Reverse total shoulder complications

While reverse total shoulder is becoming an increasingly popular procedure, we regularly see patients presenting to our clinic because of clinical failure. Here are two examples from this morning.  Both of these patients had substantially less shoulder function after their reverse total shoulder than before it was performed.

First a reverse with an augmented baseplate that has been painful and dysfunctional since the reverse arthroplasty. While the cause of the pain and functional loss has not yet been established, there is concern about the incomplete seating of the baseplate on the bone of the glenoid.

A CT scan confirmed the lack of seating of the baseplate along with an acromial fatigue fracture

Second is a patient whose shoulder was relatively functional both before and after a reverse until the sudden atraumatic onset of an acromial fracture.  While the fracture itself is no longer symptomatic the displacement of the acromion has rendered the shoulder pseudoparalytic, probably due to loss of tension in the deltoid. 

In addition to the inability to use the arm away from the side, the shoulder joint area is becoming increasing painful at rest. Note the high degree of scapular notching which raises the possibility of reaction to polyethylene particles resulting from contact of the humeral liner with the scapular bone and screw

A bit more about notching

Scapular notching in reverse shoulder arthroplasty: is it important to avoid it and how?

Anytime we have unintended contact between high density polyethylene and bone, it is a problem. Scapular notching is a radiographic finding, but the real concerns are about (1) the damage to the poly of the humeral cup, (2) loss of the bone of the scapula that supports the glenoid component, and (3) the potential for instability resulting from leverage of one against the other. See this previous post which discusses this phenomenon in some detail.

In the Grammont-type reverse total shoulder, contact of the adducted humeral component against the scapula is not uncommon as shown in this figure from a manufacturer's website.

These authors retrospectively reviewed 448 patients who underwent a Grammont-type reverse total shoulder  (461 shoulders) performed for rotator cuff tear arthropathy or osteoarthritis with cuff deficiency with a mean followup of 51 months (range, 24-206 months). They found notching of the scapula in 68% of the cases; it was present in 48% at one year after surgery. 

Notching was more common in active patients, in patients with cuff tear arthropathy, and in patients with greater degrees of superior displacement of the humeral head before surgery. Strength and range of motion were compromised in patients with notching.

Importantly, 36% of shoulders with notching had humeral radiolucent lines (in contrast to 17% in those without notching), suggesting the possibility that polyethylene particles from the humeral cup causing bone resorption. Similarly glenoid loosening was three times more common in the presence of notching.

The authors point out that standardized plain x-rays are necessary for the evaluation of notching, noting that sometimes notching is better seen on the axillary view.

Comment: Scapular notching is important and can be expected to adversely affect the long term durability and function of the reverse. It is best avoided by (1) use of a glenoid component design that offsets the center of rotation from the scapula, (2) proper positioning of the glenoid component at the inferior aspect of the glenoid, (3) avoiding superior tilt of the glenoid component, and carefully checking for contact between the humeral component and scapula at surgery when the arm is adducted and rotated. If contact is noted after component implantation, careful resection of the contacting scapular bone may be helpful.

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How you can support research in shoulder surgery Click on this link.

Here are some videos that are of shoulder interest

Shoulder arthritis - what you need to know (see this link)

The smooth and move for irreparable cuff tears (see this link)

The total shoulder arthroplasty (see this link).

The ream and run technique is shown in this link.

The cuff tear arthropathy arthroplasty (see this link).

The reverse total shoulder arthroplasty (see this link).

Shoulder rehabilitation exercises (see this link).

Reverse total shoulder arthroplasty - adverse radiographic changes

 Radiographic changes around the glenoid component in primary reverse shoulder arthroplasty at mid-term follow-up

These authors analyzed the radiographic changes around the glenoid component and determined the risk factors associated with the presence of these radiographic changes in 105 primary Grammont-style reverse total shoulders with 5 years of radiographic follow-up. 

Standardized digital radiographs obtained immediately postoperatively and at a minimum follow-up time of 5 years were analyzed to determine 

(1) glenoid component position (inclination and height) and 

(2) minor radiographic changes (Sirveaux grade 1 or 2 scapular notching; nondisplaced acromial

fracture; radiolucent lines around 1 or 2 screws; Brooker grade 1a, 1b, or 2 heterotopic calcifications; or single screw rupture), and

(3) major radiographic changes (Sirveaux grade 3 or 4 scapular notching; radiolucent lines around 3 screws or central peg; Brooker grade 1c or 3 heterotopic calcifications; prosthetic dislocation; loosening or migration; or disassembly).

Major radiologic changes were identified in 14.3% of the cases. Bivariate analysis showed that more changes were associated with the arthroplasties implanted in the first years of the study.

Multivariate analysis revealed an increased risk of severe scapular notching mainly associated with superior tilt of the baseplate and a high glenosphere position.

They also noted an increased risk of loosening with superior tilt.

Superior tilt of baseplate

Superior position of glenosphere

Comment: This is an informative case series. It demonstrates some of the challenges associated with designs of reverse total shoulder in which a glenoid hemisphere is placed directly on the glenoid bone. This results in medialization of the proximal humerus with the associated risk of scapular notching. This risk is further increased by superior positioning of the glenosphere and superior inclination of the baseplate.

These issues can be addressed by positioning the glenosphere flush with the lower edge of the glenoid bone, by avoiding superior inclination and by using an offset glenosphere, which can be accomplished with a bone graft as shown in yellow below right

or by using a glenosphere offset by a neck as shown below.

Our technique for reverse total shoulder arthroplasty is shown in this link.

How you can support research in shoulder surgery Click on this link.

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 total shoulder arthroplasty (see this link).

The ream and run technique is shown in this link.

The cuff tear arthropathy arthroplasty (see this link).

The smooth and move procedure for irreparable rotator cuff tears (see this link).

Shoulder rehabilitation exercises (see this link).

Reverse total shoulder - notching damages both bone and polyethylene

Wear and Damage in Retrieved Humeral Inlays of Reverse Total Shoulder

Arthroplasty – Where, How Much and Why?

These authors sought to quantify the linear and volumetric wear in reverse total shoulder arthroplasties (RTSA), and to qualitatively assess the PE damage modes to describe the material degradation in 39 retrieved humeral PE inlays from failed of RTSAs.

Damage on the rim of the humeral PE inlays was more frequent and severe than on the articulation surface. Irrespective of the damage mode, the inferior rim zone sustained the greatest amount of wear damage followed by the posterior zone.

Burnishing, scratching, pitting and embedded particles are most likely to occur in the articular surface area, whereas surface deformation, abrasion, delamination and gross material degradation are predominantly present in the inferior and posterior rim zones. 

The retrieved inlays exhibited a mean volumetric wear rate of 296.9 cubic mm/year. 

Components from shoulders with scapular notching showed a five-fold increase in polyethylene wear rate in comparison to those from non-notched shoulders. 

Comment: Much attention has been directed at measuring the amount of scapular bone lost from notching. 

However, as this article points out, the amount of polyethylene lost from the humeral poly cup may be of equal or greater importance.

When the poly cup is worn, polyethylene debris can cause immune cell activation, which results in inflammation in the periprosthetic tissues. In turn, this inflammation may initiate joint pain, stiffness and periprothetic osteolysis that can lead to loosening of the implant (see this link).

The best "treatment" for notching is "prevention" by assuring that there is plenty of clearance between the medial aspected of the humeral poly and the lateral aspect of the scapular neck.

                             

To see our technique for reverse total shoulder, click on this link.

To support our research to improve outcomes for patients with shoulder problems, click here.

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How you can support research in shoulder surgery Click on this link.

To see our new series of youtube videos on important shoulder surgeries and how they are done, click here.

Be sure to visit "Ream and Run - the state of the art"  regarding this radically conservative approach to shoulder arthritis at this link and this link. Also see the essentials of the ream and run.

Use the "Search" box to the right to find other topics of interest to you.

You may be interested in some of our most visited web pages   arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery 

Reverse total shoulder scapular notching - it's not only about the scapula

Impact of scapular notching on reverse total shoulder arthroplasty midterm outcomes: 5-year minimum follow-up

These authors observe that the impact of scapula notching on reverse total shoulder arthroplasty (rTSA) clinical outcomes is controversial. They conducted an analysis of 324 rTSA patients with 5 years of minimum (average (75 mo)  follow-up to evaluate the relationships between notching and clinical outcome.

47 patients (14.5%) had scapular notching; for these patients, the average notching grade was 1.7 0.8 (24 grade 1, 15 grade 2, and 8 grade 3). The average time to notch development was 51.4 months; grade 1, grade 2, and grade 3 notches developed at 49.0 months, 57.5 months, and 71.6 months, respectively. No preoperative differences were observed between cohorts. 

At latest follow-up, scapular notching patients had significantly worse outcome scores and significantly less active abduction, forward flexion, and strength.

Finally, scapular notching patients had significantly more complications, revisions, and humeral radiolucent lines.

Comment: From these results it can be seen that patients with scapular notching do, on average, less well than those without.

Scapular notching is a phenomenon observed on x-rays as shown below. It can extend to the point where the screw fixation of the glenoid base plate is jeopardized.

What cannot be seen on x-ray is what is on the other side of the notching, i.e. the polyethylene of the humeral cup. The poly fares poorly when it repeatedly contacts the bone of the scapula. When the poly is eroded (see below) small particles of poly debris are released into the joint, where they can cause pain and stiffness. This particulate debris can also contribute to loosening of the humeral and glenoid components.

Scapular notching in reverse shoulder arthroplasty: is it important to avoid it and how?

Anytime we have unintended contact between high density polyethylene and bone, it is a problem. Scapular notching is a radiographic finding, but the real concerns are about (1) the damage to the poly of the humeral cup, (2) loss of the bone of the scapula that supports the glenoid component, and (3) the potential for instability resulting from leverage of one against the other. See this previous post which discusses this phenomenon in some detail.

In the Grammont-type reverse total shoulder, contact of the adducted humeral component against the scapula is not uncommon as shown in this figure from a manufacturer's website.

These authors retrospectively reviewed 448 patients who underwent a Grammont-type reverse total shoulder  (461 shoulders) performed for rotator cuff tear arthropathy or osteoarthritis with cuff deficiency with a mean followup of 51 months (range, 24-206 months). They found notching of the scapula in 68% of the cases; it was present in 48% at one year after surgery. 

Notching was more common in active patients, in patients with cuff tear arthropathy, and in patients with greater degrees of superior displacement of the humeral head before surgery. Strength and range of motion were compromised in patients with notching.

Importantly, 36% of shoulders with notching had humeral radiolucent lines (in contrast to 17% in those without notching), suggesting the possibility that polyethylene particles from the humeral cup causing bone resorption. Similarly glenoid loosening was three times more common in the presence of notching.

The authors point out that standardized plain x-rays are necessary for the evaluation of notching, noting that sometimes notching is better seen on the axillary view.

Comment: Scapular notching is important and can be expected to adversely affect the long term durability and function of the reverse. It is best avoided by (1) use of a glenoid component design that offsets the center of rotation from the scapula, (2) proper positioning of the glenoid component at the inferior aspect of the glenoid, (3) avoiding superior tilt of the glenoid component, and carefully checking for contact between the humeral component and scapula at surgery when the arm is adducted and rotated. If contact is noted after component implantation, careful resection of the contacting scapular bone may be helpful.

To see a YouTube of our technique for a reverse total shoulder arthroplasty, click on this link.

=====

To see our new series of youtube videos on important shoulder surgeries and how they are done, click here.

Use the "Search" box to the right to find other topics of interest to you.

How you can support progress in shoulder surgery

You may be interested in some of our most visited web pages  arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

Reverse total shoulder - scapular notching with a medialized glenosphere

Can a functional difference be detected in reverse arthroplasty with 135versus 155prosthesis for the treatment of rotator cuff arthropathy: a prospective randomized study


The Anthrex Univers Revers has an adaptable inlay humeral cup that can be locked at either 135 or 155 degrees.

These authors conducted a randomized controlled trail comparing outcomes with these two inclinations in 100 patients undergoing primary reverse shoulder arthroplasty (RSA). The prostheses were otherwise identical. A neutral glenosphere was used in all cases. 

There was no difference in range of motion or functional outcome scores between the 2 groups. 

Scapular notching was observed in 58% of cases with a 155 degree inclination compared with 21% with a 135 degree inclination. 

Based on these observations, these authors now use a lateralized glenosphere with a 135 degree prosthesis.

Comment: While originally dismissed as having no clinical significance, it is now recognized that scapular notching is associated with inferior long term results from reverse total shoulder arthroplasty. We concur that a lateralized glenosphere can reduce the risk of notching as shown below.

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We have a new set of shoulder youtubes about the shoulder, check them out at this link.

Be sure to visit "Ream and Run - the state of the art"  regarding this radically conservative approach to shoulder arthritis at this link and this link

Use the "Search" box to the right to find other topics of interest to you.

How you can support progress in shoulder surgery

You may be interested in some of our most visited web pages   arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

Can notching be a problem after reverse total shoulder? Yes!

Eight years ago, a patient had this type of reverse total shoulder implanted in the right shoulder. Note the close proximity between the humeral polyethylene and the inferior screw (arrow).

Seven years later the patient was complaining of shoulder pain and had the x-ray shown below. The arrow points to scapular notching from contact of the bone of the scapular with the polyethylene of the humeral cup. This notching has exposed the inferior screw.

Eight months later, the shoulder dislocated and could not be stably reduced. The x-ray below shows the dislocated reverse with the notched scapula.

At revision surgery, the polyethylene was seen to be eroded so that it no longer functioned as a complete cup - this allowed the shoulder to dislocate. The appearance of the polyethylene is show below.

We revised this shoulder by removing the prominent screw, replacing the glenosphere with one of a larger diameter of curvature, and using humeral spacers to improve stability by increasing the compressive force at the joint.

This case demonstrates that notching can be a problem and that the resulting loss of the polyethylene concavity can allow the reverse total shoulder to dislocate.

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Use the "Search" box to the right to find other topics of interest to you.

How you can support progress in shoulder surgery

You may be interested in some of our most visited web pages   arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'

Scapular notching with the Delta Xtend

Scapular Notching After Reverse Total Shoulder Arthroplasty. Prediction Using Patient-Specific Osseous Anatomy, Implant Location, and Shoulder Motion

Scapular notching refers to the loss of bone from the inferior glenoid neck resulting from contact with the humeral component of a reverse total shoulder.

These authors evaluated patients with preoperative computed tomography (CT) scans who underwent reverse total shoulder with the Delta Xtend; 155 humeral neck-shaft angle and 38-mm [n = 10] or 42-mm [n = 19] glenosphere at a minimum of 2 years of follow-up with video motion analysis (VMA), postoperative threedimensional (3D) CT, and standard radiographs. 

The glenohumeral range of motion demonstrated by the VMA and the postoperative implant location on the CT were used in custom simulation software to determine areas of osseous contact between the humeral implant and the scapula and their relationship to scapular notching on postoperative CT. Patients with and without notching were compared with one another by univariable and multivariable 

Seventeen patients (59%) had scapular notching, which was along the posteroinferior aspect of the scapular neck in all of them and along the anteroinferior aspect of the neck in 3 of them. Osseous contact occurred in external rotation with the arm at the side in 16 of the 17 patients, in internal rotation with the arm at the side in 3, and in adduction in 12. 

Placing the glenosphere in a position that was more inferior (by a mean of 3.4 ± 2.3 mm) or lateral (by a mean of 6.2 ± 1.4 mm) would have avoided most impingement in the patients’ given range of motion. 

Their results suggest that for the Delta Xtend system with its medialized center of rotation, placing the glenosphere in a maximally inferior position while maximizing posterior and lateral placement may help minimize notching.

Comment: While the bony changes of notching can be assessed by x-rays, it is also important to consider changes on the humeral component resulting from the unwanted contact.

Notching can proceed to the point where fixation of the glenoid component is jeopardized.

It is apparent that the design of different prostheses affects the risk of notching. Lateralization of the baseplate can be effective in that regard.

Finally, as a part of the surgical technique with any prosthesis, while the trial components are in place it is important to check for unwanted contact between the humeral component and the scapula with the arm in adduction and in the full range of rotation. If this unwanted contact is present, modification of the prosthesis or its position can be effected.

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Use the "Search" box to the right to find other topics of interest to you. 

How you can support progress in shoulder surgery

You may be interested in some of our most visited web pages including:shoulder arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'