Reconstruction (MPR) of Magnetic Resonance (MRI) in patients with shoulder instability.

PURPOSE: Measurement of glenoid bone loss in the shoulder instability can be assessed by CT or MRI multiplanar imaging and is crucial for pre-operative planning. The aim of this study is to determine the intra and interobserver reliability of glenoid deficiency measurement using MRI multiplanar reconstruction with 2D assessment in the sagittal plane (MPR MRI). METHODS: We reviewed MRI images of 80 patients with anterior shoulder instability with Osirix software using MPR. Six observers with basic experience measured the glenoid, erosion edge length, and bone loss twice, with at least one-week interval between measurements. We calculated reliability and repeatability using the intra-class correlation coefficient (ICC) and minimal detectable change with 95% confidence (MDC95%). RESULTS: Intra and Inter-observer ICC and MDC95% for glenoid width and height were excellent (ICC 0,89-0,96). For erosion edge length and area of the glenoid were acceptable/good (ICC 0,61-0,89). Bone loss and Pico Index were associated with acceptable/good ICC (0,63 -0,86)) but poor MDC95% (45 - 84 %). Intra-observer reliability improved with time, while inter-observer remained unchanged. CONCLUSION: The MPR MRI measurement of the anterior glenoid lesion is very good tool for linear parameters. This method is not valid for Pico index measurement, as the area of bone loss is variable. The pace of learning is individual, therefore complex calculations based on MPR MRI are not resistant to low experience as opposed to true 3D CT.

Automatic quantification of scapular and glenoid morphology from CT scans using deep learning.

OBJECTIVES: To develop and validate an open-source deep learning model for automatically quantifying scapular and glenoid morphology using CT images of normal subjects and patients with glenohumeral osteoarthritis. MATERIALS AND METHODS: First, we used deep learning to segment the scapula from CT images and then to identify the location of 13 landmarks on the scapula, 9 of them to establish a coordinate system unaffected by osteoarthritis-related changes, and the remaining 4 landmarks on the glenoid cavity to determine the glenoid size and orientation in this scapular coordinate system. The glenoid version, glenoid inclination, critical shoulder angle, glenopolar angle, glenoid height, and glenoid width were subsequently measured in this coordinate system. A 5-fold cross-validation was performed to evaluate the performance of this approach on 60 normal/non-osteoarthritic and 56 pathological/osteoarthritic scapulae. RESULTS: The Dice similarity coefficient between manual and automatic scapular segmentations exceeded 0.97 in both normal and pathological cases. The average error in automatic scapular and glenoid landmark positioning ranged between 1 and 2.5 mm and was comparable between the automatic method and human raters. The automatic method provided acceptable estimates of glenoid version (R2 = 0.95), glenoid inclination (R2 = 0.93), critical shoulder angle (R2 = 0.95), glenopolar angle (R2 = 0.90), glenoid height (R2 = 0.88) and width (R2 = 0.94). However, a significant difference was found for glenoid inclination between manual and automatic measurements (p < 0.001). CONCLUSIONS: This open-source deep learning model enables the automatic quantification of scapular and glenoid morphology from CT scans of patients with glenohumeral osteoarthritis, with sufficient accuracy for clinical use.

Clinical and Radiographic Outcomes and Graft Incorporation Rate Assessed by CT Scan After Reverse Shoulder Arthroplasty With Glenoid Structural Bone Graft Reconstruction.

INTRODUCTION: Reverse total shoulder arthroplasty (RTSA) with structural bone graft has been described as a technique in addressing glenoid bony defects. Studies have demonstrated acceptable outcomes with structural autograft or allograft. However, most of these studies are relatively small and rarely evaluate bone graft incorporation with CT scan. The aim of this study was to assess clinical and radiographic outcomes and report graft incorporation assessed on CT scan after RTSA where structural bone autograft or allograft was used to reconstruct the glenoid. METHODS: From May 2011 through June 2016, 38 patients underwent RTSA with structural bone graft. Of these, 35 were available for a minimum 2-year follow-up and retrospectively enrolled. From July 2016 through February 2019, 32 patients undergoing RTSA with structural bone graft were prospectively enrolled. Preoperative and postoperative American Shoulder and Elbow Surgeons and visual analog scale (for pain) scores and radiographs were obtained. CT scan was obtained at least 1 year postoperatively. RESULTS: Thirty-five patients were enrolled retrospectively (52.2%) and 32 prospectively (47.8%). Autograft was used in 46 cases (68.7%) and allograft in 21 cases. The mean American Shoulder and Elbow Surgeons score improved from 33.1 (SD 18.5) to 78.2 (SD 22.4), with P < 0.0001. On postoperative radiographs, 63 cases (94.0%) showed stable RTSA constructs while four cases (6.0%) developed glenoid baseplate subsidence. Postoperative CT scan demonstrated complete graft incorporation in 45 cases (90.0%) while partial incorporation was noted in 4 cases (8.0%), and in 1 case (2.0%), there was no graft incorporation. No correlation was observed between baseplate subsidence and graft type (autograft versus allograft) or primary versus revision surgery. DISCUSSION: Reverse shoulder arthroplasty with structural bone autograft and allograft is reliable for glenoid augmentation in patients undergoing RTSA in both primary and revision settings. Bony incorporation of autograft and allograft as evaluated on CT scan is predictably high.

Biomechanical study of 3D-printed titanium alloy pad for repairing glenoid bone defect.

Background: The purpose of this study was to investigate the effect of 3D-printed technology to repair glenoid bone defect on shoulder joint stability. Methods: The shoulder joints of 25 male cadavers were tested. The 3D-printed glenoid pad was designed and fabricated. The specimens were divided into 5 groups. Group A: no bone defect and the structure of the glenoid labrum and joint capsule was intact; Group B: Anterior inferior bone defect of the shoulder glenoid; Group C: a pad with a width of 2 mm was installed; Group D: a pad with a width of 4 mm was installed; Group E: a pad with a width of 6 mm was installed. This study measured the distance the humeral head moved forward at the time of glenohumeral dislocation and the maximum load required to dislocate the shoulder. Results: The shoulder joint stability and humerus displacement was significantly lower in groups B and C compared with group A (p < .05). Compared with group A, the stability of the shoulder joint of group D was significantly improved (p < .05). However, there was no significant difference in humerus displacement between groups D and A (p > .05). In addition, compared with group A, shoulder joint stability was significantly increased and humerus displacement was significantly decreased in group E (p < .05). Conclusion: The 3D-printed technology can be used to make the shoulder glenoid pad to perfectly restore the geometric shape of the shoulder glenoid articular surface. Moreover, the 3D-printed pad is 2 mm larger than the normal glenoid width to restore the initial stability of the shoulder joint.

Double-pulley, V-shaped fixation technique for arthroscopic repair of ideberg type IA glenoid fracture.

Different techniques have been described for glenoid fractures, there is still a need for safe and effective agents to promote outcomes. From January 2016 to April 2021, the clinical data of 17 patients with pulley type IA fractures treated by the V-shaped fixation technique under shoulder arthroscopy were retrospectively analyzed. Preoperative X-ray, CT, and MRI examinations were completed. The functional score of the shoulder joint, such as the visual analog scale (VAS), Constant score, and Modified Rowe score, was used to evaluate the preoperative and final follow-up clinical outcomes. The active shoulder range of motion (ROM) was also collected preoperatively and at the final postoperative follow-up. Accordingly, intraoperative and postoperative complications were also observed. The mean follow-up was 49.52 months (16-79 months). The patients' follow-up exams showed that shoulder joint flexion, abduction, external rotation, internal rotation, and pain were not significantly different from those of the contralateral side (p > .05). The mean Constant score was 83.52 (58-98), and the average Modified Rowe score was 94.29 (70-100). X-ray and CT films of all cases showed good healing without articular depression or steps. Three patients had traumatic arthritis, with VAS <3 pain. No postoperative complications, such as infections, nerve or vessel damage, or suture anchor problems occurred during the follow-up period. Using the Double-pull, V-shaped fixation technique can stabilize the reduction of glenoid fractures while reducing the possibility of bone destruction. It is a good solution and provides an opportunity to treat rotator cuff tears associated with the procedure.

Does glenoid inclination affect the anterior stability of reverse total shoulder arthroplasty? A biomechanical study.

PURPOSE: The anterior stability of reverse total shoulder arthroplasty is affected by multiple factors. However, the effect of glenosphere inclination on stability has rarely been investigated, which is what this study aims to look into. METHODS: Reverse shoulder arthroplasty was performed on 15 cadaveric human shoulders. The anterior dislocation forces and range of motion in internal rotation in the glenohumeral joint (primary measured parameters) were tested in a shoulder simulator in different arm positions and implant configurations, as well as with a custom-made 10° inferiorly inclined glenosphere. The inclination and retroversion of the baseplate as well as the distance between the glenoid and coracoid tip in two planes (secondary measured parameters) were evaluated on CT scans. RESULTS: In biomechanical testing, the custom-made inclined glenosphere showed no significant influence on anterior stability other than glenoid lateralisation over all arm positions as well as the neck-shaft angle in two arm positions. The 6 mm lateralised glenosphere reduced internal rotation at 30° and 60° of glenohumeral abduction. In 30° of glenohumeral abduction, joint stability was increased using the 155° epiphysis compared with the 145° epiphysis. The mean inclination was 16.1°. The inclination was positively, and the distance between the glenoid and coracoid tip in the anterior-to-posterior direction was negatively correlated with anterior dislocation forces. CONCLUSIONS: The custom-made inferiorly inclined glenosphere did not influence anterior stability, but baseplate inclination itself had a significant effect on stability.

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.

Statistical shape models that predict native glenoid width based on glenoid height are inaccurate in their current form: a cross-sectional study.

BACKGROUND: The extent of measurement errors of statistical shape models that predict native glenoid width based on glenoid height to subsequently determine the amount of anterior glenoid bone loss is unclear. Therefore, the aim of this study was to (1) create a statistical shape model based on glenoid height and width measured on 3-dimensional computed tomography (3D-CT) and determine the accuracy through measurement errors and (2) determine measurement errors of existing 3D-CT statistical shape models. MATERIALS AND METHODS: A retrospective cross-sectional study included all consecutive patients who underwent CT imaging before undergoing primary surgical treatment of traumatic anterior shoulder dislocation between 2007 and 2022 at the Tohoku University Hospital and affiliated hospitals. Patients were included when instability was unilateral and CT scans of both the injured and contralateral uninjured shoulder were available. 3D segmentations were created and glenoid height and width of the injured and contralateral uninjured side (gold standard) were measured. Accuracy was determined through measurement errors, which were defined as a percentage error deviation from native glenoid width (contralateral uninjured glenoid), calculated as follows: measurement error = [(estimated glenoid width with a statistical shape model - native glenoid width) / native glenoid width] × 100%. A linear regression analysis was performed to create a statistical shape model based on glenoid height according to the formula: native glenoid width = a × glenoid height + b. RESULTS: The diagnosis and procedure codes identified 105 patients, of which 69 (66%) were eligible for inclusion. Glenoid height demonstrated a very strong correlation (r = 0.80) with native glenoid width. The linear regression formula based on this cohort was as follows: native glenoid width = 0.75 × glenoid height - 0.61, and it demonstrated an absolute average measurement error of 5% ± 4%. The formulas by Giles et al, Chen et al and Rayes et al demonstrated absolute average measurement errors of 10% ± 7%, 6% ± 5%, and 9% ± 6%, respectively. CONCLUSION: Statistical shape models that estimate native glenoid width based on glenoid height demonstrate unacceptable measurement errors, despite a high correlation. Therefore, great caution is advised when using these models to determine glenoid bone loss percentage. To minimize errors caused by morphologic differences, preference goes to methods that use the contralateral side as reference.

Morpho-functional analysis of the temporomandibular joint following mandible-first bimaxillary surgery with mandible-only patient-specific implants.

The aim of this study was to evaluate condylar and glenoid fossa remodeling after bimaxillary orthognathic surgery guided by patient-specific mandibular implants. In total, 18 patients suffering from dentofacial dysmorphism underwent a virtually planned bimaxillary mandibular PSI-guided orthognathic procedure. One month prior to surgery, patients underwent a CBCT scan and optical scans of the dental arches; these datasets were re-acquired 1 month and at least 9 months postsurgery. Three-dimensional models of the condyles, glenoid fossae, and interarticular surface space (IASS) were obtained and compared to evaluate the roto-translational positional discrepancy and surface variation of each condyle and glenoid fossa, and the IASS variation. The condylar position varied by an average of 4.31° and 2.18 mm, mainly due to surgically unavoidable ramus position correction. Condylar resorption remodeling was minimal (average ≤ 0.1 mm), and affected skeletal class III patients the most. Later condylar remodeling was positively correlated with patient age. No significant glenoid fossa remodeling was observed. No postoperative orofacial pain was recorded at clinical follow-up. The procedure was accurate in minimizing the shift in relationship between the bony components of the TMJ and their remodeling, and was effective in avoiding postoperative onset of orofacial pain. An increase in sample size, however, would be useful to confirm our findings.

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.

Three-dimensional analysis of biplanar glenoid deformities: what are they and can they be virtually reconstructed with anatomic total shoulder arthroplasty implants?

BACKGROUND: Descriptions of glenoid deformities in glenohumeral osteoarthritis (GHOA) have focused on the axial plane. Less is known regarding arthritic glenoids with higher amounts of superior inclination and little evidence exists to guide management of inclination or combined version-inclination deformity when performing anatomic total shoulder arthroplasty (aTSA). We hypothesized that biplanar deformities (BD) would be present in a higher proportion of GHOA patients than previously appreciated, and these deformities would be difficult to adequately reconstruct with contemporary aTSA implants. METHODS: A retrospective query was performed of GHOA patients indicated for TSA 2012-2017 with a computed tomography (CT) scan within three months of surgery. Images were uploaded to three-dimensional (3D) software for automated measurements. Glenoids with superior inclination ≥10°, and retroversion ≥20° were considered to have BD. Walch classification was determined, and C-type glenoids were excluded. Rotator-cuff muscle cross-sectional area (CSA) was measured and fatty infiltration was graded. Glenoids with BD were virtually planned for aTSA with correction to neutral inclination and version, then with 5° superior inclination and 10° retroversion. RESULTS: Two-hundred and sixty-eight shoulders in 250 patients were included; average age was 65 years, 67% male. There were no differences in inclination between Walch types (P = .25). Twenty-nine shoulders with BD were identified (11%). These deformities were not associated with age (P = .47) or gender (P = .50) but were skewed towards Walch B-type, specifically B2 (P = .03). Acromial index and posterior humeral head subluxation were higher in BD patients (P = .04, P < .001, respectively). Biplanar deformities had similar cuff CSA compared to those without but were less frequently associated with fatty infiltration of the subscapularis (P = .05). When correcting to neutral version and inclination, 41% BD could not be reconstructed. Of those that could, 94% required augmented implants. When correcting to 5° superior inclination and 10° retroversion, 10% could not be reconstructed. Of those that could, 58% required augmented implants. With partial correction, augment use was predicted by retroversion >26° (P = .009). Inclination did not predict augment use (P = .90). Final implant position commonly involved unseating in the posterosuperior quadrant and cancellous exposure in the anteroinferior quadrant. CONCLUSIONS: This retrospective computed tomography (CT)-based study of 268 shoulders with GHOA found an 11% prevalence of BD. These deformities were commonly associated with Walch B2 wear patterns. Virtual aTSA planning showed a high failure rate (41%) when correcting to neutral version and inclination. Posteriorly augmented implants were frequently required, and often still involved unseating in the posterosuperior quadrant, increased cancellous exposure in the anteroinferior quadrant, and vault perforation.

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.

Are glenoid retroversion, humeral subluxation, and Walch classification associated with a muscle imbalance?

BACKGROUND: The etiology of humeral posterior subluxation remains unknown, and it has been hypothesized that horizontal muscle imbalance could cause this condition. The objective of this study was to compare the ratio of anterior-to-posterior rotator cuff and deltoid muscle volume as a function of humeral subluxation and glenoid morphology when analyzed as a continuous variable in arthritic shoulders. METHODS: In total, 333 computed tomography scans of shoulders (273 arthritic shoulders and 60 healthy controls) were included in this study and were segmented automatically. For each muscle, the volume of muscle fibers without intramuscular fat was measured. The ratio between the volume of the subscapularis and the volume of the infraspinatus plus teres minor (AP ratio) and the ratio between the anterior and posterior deltoids (APdeltoid) were calculated. Statistical analyses were performed to determine whether a correlation could be found between these ratios and glenoid version, humeral subluxation, and/or glenoid type per the Walch classification. RESULTS: Within the arthritic cohort, no statistically significant difference in the AP ratio was found between type A glenoids (1.09 ± 0.22) and type B glenoids (1.03 ± 0.16, P = .09), type D glenoids (1.12 ± 0.27, P = .77), or type C glenoids (1.10 ± 0.19, P > .999). No correlation was found between the AP ratio and glenoid version (ρ = -0.0360, P = .55) or humeral subluxation (ρ = 0.076, P = .21). The APdeltoid ratio of type A glenoids (0.48 ± 0.15) was significantly greater than that of type B glenoids (0.35 ± 0.16, P < .01) and type C glenoids (0.21 ± 0.10, P < .01) but was not significantly different from that of type D glenoids (0.64 ± 0.34, P > .999). When evaluating both healthy control and arthritic shoulders, moderate correlations were found between the APdeltoid ratio and both glenoid version (ρ = 0.55, P < .01) and humeral subluxation (ρ = -0.61, P < .01). CONCLUSION: This in vitro study supports the use of software for fully automated 3-dimensional reconstruction of the 4 rotator cuff muscles and the deltoid. Compared with previous 2-dimensional computed tomography scan studies, our study did not find any correlation between the anteroposterior muscle volume ratio and glenoid parameters in arthritic shoulders. However, once deformity occurred, the observed APdeltoid ratio was lower with type B and C glenoids. These findings suggest that rotator cuff muscle imbalance may not be the precipitating etiology for the posterior humeral subluxation and secondary posterior glenoid erosion characteristic of Walch type B glenoids.

Reliability assessment of new radiographic scales to evaluate radiolucency and bony in-between fin growth of partially cemented all-polyethylene glenoid components.

BACKGROUND: Current methods available for assessment of radiolucency and in-between fin (IBF) growth of a glenoid component have not undergone interobserver reliability testing for an all-polyethylene fluted central peg (FCP) glenoid. The purpose of this study was to evaluate anteroposterior radiographs of an FCP glenoid component at ≥48 months comparing commonly used scales to a new method adapted to the FCP. Our hypothesis was that the new method would result in acceptable intra- and interobserver agreement and a more accurate description of radiographic findings. METHODS: We reviewed ≥48-month follow-up radiographs of patients treated with a primary aTSA using an FCP glenoid. Eighty-three patients were included in the review. Radiographs were evaluated by 5 reviewers using novel IBF radiodensity and radiolucency assessments and the Wirth and Lazarus methods. To assess intraobserver reliability, a subset of 40 images was reviewed. Kappa statistics were calculated to determine intra- and interobserver reliability; correlations were assessed using Pearson correlation. RESULTS: Interobserver agreement (κ score) was as follows: IBF 0.71, radiolucency 0.68, Wirth 0.48, and Lazarus 0.22. Intraobserver agreement ranges were as follows: IBF radiodensity 0.36-0.67, radiolucency 0.55-0.62, Wirth 0.11-0.73, and Lazarus 0.04-0.46. Correlation analysis revealed the following: IBF to Wirth r = 0.93, radiolucency to Lazarus r = 0.92 (P value <.001 for all). CONCLUSION: This study introduces a radiographic assessment method developed specifically for an FCP glenoid component. Results show high interobserver and acceptable intraobserver reliability for the method presented in this study. The new scales provide a more accurate description of radiographic findings, helping to identify glenoid components that may be at risk for loosening.

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.