Os acromiale: a review of its incidence, pathophysiology, and clinical management

Do preoperative scapular fractures affect long-term outcomes after reverse shoulder arthroplasty?

BACKGROUND

Postoperative scapular stress fractures (SSFs) are a formidable problem after reverse shoulder arthroplasty (RSA). Less is known about patients who have these fractures preoperatively. The primary aim of this study was to examine postoperative satisfaction in patients undergoing primary RSA who have preoperative SSF and compared to a matched cohort without preoperative fracture. The secondary aim was to examine the differences in patient-reported outcomes between and within study cohorts.

METHODS

A retrospective chart review of primary RSAs performed by a single surgeon from 2000 to 2020 was conducted. Patients diagnosed with cuff tear arthropathy (CTA), massive cuff tear (MCT), or rheumatoid arthritis (RA) were included. Five hundred twenty-five shoulders met inclusion criteria. Fractures identified on preoperative computed tomography scans were divided into 3 groups: (1) os acromiale, (2) multifragments (MFs), and (3) Levy types. Seventy-two shoulders had an occurrence of SSF. The remaining 453 shoulders were separated into a nonfractured cohort. American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) and visual analog scale (VAS) scores were compared pre- and postoperatively in the total fracture group and the nonfractured group cohort. The multifragment subgroup was also compared to the pooled Os/Levy subgroup.

RESULTS

The total incidence of SSF in all shoulders was 13.7%. There was a difference in satisfaction scores at all time points between the nonfracture (7.9 ± 2.8) and total fracture group (5.4 ± 3.6, P < .001, at last visit). There was also a greater ASES total score in the nonfractured group vs the total fracture group at the final visit (69.4 ± 23.4 and 62.1 ± 24.2; P = .02). The MF group had worse ASES functional or VAS functional scores than the Os/Levy group at all time points: at 1 year, ASES function: MF 24.2 ± 14.5 and Os/Levy 30.7 ± 14.2 (P = .045); at 2 years, ASES function: MF 21.4 ± 14.4 and Os/Levy 35.5 ± 10.6 (P < .001); and at last follow-up, VAS function: MF 4.8 ± 2.8 and Os/Levy 6.4 ± 3.2 (P = .023).

DISCUSSION

Scapular fractures were proportionally most common in patients diagnosed with CTA (16.3%) compared with a 9.2% and 8.6% incidence in patients diagnosed with MCT and RA, respectively. Patients with preoperative SSF still see an improvement in ASES scores after RSA but do have lower satisfaction scores compared with the nonfractured cohort. The multifragment fracture group has lower functional and satisfaction scores at all postoperative time points compared with both the nonfracture and the Os/Levy fracture group.

Anatomy and Deficiency of the Deltoid Muscle: A Review of Literature

BACKGROUND/OBJECTIVE

The deltoid muscle is impacted by common injuries and clinical procedures. This study aims to summarize the anatomy, injuries, and clinical considerations involving the deltoid muscle.

METHOD

A literature search was performed using PubMed and Google Scholar using keywords that focused on the deltoid muscle in the shoulder. Primary research articles and appropriate summary articles were selected for review.

RESULTS

Reduced deltoid muscle function can be caused by axillary nerve injury, rupture of the deltoid itself, or iatrogenic damage to the muscle. The deltoid muscle has an intimate relationship with the axillary nerve and neighboring rotator cuff muscles. Injury to these nearby structures may be masked by compensating deltoid strength. Examination maneuvers in clinic such as the Akimbo Test should be used to isolate the deltoid muscle to determine if the presenting weakness is from the deltoid itself or from other surrounding injury. Additionally, prior to performing clinical procedures, it is important to be cognitive of the injuries that can occur. For example, incisions that extend distally from the acromion should not extend beyond 5-7 cm as this is the common location of the axillary nerve and vaccine administration should take measures to avoid misplaced injections to avoid unnecessary trauma.

CONCLUSION

Deficiency of the deltoid muscle can be debilitating to patients and it is best clinical practice be aware of the anatomy, various causes, tests, and avoidance measures to help diagnose, restore or preserve normal functioning.

The frequency of os acromiale in 751 shoulder MRI of Saudi population

Background: Os acromiale (OA) is an uncommon pathology with a variable prevalence rate among different populations. Objectives: The aim of this study was to report the frequency of OA utilizing shoulder MRI of patients with shoulder pathology. Methods: It was a retrospective study. After obtaining our IRB approval, we gathered all shoulder and upper arm MRIs from the radiology department and evaluated them. Results: The prevalence of OA was found to be 3.32%. The mean age of the affected patients was 50.87 years (25-81). Conclusion: The rate of OA in patients presenting with shoulder pain is 3.32% in Saudi Arabia, which correlates with what has been previously reported in the literature.

Open treatment options in massive rotator cuff tears associated with acromion non-union

We evaluated the available English literature for cases of acromion non-union and rotator cuff tear, looking at surgical methods of treatment as well as at functional results. As expected, the literature regarding rotator cuff pathology was found to be abundant, and a good number of articles were found regarding acromion non-union, but articles concerning the association of the two were scarce. Treatment recommendations varied, and were made on a case-to-case fashion. The accepted treatment methods for acromion non-union consist of non-surgical management, open or arthroscopic fragment removal, open or arthroscopic reduction and fixation (bone grafting may be used), while the rotator cuff witll be reinserted with anchors. In this rare occurence, a large rotator cuff tear with retracted tendons combined with an acromion non-union are usually repaired by an open technique in an one-stage surgery, with good results. In order to chose the right treatment option scapular kinematics must be taken into consideration especially when acromial fractures are associated with rotator cuff tears.

Os acromiale: prevalence and associated patient-related factors-a population-based study of three thousand and fifty participants

Purpose

The presence of os acromiale is of clinical relevance before performing shoulder surgery but ethnic differences and little information regarding associated factors seem to be present. Population-based studies to clarify these topics are essential so the purpose of this study was to assess the prevalence, anatomy, and associations of os acromiale in a general adult population.

Methods

Both shoulders of 3050 participants from the population-based Study of Health in Pomerania (SHIP) were assessed on magnetic resonance imaging (MRI). Associations with the os acromiale were calculated for sex, age, body height, body weight, and heavy mechanical oscillations on the upper extremity.

Results

In total, 1.9% (58/3050) had an os acromiale, while 21 were unilateral left, 23 were unilateral right, and 14 were bilateral. Sixty-eight meso-acromions, three pre-acromions, and one meta-acromion were detected. Os acromiale were more frequent in men (right side: p = 0.037, left side: p = 0.005). Overall, no differences in sides (p = 0.808), to participants’ age (right: p = 0.993, left: p = 0.499), body height (right side: p = 0.241, left side: p = 0.154), and the exposure to heavy mechanical oscillations on the upper extremity (right: p = 0.054, left: p = 0.117) were detected.

Conclusion

Our results support the genetic theory for the aetiology of the os acromiale due to the lower prevalence of the os acromiale in north-eastern Germany compared to the worldwide prevalence (1.9 to 7%) and the lacking association to lifestyle, age, gender, or sides. Additionally, it is important to be aware of possible os acromiale before surgery.

Prevalence of Os Acromiale in Thai Patients With Shoulder Problems: A Magnetic Resonance Imaging Study

Background:

Os acromiale is an anatomic variant in which the acromial ossification center fails to fuse. It may lead to painful shoulder conditions and surgical intervention may be required for treatment. The prevalence of os acromiale in South Koreans (0.7%) has previously been the representative number for the Asian population, and it is lower than that in the Black and White populations.

Purpose:

To determine the prevalence of os acromiale in Thai patients with shoulder disabilities who underwent magnetic resonance imaging (MRI).

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

We retrospectively reviewed the MRI scans of patients with shoulder disabilities between January 2019 and May 2021 at a single institution. The relationship of sex, age, and shoulder diagnosis to the presence of os acromiale was then analyzed.

Results:

A total of 940 MRI scans in 848 patients were evaluated, of which 20 shoulders were detected to have os acromiale, a prevalence of 2.13%. The mean age of the patients was 60.25 years, with 60% being female and 40% male. Of the 20 os acromiale cases, 17 (85%) were preacromiale, 1 (5%) mesoacromiale, and 2 (10%) meta-acromiale. The associated diagnoses were as follows: 75%, full-thickness rotator cuff (RC) tear; 10%, partial-thickness RC tear; 5%, RC tendinopathy with symptomatic os acromiale; 5%, anterior shoulder instability with full-thickness RC tear; and 5%, frozen shoulder. Age, sex, and associated shoulder disability were not associated with the presence of os acromiale.

Conclusion:

In Thai patients with shoulder problems who required MRI evaluation, the prevalence of os acromiale was 2.13%. This is lower than the prevalence from other ethnic groups but slightly higher than that from the same ethnic group (Korea). There was no relation between the presence of os acromiale and shoulder pain, regardless of diagnosis.

Os acromiale may be a contraindication of the clavicle hook plate: case reports and literature review

Background

Os acromiale can be potentially missed or misdiagnosed as acromion fracture, and this can affect treatment determination if it is complicated with an ipsilateral shoulder injury. The clavicle hook plate is a widely used technique for distal clavicle injuries, leading to transacromial erosion, particularly when in the presence of os acromiale.

Case presentation

A 70-year-old man and a 78-year-old man who had limited mobility and severe pain in their right shoulders following falls attended the emergency center. Both patients were diagnosed with os acromiale with CT or MRI and acute distal clavicle fracture or acromioclavicular joint dislocation. Following a comprehensive evaluation, os acromiale may limit the application of a clavicle hook plate due to potential transacromial erosion. The distal clavicle fracture with ipsilateral os acromiale received treatment with a volar radius locking T plate, and the acromioclavicular joint dislocation with ipsilateral os acromiale was reconstructed using suture anchors. Both yielded satisfactory outcomes and voided transacromial erosion.

Conclusions

Ipsilateral os acromiale may be a relative contraindication to the clavicle hook plate. An axillary lateral radiograph is recommended to detect potential os acromiale in patients using a hook plate.

Comparison of Anterior and Posterior Decompressions in Treatment of Traumatic Thoracolumbar Spinal Fractures Complicated with Spinal Cord Injury

Background

For patients with thoracolumbar spinal fractures complicated with spinal cord injury, timely surgery is the first choice. We compared the effects of anterior and posterior decompressions in treatment of these patients.

Material/Methods

A total of 80 male patients with traumatic thoracolumbar spinal fractures and spinal cord injury were prospectively selected and divided into 2 groups. The control group underwent posterior decompression and internal fixation and the observation group underwent real-time anterior decompression.

Results

The observation group had longer operative time and length of postoperative hospital stay, larger intraoperative blood loss, remarkably greater immediate postoperative anterior height and middle column height of the fractured vertebrae, and a notably smaller Cobb’s angle than in the control group. The total ASIA score was significantly higher in the observation group than in the control group immediately after surgery and at 6 months and 1 year after surgery. The maximal urine flow, maximal detrusor pressure, and bladder compliance were also evidently higher in the observation group than in the control group during 1 year of follow-up. Compared with the control group, the International Index of Erectile Function-5 (IIEF-5) score in the observation group was significantly higher at 3 months, 6 months, and 1 year after surgery.

Conclusions

Compared with the posterior approach, anterior decompression in patients with thoracolumbar spinal fractures complicated with spinal cord injury can effectually enhance the surgical efficiency, and restore the physiological anatomy of the fractured vertebrae, thereby improving patient quality of life.

Imaging of the Acromioclavicular Joint: Anatomy, Function, Pathologic Features, and Treatment

The acromioclavicular joint is an important component of the shoulder girdle; it links the axial skeleton with the upper limb. This joint, a planar diarthrodial articulation between the clavicle and the acromion, contains a meniscus-like fibrous disk that is prone to degeneration. The acromioclavicular capsule and ligaments stabilize the joint in the horizontal direction, while the coracoclavicular ligament complex provides vertical stability. Dynamic stability is afforded by the deltoid and trapezius muscles during clavicular and scapular motion. The acromioclavicular joint is susceptible to a broad spectrum of pathologic entities, traumatic and degenerative disorders being the most common. Acromioclavicular joint injury typically affects young adult males and can be categorized by using the Rockwood classification system as one of six types on the basis of the direction and degree of osseous displacement seen on conventional radiographs. MRI enables the radiologist to more accurately assess the regional soft-tissue structures in the setting of high-grade acromioclavicular separation, helping to guide the surgeon's selection of the appropriate management. Involvement of the acromioclavicular joint and its stabilizing ligaments is also important for understanding and classifying distal clavicle fractures. Other pathologic processes encountered at this joint include degenerative disorders; overuse syndromes; and, less commonly, inflammatory arthritides, infection, metabolic disorders, and developmental malformations. Treatment options for acromioclavicular dysfunction include conservative measures, resection arthroplasty for recalcitrant symptoms, and surgical reconstruction techniques for stabilization after major trauma.