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.

Anatomical variations of the acromial and coracoid process: clinical relevance.

PURPOSE: The acromial and coracoid process morphology is of clinical relevance due to associations with functional limitations and shoulder pathology. Our objective was to describe the anatomical characteristics of the acromial and coracoid process using computed tomography (CT). METHODS: Descriptive, observational, transversal and retrospective study. A total of 155 CT of patients without shoulder pathology, of both genders, and indistinct age were evaluated and grouped by age: Group 1 < 25 years; group 2 25-40 years; group 3 > 40 years. The following parameters were evaluated: Acromial type (AcT), vertical coracoid distance (VCD), acromial tilt (AT), acromial projection (AP), critical shoulder angle (CSA), type of the subcoracoid outlet (TSO), and the area of the subcoracoid outlet (ASO). RESULTS: Statistically significant differences were found between men and women for VCD (14.44 ± 4.79 vs. 11.76 ± 4.00 mm; p < 0.001) and AP (3.66 ± 4.71 vs. 1.62 ± 4.99 mm; p < 0.05) as well as between age groups 1 and 3 for AT (35.08 ± 11.53 vs. 28.41 ± 6.60; p < 0.05) and ASO (398.99 ± 153.91 vs. 255.56 ± 124.58 mm2; p < 0.001). An unexpected high ASO variation was identified with 11% of S-shaped acromion and 1.3% clock-shaped TSO. CONCLUSION: The age group between 25-40 years had the most uniform distribution of data. There is a high morphological variability present in an asymptomatic population, which should be considered in the clinical assessment such as shoulder impingement syndrome.

Incidental detection of Os acromiale mimicking a fracture on 18F-Fluoride PET-CT.

Os acromiale represents an unfused accessory centre of ossification of the acromion of scapula. It may cause shoulder impingement, rotator cuff tear or degenerative acromio-clavicular joint disease. A 38-year-old male with history of degenerative disc disease presented with persistent backache. MRI of the lumbar spine had earlier showed left paracentral disc protrusion of L5/S1 vertebrae impinging the left S1 nerve root for which the patient underwent fluoroscopic guided nerve root block. Due to persistent bilateral sciatica and worsening leg pain a decompression surgery was planned. A bone scan was requested to exclude other causes of pain prior to surgery for which the patient underwent 18F- Fluoride PET-CT examination. We report a case of incidental detection of Os acromiale mimicking fracture. As the management strategy for both is quite different this case highlights the importance of correct recognition of this identity for appropriate management.

Management of symptomatic os acromiale: a survey of the American shoulder and elbow surgeons.

BACKGROUND: The purpose of this paper was to survey members of the American Shoulder and Elbow Surgeons (ASES) to assess their opinion on management options, help highlight important clinical factors, and elucidate surgical preferences for the treatment of a symptomatic meso-os. METHODS: An online questionnaire was distributed to the active members of the ASES. The survey queried surgeon demographics and perioperative management preferences, and presented multiple clinical case scenarios of patients with a presumed symptomatic, unstable os acromiale. RESULTS: There were 116 ASES members who responded to the survey, and 26% (n = 30) who stated they do not operatively manage a symptomatic os. We identified two main clusters of respondents. Cluster 1 (n = 67) (as compared to cluster 2, n = 19) was comprised of surgeons with significantly more experience treating a symptomatic os acromiale (p < 0.05). These surgeons regarded gender, age, BMI, and hand dominance as important clinical factors when deciding when to proceed to surgery. Overall, arthroscopic management of the os was preferred, but those surgeons more experienced in treating os acromiale preferred open reduction and internal fixation (ORIF) in specific clinical cases. CONCLUSION: The survey findings reflect the current lack of consensus in the treatment of a unstable, symptomatic os acromiale. Overall, arthroscopic management was preferred by most surgeons, though ORIF was preferred in certain clinical scenarios by those more experienced with os acromiale. The overall preference for arthroscopy suggests a possible shift in the treatment paradigm for patients with symptomatic meso-acromions, but higher level studies are needed to substantiate these findings.

Clinical results and complications following surgical management of symptomatic os acromiale: a systematic review.

BACKGROUND: This review compares the outcomes and complication rates of three surgical strategies used for the management of symptomatic os acromiale. The purpose of this study was to help guide best practice recommendations. METHODS: A systematic review of nine prospective studies, seven retrospective studies, and three case studies published across ten countries between 1993 and 2018 was performed. Adult patients (i.e., ≥ 18 years of age) with a symptomatic os acromiale that failed nonoperative management were included in this review. Surgical techniques utilized within the included studies include excision, acromioplasty, and open reduction and internal fixation (ORIF). The primary outcomes of interest included patient satisfaction. Range of motion and several standardized outcome measurement tools were also included in the final analysis. RESULTS: Patient satisfaction was highest in the excision and ORIF groups, with 92% and 82% of patients reporting good to excellent postoperative results, respectively, compared to 63% in the acromioplasty group. All three patient groups experienced improvements in postoperative outcomes (i.e., active range of motion and patient-reported outcome scores). The excision group experienced a complication rate of 1%, while the acromioplasty group experienced a complication rate of 11% and the ORIF group a rate of 67%. CONCLUSION: This study reports on the largest sample of patients who underwent surgical treatment for a symptomatic os acromiale. We have demonstrated that excision of the os with meticulous repair of the deltoid resulted in the best clinical outcomes with the least complications. In healthy adult patients with a large os fragment and a normal rotator cuff, surgical fixation may provide increased preservation of deltoid function while offering good to excellent patient satisfaction. However, patients must be informed that a second procedure may be required to remove symptomatic hardware.

Symptomatic, Unstable Os Acromiale.

Management of a persistently symptomatic, unstable os acromiale remains controversial. An unstable os acromiale is an easy diagnosis to miss and should be specifically evaluated for in patients with shoulder pain and a high degree of clinical suspicion. Surgical options include open or arthroscopic excision and open reduction and internal fixation. Open excision of large fragments has had poor results. Arthroscopic treatment is commonly used for small fragments (preacromion), and the technique has also been used in larger fragments (meso-os), but concerns persist over postoperative weakness secondary to shortening of the deltoid lever arm. Open reduction and internal fixation through a transacromial approach has been shown to have predictable union rates but can be complicated by symptomatic implant. Recent biomechanical studies have expanded our understanding of optimal fixation constructs, which may also decrease implant-related issues. Ultimately, the choice of which procedure to use will be dictated by patient factors such as age, activity level, and the nature of rotator cuff pathology. LEVEL OF EVIDENCE:: Level V.

Initial experience with 18F-sodium fluoride (NaF) PET-CT: a viable functional biomarker in symptomatic Os acromiale.

OBJECTIVE: Os acromiale (OA) is a failure of complete fusion of the acromial process. It is usually asymptomatic and discovered incidentally. OA can contribute to shoulder impingement symptoms and rotator cuff tears. 18F Sodium Fluoride (NaF) Positron Emission Tomography -CT (PET-CT) is an emerging and highly sensitive modality for oncological skeletal staging, and can show a variety of non-malignant uptake. We have analysed the relationship between 18F-NaF uptake in OA and associated symptoms of shoulder pain. METHODS: Study population included 21 patients (mean age 60.2 ± 12 years; 13 females and 8 males) with OA who underwent PET-CT scan by injecting 2.22 MBq kg-1 of 18F-NaF. The relationship between 18F-NaF uptake and OA as a cause of pain was analysed. A 3-point grading system was used to evaluate uptake of 18F-NaF. RESULTS: In total 27 OA (12 symptomatic and 15 asymptomatic) were enrolled. All symptomatic OA showed focal increase tracer uptake of Grade 2, while asymptomatic OA did not have significant activity Grade 0 (n = 11) and Grade 1 (n = 4). CONCLUSION: 18F-NaF PET-CT appears to be a useful adjunct in the assessment of symptomatic OA with its particular strength being its high negative predictive value. Advances in knowledge: 18F-NaF PET-CT may be used as an ancillary tool for identifying symptomatic OA  as a cause of shoulder pain in cases where other obvious causes of shoulder pain have been excluded.

Reverse shoulder arthroplasty in patients with os acromiale.

BACKGROUND: Os acromiale has been reported in up to 15% of the general population. Reverse total shoulder arthroplasty (RTSA) increases deltoid tension, which could potentially lead to excessive stress on a pre-existent os acromiale. The purpose of this study was to determine the outcome and complications of primary RTSA in patients with radiographic evidence of an os acromiale. METHODS: Between 2005 and 2013, 25 shoulders underwent primary RTSA with an associated os acromiale, which was classified preacromion (3), mesoacromion (20), and meta-acromion (2). All patients were observed for a minimum of 2 years or until reoperation. Mean follow-up time was 30.8 (range, 1-81.4) months. Outcomes included pain scores, range of motion, patient satisfaction, American Shoulder and Elbow Surgeons scores, and radiographic outcomes. RESULTS: RTSA led to an improvement in pain scores in 24 of 25 shoulders. Mean elevation, external rotation, and internal rotation were improved at final follow-up (124°, 46°, and L4, respectively). Three patients required reoperation, including revision surgery for dislocation (2) and excision of a painful os acromiale (1). Postoperative tilting of the os acromiale was noted in 7 shoulders (28%). There was no statistically significant difference in any outcome measures between shoulders with and shoulders without postoperative tilt of the os acromiale. DISCUSSION AND CONCLUSION: The outcome of RTSA does not seem to be negatively affected by the presence of an os acromiale. Pain around an os acromiale after RTSA is rare. Inferior tilting is observed in approximately one-third of the shoulders after RTSA and does not seem to change the overall outcome.

Bilateral bony fusion around the supraspinatus muscle inducing muscle hypoplasia and shoulder pain.

We describe the case of a 30-year-old man who developed chronic bilateral shoulder pain that relapsed and remitted over the course of 1 year. The patient was diagnosed with congenital shoulder fusion anomalies. The right shoulder showed anomalous accessory articulation between the distal third of the clavicle and the acromion along with normal articulation of the shoulder on CT. At the left shoulder, bony fusions were present between the distal portion of the clavicle, the acromion, and the coracoid process, and between the coracoid process, upper portion of the glenoid, and upper body of the scapula, which formed a bony canal and was responsible for hypoplasia of the supraspinatus muscle on CT and MRI. To our knowledge, this is the first description of such congenital shoulder anomalies with extreme bony fusion and is an illustrative example of how imaging may be used to differentiate fusion from other congenital abnormalities of the shoulder to aid diagnosis.

Arthroscopic excision of unstable os acromiale associated with impingement syndrome: a case report.

Os acromiale is a rare anatomical variant that is caused by failure of fusion of the acromial apophysis and is usually asymptomatic. We report a case of impingement syndrome of the left shoulder secondary to unstable os acromiale, which was initially overlooked and confirmed only during arthroscopic examination. Arthroscopic excision of the unstable fragment was successful without residual dysfunction of the deltoid muscle.

Correlación entre la anatomía acromial y roturas del manguito rotador: estudio caso-control / Relationship between acromial anatomy and rotator cuff tears: a case control-study

Determinar si existe correlación entre la anatomía acromial documentada por radiología y la presencia de roturas del manguito rotador (MR) evaluadas en forma artroscópica. Hipótesis: Existe correlación positiva entre la morfología acromial y las roturas del MR. Métodos: Serie retrospectiva caso-control de 279 casos consecutivos tratados mediante cirugía artroscópica. Se analizaron 2 cohortes; un grupo con roturas completas del MR (N = 155) y un grupo control, tratados por inestabilidad glenohumeral (N = 124) a los que se documentó indemnidad del MR durante la artroscopia. Se documentó la anatomía acromial preoperatoria mediante radiografías de hombro anteroposterior verdadera y axial subacromial y se midieron la pendiente acromial según Bigliani (B), la inclinación acromial según Kitay (K) y el índice acromial según Nyffeler (AI). Resultados: Las diferencias entre los valores promedios de B y K entre grupos no fueron significativas (p = 0,6 y p = 0,3). No existió correlación entre B y AI (r = 0,054; p = 0,377). Evidenciamos una correlación positiva en ambos grupos entre la inclinación acromial (r = 0,2; p = 0,008) y la pendiente acromial (r = 0,1; p = 0,03). Encontramos diferencias significativas en el IA entre grupos, que fue mayor para los casos (p = 0,01). Conclusión: En los resultados de las mediciones radiológicas de la anatomía acromial en nuestra población, documentamos una correlación significativa entre extensión del AI y roturas del MR confirmadas durante artroscopia...

To study the anatomical relationship between acromial morphology documented on X- rays and rotator cuff (RC) tears evaluated using arthroscopy. Hypothesis: There is a positive correlation as regards acromial morphology and RC tears. Methods:A retrospective, case control series of 279 consecutives cases, who underwent arthroscopic surgery were included in this study; cases were separated into 2 cohorts; one group with complete RC tears (N=155) and a control group treated for glenohumeral instability (N=124) with indemnity of the RC confirmed during arthroscopy. Pre-operative acromial anatomy was documented with X- rays – true anteroposterior and sub-acromial outlet views – measuring the acromial slope according to Bigliani (B), acromial tilt according to Kitay (K), and acromial index according to Nyffeler (AI). Results: The differences in the mean values of B and K between groups were not significant (P=.6 and P=.3). There was no correlation between B and AI (r= 0.05; P=.3). A positive correlation was observed between the acromial tilt (r= 0.2; P=.008) and acromial slope (r= 0.1; P=.03). A significant difference was found regarding AI, with greater values in the case group (P=.01). Conclusion:In this study, the acromial slope according to Bigliani, and acromial tilt according to Kitay, does not correlate with RC tears. A positive correlation of the AI with RC tears was observed...

Relevance of discrete traits in forensic anthropology: From the first cervical vertebra to the pelvic girdle.

In forensic anthropology, identification begins by determining the sex, age, ancestry and stature of the individuals. Asymptomatic variations present on the skeleton, known as discrete traits, can be useful to identify individuals, or at least contribute to complete their biological profile. We decided to focus our work on the upper part of the skeleton, from the first vertebra to the pelvic girdle, and we chose to present 8 discrete traits (spina bifida occulta, butterfly vertebra, supraclavicular nerve foramen, coracoclavicular joint, os acromiale, suprascapular foramen, manubrium foramen and pubic spine), because they show a frequency lower than 10%. We examined 502 anonymous CT scans from polytraumatized individuals, aged 15 to 65 years, in order to detect the selected discrete traits. Age and sex were known for each subject. Thin sections in the axial, coronal and sagittal planes and 3D volume rendering images were created and examined for the visualization of the selected discrete traits. Supraclavicular foramina were found only in males and only on the left clavicle. Coracoclavicular joints were observed only in males. The majority of individuals with a suprascapular foramen were older than 50 years of age. Pubic spines were observed mostly in females. Other traits did not present significant association with sex, age and laterality. No association between traits was highlighted. Better knowledge of human skeletal variations will help anthropologists come closer to a positive identification, especially if these variations are rare, therefore making them more discriminant.

Use of SPECT/CT with 99mTc-MDP Bone Scintigraphy to Diagnose Symptomatic Os Acromiale.

Os acromiale is an anatomic variant that in rare cases can cause pain. (99m)Tc-methylene diphosphonate bone scintigraphy with SPECT/CT can play an important role in diagnosing this clinical entity. We present a male football player with shoulder pain secondary to a symptomatic os acromiale, and we demonstrate the findings on bone scanning with limited SPECT/CT that diagnosed this important clinical abnormality.

Differentiating os acromiale from normally developing acromial ossification centers using magnetic resonance imaging.

OBJECTIVE: Acromial fusion may not be complete until age 18-25, making it questionable to diagnose os acromiale in adolescents. Os acromiale may exist in adolescents and can be differentiated from a developing acromial ossification center based on MRI findings. MATERIALS AND METHODS: A total of 128 MRIs of the shoulder were randomly and blindly reviewed retrospectively by two musculoskeletal radiologists. The MRIs consisted of two groups: (1) 56 of os acromiale in adults (25-74 years old, mean, 50) and (2) 72 consecutive of adolescents (12-17 years old, mean, 14.5). The following were assessed at the interface between the distal acromion and os acromiale/developing ossification center(s): presence of os acromiale vs. developing acromion, orientation, margins, and edema within and adjacent to it. RESULTS: Fifty-one adults and 49 adolescents were included. Exclusions were due to poor image quality or confounding findings (n = 7) or complete acromial fusion (n = 21 adolescents). Utilizing accepted definitions of os acromiale, all adult cases (100 %) were accurately diagnosed as os acromiale, with transverse interface orientation and irregular margins (94 %, R = 0.86, p < 0.00001). Forty-five (92 %) adolescent cases were accurately diagnosed as normally developing acromion with arched interface and lobulated margins (92 %, R = 0.92, p < 0.000001). Four (8 %) adolescent cases were diagnosed as having os acromiale, with transverse orientation and irregular margins. Thirty-five (69 %) and 46 (90 %) adults had marrow and interface edema, respectively. Six (12 %) and eight (16 %) adolescents had marrow and interface edema, respectively, including the four concluded to be os acromiale. CONCLUSIONS: Adolescents may have imaging findings consistent with os acromiale. The diagnosis of os acromiale should be based on imaging features and not limited by age.

Biomechanical evaluation of internal fixation techniques for unstable meso-type os acromiale.

BACKGROUND: Several internal fixation surgical techniques have been described for the treatment of symptomatic os acromiale. The purpose of this study was to compare the biomechanical characteristics of different internal fixation techniques for the operative treatment of unstable meso-type os acromiale in a cadaveric model. METHODS: Testing was performed on 12 matched pairs of cadaveric acromia with simulated meso-type os acromiale. Twelve specimens were prepared with 2 cannulated 4.0-mm screws only (SO group), inserted in the anterior-posterior direction. Contralateral specimens were repaired with screws and a tension band (TB group). An inferiorly directed load to the anterior acromion was applied at a rate of 60 mm/min until failure. Ultimate failure load, stiffness, and fracture pattern were recorded and analyzed. RESULTS: Ultimate failure load was significantly higher for the TB group (mean, 336 N ± 126 N; range, 166-623 N; P = .01) than for the SO group (mean, 242 N ± 57 N; range, 186-365 N). In contrast, no significant difference in stiffness was found between the SO group (mean, 22.1 N/mm ± 4.7 N/mm; range, 13.0-33.3 N/mm; P = .94)) and the TB group (mean, 22.2 N/mm ± 2.9 N/mm; range, 18.2-26.6 N/mm). CONCLUSION: Surgical repair of simulated unstable meso-type os acromiale by a combination of cannulated screws with a tension band leads to significantly higher repair strength at time zero in a cadaveric model compared with cannulated screws alone.

A new form of shoulder dysplasia in an 11-year-old boy.

Pain and impaired function in the shoulder can result from a variety of conditions. Dysplasias of the shoulder girdle are usually asymptomatic; previous literature reports on shoulder malformation have focused on glenoid dysplasia or complete agenesis of the clavicle. We report the case of an 11 year old patient with severe shoulder pain after strenuous physical exercise. Physical inspection showed a prominent clavicle and anteriorly displaced humerus. X-ray demonstrated an abnormally shortened clavicle and a hypoplastic acromion; MRI imaging revealed an elongated deltoid muscle leading over the humeral head. The patient recovered with analgesics and careful mobilization. This is the first reported case of a dysplasia of both the acromion and the clavicle. This developmental abnormality can lead to significant pain, but apparently responds well to conservative treatment. It is possible that this condition is underdiagnosed or represents significantly delayed development.

Scapula fracture and os acromiale after reverse total shoulder arthroplasty.

An 80-year-old woman underwent a right reverse total shoulder arthroplasty for cuff tear arthropathy with no complications. She was discharged 3 days after surgery with well-controlled pain. However, 6 days postoperatively, she reported the onset of excruciating pain in her right shoulder, and conventional radiographs, including an axillary radiograph, were obtained.

The prevalence of Os acromiale: a systematic review and meta-analysis.

Os acromiale (OA) results from a failure of consolidation between the ossification centers of the acromial epiphysis. Its prevalence and its interactions with ancestry, gender, laterality, and side have been variously reported in the literature. The aims of this review are to provide an accurate estimate of OA prevalence and to investigate its association with other variables in an attempt to comprehend its etiology. Twenty-three studies met the inclusion criteria. The results of meta-analyses of large-sample studies revealed: (a) a crude overall prevalence of 7.0%, (b) a crude cadaveric prevalence of 7.6%, (c) a crude archeological (skeletal) prevalence of 5.6%, (d) a crude radiological prevalence of 4.2%, (e) a true anatomical prevalence of 9.6%, (f) a significantly higher frequency in persons of black ancestry than in persons of white, Native American and Middle Eastern ancestries (OR ≈ 3), (g) significantly higher unilateral and bilateral frequencies in black ancestry (OR of 2 and 4, respectively), (h) nonsignificant interactions of OA frequency with gender and side. The commonest type of OA was the meso-acromion type (76.6%). Degenerative changes were present in 66.6% of OAs. The results of this evidence-based anatomical review support a genetic basis for OA rather than the mechanical trauma-induction hypothesis.

Os acromiale: a review and an introduction of a new surgical technique for management.

Os acromiale is a common finding in shoulder surgery. We review the anatomy, prevalence, pathophysiology, and treatment options for this diagnosis. In addition, we report on a case series of 6 patients with a symptomatic meso os acromiale who were treated with a new technique involving arthroscopic acromioplasty in conjunction with the excision of the acromial nonunion site. We have demonstrated this novel treatment method to be a safe and effective technique in this case series. This arthroscopic partial resection of an os acromiale is considered to be an alternative option for treating a symptomatic meso os acromiale.