Inferior Glenoid Research Articles

A clinical study on the effect of axillary approach in the treatment of Ideberg type II scapular glenoid fractures

BackgroundDue to its deep position and complex surrounding anatomy, the scapular glenoid fracture was relatively difficult to deal with especially in cases of severe fracture displacement. Improper treatment may lead to failure of internal fixation and poor fracture reduction, severely affecting the function of the shoulder joint. Inferior scapular glenoid fracture was Ideberg type II fracture, and posterior approach was commonly used to deal with inferior scapular glenoid fracture. However, there are shortcomings of above surgical approach for inferior scapular glenoid fracture, such as insufficient exposure of the operative field, significant trauma, and limited screw fixation direction. This study adopts the axillary approach for surgery, which has certain advantages.MethodsThe clinical data of 13 patients with Ideberg type II scapular glenoid fractures treated from December 2018 to January 2024 were retrospectively analyzed. There were 8 males and 5 females, with an age range of 19 to 58 years and an average age of 38 years. The causes of injury were falls from heights in 7 cases and car accidents in 6 cases. There were 5 cases on the left side and 8 cases on the right side. The time from injury to surgery was 2 to 11 days, with an average of 5.5 days. All cases underwent open reduction and internal fixation through the axillary approach. Postoperative X-ray and CT three-dimensional reconstruction were performed on the next day to evaluate the fracture reduction and the position of internal fixation. During the follow-up period, follow-up examinations were performed every two months in the first half of the year and every three months in the second half. CT scans were performed during the examinations to assess the glenohumeral joint congruence, fracture healing, and position of internal fixation. The shoulder joint function was evaluated at 6 months postoperatively according to the Constant-Murley value score.ResultsThe patients all achieved primary wound healing after surgery, without any complications such as infection or nerve injury. Re-examination on the second day after operation, all fractures obtained excellent reduction, and the internal fixation was in excellent position, and no screw was found to enter the joint cavity. All patients in this group were followed up for 6 to 25 months, with an average follow-up time of 11.7 months. All fractures were bony unioned, and the healing time ranged from 4 to 6 months, with an average healing time of 4.8 months. At 6-month follow-up, according to the Constant-Murley score, 11 cases were excellent and 2 case was good.ConclusionOpen reduction and internal fixation through the axillary approach is an feasible and safe surgical method for the treatment in scapular Ideberg type II glenoid fractures with less stripping of soft tissue, minimal surgical trauma, and the incision is concealed and beautiful. It can provide a strong internal fixation for fractures, so patients can perform functional exercise early after operation, and the clinical results is satisfactory.

Inferior Glenoid HyperOSTosis (GHOST) Lesion Development Following Reverse Total Shoulder Arthroplasty

BackgroundPatients undergoing reverse shoulder arthroplasty (RTSA) have been noted on postoperative radiographs to have a curved bony overgrowth on the inferior glenoid neck. This study aims to investigate potential risk factors for and postoperative effects of these ossifications, here called glenoid hyperostosis (GHOST) lesions due to their location. MethodsA retrospective review of patients undergoing reverse total shoulder arthroplasty between 2007 and 2020 at a single institution was performed. Predictors including gender, age, implant sizing, and preoperative diagnosis were examined using logistic regression analysis. Outcomes including readmission rate, revision rate, preoperative and postoperative range of motion, visual analog scale (VAS) pain scores, and American Shoulder and Elbow Surgeons (ASES) functional outcome scores were also analyzed using two-sample t-tests. ResultsPreoperative and postoperative radiographs of 170 primary reverse shoulder arthroplasty patients were assessed. 25.9% of RTSAs were identified to have a GHOST lesion. When adjusting for race, age, BMI, preoperative diagnosis, male patients were still associated with 2.28 odds of developing a GHOST lesion compared to female patients (95% CI: 1.08 – 4.86). Other elements such as age, race, BMI, laterality, preoperative diagnosis, implant manufacturer, and implant sizing demonstrated no statistically significant association to GHOST lesion presence. Postoperatively, GHOST lesion development was not associated with range of motion or ASES score. However, presence of GHOST lesions on radiographs was associated with increased pain scores for patients at 2 months (p = 0.034) and 12 months (p = 0.029) postoperatively. DiscussionInferior glenoid hyperostosis (GHOST) lesions is a common and potentially benign finding following reverse shoulder arthroplasty, with unclear etiology. Risk factors for GHOST lesions included male gender, while patient demographics, implant type or size, shoulder lateralization and distalization were not associated with lesion formation. Clinically, greater short-term VAS scores were seen in patients with GHOST lesions. However, there were no differences observed between the two groups in ASES scores or postoperative range of motion at later time points. Further research is needed to identify risk factors and assess the clinical implications of GHOST lesions.

Arthroscopic subscapularis augmentation of the classic Bankart repair leads to satisfactory clinical and functional mid-term outcomes in patients with recurrent anterior shoulder instability and less than a subcritical glenoid bone loss.

The long-term failure rate of the arthroscopic Bankart repair may reach unacceptable values, raising the need to augment this classic procedure. Arthroscopic subscapularis augmentation is the tenodesis of the upper part of the subscapularis tendon to the anterior glenoid rim. The aim of the study was to evaluate the mid-term clinical and functional outcomes of patients operated with arthroscopic subscapularis augmentation of the classic Bankart repair due to recurrent anterior shoulder instability. This is a retrospective single-centre case series study with prospectively collected data. All patients suffered from recurrent anterior shoulder instability and had glenoid bone loss less than 13.5% of the inferior glenoid diameter (subcritical glenoid bone loss). Patients with greater anterior glenoid bone defect, engaging Hill-Sachs lesions, multidirectional instability or subscapularis insufficiency were excluded. Postoperatively, all patients were evaluated for recurrence and apprehension. The patient's shoulder range of motion and functional scores were recorded. The final study cohort included 34 patients with a mean age of 29.3 ± 10.2 years. The mean follow-up period was 42.4 ± 10.7 months (range, 24-62 months). Two out of 34 patients (5.8%) experienced a re-dislocation postoperatively, while one additional patient had a subjective feeling of apprehension. External rotation at the last follow-up was lower compared to preoperative values or the healthy side, but only one patient had restrictions in his sporting activities. The functional scores were significantly increased compared to the preoperative values. Twenty-two out of 26 patients (84.6%) returned to the same level of sporting activities, and 30/34 patients (88.2%) were highly satisfied with the results. Arthroscopic subscapularis augmentation of the classic Bankart repair reduces the dislocation recurrence rate and leads to satisfactory clinical and functional mid-term outcomes in patients with recurrent anterior shoulder instability and less than a subcritical glenoid bone loss. Level IV.

Arthroscopic Debridement and Resection of a Bennett Lesion in a Collegiate Baseball Pitcher

Background: Overhead throwing athletes are predisposed to ossification along the superior to inferior posterior glenoid rim, termed thrower's exostosis or a Bennett lesion. These lesions can result in posterior shoulder pain during throwing and decreased shoulder range of motion, and they can be associated with posterior labral tears and undersurface rotator cuff tears. In this video technique, we describe the arthroscopic debridement and resection of a symptomatic unstable Bennett lesion in a collegiate baseball pitcher who had unsuccessful nonoperative treatment. Indications: Currently, there is no standard treatment algorithm for Bennett lesions. Arthroscopic intervention is typically indicated in overhead throwers who have unsuccessful nonoperative protocols, including stretching of the posterior capsule, strengthening of the rotator cuff, and injections. Technique Description: In the lateral decubitus position, standard posterior viewing and anterior working arthroscopic portals are created followed by diagnostic arthroscopy. A high anterior accessory portal is created to view the posterior labrum and evaluate for tears. The location of the Bennett lesion is determined using a switching stick or probe. In this case, an accessory posterior viewing portal and capsulotomy are created under spinal needle visualization and a 70° scope is utilized for an improved view. Through the capsulotomy, a motorized shaver and radiofrequency wand is used to work along the posterior inferior glenoid neck to expose the lesion. Once the lesion is fully demarked, a hooded bur is utilized to debride the entirety of the lesion back to the smooth bony surface of the glenoid neck. After resection, the capsule is left open to avoid overtightening the posterior capsule in overhead throwing athletes. Results: Arthroscopic debridement and resection of a symptomatic Bennett lesion in a collegiate baseball pitcher allowed the patient to return to pain-free pitching at the same level of collegiate play the following season. Discussion/Conclusion: An unstable Bennett lesion can be a source of pain in the overhead throwing athlete. If nonoperative treatment modalities fail to resolve symptoms, arthroscopic debridement and excision of this lesion utilizing a posterior capsulotomy and accessory posterior viewing portal as described in this video technique is a safe and effective surgical option. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Arthroscopic Anterior and Inferior Labral Repair for Traumatic Shoulder Instability

Background: Anterior glenohumeral instability is common in the young and athletic population and can develop from a dislocation or subluxation event. Avulsion of the anterior inferior glenoid labrum (Bankart lesion) occurs in over 90% of these events. In patients who have unsuccessful conservative management or present with a high risk for redislocation, surgical intervention is indicated. This video presents our technique for arthroscopic anterior and inferior labral repair. Indications: In addition to those patients who have unsuccessful conservative management, surgical management of anterior glenohumeral instability is indicated in patients who are at high risk for redislocation after an initial instability event. These patients include young age and participation in contact sports. Generally, glenoid bone loss over 25% warrants open bony augmentation, but arthroscopic bony augmentation techniques are evolving. Further, the management of “near-track” lesions, or “on-track” lesions with a small distance to dislocation value, remains controversial. Technique Description: This procedure is performed in the lateral decubitus position. A second anterior portal is created distal and lateral to the first anterior portal, entering the shoulder joint just above the subscapularis. The anterior-inferior labrum is prepared with an arthroscopic elevator, followed by a rasp and superior labral anterior and posterior burr. A suture tape is then shuttled around the labrum and the anchor drilled in the appropriate position at the glenoid rim, not violating the cartilage. Anchor placement occurs from an inferior to a superior fashion until the entire labral injury is repaired. Results: This video presents a technique to achieve arthroscopic fixation of an anterior-inferior labral tear in a young athlete with anterior glenohumeral instability. Patients are taken through 3 phases of rehabilitation before return to sport-specific activities, such as contact sports, around 6 months postoperatively. Return-to-sport rates for contact and collision athletes range from 80% to 100%, with recurrent rates ranging from 5% to 20%. Discussion/Conclusion: Arthroscopic anterior-inferior labral repair is a useful technique for minimally invasive glenohumeral stabilization in indicated patients who have minimal glenoid bone loss. Portal placement, labral mobilization, and glenoid preparation are paramount in optimizing the healing potential of the fixation construct. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Structural Bone Grafting with Reverse Shoulder Arthroplasty for Osteoarthritis with Severe Glenoid Bone Loss: outcomes using a long post

Severe posterior glenoid bone loss with glenohumeral osteoarthritis with an intact rotator cuff can be managed with reverse shoulder arthroplasty but requires lateralization and version correction to avoid potential complications, such as instability, notching and implant failure. Angled bone grafting with humeral head autograft can provide durable glenoid bone stock, but results have been mixed. The purpose of this study was to evaluate patient-reported and objective outcomes as well as complication and failure rates for patients who underwent angled humeral head autografting for severe retroversion. All patients who underwent a primary RSA with angled humeral head autograft and Stryker Tornier long central post baseplate for severe glenoid bone loss in the setting of glenohumeral osteoarthritis with an intact rotator cuff at our institution between November 2018 and February of 2022 were identified. Individuals with a primary diagnosis of osteoarthritis and preoperative glenoid retroversion of ≥30° were included. Patients undergoing revision procedures, planned two-stage arthroplasty were excluded. Differences in pre- and postoperative range of motion, as well as patient-reported outcomes were assessed. Intraoperative complications, postoperative complications, and re-operation rates were analyzed. A total of 24 shoulders in 23 patients (61% male), with a mean age of 65.6 years were included. Average preoperative retroversion was 37.4° (range: 30° - 51°). Mean follow-up was 2.9 years (range: 2 - 4.3 years). Significant improvements were found in flexion, abduction, and external rotation. Patient-reported subjective outcomes were excellent, with average ASES score of 93.6 and average SSV 93.8%. Sixteen (67%) shoulders received postoperative CT scans and all were found to have incorporated. Complications included one shoulder hematoma requiring incision and drainage without revision, and a post-traumatic fracture of the inferior glenoid screw at 11 months, requiring revision RSA with bone grafting. No atraumatic catastrophic failures occurred due to component loosening. This study suggests that using angled humeral head bone grafting is a good solution for version correction in extreme posterior glenoid bone loss. Significant improvements are reported in ROM, pain, and subjective functional scores, with excellent graft incorporation rates and a low complication profile at early follow-up. Further work should focus on gathering higher levels of evidence, detailed radiographic analyses and exploring humeral head bone grafting for other indications.

Arthroscopic Autologous Iliac Crest Grafting with an Adjustable Loop Suspensory Device Yields Favorable Outcomes for Anterior Shoulder Instability with Glenoid Defects.

This study aims to evaluate the clinical and radiological outcomes of the arthroscopic autologous iliac crest grafting (AICG) procedure with an adjustable-loop suspensory fixation device in the treatment of anterior shoulder instability (ASI) with glenoid bone defects. A retrospective review was conducted on the patients who underwent arthroscopic AICG with an adjustable-loop suspensory fixation device from January 2017 to December 2020. Patients with traumatic ASI, significant glenoid bone defects, and a minimum follow-up of 24 months were included. Patient-reported outcomes (PROs), including the Oxford Shoulder Instability Score (OSIS), the Rowe score, the Walch-Duplay score, the Constant score, and the Visual Analogue Score (VAS), were compared preoperatively and postoperatively. Radiological assessments using computed tomography (CT) were performed before and after the procedure. Additional data on active range of motion, recurrence events, and complications were recorded. A total of 42 patients were included in the study, with a mean follow-up time of 35.2 months ranging from 25.1 to 55.9 months. Mean preoperative OSIS, Rowe score, Walch-Duplay score, and Constant score significantly improved from 24.4±7.2, 25.0±9.0, 25.2±9.8, 87.5±7.1 to 42.4±4.9, 92.4±8.1, 87.9±8.3, 93.6±4.5 at the last follow-up, respectively. All patients exceeded the minimal clinically important difference (MCID) for OSIS, Rowe, and Walch-Duplay scores. The graft union rate was 100%, and the glenoid area increased significantly from 82.5% preoperatively to 100.1% at the final follow-up. No patient experienced a recurrence of instability. Two recorded complications included one case of dysesthesia around the donor site and one case of postoperative shoulder stiffness. The outcomes of the arthroscopic AICG procedure, which utilizes an adjustable-loop suspensory fixation device, demonstrated stable bone graft fixation, high rates of graft integration, favorable clinical results, and a low incidence of complications. Moreover, the remodeling of the graft during the follow-up period significantly restored the width and concavity of the inferior glenoid, contributing to the overall recovery. Level IV, retrospective case series.

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

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.

Effect of Glenoid Bone Loss and Shoulder Position on Axillary Nerve Anatomy During the Latarjet Procedure.

The Latarjet procedure is increasingly being utilized for the treatment of glenoid bone loss and has a relatively high neurological complication rate. Understanding the position-dependent anatomy of the axillary nerve (AN) is crucial to preventing injuries. To quantify the effects of changes in the shoulder position and degree of glenoid bone loss during the Latarjet procedure on the position of the AN. Controlled laboratory study. A total of 10 cadaveric shoulders were dissected, leaving the tendons of the rotator cuff and deltoid for muscle loading. The 3-dimensional position of the AN was quantified relative to the inferior glenoid under 3 conditions: (1) intact shoulder, (2) Latarjet procedure with 15% bone loss, and (3) Latarjet procedure with 30% bone loss. Measurements were obtained at 0°, 30°, and 60° of glenohumeral abduction (equivalent to 0°, 45°, and 90° of shoulder abduction) and at 0°, 45°, and 90° of humeral external rotation (ER). Abduction of the shoulder to 60° resulted in a posterior (9.5 ± 1.1 mm; P < .001), superior (3.0 ± 1.2 mm; P = .013), and lateral (19.1 ± 2.3 mm; P < .001) shift of the AN, and ER to 90° resulted in anterior translation (10.0 ± 1.2 mm; P < .001). Overall, ER increased the minimum AN-glenoid distance at 30° of abduction (14.9 ± 1.3 mm [0° of ER] vs 17.3 ± 1.5 mm [90° of ER]; P = .045). The Latarjet procedure with both 15 and 30% glenoid bone loss resulted in a superior and medial shift of the AN relative to the intact state. A decreased minimum AN-glenoid distance was seen after the Latarjet procedure with 30% bone loss at 60° abduction and 90° ER (17.7 ± 1.6 mm [intact] vs 13.9 ± 1.6 mm [30% bone loss]; P = .007), but no significant differences were seen after the Latarjet procedure with 15% bone loss. Abduction of the shoulder induced a superior, lateral, and posterior shift of the AN, and ER caused anterior translation. Interestingly, the Latarjet procedure, when performed on shoulders with extensive glenoid bone loss, significantly reduced the minimum AN-glenoid distance during shoulder abduction and ER. These novel findings imply that patients with substantial glenoid bone loss may be at a higher risk of AN injuries during critical portions of the procedure. Consequently, it is imperative that surgeons account for alterations in nerve anatomy during revision procedures. This study attempts to improve understanding of the position-dependent effect of shoulder position and glenoid bone loss after the Latarjet procedure on AN anatomy. Improved knowledge of AN anatomy is crucial to preventing potentially devastating AN injuries during the Latarjet procedure.

Revision Anterior Glenoid Reconstruction With Distal Tibia Allograft Combined With Open Capsular Shift

Background: Managing patients with recurrent anterior shoulder instability and glenoid bony deficiency remains a challenge. Multiple graft options, including iliac crest, distal clavicle, coracoid, and distal tibia allograft have been used. There is a growing body of evidence that supports distal tibia allograft for glenoid restoration in patients with shoulder instability due to its ability to restore the articular surface as well as the glenoid depth and curvature. Indications: Surgical indications for anterior glenoid reconstruction with distal tibia allograft combined with open capsular shift include patients with recurrent shoulder instability and glenoid bone loss. Technique Description: A deltopectoral interval is utilized and the subscapularis is split in lines with its fibers. The subscapularis and capsule are split together in a horizontal fashion and tagged together. Any prior hardware is then removed utilizing appropriate removal sets, a burr, and a broken screw set if necessary. The anterior glenoid is then prepared and the defect is measured. Bone marrow aspirate is then harvested from the proximal humerus using a vortex needle. The distal tibia allograft is then cut to size and prepared utilizing pulsed lavage, pressurized sterile carbon dioxide, and the bone marrow aspirate. The allograft is then fixed with solid stainless steel 3.5-mm cortical screws with washers. The medial, glenoid based capsular repair it completed by placing 1.8-mm knotless FiberTak anchor at the bottom of the distal tibia allograft. A free needle is utilized to place a horizontal mattress stitch from the anchor to the inferior capsule, which is then loaded onto a shuttling suture, to repair it to the anterior inferior glenoid. A knotless anchor is then placed right off the chondral margin of the humeral head, and this is used to repair both the capsule and subscapularis in the correct position by passing through both inferior and superior leaflets. This is then loaded onto the knotless anchor and reduced, which shifts the subscapularis and capsule laterally. The remainder of the subscapularis split is then closed. Patients are then placed in a sling with an abduction pillow with no shoulder range of motion for 6 weeks. They can then progress their therapy with a goal of returning to sport at 6 months. Results: Several large systemic reviews have shown that return to sport rates after anterior glenoid reconstruction range between 80% and 90%, with returning to the same level of play in the 70% range. Discussion: Anterior glenoid reconstruction utilizing distal tibia allograft combined with an open capsular shift is a durable surgical option for patients presenting with shoulder instability and glenoid bone loss. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Comparative Analysis of Eccentric Glenosphere in Reverse Total Shoulder Arthroplasty: A Computer Simulation Study.

The aim was to evaluate the effects of different glenosphere eccentricities on impingement, range of motion (ROM), and muscle length during standard activities in reverse total shoulder arthroplasty (RSA). In this study, we utilized computational modeling techniques to create native shoulder and shoulder models undergoing RSA and simulate shoulder movements in all abduction-adduction, flexion-extension, and rotation. We tested a total of 36 different glenosphere configurations, which included three different inferior tilts (0°, +10°, +20°) and two different lateral offsets (0 mm and +4 mm), as well as six different glenosphere eccentricities (concentricity, inferior, posterior, anterior, anteroinferior, and posteroinferior). We evaluated the maximum impingement-free ROM, impingement sites, and muscle lengths. All glenosphere configurations exceeded 50% of native shoulder ROM in three planes and total global ROM. In abduction-adduction, there was no significant difference among the different glenosphere eccentricities (p > 0.05). In flexion-extension, the posteroinferior eccentricity had the maximum ROM among the different eccentricities, but no significant difference among the different glenosphere eccentricities (p > 0.05). In rotation, there was a significant difference overall, and anteroinferior eccentricity had a significant advantage over concentricity (p < 0.05). In total global ROM, anteroinferior eccentricity had a significant advantage over concentricity when lateral offset was 0 mm (p < 0.05). In all models of glenosphere eccentricities, only the elongation of the infraspinatus muscle was statistically significant (p < 0.05). Glenosphere eccentricity significantly influenced rotation, total global ROM, and the length of the subscapularis muscle. Among them, anteroinferior offset achieved the maximum ROM in abduction-adduction, rotation, and total global activities. Both anteroinferior and inferior glenoid eccentricity showed significant advantages over the concentricity in rotation and total global ROM. Basic Science Study; Computer Modeling.

The base plate orientation angle: a plain radiographic technique for designing the base plate’s inclination in reverse shoulder arthroplasty

Superior inclination of the base plate in reverse shoulder arthroplasty (RSA) is underestimated and may lead to major setbacks in terms of functional outcomes due to the altered biomechanics. Joint instability, scapular notching, and loosening of the glenoid component are considered the most serious sequelae. Therefore, a thorough preoperative radiological assessment of the affected shoulder joint and customized design of the prosthesis according to the glenoid morphology are decisive and directly correlated to the outcome. In this article, we propose a simple radiographic technique to assess the inclination of the glenoid preoperatively, which identifies the need for intraoperative correction. One hundred inconspicuous shoulder radiographs were included in the control group (CG) to define the normal ranges of the base plate orientation angle (BOA) and the base plate correction angle (BCA). Further, both angles were measured on 2-dimensional (2D) computed tomography scans of patients with proximal humerus fractures as well as radiographs, 2D and 3-dimensional (3D) computed tomography scans of patients with cuff tear arthropathy who underwent RSA between 2018 and 2021. The interobserver reliability among three independent testers was evaluated by calculating the intraclass correlation coefficient. In cuff tear arthropathy cases, the BOA and BCA measurements on different imaging modalities were compared using the Wilcoxon test. Possible variations of both angles' values based on glenoid erosion types, according to the Favard classification, were also investigated. Regardless of the imaging modality used, the interobserver reliability was excellent among three independent observers. In the CG, the mean BOA and BCA values were 118°±6° and 17°±5°, respectively. The mean corrected BOA values of the CG and fracture group were 136°±5° and 140°±5°, respectively. In contrast to the BCA values, the BOA measurements on radiographs showed a statistically significant difference compared to those obtained on 2D- and 3D scans in the cuff arthropathy group. Further, both angles' values varied according to the extent and location of the glenoid erosion. The lowest mean BOA and highest mean BCA values were observed in cases with Favard glenoid type E3. The BOA and the BCA are reliable tools proposed to aid in precisely positioning the glenoid component in RSA in the preoperative setting. Whereas, the BOA determines the inclination of the inferior glenoid segment, the BCA represents the extent of correction required to obtain a neutral inclination of the base plate. Glenoid type E3 of the Favard classification with superior wear is particularly susceptible to base plate superior tilt.

Magnetic Resonance Imaging Analysis Demonstrates Improved Reliability in Measuring Shoulder Glenoid Bone Loss Using a Two-Thirds Glenoid Height Technique Compared to the “Best-fit Circle”

To evaluate the superior to inferior glenoid height as a reliable reference in best-fit circle creation for glenoid anatomy. The morphology of the native glenoid was evaluated using magnetic resonance imaging (MRI) in patients without shoulder instability. Using T1 sagittal MRI images, two reviewers independently estimated glenoid size using the two-thirds technique and the "best-fit circle" technique at two different times. A student's t-test was used to determine significant difference between the two methodologies. Inter- and intra-rater reliability were calculated using interclass and intraclass coefficients. This study included 112 patients. Using the results of glenoid height and "best-fit circle" diameter, the diameter of the "best-fit circle" was found to intersect the glenoid line at 67.8% of the glenoid height on average. We found no significant difference between the two measures of glenoid diameter (27.6 vs 27.9, p =.456). The interclass and intraclass coefficients for the two-third method were 0.85 and 0.88, respectively. The inter-class and intra-class coefficients for the perfect circle methods were 0.84 and 0.73, respectively. We determined that the diameter of a circle placed on the inferior glenoid using the 'best-fit circle' technique corresponds to 67.8% of the glenoid height. Additionally, we found that constructing a perfect circle using a diameter equal to two-thirds the height of the glenoid may improve intra-class reliability.

Poster 193: Glenoid Bone Loss Evaluation: Utilization of Current Methods

Objectives: Preoperative evaluation of glenoid bone loss is essential in surgical planning and for patients’ expectations of their surgical outcome. The four literature backed methods for measuring glenoid bone loss include the chord method, percent diameter method, the intraoperative probe method, and Pico method. Using the intraoperative probe method, it has been suggested that 25% bone loss of the inferior glenoid may be the threshold of significant bone loss. In contrast, other studies show bone loss using percent diameter above 13.5-17.3% has been associated with significantly worse clinical outcomes. Differences in bone loss measurements method utilization can lead orthopedic surgeons to proceeding with soft-tissue stabilization in a high-risk patient or alternatively to an unnecessary osseous augmentation procedure. Therefore, it is important to understand how orthopedic surgeons measure bone loss. While 3D CT and the Pico method have been previously described as the gold standard in bone loss evaluation for their highest accuracy and interobserver reliability, it is unclear how most orthopedic surgeons evaluate for bone loss in their practice. The purpose of this study is to investigate how orthopedic surgeons measure glenoid bone loss. Methods: Based on existing literature, a 16-question survey was created by the senior author. This survey included questions investigating participants’ demographic information, typical surgical practice and volume, and glenoid bone loss identification method. The survey was sent out to members of the American Orthopedic Society for Sports Medicine (AOSSM) and Arthroscopy Association of North America (AANA). Results: One-hundred-seventy-two orthopedic surgeons responded to the survey with an average of 13.4 years in practice and average number of instability surgeries performed each year of 31.2 +/- 35. In regard to subspecialty, 137 participants completed a sports medicine fellowship, 18 completed a shoulder and elbow fellowship, 10 completed both a sports medicine and shoulder and elbow fellowship, 1 completed a sports medicine and pediatric sports medicine fellowship, and 1 completed a sports medicine and trauma fellowship (97% response rate). Responders were from a variety of geographic locations: 26% were from the Northeast, 30% were from the Midwest, 21% were from the South, 10% were from Mountain States, 10% were from the West Coast, 1 was from Hawaii, 1 was from Alaska, 1 was from Columbia, and 1 practiced in Italy (98% response rate). 46% of responders belong to a private practice, while 34% practice at an academic institution. An additional 16% reported a hospital- based practice, 2% reported military affiliation, and 2% work in a private practice with academic affiliations (99% response rate). 91.3% of responders said that they routinely measure glenoid bone loss. 3D CT was the imaging modality most commonly used for bone loss evaluation (125), followed by 2D MRI (86), X-rays (68), 2D CT (60), and 3D MRI (11) (Figure 1). The frequency of four common bone loss evaluation methods were analyzed: percent diameter loss was the most commonly used and was used routinely, the intraoperative probe length method was used occasionally, Pico method was used rarely, and the chord length method was used never (Figure 2). There was no significant effect of time in practice, practice location, and fellowship training on bone loss methods. Those in private practice or a medical group setting had a higher frequency of using the intraoperative probe length method. Conclusions: The result of this study suggests that there is significant inconsistency in how orthopedic surgeons evaluate and measure glenoid bone loss in the setting of shoulder instability. While physicians commonly use the most reliable imaging modality (3D CT), the most accurate literature backed method for evaluating bone loss (Pico method) is seldom used. Future research is necessary to understand the limiting factor for orthopedic surgeons to incorporate validated glenoid bone loss measurements into their practice and develop new automated methods to improve overall utilization.

Pyrocarbon hemiprostheses show little glenoid erosion and good clinical function at 5.5 years of follow-up

The success of traditional shoulder hemiarthroplasty with cobalt-chromium (CoCr) heads is limited by a painful glenoid erosion with problematic bone loss. Hemiprostheses with pyrolytic carbon (PyC) heads have shown reduced glenoid erosion in experimental laboratory studies. Few in vivo data are available. Single-center consecutive cohort study of 31 of 34 patients (91%) who underwent PyC hemiarthroplasty between 09.2013 and 06.2018. For eleven of these concentric glenoid reaming was additionally performed. The mean follow-up was 5.5 (range 3.5 - 7) years. Standardized x-rays were taken and clinical function (Constant score) and pain on the visual analogue scale (VAS) were recorded. AP x-rays were analyzed according to an established method by 2 independent observers: A line parallel to the superior and inferior glenoid rim was translated to the most medial point of the glenoid surface. A further parallel line was placed on the spinoglenoid notch (SGN) and the distance between the two lines was measured. Measurements were scaled using the known diameter of the implanted humeral head component. To assess eccentric erosion AP and axial images were classified according to Favard and Walch respectively. The mean medial glenoid erosion was 1.4 mm over 5.5 years. In the first year there was 0.8 mm of erosion, significantly more than the average erosion per year of 0.3 mm (p < 0.001). Mean erosion per year of patients with glenoid reaming was 0.4 mm, without reaming 0.2 mm (p = 0.09). An evolution of glenoid morphology was observed in 6 patients, of which 4 had a progression of the erosion grade. Prosthesis survival rate was 100%. The Constant score improved from 45.0 preoperatively to 78.0 2-3 years postoperatively and 78.8 at latest follow-up 5.5 years postoperatively (p < 0.001). Pain decreased from VAS 6.7 (3 - 9) preoperatively to 2.2 (0 - 8) at latest follow-up (p < 0.001). There was a weak correlation (r = 0.37) between erosion and pain improvement (p = 0.039) and no correlation between erosion and delta Constant score (r = 0.06). PyC HA caused little glenoid erosion and a sustained improvement in clinical function in our cohort at mid-term follow-up. PyC demonstrates a biphasic development of glenoid erosion, with a reduced rate after the first year. PyC hemiarthroplasty should therefore be considered as an alternative to total shoulder arthroplasty or CoCr hemiarthroplasty for patients with a high risk of glenoid component complications.

Lateral Decubitus Positioning For Shoulder Arthroscopy

Background: Lateral decubitus positioning is a frequently employed technique to perform shoulder arthroscopy. Proper patient positioning and equipment setup is crucial to ensure a safe and efficient surgery. Indications: The common indications for performing a shoulder arthroscopy in the lateral decubitus position include anterior shoulder stabilization, posterior shoulder stabilization, superior labrum anterior to posterior (SLAP) repair, diagnostic arthroscopy for internal impingement, and arthroscopic capsular release for adhesive capsulitis. Technique Description: After undergoing general endotracheal anesthesia in the supine position on a standard operating room table, the patient is rotated into the lateral decubitus position with the operative arm facing upward. The patient’s head is supported with a pillow to ensure a neutral position. The nonoperative arm is flexed forward and rests on a padded arm board. The sides of a bean bag are applied to the patient’s torso to maintain the lateral decubitus position, and the bean bag is deflated to remain rigid. An axillary roll is placed under the axilla, and foam pads are placed below the “down leg” and between both legs. A commercial arm jack is positioned on the anterior, proximal side of the operating room table to allow for 20° of shoulder abduction, which maximizes the glenohumeral joint space. Results: Advantages of the lateral decubitus position over the beach chair position include improved access to the anterior, inferior, and posterior glenoid; more ergonomic positioning for the operating surgeon; lower risk for patient cerebral hypoperfusion; and reduced rates of recurrent instability following arthroscopic stabilization in comparison to procedures performed in the beach chair position. Disadvantages of the lateral decubitus position include risk of traction-related neurovascular injury, requirement of an arm suspension device, and increased difficulty in rotating the shoulder intraoperatively. Discussion/Conclusion: Lateral decubitus positioning is commonly used to achieve a circumferential view of the glenohumeral joint in shoulder arthroscopy. This surgical position yields several advantages for the operating surgeon and has been shown to be associated with improved clinical outcomes after shoulder instability surgery. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Arthroscopically Assisted Anterior Bone Block for Shoulder Instability

Background: Shoulder instability is a common complaint, with treatment depending on the severity of the bony defect. Advancements in arthroscopic techniques have allowed for a less invasive surgery with decreased postoperative pain, improved graft placement, and better visualization. Indications: Large bony defects of the glenoid require bone block augmentation to reduce recurrent instability. In this presentation, arthroscopically assisted anterior bone block was performed with a distal tibial allograft to address recurrent anterior shoulder instability with a large glenoid defect. Technique Description: The patient is placed in a lateral decubitus position. Standard arthroscopic portals are made. The bone block is fashioned from a distal tibial allograft. Using a guide, drill holes are placed in the bone block. The guide is inserted from the posterior portal and placed parallel to the joint surface. Using drill sleeves, superior and inferior screw holes are drilled and a metal cannula is left in place to allow for shuttling of suture. Two anchors are placed on the glenoid to allow for capsule labral junction to be brought up to the graft once the graft is in place. The bone block is delivered through a dilated anterior portal and reduced. The sutures are tensioned. A button is placed on each set of looped sutures, a Nice knot is placed into each, and a tensioning device is tensioned. Once compression is achieved, knots are tied to perform final fixation over the buttons. A suture passing device is used to grab inferior capsule and labrum to the priorly placed anchor on the inferior glenoid and tied. Results: Arthroscopically assisted anterior bone block for shoulder instability has been demonstrated to have similar clinical and radiographic outcomes when compared with open treatment. However, arthroscopically assisted Latarjet has been shown to have decreased soft tissue disruption and possible improvements in graft placement. Discussion/Conclusion: Arthroscopically assisted anterior bone block is a technically demanding surgery but has been shown to have similar outcomes when compared with open treatment. In this video, we demonstrate an arthroscopically assisted anterior bone block for recurrent anterior shoulder instability. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

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

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. 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 etal, 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. 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°. 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.

Bony glenoid reconstruction in revision arthroplasty

Glenoid pathologies are one of the main indications for shoulder arthroplasty revisions. In most cases, the glenoid bone defect is associated with insufficiency of the rotator cuff, so that only reverse total shoulder arthroplasty can be considered as arevision implant. For stable permanent fixation of the reverse glenoid component, to avoid inferior glenoid notching, and to achieve optimal function, physiological restoration of three-dimensional glenoid anatomy is necessary. In order to approach the individual glenoid pathologies in adifferentiated and optimal manner, it is important to classify the defects. Abasic distinction must be made between centric contained and eccentric uncontained defects. Combinations often occur. It is also important to consider the severity, depth, and three-dimensional orientation of the defect. Therefore, aCT analysis of the glenoid is essential preoperatively. The data obtained should serve as the basis for computer-assisted planning to determine the optimal position of the glenoid baseplate and the type and shape of the bone graft for the reconstruction. For patients with good bone quality, we recommend defect reconstruction with autologous iliac crest. The type of graft configuration and fixation and the decision between aone- and two-stage procedure depend on the type and severity of the defect. With technically correct reconstruction and proper prosthesis implantation, sufficient integration of the bone graft and durable fixation of the glenoid component can be expected with satisfactory clinical results. After bony reconstruction of the defects, repeated treatment with areverse arthroplasty is possible in the long term in the event of renewed glenoid problems.

Superior and Anterior Glenoid Labral Tears Are Associated With Increased Neurofilament Concentration

Background: Pain is a common presentation after glenohumeral labral injuries. However, the source of that pain is undetermined. Purpose/Hypothesis: We aimed to determine if there is a differential expression of nerve fibers around the glenoid labrum and if torn labra have increased neuronal expression compared with untorn labra (rotator cuff repair labra). We hypothesized that the superior labrum would have a higher concentration of neurofilament than would the rest of the labrum and that the concentration of neurofilament would increase at the site of a labral tear. Study Design: Descriptive laboratory study. Methods: Seven labra were sampled at the 3-, 5-, 9-, and 12-o’clock positions during total shoulder arthroplasty. Samples were also collected at the 3-, 5-, and 12-o’clock positions during rotator cuff repair (16 labra), anterior labral repair (6 labra), type II superior labral anterior to posterior (SLAP) repair (4 labra), and capsular release for idiopathic capsulitis (5 labra). Sections were immunostained with antibodies to neurofilament, a specific neuronal marker that is used to identify central and peripheral nerve fibers, and the concentration and intensity of immunostained-positive cells assessed. Results: The concentration of neurofilament staining was similar in the superior, anterior, posterior, and inferior glenoid labrum in untorn labra (8 neurofilament expressing cells per square millimeter; P = .3). Torn labra exhibited a 3- to 4-fold increase in neuronal expression, which was isolated to the location of the tear in SLAP (P = .09) and anterior labral tears (P = .02). The concentration of neurofilament expressing cells in torn glenoid labrum samples was comparable that in with the glenoid labrum of adhesive capsulitis samples (P = .7). Conclusion: This study supports the hypothesis that after a tear of the anterior or superior labrum the labrum in that region becomes populated with new nerves fibers and that these fibers may be responsible for the pain noted by patients with superior (SLAP) and/or anterior labral (Bankart) tears. Clinical Relevance: This study suggests that neural infiltration contributes to the pain experienced by patients with labral tears. It may help with patient education and direct future management of labral lesions.