The complexities of glenohumeral arthritic pathoanatomy

 Glenohumeral arthritis comes in a wide variety of forms. While these are often described in terms of glenoid version, inclination, biconcavity, and bone loss, these terms only partially capture the complexity of each arthritic shoulder as exemplified by this 3D reconstruction

To further complicate things, changes in glenoid pathoanatomy may be associated with other important features of the shoulder. For example, superior inclination can be associated with rotator cuff dysfunction (see for example link, link, link) which may have a profound effect on anatomic glenoid component durability and post arthroplasty shoulder function.

The authors of Mid-term Radiographic Outcomes of Anatomic Total Shoulder Arthroplasty in Biplanar Glenoid Deformities sought to separate the effects of  combined retroversion ≥ 20 degrees + inclination ≥ 10 degrees in 28 shoulders from a matched set of 28 shoulders with retroversion ≥ 20 degrees alone. All shoulders were managed with "hi side reaming" and a standard glenoid component.

The goal at surgery was to achieve 80% glenoid component seating and final retroversion within 10-15 degrees of neutral with no specific attempts to correct glenoid inclination.

Using preoperative CT-based 3D planning software, they found that the biplanar shoulders had greater inclination (14.5 ̊ versus 5.3̊) and greater retroversion (30.0 ̊ versus 25.6 ̊)

Using postoperative plain radiographs, they found that biplanar shoulders had greater implant superior inclination (5.9 ̊ vs. 3.0 ̊). 

In that 2 different imaging methods were used it is difficult to know if 14.5̊ vs 5.9 ̊ represents the actual amount of change in inclination. 

The initial postoperative posterior decentering was 3.5% vs 1.8%.

On final follow-up plain radiographs, biplanar shoulders had higher Lazarus radiolucent scores (2.4 vs. 1.6) and higher proportion with glenoid radiolucency (68% vs. 39%). 

Preoperative biplanar deformity was the only significant predictor of glenoiod radiolucency (odds ratio 3.3).

Posterior decentering increased for both groups to 7.6% vs 4.0%.

Comment: This is an interesting paper calling attention to the variability in preoperative glenohumeral arthritic pathoanatomy.

In considering the possible contributing factors to the increased rate of glenoid lucencies in the biplanar shoulders one could consider (a) concomitant cuff dysfunction in the shoulders with increased inclination (see above), (b) the increased rate of posterior decentering, (c) the greater postoperative inclination risking rocking horse loosening from superiorly directed loading of the glenoid component, and (d) the increased amount of bone removal necessary to achieve 80% seating in the superiorly inclined shoulders.

Additional larger studies will help sort out the relative importance of these variables. It would be desirable if these future studies used the same method of measuring glenoid inclination, glenoid version, and humeral head centering preoperatively and postoperatively so that one could determine the amount of change in these two important variables.

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). 

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The vicious circle of glenohumeral arthritis - can it be stopped?

In 1990, the late Doug Harryman published Translation of the humeral head on the glenoid with passive glenohumeral motion in which he described the effects of anterior capsular tightness on posterior humeral head translation in osteoarthritis. Here is a figure from that article.

The effect of anterior capsular tightness was further described in Practical Evaluation and Management of the Shoulder (see this link)

illustrating that this posterior translation can result in posterior glenoid wear

In Edge displacement and deformation of glenoid components in response to eccentric loading. The effect of preparation of the glenoid bone, Collins et al found that the thickness of glenoid articular cartilage was greatest in its posterior aspect, making this part of the glenoid socket at greatest risk for wear. In the case of the type B1 glenoid - where there is no obvious bony biconcavity - there is in fact a biconcavity in the articular surface due to loss of this posterior glenoid articular cartilage.  

                                         

which progresses to posterior glenoid bone wear becoming a type B2 glenoid

                                                     

as revealed by the axillary "truth" view

                                     

This posterior decentering is associated with loss of external rotation

Thus we have the vicious circle in which tightness and stiffness of the anterior capsule leads to posterior decentering of the humeral head leading to erosion of the posterior articular cartilage and bone which leads to limited external rotation leading to more tightness and stiffness of the anterior capsule.

as illustrated here:

             

A recent article The Association Between Anterior Shoulder Joint Capsule Thickening and Glenoid Deformity in Primary Glenohumeral Osteoarthritis builds on these points. These authors sought to determine the relationship between anterior capsular thickening and glenoid deformity in primary glenohumeral osteoarthritis in 134 osteoarthritic shoulders with magnetic resonance imaging (MRI) and computed tomography (CT) scans. 

They found that the anterior capsule was thickest in glenoid types B2 (5.5 mm) and B3 (6.1 mm), and thinnest in A1 (3.7 mm). Adjusted for age and sex, glenoid types B2 and B3 showed the strongest association with increased anterior capsule thickness, compared to glenoid type A1. Increased capsular thickness correlated with greater glenoid retroversion and posterior humeral head subluxation. In multivariable analysis, for every 1-mm increase in anterior capsular thickening, there was an adjusted mean increase of 3.2 degrees in glenoid retroversion and a 3.8% increase in posterior humeral head subluxation.

Taken together, these observations bring up the question: can interventions (such as mobilization exercises or anterior capsular releases) implemented early in the course of osteoarthritis interrupt the vicious cycle?

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).

The biconcave glenoid - what glenoid component to use?

Early Clinical and Radiographic Outcomes of Anatomic Total Shoulder Arthroplasty with a Bi-convex Posterior Augmented Glenoid for Patients with Posterior Glenoid Erosion: Minimum 2-Year Follow-Up

These authors report minimum two-year follow-up for all- polyethylene, biconvex augmented anatomic glenoid component for the management of shoulders with posterior glenoid erosion.

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According the the user guide (see this link), this procedure requires removal of bone by reaming to convert the variable anatomy of a B2 glenoid to a standardized biconcavity that fits the back of the implant. This is accomplished by using one reamer system for the anterior concavity 

and a second reamer system to shape the posterior concavity

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The authors emphasize several additional characteristics of this system: "This implant is available in four sizes, with 3 different amounts of augmentation. Also, given laterality-specific orientation of the pegs/augment it has right and left options. It also has two anchor options, a  fluted peg design and a keeled option, with availability dependent on geographic regulatory clearance." and when this implant is used for a B3 or C (monoconcave) glenoid, removal of anterior bone is required to create the biconcavity to match the back of the component. 

They conducted a retrospective review of  patients having an anatomic total shoulder (aTSA) from 7 clinical sites using this biconvex posterior augmented glenoid (PAG).

86 of 110 consecutive patients during the study period (78% follow-up) met the inclusion criteria and were included in their analysis. Of the 86, 33 had a B1 glenoid, 43 had a B2 glenoid, 5 had a B3 glenoid, and 5 had a C glenoid. 

Mean follow-up was 35 ± 10 months. There was one patient with both a prosthetic joint infection and radiographic glenoid loosening that required revision. 79/86 had a  Lazarus score of 0 (no radiolucency seen about peg or keel) at final follow-up. The clinical results are shown below.

Comment: For many years many surgeons have successfully treated many patients with the full range of glenoid pathologies using a standard all-polyethylene glenoid (for the technique see this link).

See for example One and two-year clinical outcomes for a polyethylene glenoid

with a fluted peg: one thousand two hundred seventy individual patients from eleven centers.

The goal of Early Clinical and Radiographic Outcomes of Anatomic Total Shoulder Arthroplasty with a Bi-convex Posterior Augmented Glenoid for Patients with Posterior Glenoid Erosion: Minimum 2-Year Follow-Up was to present an experience with a more complex approach to managing arthritic shoulder with posterior glenoid bone loss using a glenoid component with a bi-convex backside and a sequence of specialized instrument as shown below and in this link

While a goal of this implant system is to modify glenoid retroversion, version change may not be necessary as pointed out in articles such as  Does Postoperative Glenoid Retroversion Affect the 2-Year Clinical and Radiographic Outcomes for Total Shoulder Arthroplasty?, which concluded that "postoperative glenoid retroversion was not associated with inferior clinical results at two years after surgery." 

While a goal of this special glenoid component is to improve the management of patients with posterior glenoid bone deficiencies, it remains to be seen whether this approach is superior to managing these deficiencies with a standard glenoid component as reported in articles such as Anatomic Total Shoulder Arthroplasty with All Polyethylene Glenoid Component for Primary Osteoarthritis with Glenoid Deficiencies, which concluded that "Shoulder arthroplasty with a standard glenoid inserted without changing version can significantly improve patient comfort and function and consistently center the humeral head on the glenoid face in shoulders with type-B2 and

B3 glenoids, achieving >80% osseous integration into the central peg. These clinical and radiographic outcomes for type B2 and B3 glenoids were not inferior to those outcomes for other glenoid types.

This article does not present data on the increase in cost or surgical time for this implant in comparison to a standard polyethylene component, so the value of this technology (benefit to the patient / cost) cannot be evaluated at this point.

Follow on twitter: https://twitter.com/shoulderarth

Follow on facebook: https://www.facebook.com/frederick.matsen

Follow on LinkedIn: https://www.linkedin.com/in/rick-matsen-88b1a8133/

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).

 

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Severe B2 glenoid in a 40 year old active man

An active man in his 40s presented with pain and stiffness in the left shoulder after a remote childhood injury. X-rays at the time of presentation demonstrated glenohumeral arthritis with severe posterior decentering of the humeral head on a retroverted, biconcave type B2 glenoid as shown below.

After discussion of the options, including anatomic total shoulder arthroplasty and reverse total shoulder arthroplasty, he elected to proceed with a ream run procedure (see this link).

At four years after surgery, he reported essentially full and comfortable function of his shoulder with improved active elevation from 90 degrees before surgery to 160 degrees. His radiographs at 4 years (below) show an anteriorly eccentric humeral head centered on a remodeled glenoid with radiographic space between the humeral prosthesis and the mature glenoid bone surface.

Follow on twitter: https://twitter.com/shoulderarth

Follow on facebook: https://www.facebook.com/frederick.matsen

Follow on LinkedIn: https://www.linkedin.com/in/rick-matsen-88b1a8133/

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)

Shoulder arthritis - x-ray appearance (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).

Management of severe B2 glenoid in an active young man

An active surfer/athlete presented with pain and stiffness of both shoulders and the x-rays shown below. Each of the axillary "truth" views shows posterior decentering of the humeral head on a biconcave glenoid.

 

After considering the options of an anatomic total shoulder, an anatomic total shoulder with a posteriorly augmented glenoid component, and a reverse total shoulder, the patient elected to proceed with a ream and run procedure on each shoulder, two years apart.

The four year post operative films for the right shoulder are shown below. Note the use of an anteriorly eccentric humeral head component to control posterior translation.

The two year postoperative films of the left shoulder are shown below. Note again the use of an anteriorly eccentric humeral head component. 

He is back to surfing, tennis, lifting weights and swimming 1,000 yards, activities he was unable to perform before his shoulder arthroplasties.

The active motion of both shoulders is shown below.

As expected, these shoulders had difficulty in regaining functional motion after their prolonged stiffness. In such cases, we use outpatient manipulation under anesthesia and complete muscle relaxation to supplement the patient's rehabilitation effort. In this case several manipulations were peformed on each shoulder. 

We asked him to comment on the use of manipulation in his case. He responded, "Regarding the MUA experience, with both shoulders the MUA benefits seemed to wear off within a couple of weeks until the ones I had done at the two year mark. I could tell each time within even a couple of days that I was tightening up again. But for some reason two years seems to be long enough that my body stops laying down so much scar tissue."

He adds, "one other thing I wanted to mention that has been extremely helpful. For the last few weeks once a day I spend about ten minutes with a baseball (lacrosse ball without seams would likely be better) and lay on my back and use body weight on the ball to work the sore part of the joint. It has made a big difference in soreness that would occur normally from lifting weights, playing tennis, swimming, which are all things I do on a fairly regular basis (each activity at least once a week)"

Comment: This is an exceptionally motivated young man, who has been completely dedicated to his rehabilitation program. His experience with manipulation as long as two years after surgery has been instructive. 

Follow on twitter: https://twitter.com/shoulderarth

Follow on facebook: https://www.facebook.com/frederick.matsen

Follow on LinkedIn: https://www.linkedin.com/in/rick-matsen-88b1a8133/

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)

Shoulder arthritis - x-ray appearance (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).

This is a non-commercial site, the purpose of which is education, consistent with "Fair Use" as defined in Title 17 of the U.S. Code.          

Note that author has no financial relationships with any orthopaedic companies.

The biconcave glenoid

 Biconcave Glenoids Show Three Differently Orientated Posterior Erosion Patterns

These authors assessed glenoid morphology and evaluated the influence of acromial orientation in posterior glenoid erosion patterns in 68 patients (average age 64, 49 males, 19 females) planned to have reverse total shoulder arthroplasty. 

Using a reference 90 degrees as straight posterior and 0 degrees as straight superior, the average direction of glenoid erosion was 85.9 degrees with a large standard deviation of 22 degrees. 

The eroded part of the glenoid averaged 52% (±12%) of the glenoid surface. 

Glenoid version was 73±7° (90° was used to describe a glenoid with no version)

Premorbid glenoid retroversion averaged 81±8°)

Glenoid inclination averaged 85.4° (± 6.6°)

,

39 were classified as posterior central erosion (87°). These had the greatest depth of erosion (7mm)

12 as posterior inferior (116 degrees) and

17 as posterior superior (62 degrees)

No significant differences between the observed erosion patterns or any relevant correlations were found with respect to the orientation of the acromion.

Comment: This is a detailed analysis of the glenoid pathoanatomy found in a series of biconcave glenoids. The authors point out that the glenoid erosion in a biconcave glenoid is not always straight posterior. Therefore, "posterior augments" may not always fit the pattern of bone loss. 

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 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).

Management of a severe B2 glenoid in a 55 year old active man

A fifty-five year old outdoorsman presented with pain, stiffness and feelings of instability in the right shoulder.

An AP x-ray in the plane of the scapula showed osteoarthritis with overlap of the humeral and glenoid articular surfaces.

An axillary "truth" view showed osteoarthritis with a biconcave glenoid, severe posterior decentering and a cyst in the posterior glenoid. 

Because of his active lifestyle, the patient elected a ream and run arthroplasty to avoid the risks and limitations of a plastic glenoid prosthesis. 

No CT scan, preoperative planning software or special components were needed prior to the ream and run procedure.

The glenoid was reamed to 58 mm diameter without attempting change glenoid version. After trialing, a 56 mm diameter of curvature humeral head with a 21 mm thickness and anterior eccentricity and a 14 mm stem was impaction autografted into his humeral canal.  No rotator interval plication was needed.

Now ten years after his ream and run procedure, his AP view shows a regenerated glenoid joint surface and a secure impaction grafted stem without evidence of stress shielding

His axillary "truth" view shows again a regenerated glenoid joint surface with centering of the anteriorly eccentric humeral head on the glenoid. The biconcavity and decentering evident on his preoperative axillary have been eliminated.

In a recent email he reported that his range of motion is essentially equal to that of his contralateral unaffected side. He is swimming laps, tennis serving, throwing and engaging in his outdoor activities. 

Interestingly he points out with regular stretching, his range of motion has progressively improved over the last decade.

He concludes that the ream and run "may not be for everyone, but those hoping to regain active use of their arm for sports and recreation, it’s a lifesaver. I have a high degree of confidence in the continued performance of the joint for the remainder of my active outdoor life."

To see a YouTube video on how the ream and run is done, click on this link.

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

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.

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'

 

The arthritic shoulder: version, biconcavity and humeral head decentering

A good understanding of arthritic shoulder arthroplasty can be gained from standard plain x-ray views without the need for CT scans or 3D planning software.

Here is the anteroposterior view of the right shoulder of a former baseball pitcher in his early 30's several years after a posterior labral repair. The film shows loss of radiographic joint space and osteophytes.

His axillary "truth" view, taken with the arm in a functional position of elevation, shows the humeral head sitting in the posterior concavity of a biconcave glenoid

With a usual amount of glenoid retroversion

And substantial posterior decentering of the humeral head on the face of the glenoid

The amount of decentering can be measured in terms of the amount of posterior displacement of the center of the humeral head in reference to the perpendicular bisector of a line segment connecting the anterior and posterior edges of the glenoid.

This is all the information needed to plan his reconstructive surgery which will be a ream and run.

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To see a YouTube video on how the ream and run is done, click on this link.

===

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

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.

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'