Superior approach to the glenoid for treating acromion fractures combined with ideberg type III scapular glenoid fractures: a technical note.

PURPOSE: Scapular glenoid fractures, categorized based on the Ideberg classification, are commonly addressed surgically through approaches like the anterior deltoid-pectoral approach, posterior Judet approach, modified Judet approach, or posterior axillary approach. However, these methods present limitations in exposing the superior part of the glenoid. Therefore, we propose an approach for patients with concomitant acromion fractures, involving the anterior lateral flipping of the fractured acromion, allowing direct superior visualization of the superior and posterior superior parts of the glenoid. METHOD: Retrospective analysis was conducted on the data of five patients with shoulder fractures combined with scapular Ideberg III fractures between June 2018 and May 2023. All patients were treated using the shoulder approach above the scapular spine. There were four males and one female, aged 23-54 years with an average age of 36.6 years. One case involved the left shoulder, and four cases involved the right shoulder. X-rays and CT were taken before and after surgery to assess the location of the fractures and the healing status. Clinical evaluation included the assessment of efficacy using the Constant-Murley scoring criteria and analysis of surgical complications. RESULTS: All five patients were followed up for a duration of 14-36 months. All fractures healed completely, with an average healing time of 4.3 months (range: 3-6 months). There were no complications such as suprascapular nerve injury, nonunion, wound infection, or shoulder joint instability observed postoperatively. At the final follow-up, the Constant-Murley shoulder joint function score ranged from 84 to 98 points, with an average of 91.4 points. Three patients achieved an excellent rating in shoulder joint function score, while two patients achieved a good rating. CONCLUSION: The shoulder approach above the scapular spine exhibits advantages such as easy exposure and reduction, minimal intraoperative trauma, and clear visualization.

Risk Factors Analysis and Prediction of Rotator Cuff Tears: A Retrospective Study.

AIM: Rotator cuff tears (RCTs) are a major cause of shoulder pain and disability, affecting millions worldwide. Understanding the risk factors and developing reliable predictive measures for RCTs is essential for early diagnosis, targeted prevention, and effective treatment of this patient population. This study seeks to enhance our understanding by analyzing the acromiohumeral distance (AHD) and Constant-Murley Score (CMS) in patients with and without RCTs, thereby aiding the development of a predictive model aimed at improving clinical outcomes and prevention strategies in rotator cuff pathology. METHODS: This retrospective analysis involved 201 patients with shoulder pain, categorized into RCT (n = 72) and no RCTs (N-RCTs, n = 129) groups based on Magnetic Resonance Imaging (MRI) findings. We compared demographics, AHD, CMS, and rotator cuff status between groups and utilized logistic regression for identifying RCT predictors, leading to the development of a multifactorial predictive model. RESULTS: The mean AHD was 6.60 ± 1.12 mm. The RCT group showed a marginally higher AHD than the N-RCT group (p = 0.669). CMS scores were significantly lower in the RCT group (p < 0.001). Dominant side involvement (Odds Ratio (OR) 2.244), type III acromion (OR 6.106), and lower CMS (OR 0.938) significantly correlated with RCTs. The predictive model demonstrated an area under the curve (AUC) of 0.701 for RCT diagnosis. CONCLUSIONS: Reduced CMS, dominance of the affected side, and type III acromion emerged as key risk factors for RCTs. Our predictive model, incorporating these factors, holds promise for RCT diagnosis, with future studies needed for further validation.

Ipsilateral fractures of the acromion and coracoid processes of the scapula.

A fracture of the acromion and coracoid processes of scapula is rarely seen in the outpatient clinic, due to the acromion's anatomical position and shape, as well as the strong ligaments and muscles that are attached to it. These fractures are caused by either direct or indirect high-energy trauma injuries to the shoulder joint, leading to severe pain and a grossly restricted range of motion. Several acromial classifications were reported, but this type of longitudinal plane fracture of the acromion process in our case is yet to be described in the current literature. We present a rare combination of the coracoid process and unstable acromion bony projection fractures that have not previously been noted for this type of fracture. The closest to this is Kuhn's type III classification. A 51-year-old male presented to our emergency department complaining of the right shoulder pain and difficulty raising his arm following a 2-wheeler accident. The patient was managed by open reduction and internal fixation with 3 cannulated cancellous screws fixation and progressed well with no postoperative complications. He was asymptomatic postoperatively and regained full range of motion after 4 months.

Mitigating Fracture of the Acromion and Scapular Spine After Reverse Shoulder Arthroplasty: A Critical Analysis Review of Patient and Surgical Risk Factors.

LEVEL OF EVIDENCE: Level V. Narrative Review. See Instructions for Authors for a complete description of levels of evidence.

Nonunion of the so-called acromion: a systematic review with consideration of the terminology.

INTRODUCTION: There is no widely accepted standard for the classification and treatment of traumatic acromion/scapular spine fracture nonunion due to the scarcity of this condition and the confusion of terminology. MATERIALS AND METHODS: PubMed and Scopus were searched using "scapular fracture" and "acromion fracture" or "scapular spine fracture" as search terms. The inclusion criteria were English full-text articles concerning acromion/scapular spine fracture nonunion that described patient characteristics and presented appropriate images. The exclusion criteria were cases without appropriate images. Citation tracking was conducted to find additional articles and notable full-text articles written in other languages. Fractures were classified using our newly proposed classification system. RESULTS: Twenty-nine patients (19 men, 10 women) with 29 nonunions were identified. There were four type I, 15 type II, and 10 type III fracture nonunions. Only 11 fractures were isolated. The mean period from initial injury to final diagnosis was 35.2 ± 73.2 months (range 3-360 months) (n = 25). The most frequent cause of delayed diagnosis was conservative treatment for fracture in 11 patients, followed by oversight by the physician in 8. The most common reason for seeking medical advice was shoulder pain. Six patients received conservative therapy, and 23 received operative treatment. Fixation materials included various plates in 15 patients, and tension band wiring in 5. Bone grafting was performed in 16 patients (73%, 16/22). Of the 19 surgically treated patients with adequate follow-up, the outcome was rated excellent in 79%. CONCLUSIONS: Isolated acromion/scapular spine fracture nonunion is rare. Fracture type II and III, arising in the anatomical scapular spine, accounted for 86% of the fractures. Computed tomography is required to prevent fracture oversight. Surgical therapy produces good stable results. However, it is important to select the appropriate surgical fixation method and material after considering the anatomical characteristics of the fracture and stress on the fractured portion. LEVEL OF EVIDENCE: V.

Diagnosis and Management of Early Complications After Reverse Shoulder Arthroplasty.

Reverse shoulder arthroplasty has become the predominant shoulder arthroplasty procedure. Despite newer design modifications, complications still occur after reverse shoulder arthroplasty. Early complications include instability, acromial and scapular spine stress fractures, periprosthetic fractures, periprosthetic joint infections, and neurologic injury. It is important to discuss the diagnosis and management of these early complications.

The study of screw placement parameters for Ogawa type I acromial fractures by 3D simulation.

BACKGROUND: Acromial fractures are rare and there is no consensus on fixation, but an increasing number of studies have reported using two screws to fix Ogawa type I acromial fractures. The objective of this study was to obtain the ideal length, diameter, insertion point, and angle of the screw using a novel 3D simulation. METHODS: The scapular CT data of 100 individuals were obtained to reconstruct 3D models. The transparency of the 3D model was then downgraded along the axial perspective (the view perpendicular to the cross section of the acromion axis) to find the maximum translucent area. Two virtual screws were placed at the anterior edge of the acromion until they penetrated the posterior cortical bon. The largest diameters and lengths of the screw were measured, and the direction and insertion point of the screw were observed. RESULTS: The mean maximum lengths of the medial and lateral screws were 43.33 ± 6.17 mm and 39.23 ± 6.01 mm, respectively. The mean maximum diameters of the medial and lateral screws were 4.71 ± 1.23 mm and 4.97 ± 1.07 mm, respectively. Differences in screw length, diameter, and insertion point between males and females were found. The differences in screw angle between sexes were not statistically significant. CONCLUSIONS: Based on a 3D model test, we recommend the size, entry points, and angles of screws for Ogawa type I acromial fractures, providing valuable guidance for clinical work. More accurate screw parameters can be obtained preoperatively by establishing an individualized 3D model.

A Simple Bone Cyst of the Acromion: Case Report / Cisto ósseo simples do acrômio: Relato de caso

Abstract Simple bone cysts rarely occur in the scapula, and, to our knowledge, they have not been reported in the acromion. In the present report, we present the case of a 24-year-old female patient who was successfully treated by curettage and grafting using xenografting. No recurrence findings were observed during the follow-up six months postoperatively, the patient had recovered full range of motion, and she was able to perform all routine activities satisfactorily.

Resumo Cistos ósseos simples são raros na escápula, e, pelo que sabemos, não foram relatados no acrômio. Aqui, apresentamos uma paciente do sexo feminino, de 24 anos, submetida com sucesso ao tratamento composto por curetagem e xenoenxerto. Não foram observados achados de recidiva no acompanhamento pós-operatório de seis meses, quando a paciente apresentou amplitude total de movimento e foi capaz de realizar todas as atividades rotineiras de maneira satisfatória.

Incidence and risk factors of acromial fracture following reverse total shoulder arthroplasty.

BACKGROUND: The occurrence and related predictors of acromial fracture following reverse total shoulder arthroplasty (RTSA) have not been fully elucidated. The aim of this study was to determine the incidence and risk factors of acromial fractures after RTSA. METHODS: We conducted a multicenter, retrospective case-control study of 787 cases (29 in acromial fracture group and 758 in control group) that underwent RTSA performed by 6 surgeons. The mean duration of follow-up after RTSA was 31.6 ± 21.8 months (range, 12-136 months). Demographic variables (age, sex, arm dominance, body mass index, working status, bone mineral density [BMD]), clinical variables (preoperative diagnosis, previous operation, implant design, preoperative clinical scores, screw size in glenoid fixation, postoperative rehabilitation), and radiographic variables (acromial thickness, critical shoulder angle, deltoid length, humeral offset to lateral acromion) were investigated. To determine risk correlation, univariate analysis and multivariate logistic regression analysis with calculated odds ratios (ORs) were performed. RESULTS: Postoperative acromial fractures occurred in 29 of the 787 shoulders with RTSA (3.7%). Acromial fractures were detected at a mean of 10.0 months (range, 1-66 months) postoperatively. Univariate analysis revealed that the occurrence of an acromial fracture was significantly associated with a previous operation (38% [11 of 29] vs. 21% [156 of 758], P = .025) and BMD (-2.33 vs. -1.74, P = .013). Multivariate logistic regression analysis found that the occurrence of a postoperative acromial fracture was significantly associated with a previous operation (P = .034; OR, 2.91; 95% confidence interval, 1.08-7.84) and deltoid length (P = .004; OR, 1.04; 95% confidence interval, 1.01-1.07). CONCLUSION: Acromial fracture following RTSA is not an uncommon complication, with an overall incidence of 3.7%. A previous operation, increased deltoid length, and low BMD were risk factors of acromial fracture following RTSA.

Acromial and Scapular Fractures After Reverse Total Shoulder Arthroplasty with a Medialized Glenoid and Lateralized Humeral Implant: An Analysis of Outcomes and Risk Factors.

This article was updated on TK because of a previous error, which was discovered after the preliminary version of the article was posted online. In Table VII, the fracture rate in the study by Walch et al. that had read "4.6% (21 of 457)" now reads "0.9% (4 of 457)." BACKGROUND: Acromial and scapular fractures after reverse total shoulder arthroplasty (rTSA) are rare and challenging complications, and little information is available in the literature to identify patients who are at risk. This study analyzes risk factors for, and compares the outcomes of patients with and without, acromial and scapular fractures after rTSA with a medialized glenoid/lateralized humeral implant. METHODS: Four thousand one hundred and twenty-five shoulders in 3,995 patients were treated with primary rTSA with 1 design of reverse shoulder prosthesis by 23 orthopaedic surgeons. Sixty-one of the 4,125 shoulders had radiographically identified acromial and scapular fractures. Demographic characteristics, comorbidities, implant-related data, and clinical outcomes were compared between patients with and without fractures to identify risk factors. A multivariate logistic regression, 2-tailed unpaired t test, and chi-square test or Fisher exact test identified significant differences (p < 0.05). RESULTS: After a minimum duration of follow-up of 2 years, the rate of acromial and scapular fractures was 1.77%, with the fractures occurring at a mean (and standard deviation) of 17.7 ± 21.1 months after surgery. Ten patients had a Levy Type-1 fracture, 32 had a Type-2 fracture, 18 had a Type-3 fracture, and 1 fracture could not be classified. Patients with acromial and scapular fractures were more likely to be female (84.0% versus 64.5% [p = 0.004]; odds ratio [OR] = 2.75 [95% confidence interval (CI) = 1.45 to 5.78]), to have rheumatoid arthritis (9.8% versus 3.3% [p = 0.010]; OR = 3.14 [95% CI = 1.18 to 6.95]), to have rotator cuff tear arthropathy (54.1% versus 37.8% [p = 0.005]; OR = 2.07 [95% CI = 1.24 to 3.47]), and to have more baseplate screws (4.1 versus 3.8 screws [p = 0.017]; OR = 1.53 [95% CI = 1.08 to 2.17]) than those without fractures. No other implant-related differences were observed in the multivariate analysis. Patients with fractures had significantly worse outcomes than patients without fractures, and the difference in mean improvement between these 2 cohorts exceeded the minimum clinically important difference for the majority of measures. CONCLUSIONS: Acromial and scapular fractures after rTSA are uncommon, and patients with these fractures have significantly worse clinical outcomes. Risk factors, including female sex, rheumatoid arthritis, cuff tear arthropathy, and usage of more baseplate screws were identified on multivariate logistic regression analysis. Consideration of these findings and patient-specific risk factors may help the orthopaedic surgeon (1) to better inform patients about this rare complication preoperatively and (2) to be more vigilant for this complication when evaluating patients postoperatively. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Locked 90°-double plating of scapular spine fracture after reverse shoulder arthroplasty with union and good outcome despite plate adjacent acromion fracture.

We report the case of a 74-year-old woman who sustained a scapular spine (SS) fracture after a fall 4 weeks after reverse shoulder arthroplasty (RSA). Open reduction and internal fixation (ORIF) with locked 90°-double plating resulted in union of the SS fracture with a good outcome (subjective shoulder value: 80%; Constant score 67; 1 year) despite of an adjacent lateral acromion fracture 3 weeks after ORIF. This is the second description in the literature of a successful double plate ORIF with union of an SS fracture after RSA. SS fractures are known to lead to poor RSA outcomes with a high mal-union rate and non-union rate. We describe the positioning of the plates and technical steps for successful ORIF to avoid complications, discuss the aftercare and report the outcome.

Isolated Acromial Fracture in a Cyclist: A Case Report and Review of the Literature.

CASE: An isolated acromial fracture was diagnosed in a 45-year-old subject, recreational athlete, during a cycling fall on the shoulder. Clinical examination combined with x-ray and computerized tomography scan confirmed the isolated injury. Open reduction and osteosynthesis using a tension band technique was performed. The patient was immobilized in a sling for 6 weeks, and fixation hardware was removed after 6 months. At the 1-year follow-up, patient had returned to his preinjury level of athletic activity. CONCLUSION: Isolated acromial fracture is an uncommon sports-related injury. Although several treatment modalities exist, nonoperative, immobilization treatment is typically effective if fracture is not displaced. Osteosynthesis should be considered if there is subacromial impingement or fracture displacement >10 mm.

Anatomic Restoration of Triple Disruption of the Superior Shoulder Suspensory Complex: A Case Report and Review of the Literature.

BACKGROUND: Multiple disruptions of the superior shoulder suspensory complex (SSSC) involving more than two components are extremely rare. In some extreme situations, three components of the SSSC structure can be involved. The ideal treatment for this type of injury is debatable. CASE PRESENTATION: A 21-year-old woman was referred to our emergency center following a traffic accident. A three-dimensional CT scan showed triple disruption of the SSSC involving concomitant ipsilateral fractures of the coracoid, the acromion, and the distal clavicle. The connection between the upper limber and the axial skeleton was destroyed. There was no evidence of associated injury and the neurovascular examination of the injured upper limb was normal. The patient underwent an open reduction and internal fixation to restore the anatomic integrity of the SSSC. The arm was supported in a broad arm sling for 2 weeks after surgery. Gentle passive range of motion activity under analgesic was encouraged from the second day postoperatively. One year and half after the operation, the patient had regained pain free and unrestricted shoulder stability and mobility. CONCLUSION: The manifestations of multiple disruptions of the SSSC may be variable. This case illustrated the challenges of treating the multiple disruption of the SSSC structure. It also showed that surgical intervention for this rare combination injury yields an excellent functional result. The good outcome achieved in this patient demonstrates that surgical intervention might be an optional resolution for multiple disruptions of the SSSC.

Scapular Ring Preservation: Coracoacromial Ligament Transection Increases Scapular Spine Strains Following Reverse Total Shoulder Arthroplasty.

BACKGROUND: Scapular fractures following reverse total shoulder arthroplasty (RSA) are devastating complications with substantial functional implications. The role of the coracoacromial ligament (CAL), which is often transected during surgical exposure for RSA, is not fully known. We hypothesized that the CAL contributes to the structural integrity of the "scapular ring" and that the transection of this ligament during RSA alters the scapular strain patterns. METHODS: RSA was performed on 8 cadaveric specimens without evidence of a prior surgical procedure in the shoulder. Strain rosettes were fixed onto the acromial body (at the location of Levy type-II fractures) and the scapular spine (Levy type III). With use of a shoulder simulator, strains were recorded at 0°, 30°, and 60° glenohumeral abductions before and after CAL transection. The deltoid and glenohumeral joints were functionally loaded (middle deltoid = 150 N, posterior deltoid = 75 N, and joint compression = 300 N). Maximum principal strains were calculated from each rosette at each abduction angle. A repeated-measures analysis of variance with post hoc analysis was performed to compare the maximum principal strain at each abduction angle. RESULTS: With the CAL intact, there was no significant difference between strain experienced by the acromion and scapular spine at 0°, 30°, and 60° of glenohumeral abduction. CAL transection generated significantly increased strain in the scapular spine at all abduction angles compared with an intact CAL. The maximum scapular spine strain observed was increased 19.7% at 0° of abduction following CAL transection (1,216 ± 300.0 microstrain; p = 0.011). Following CAL transection, acromial strains paradoxically decreased at all abduction angles (p < 0.05 for all). The smallest strains were observed at 60° of glenohumeral abduction at the acromion following CAL transection (296 ± 121.3 microstrain; p = 0.048). CONCLUSIONS: The CAL is an important structure that completes the "scapular ring" and therefore serves to help distribute strain in a more normalized fashion. Transection of the CAL substantially alters strain patterns, resulting in increased strain at the scapular spine following RSA. CLINICAL RELEVANCE: CAL preservation is a modifiable risk factor that may reduce the risk of bone microdamage and thus the occurrence of fatigue/stress fractures in the scapular spine following RSA.

Treatment of an Acromial Stress Fracture After Reverse Total Shoulder Arthroplasty With Teriparatide: A Case Report.

CASE: A 78-year-old woman who underwent reverse total shoulder arthroplasty (RTSA) for proximal humerus fracture developed a Type-3 acromial stress fracture, resulting in increased pain and decreased function 9 months post-op. She was managed nonoperatively with adjunctive teriparatide (FORTEO), and after a 4-month course, she had regained excellent motion and achieved union. CONCLUSION: Teriparatide is a viable adjunct in treating patients nonoperatively with acromial stress fractures after RTSA.

Feasibility of the acromion index as a reference of severity of stratified supraspinatus tendon injury: a secondary analysis.

BACKGROUND: The acromion index (AI) is the acromial lateral extension above the head of the humerus. Some researchers have advocated that the AI indicates the severity of the tear size of the full-thickness supraspinatus tendon. PURPOSE: To validate the reproducibility of the AI between shoulder magnetic resonance imaging (MRI) and standard X-ray and to verify whether the AI is a useful index for stratifying the severity of supraspinatus tendon injuries, as well as full-thickness tears. MATERIAL AND METHODS: We enrolled 200 patients with impingement syndrome who were subsequently evaluated with standard X-ray of the shoulder in the anteroposterior view, as well as an MRI. We performed a pilot study to validate the reproducibility of the AI using standard X-ray and MRI, and to compare the AI between these imaging modalities. The severity of supraspinatus tendon injury was classified into four groups (0 = no evidence of injury, 1 = partial tear, 2 = full-thickness tear, and 3 = complete rupture) based on an official reading of the shoulder MRI. We compared the AIs of both modalities between the groups. RESULTS: Intraclass correlation coefficients of the AIs between the two examiners were 0.819 for MRI and 0.808 for plain X-ray. The mean AI from standard X-ray was greater than that from MRI (P<0.0001). There was no statistical correlation between the AI and the severity of supraspinatus tendon injury. CONCLUSION: Our findings indicate that the AI cannot be generally used as a predictive reference for the stratified severities of supraspinatus tendon injury.

Postoperative results of Ogawa type IIB meta-acromion fracture fixation with a 90° twisted reconstruction plate.

INTRODUCTION: Acromion fractures are rare and difficult to treat. There is no consensus on type of fixation. Due to the rarity of the injury, it is difficult to compare different techniques of osteosynthesis. OBJECTIVES: The aim of this study was to present the long-term results of an alternative method of plating Ogawa type IIB meta-acromion fractures and to review the literature. DESIGN: Retrospective study. MATERIALS AND METHODS: We present a case series of 11 consecutive patients with displaced Ogawa type IIB meta-acromion fracture, treated with open reduction internal fixation using a 3.5-mm contoured pelvic reconstruction plate with a 90° twist. Patients' mean age was 53.3 years (23-80 years) and the mean follow-up was 48.3 months (15 months-9 years). The outcomes related to pain and shoulder function were evaluated by Modified American Shoulder and Elbow Surgeons Score (ASES) and SF-36 score. All patients were asked about their satisfaction level. RESULTS: Nine out of eleven patients were included in this study. Eight of them obtained union and all were satisfied with the final outcome. The mean ASES and SF-36 score were 69.75 (42.4-98.14) and 61.37 (41.64-94.99), respectively, with poor scores to be largely associated with comorbidities and concomitant injuries. CONCLUSIONS: The use of 3.5-mm reconstruction plate with a 90° twist for open reduction internal fixation (ORIF) of meta-acromion fractures presents satisfactory results and could be technically a more stable biomechanical construct in comparison to the existing surgical techniques.

Acromial Fractures Following Reverse Total Shoulder Arthroplasty: A Cohort Controlled Analysis.

Fractures of the acromion can develop after reverse total shoulder arthroplasty (RTSA). This study sought to identify risk factors for acromial fractures in patients with RTSA. A total of 1146 RTSAs were performed at the authors' institution between 1999 and 2016. In 21 patients (1.8%), the authors identified an acromial fracture during the postoperative course. These patients were compared with a matched cohort of 84 patients who had not developed an acromial fracture postoperatively. As an indicator of changes in pre- to postoperative deltoid loading, the authors created an angle called the "delta angle." There was an elevated risk for acromial fractures with lower lateralization of the humerus from pre- to postoperatively (4.1±7.1 mm vs 8.4±6.1 mm; P=.006), lower preoperative anteroposterior acromial slope (117.3°±11.2° vs 121.7°±17.0°; P=.044), and higher glenoid inclination (beta angle, 72.0°±5.5° vs 76.5°±6.8°; P=.005). Pre- to postoperative changes in the beta angle (9.2°±8.0° vs 4.4°±9.4°; P=.022) and the delta angle (29.4°±8.1° vs 19.5°±9.7°; P<.001) were larger in the fracture group. In addition, diagnosed and treated osteoporosis appeared to be a risk factor for acromial fractures (33% vs 13%; P=.047). The delta angle after RTSA seems to correlate with the risk of developing an acromial fracture. Patients with a high glenoid inclination and/or osteoporosis should be informed that they are at risk. Further, surgeons should be aware that lower distalization together with greater medialization of the center of rotation was associated with more acromial fractures in this study. [Orthopedics. 2020; 43(1):15-22.].

Os acromiale: systematic review of surgical outcomes.

BACKGROUND: The literature is unclear as to the optimal surgical management of a symptomatic os acromiale that has failed nonoperative treatment. Surgical options include excision, acromioplasty, and open reduction and internal fixation. The purpose of this study is to summarize the described methods and compare their reported outcomes with the goal to provide direction on how to surgically manage os acromiale. METHODS: We performed a systematic review of the current medical literature. Fifteen studies met all the inclusion criteria. Two hundred eleven total subjects (220 shoulders) underwent surgical treatment for a symptomatic os acromiale. There were 140 men and 71 women with a mean age of 49.6 ± 9.1 years. The mean follow-up duration was 40 ± 11.6 months. Surgical techniques used in the included studies were excision, acromioplasty, and open reduction with internal fixation. Concurrent surgical procedures performed were also included. RESULTS: Meso-os acromiale was the most common type (167 cases, 94.4%). The most common surgical technique was internal fixation (135 cases, 60.8%), with screw fixation being the majority (76 cases, 56.3%). Excision (65 cases, 29.3%) was the second most used technique. The most common concurrent surgical procedure performed was rotator cuff repair (125 cases, 56.3%), followed by distal clavicle excision (31 cases, 14%). CONCLUSIONS: All surgical techniques employed resulted in improvement in postsurgical clinical outcomes without any technique demonstrating superior results. Operative management of a symptomatic os acromiale that has failed initial nonoperative treatment leads to decreased symptoms and improvement in clinical outcomes.

Acromial stress fracture following reverse total shoulder arthroplasty: incidence and predictors.

BACKGROUND: Increased use of reverse total shoulder arthroplasty (RTSA) has led to an understanding of unique complications such as acromial stress fractures (ASFs). The factors associated with ASFs are not fully known. This study investigates the incidence and predictors of ASFs following RTSA. METHODS: All RTSAs performed at a single tertiary referral hospital were retrospectively reviewed. ASF findings were classified as a definitive acromial or scapular spine stress fracture based on radiographic findings or stress reaction based on clinical findings (pain and tenderness at the acromion or acromial spine) without radiographic changes. Preoperative and postoperative radiographs were reviewed for radiographic predictors of postoperative acromial stress pathology. Clinical factors and implant characteristics were also investigated. RESULTS: Between September 2010 and January 2017, a total of 1170 RTSAs were performed, with 958 cases (81.9%) having at least 3 months' clinical follow-up (mean, 407 days; range, 90-1698 days). There were 40 ASFs (4.2%) and 61 acromial stress reactions (6.4%). For fractures and reactions, symptom onset averaged 8.8 and 7.3 months (P = .37), respectively, with durations of 4.5 and 2.9 months (P = .02), respectively, following RTSA. Independent predictors of acromial stress pathology were female sex, decreased change in deltoid length, and increased preoperative glenohumeral center-of-rotation medialization. CONCLUSION: Acromion-related symptoms are common following RTSA. Female patients with increased preoperative center-of-rotation medialization had an increased incidence of ASFs. Although this study establishes which patients are at risk of ASFs, methods for prevention of ASFs in these patients remain unclear.