Acromial fractures after reverse total shoulder - current thoughts

Acromial stress fractures (ASFs) and scapular spine stress fractures (SSFs) are important complications of reverse total shoulder arthroplasty, limiting patient comfort and function and creating difficult surgical challenges for open reduction and internal fixation. 

Acromial stress fractures and scapular spine stress fractures are related primarily to unmodifiable patient risk factors: (1) poor bone density (osteoporosis, female sex, older age, and inflammatory arthritis) and (2) diagnoses of rotator cuff deficiency (cuff tear arthropathy and massive rotator cuff tear). These factors need to be identified preoperatively and discussed with the patient with respect to the decision to proceed with RSA, the postoperative progression of rehabilitation and monitoring for unexpected pain and loss of function, as well the consideration of more conservative surgical options for appropriately selected patients at risk (see Managing rotator cuff tear arthropathy: a role for cuff tear arthropathy hemiarthroplasty as well as reverse total shoulder arthroplasty).

Although patient factors are the primary determinant of the risk of ASF and SSF, implant selection and positioning are less important but modifiable risk factors for the surgeon to consider.  Notably the important measures of the final reconstructed geometry are (1) the location of the center of rotation with respect to the scapula and (2) the location of the proximal humerus in relation to the scapula (not whether the implant is “onlay or inlay” or how the implants are classified (GM/HL, GM/HM, GL/HL, GL/HL)).

These surgeon-controlled variables need to be considered not only with respect to their effect on the risk of stress fractures but also with respect to their effect on patient comfort and function. For example, increased glenoid lateralization appears to be associated with a greater risk of ASFs, but it also is associated with improved rotation and lower rates of scapular notching and impingement.  As another example, increased humeral lateralization appears to be associated with lower risk of stress fractures, but may also give rise to an increased risk of unwanted contact between the abducted arm and the acromion. 

Additional elements deserve consideration. 

(1)  Are we using the best method for determining the location of the center of rotation with respect to the scapula and the location of the proximal humerus in relation to the scapula (see figure above)? For example, the use of angles, such as the "lateralization shoulder angle" (LSA) and the "distalization shoulder angle" (DSA) to characterize linear measures of lateralization and distalization may be suboptimal for documenting the proximal/distal and medial/lateral position of the center of rotation and the proximal humerus. 

(2) Should we be focusing only on the postoperative geometrical relationships, or should we also be paying attention to the preoperative to postoperative changes in these relationships, recognizing that the magnitude and direction of these changes may also influence the loads on the acromion and scapular spine? See A method for documenting the change in center of rotation with reverse total shoulder arthroplasty and its application to a consecutive series of 68 shoulders having reconstruction with one of two different reverse prostheses

Here are some recent relevant references.

Robert H. Cofield, MD, Award for Best Oral Presentation 2023: Up to 8 mm of glenoid-sided lateralization does not increase the risk of acromial or scapular spine stress fracture following reverse shoulder arthroplasty with a 135 degrees inlay humeral component Glenoid-sided lateralization in reverse shoulder arthroplasty (RSA) decreases bony impingement and improves rotational range of motion, but has been theorized to increase the risk of acromial or scapular spine fractures (ASFs).  Up to 8 mm of glenoid-sided metallic lateralization did not appear to increase the risk of ASF when combined with a 135 degrees inlay humeral implant. Humeral distalization increased the risk of ASF, particularly when there is a larger change between pre- and postoperative AHD or higher inferior glenosphere overhang. In cases of pronounced preoperative superior humeral migration, it may be a consideration to avoid excessive postoperative distalization, but minimizing bony impingement via glenoid-sided lateralization appears to be safe.

Implant-Positioning and Patient Factors Associated with Acromial and Scapular Spine Fractures After Reverse Shoulder Arthroplasty  Patient factors associated with poor bone density (inflammatory arthritis, osteoporosis, prior shoulder surgery, female sex, older age) and rotator cuff deficiency (massive rotator cuff tear, cuff tear arthropathy) appear to be the strongest predictors of ASFs and SSFs after RSA. To a lesser degree, final implant positioning may also affect ASF and SSF prevalence; increased humeral lateralization was found to be associated with lower fracture rates whereas excessive glenoid-sided and global lateralization were associated with higher fracture rates.

Predictive factors of acromial fractures following reverse total shoulder arthroplasty: a subgroup analysis of 860 shoulders This analysis showed that higher postoperative LSA, lower DSA and a lower ACHD (acromial/humeral distance) were predictive factors only for Levy type III fractures, but not for types I or II. 

Incidence, risk factors, and complications of acromial stress fractures after reverse total shoulder arthroplasty Patient-specific factors that were independently associated with the occurrence of an ASF included osteoporosis, rheumatologic disease, shoulder corticosteroid injection within 3 months before surgery, and chronic oral corticosteroid use. Among patients with osteoporosis, the initiation of physical therapy within 6 weeks after surgery also increased the risk of ASF.

Acromial stress fractures and reactions after reverse total shoulder arthroplasty: a case-control study two factors were independently associated with the occurrence of an acromial stress fracture/reaction after RTSA: corticosteroids use and previous shoulder surgery.

Does prior rotator cuff surgery influence the outcomes and complications after reverse total shoulder arthroplasty in patients with cuff tear arthropathy or massive rotator cuff tear? A propensity score-matched study a history of prior rotator cuff surgery was associated with a high incidence of acromial stress fracture

Coracoacromial ligament integrity influences scapular spine strain after reverse shoulder arthroplasty This biomechanical study in cadavers examined the effect of coracoacromial (CA) ligament state (intact vs. released) and arm position on acromial and scapular spine strain following reverse total shoulder arthroplasty (rTSA).  Scapular spine strain was quantified via 4 strain gauges placed along anatomic locations on the acromion and scapular spine.  CA ligament release in the setting of rTSA resulted in increased scapular spine and acromial strain with the arm adducted, although these increases in strain were not statistically significant. 

Low acromial insufficiency fracture rate in reverse shoulder arthroplasty with distal clavicle excision This study investigated the rate of acromial insufficiency fractures (AIF) in patients undergoing reverse shoulder arthroplasty (RSA) with concomitant distal clavicle excision (DCE).  There were 3/174 acromial insufficiency fractures (1.7%). Twelve patients had insufficiency reactions (6.9%). Patients with acromial pathology were more likely to be female, and have a diagnosis of osteoporosis, and inflammatory arthritis. Unfortunately, there was no comparison group of RSAs without distal clavicle excision

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

Acquired Acromion Compromise, Including Thinning and Fragmentation, Is Not Associated With Poor Outcomes After Reverse Shoulder Arthroplasty Preoperative acromial compromise was defined as follows: (1) thinning of the acromion (< 3 mm), which means a thickness of less than 30% of the normal acromion thickness (8 to 9 mm), and (2) acromial fragmentation.  In patients with acquired acromial compromise-such as thinning or fragmented acromion because of advanced cuff tear arthropathy or previous acromioplasty, primary RSA resulted in no differences in functional outcome score, ROM, shoulder strength, and overall complications compared with patients without acromial compromise.

Variations in the Anatomic Morphology of the Scapular Spine and Implications on Fracture After Reverse Shoulder Arthroplasty This study evaluated the role of anatomic scapular morphology in acromion and scapular spine fracture (SSAF) risk after reverse shoulder arthroplasty (RSA).  Scapular measurements were captured including scapular width measurements at the acromion (Z1), middle of the scapular spine (Z2), and medial to the first major angulation (Z3). 

 Patients with thicker acromions (Z1) and thinner medial scapular spines (Z3) had increased fracture risk. The mean zone 1 and 3 measurements for the control group were 18.6 ± 3.7 mm and 3.2 ± 1 mm, respectively, compared with 22.5 ± 5.9 mm and 2 ± 0.7 mm, respectively, in the SSAF cohort. This trend was also reflected in the calculated scapular spine proportion (SSP),Z1/Z3. A regression analysis was used to quantify the risk for scapular spine fracture after RSA as a function of SSP. Under this calculation, an SSP = 5 represented a <5% fracture risk; SSP = 9.2, 50%; SSP = 10.8, 75%; and SSP = 13.5, 95% risk.

Acromial and scapular fractures after reverse shoulder arthroplasty: comparison of 3018 reverse total shoulders by inlay and onlay humeral component design When comparing by inlay vs. onlay humeral component design, the rates of postoperative acromial or scapular spine fractures were statistically similar.

Reverse shoulder arthroplasty for patients with cuff tear arthropathy: do clinical outcomes differ by inlay vs. onlay design? At 2-year minimum follow-up, the position of the humeral tray in RSA prostheses (either inlay or onlay) for cuff tear arthropathy was not associated with PROs, shoulder ROM, or rates of complications, including baseplate loosening, acromial stress fracture, and scapular notching.

Increased Deltoid and Acromial Stress with Glenoid Lateralization and Onlay Humeral Stem Constructs in Reverse Shoulder Arthroplasty Finite element analysis was performed using a RSA system with both inlay and onlay configurations.  Increased lateralization of the glenoid component resulted in increased levels of deltoid and acromial stress. For a given amount of glenoid lateralization, utilization of an inlay stem decreased acromial and deltoid stresses compared to onlay constructs. 

High delta angle after reverse total shoulder arthroplasty increases stresses of the acromion: biomechanical study of different implant positions. High delta angle (combination of inferiorization and medialization of the center of rotation [COR]) after RTSA may be a risk factor for acromial fracture.

In a rigid body model of the upper extremity muscle, forces of the deltoid muscle were calculated before and after implanting RTSA in different arm and implant positions.  High delta angles correlated with an increase in acromial stress. Both lateralization of the COR and the humerus decreased the acromial stress in this study. The lateralization of the humerus has the highest impact on acromial stress.These results are contrary to some in the current literature, thus further studies with focus on the acromial stress are needed.

You can support cutting edge shoulder research that is leading to better care for patients with shoulder problems, click on this link

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Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The ream and run procedure (see this link).
The total shoulder arthroplasty (see this link).
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link)
Shoulder rehabilitation exercises (see this link).

Treating rotator cuff tear arthropathy without risking acromial and spine stress fractures

 It is well recognized that female sex, osteopenia, rotator cuff tear arthropathy, inflammatory joint disease and thin acromial bone are risk factors for acromial and scapular spine fractures after reverse total shoulder arthroplasty. Unfortunately, these conditions are commonly encountered in shoulder surgery.

A 71 year old woman presented with all of these conditions, retained active elevation above 90 degrees, and answered "yes" to only 3 functions of the 12 Simple Shoulder Test questions.

Her right shoulder x-ray at the time of presentation is shown below, demonstrating a thinned acromion, osteopenia, and acromiohumeral contact.

After discussion of the surgical options, including a reverse total shoulder, she elected to proceed with a CTA hemiarthroplasty. At the time of surgery, her supraspinatus and infraspinatus were detached and irreparable. Her subscapularis was detached but reparable.

A thin humeral stem was inserted with impaction autografting to provide a small filling ratio.

Nine years later she returned for evaluation of her contralateral shoulder. 

Her CTA hemiarthroplasty shoulder had 140 degrees of comfortable active elevation.

Her nine year followup film is shown below, demonstrating an intact acromion and no evidence of component loosening.

Comment: In our experience patients selected for the CTA hemiarthroplasty have been free of acromial/scapular spine fractures, dislocations, and prosthetic loosening. See CTA hemiartroplasty or reverse total shoulder for cuff tear arthropathy.

Comments welcome at shoulderarthritis@uw.edu

You can support cutting edge shoulder research that is leading to better care for patients with shoulder problems, click on this link


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Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The ream and run procedure (see this link).
The total shoulder arthroplasty (see this link).
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link).

Shoulder rehabilitation exercises (see this link). 

  

Acromial and spine stress fractures after reverse total shoulder.

As is the case for most stress fractures, acromial and spine stress fractures (ASF) after reverse total shoulder (RSA) result from changes in the magnitude, direction and frequency of loads applied to the bone. The observation that ASF are more common in shoulders with cuff deficiency suggests that an intact cuff may reduce the changes in loads on the acromion and scapular spine by assuming a portion of the humeroscapular forces.

Changes in acromial and scapular spine loading result from surgeon-controlled factors, including implant design and implant placement. Glenoid-sided lateralization can increase shoulder range of motion by reducing abutment between the humerus and the scapula as well as reducing the risk of scapular notching. What are the down-sides of glenoid-sided lateralization?

The authors of "Up to 8 mm of glenoid-sided lateralization does not increase the risk of acromial or scapular spine stress fracture following reverse shoulder arthroplasty with a 135 degree inlay humeral component" (recipient of the Robert H. Cofield Award) identified 26 ASFs (5.5%) among 470 RSAs. 

In communication with the corresponding author, it was verified that glenoid-sided lateralization in the system used in this study reflects the combination of baseplate offset (0, 2 or 4mm) and glenosphere offset (0 to 8 mm). See red arrow in the figure below.

In this series, glenoid sided lateralization ranged from 0 to 8 mm. The amount of glenoid sided lateralization was not associated with ASF risk: the incidence of fracture did not increase with greater glenoid-sided lateralization (0-2 mm, 7.4%; 4 mm, 5.6%; 6 mm, 4.4%; 8 mm, 6.0).  

However, humeral distalization did increase the risk of ASFs. The pre- to postoperative change in acromiohumeral distance (AHD, measured as shown above) was higher in the stress fracture group (2.0 ± 0.7 cm vs. 1.7 ± 0.7 cm). For every centimeter increase in the change in AHD, there was a 121% increased risk for fracture. 

It can be concluded that for this implant system (a 135 degree inlay humeral component) the change in humeral position relative to the acromion  (whether from inferior tilt of the glenosphere, increased inferior overhang of the glenosphere, as well as from the type and positioning of the humeral implant) can change the magnitude and direction of the forces experienced by the acromion, creating a risk for stress fracture.

Minimizing the surgeon-controlled risk factors - such as avoiding over-lenthening - seems particularly important in shoulders that are intrinsically at increase risk for ASF, such as those with superior displacement of the humeral head relative to the scapula, a thin acromion, osteopenia, inflammatory arthropathy, advanced age and rotator cuff deficiency (see figure below).

Comment to shoulderarthritis@uw.edu

You can support cutting edge shoulder research that is leading to better care for patients with shoulder problems, click on this link

Follow on twitter/X: https://x.com/RickMatsen
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Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The ream and run procedure (see this link).
The total shoulder arthroplasty (see this link).
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link).

Shoulder rehabilitation exercises (see this link). 

Acromial / scapular spine fractures after reverse total shoulder arthroplasty

Acromial (ASF) and scapular spine (SSF) stress fractures are clinically important complications of reverse total shoulder arthroplasty (RSA) occurring in as many as 15% of patients having this procedure. The risk of these complications depends on characteristics of the patient, the shoulder, the prosthesis and the procedure. In an attempt to evaluate the non-modifiable and modifiable risk factors the authors of Implant-Positioning and Patient Factors Associated with Acromial and Scapular Spine Fractures After Reverse Shoulder Arthroplasty: A Study by the ASES Complications of RSA Multicenter Research Group conducted a multicenter study of 6,320 patients having a minimum 3-month follow-up (recognizing that a substantial number of these stress fractures occur later than three months post RSA).

Radiographic data, including the lateralization shoulder angle, distalization shoulder angle, glenoid offset, and lateral humeral offset were collected in a 2:1 control-to-fracture ratio and analyzed to evaluate their association with ASFs/SSFs. 

The overall stress fracture rate was 3.8% (180 ASFs [2.8%] and 59 SSFs [0.9%]). 

Unmodifiable patient risk factors for acromial fractures included inflammatory arthritis (odds ratio [OR] = 2.29, p < 0.001), osteoporosis (OR = 2.00, p < 0.001), female sex (OR = 1.74, p = 0.003), and older age (OR = 1.02, p = 0.018)

Unmodifiable shoulder risk factors included a massive rotator cuff tear (OR = 2.05, p = 0.010), , prior shoulder surgery (OR = 1.82, p < 0.001), and cuff tear arthropathy (OR = 1.76, p = 0.002)

Modifiable procedure risk factors were less important (greater glenoid lateral offset (OR = 1.06, p = 0.025)).

Unmodifiable patient risk factors for scapular spine fractures included female sex (OR = 2.45, p = 0.009), osteoporosis (OR = 2.18, p = 0.009), and inflammatory arthritis (OR = 2.04, p = 0.024). 

Unmodifiable shoulder risk factors for scapular spine fractures included rotator cuff disease (OR = 2.36, p = 0.003)

No modifiable procedure risk factors for scapular spine fractures (including glenoid lateral offset) were identified.

On multivariable analysis, increased humeral lateralization was found to be associated with lower fracture rates whereas excessive glenoid-sided and global lateralization were associated with higher fracture rates.

Comment: Reverse total shoulder arthroplasty is being increasingly used to treat osteoarthritis with an intact rotator cuff as an alternative to anatomic total shoulder arthroplasty (ATSA). Patients with osteoarthritis and an intact rotator cuff are less at risk for stress fractures than those patients for which ATSA is not an option (rotator cuff tear arthropathy, massive rotator cuff tear). Currently about 50% of RSAs are performed for osteoarthritis with intact cuff (see this link).

 Yet patients having RSA for osteoarthritis with intact cuff comprise only 10% of patients with stress fractures (see this link). 

Because of the indication drift towards RSA for patients with osteoarthritis and an intact rotator cuff, the overall rate of stress fractures after RSA is decreasing, because more RSAs are being done on patients at low risk.

It is not known if the rate of stress fractures in high risk patients is changing.

RSA dramatically changes the loading of the acromion and scapular spine. As is the case with runners and stress fractures, some patients and some bones can tolerate the loading changes better than others. Perhaps we would be advised to consider patients having RSA in two groups:

Patients and shoulders with unmodifiable factors (female sex, advanced age, osteoporosis, inflammatory arthritis, prior surgery, cuff disease) remain at risk and deserve a separate study to identify potential risk-lowering surgical strategies, such as glenoid-sided medialization. 

On the other hand patients without these risk factors may be better served by investigating factors that optimize function rather than focusing on further lowering stress fracture risk. For example in such patients glenoid-sided lateralization may safely improve shoulder rotation while lowering rates of scapular notching and impingement.

You can support cutting edge shoulder research that is leading to better care for patients with shoulder problems, click on this link

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Contact: shoulderarthritis@uw.edu

Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The ream and run procedure (see this link).
The total shoulder arthroplasty (see this link).
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link).
Shoulder rehabilitation exercises (see this link).

Risk factors for acromial and scapular spine fractures - are we any smarter about preventing these complications?

Acromial and scapular spine fractures are major complications of reverse total shoulder arthroplasty with a substantial negative impact on the clinical outcome of the procedure. The management of these fractures is challenging with high rates of malunion and nonunion, decreased function, and complications (see Acromial and scapular spine fractures after reverse total shoulder arthroplasty)

Surgeons and patients are concerned about reducing the incidence of these fractures through the identification of modifiable risk fractures.

The 57 authors of Risk Factors of Acromial and Scapular Spine Stress Fractures Differ by Indication: A Study by the ASES Complications of Reverse Shoulder Arthroplasty Multicenter Research Group point out that both patient and surgical (implant and technique) characteristics affect the risk of fracture of the acromion and scapular spine.

Their study included 4764 patients with preoperative diagnoses of arthritis (GHOA),  cuff tear arthropathy (CTA), or massive cuff tear (MCT) with the minimum follow-up of 3 months (range: 3-84). The incidence of cumulative stress fracture was 4.1%. The incidence of stress fracture in the GHOA cohort was 2.1% compared to 5.2% in the CTA/MCT cohort. Presence of inflammatory arthritis and osteoporosis were associated with an increased risk of these fractures. Most of the fractures were atraumatic. 

Comment: Because of its short minimum followup after reverse total shoulder surgery (3 months) this study may underestimate the rate of these fractures. The publication Incidence, radiographic predictors, and clinicaloutcome of acromial stress reaction and acromial fractures in reverse total shoulder arthroplasty found that acromial and scapular spine fractures are detected at a mean of 16 ±
24 months after RSA.

The authors of Risk Factors of Acromial and Scapular Spine Stress Fractures Differ by Indication: A Study by the ASES Complications of Reverse Shoulder Arthroplasty Multicenter Research  Group concluded that "Patients with CTA/MCT and postoperative stress fracture are more likely to be female, have osteoporosis, and have a diagnosis of inflammatory arthritis, while patients with GHOA are at risk of stress fracture with a diagnosis of inflammatory arthritis alone." However, the diagnosis is not a modifiable risk factor; neither is age, sex, preoperative pathoanatomy, or the degree of osteoporosis. 

Modifiable risk factors may include surgical technique, implant characteristics, component position and postoperative activity. This study did not investigate the relationship of these modifiable characteristics to the rate of acromial / scapular spine fracture after reverse total shoulder.

Hopefully analysis of these modifiable risk factors is forthcoming from the ASES Complications of Research Shoulder Arthroplasty Multicenter Research Group.

You can support cutting edge shoulder research that is leading to better care for patients with shoulder problems, click on this link.

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Follow on facebook: click on this link
Follow on facebook: https://www.facebook.com/frederick.matsen
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Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The ream and run procedure (see this link).
The total shoulder arthroplasty (see this link).
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link).
Shoulder rehabilitation exercises (see this link).

Acromial and spine fractures after reverse total shoulder risk and prevention.

Acromial and scapular spine fractures are unique and significant complications of reverse total shoulder arthroplasty; they are not seen after other types of arthroplasty.

A recent multicenter study Predictors of acromial and scapular stress fracture after reverse shoulder arthroplasty: a study by the ASES Complications of RSA Multicenter Research Group found that these fractures occurred in one out of 25 cases of reverse total shoulder arthroplasty.

These fractures occur months or even years after the index reverse total shoulder. They may present with the subtle onset of pain over the acromion and spine and subtle radiographic findings.





or they may present as catastrophic loss of shoulder function with obvious x-ray changes.



The Levy classification of these fractures distinguishes the most serious (red) from the less serious (green), but all fracture types compromise the comfort and function of the shoulder.

Because they often occur in osteopenic bone, internal fixation of these fractures can be difficult and unrewarding for the patient.

Recently, the authors of Impact of Accumulating Risk Factors on the Acromial and Scapular Fracture Rate after Reverse Total Shoulder Arthroplasty with a Medialized Glenoid/Lateralized Humerus Onlay Prosthesis studied the compounding effect risk factors for acromial and scapular fractures in 9,079 patients having a medialized glenoid/lateralized humerus onlay rTSA prosthesis.





138 of 9,079 patients were radiographically identified to have a fracture of the acromion or scapula for a rate of 1.52%.
61% of the patients without fractures were female, whereas 80% of the patients with fractures were female

73.9% of these fractures occurred in the first year after surgery and 33.3% occurred within 3 months of surgery.

The most serious type of fracture (Type 3) were diagnosed a year and a half after surgery:
39.1% of the patients had a Type 1 fracture at an average of 9.1 ± 12.5 months after surgery,
39.1% of the patients had a Type 2 fracture at an average of 6.5 ± 12.1 months, and
21.7% of the patients had a Type 3 fracture at an average of 19.2 ± 20.9 months

Almost half of the patients in the fracture and non fracture groups had a preoperative diagnosis of osteoarthritis. The distribution of diagnoses was a bit different between the two groups.






Note that some of the patients were assigned multiple diagnoses, so the percents in the charts above add up to >100%.

Patients with the greatest fracture risk were females over 70 years of age with a diagnosis of rheumatoid arthritis.

Patients with these fractures had significantly worse self assessed shoulder comfortant and function (average Simple Shoulder Test = 6.4) in comparison to patients without fractures (SST = 9.2). Patients with Levy type 3 fractures had the worst outcomes (SST = 4.9) and had the least preoperative to postoperative improvement (change in SST = 1.8).

Comment: Whether they occur in one 1 of 25 or 1 out of 66 cases, fractures of the acromion and spine are a serious complication of reverse total shoulder arthroplasty with inferior clinical outcomes for the patient. This study looks at some of the factors that may affect the risk if these fractures. Other investigations have considered additional possible risk factors in addition to age, sex and diagnosis: bone density, prior acromioplasty, drill holes and screws in the base of the spine, excessive distalization of the tuberosity, contact between the acromion and the tuberosity, neck/shaft angle and the degree of lateralization/medialization of the glenosphere and humerus.

In this study patients with advanced age, female sex and the diagnosis of RA were at highest risk, yet less than 6% of the patients with fractures had these risk factors. What about the remaining 94%?

One strategy is to recognize that patients having anatomic arthroplasty are not at risk for these fractures. Almost half of the patients with fracture carried the diagnosis of osteoarthritis, which can usually be treated with an anatomic total shoulder - avoiding the risk of these fractures.

Therefore, the authors suggest that alternative treatments like anatomic total shoulder arthroplasty (aTSA) or hemiarthroplasty with or without use of a CTA humeral head may be alternative considerations for some of the patients receiving reverse total shoulder arthroplasty. To that point, the mean preoperative active elevation was >80 degrees for all the patients with standard deviations ≥40 degrees. Thus almost half of patients did not have pseudoparalysis and may have been well served by an anatomic or CTA hemiarthroplasty.

You can support cutting edge shoulder research that is leading to better care for patients with shoulder problems, click on this link.

Follow on twitter: https://twitter.com/shoulderarth
Follow on facebook: click on this link
Follow on facebook: https://www.facebook.com/frederick.matsen
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Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The ream and run procedure (see this link).
The total shoulder arthroplasty (see this link).
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link).
Shoulder rehabilitation exercises (see this link).