Glenoid erosion after shoulder hemiarthroplasty

Risk factors for glenoid erosion in patients with shoulder hemiarthroplasty: an analysis of 118 cases.

These authors studied the erosion of the glenoid in 118 shoulders (113 patients) at an average of 31 (range 5-86 months) after a humeral hemiarthroplasty performed for primary or secondary osteoarthritis or fractures.

24 cases of hemiarthroplasty were excluded from the study because they had a periprosthetic infection, severe Parkinson disease, or follow-up <1 year (two patients with a follow-up <1 year (5 and 10 months, respectively) were included because of severe erosion within that time).

At the postoperative visits,  a series of standardized radiographs were taken: anteroposterior centered on the glenoid, anteroposterior centered on the humerus in neutral rotation, lateral (Neer view), and axillary view.

Glenoid erosion was graded independently by 2 observers using the method described in this link. Erosion was labeled as none (grade 1), mild (grade 2; erosion into subchondral bone), moderate (grade 3; medialization of subchondral bone with hemispheric deformation), or severe (grade 4; complete deformation/destruction of the glenoid or hemispheric deformation until/beyond the base of the coracoid). With this method the inter-rater reliability was 0.76 (95% CI, 0.67-0.83).

The difference between the average of the two observers for the preoperative and for the postoperative erosion was calculated. Severe erosion was defined as erosion of grade ≥2.5.

An attempt was made to quantify glenoid erosion by drawing a vertical tangent to the lateral edge of the acromion and measure the distance from that line to the most medial point of the prosthetic
head. However, these measurements proved to be unreliable and were excluded from further analysis.

These authors found severe erosion in approximately one-third of their cases within a mean postoperative time of 2.5 years.

Predisposing factors for erosion were

(a) glenoid cysts (odds ratio, 5.4; P < .001, approximately 3 times more frequent in women), 

(b) fatty infiltration of the rotator cuff musculature (R, 0.43; P < .001), and 

(c) rheumatoid arthritis (odds ratio, 3.6; P = .049).

A valgus position of the prosthetic head relative to the glenoid (angle >50°) may have been associated with local destruction of the glenoid cartilage.

Age, the version of the glenoid, and the size of the prosthetic head showed no significant association with glenoid erosion.

Analysis of kinetics in cases of severe erosion showed 2 basic erosion patterns: continuous erosion over time (11 cases) and severe erosion occurring rapidly after implantation (13 cases).

12 patients had revision surgery

Comment: This study combined hemiarthroplasties for glenohumeral arthritis (in which case the glenoid can be assumed to be abnormal) with hemiarthroplasties for acute humeral fractures (in which case the glenoid can be assumed to be normal). Thus, as expected, in the fracture cohort, there was significantly less erosion.

It would have been of interest to see the correlation between the amount of glenoid erosion and the patient self-assessed shoulder comfort and function: did patients with more erosion have worse clinical outcomes?

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The eroded glenoid in total shoulders

Total shoulder arthroplasty does not correct the orientation of the eroded glenoid


This article brings up the important topic of management of the glenoid with posterior erosion - a very common finding in glenohumeral arthritis. Here's an example showing glenoid retroversion, posterior glenoid erosion and posterior humeral subluxation.

The authors sought to determine the extent to which the glenoid component position was governed by the preoperative erosion of the glenoid and whether excessive erosion of the glenoid was associated with perforation of the glenoid vault on insertion of a glenoid component. Using preoperative and postoperative CT scans the authors asssessed version, inclination, rotation, and offset of the glenoid relative to the scapula plane.

The surgical technique sought to position the glenoid perpendicular to the plane of the scapula. Asymmetrical reaming was used to change the orientation of the glenoid. The authors reference a method we described in 1994 for identifying the glenoid centerline to guide their reaming. They found that their preparation of the glenoid did not substantially change the version of the glenoid and that the keel of their glenoid component perforated the glenoid vault in 5 of 29 cases - especially in cases of severe posterior erosion in which the anterior cortex was perforated.

The authors do a nice job of pointing out the competing priorities in achieving a durable, stable, functional arthroplasty:

(1) normalizing glenoid version

(2) avoiding glenoid vault perforation

(3) preserving glenoid bone stock

(4) achieving glenohumeral stability

While it has been stated that glenoid penetration is associated with early loosening, we have not seen documentation of this statement.

Our goal in arthroplasty prioritizes the last two of these:  preserving glenoid bone stock and achieving glenohumeral stability as shown in this post regarding the ream and run and in this post regarding the total shoulder. 

The patient whose preoperative x-ray is shown above elected to have a ream and run. His post operative films so the humeral prosthesis centered in a glenoid that was only reamed enough to create a single concentric concavity.

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Resurfacing humeral prosthesis: do we really reconstruct the anatomy?

Resurfacing humeral prosthesis: do we really reconstruct the anatomy?


One of the options for reconstructing an arthritic humeral head is a resurfacing prosthesis. The goal is to resurface the humeral articular surface while preserving the remainder of the proximal humerus. Because of the retention of much of the humeral head and anatomic neck, access to the glenoid to address the glenoid articular surface is compromised. As a result, most resurfacings are done has hemiarthroplasties, even though in most cases of glenohumeral arthritis both the humeral and glenoid articular surfaces are involved. As pointed out in a previous post, hemiarthroplasty or resurfacing do not restore the desired glenohumeral contact.

In this article the authors reviewed 64 shoulders with at least two years followup after resurfacing for primary osteoarthritis in 26, secondary osteoarthritis in 21, avascular necrosis in 4, rheumatoid arthritis in 4, dysplasia in 4, and for others indications in 5.

According to the Walch et al classification, 45 shoulders had central wear (A) and 14 and eccentric wear (B) while 5 had dysplastic glenoids.

The followup Constant score averaged 68 ± 20 points (range 29-100). Quick-DASH score averaged 28 ± 21 points (range, 0-88 points). Neer ratings were very satisfactory in 28 shoulders, satisfactory in 16, and nonsatisfactory in 20.

Postoperative radiographs showed showed a tendency to glenoid wear which appeared to correlate with with reappearance of pain.

The authors conclude that a resurfacing shoulder implant without glenoid resurfacing
leads to glenoid wear.

Thus the question in resurfacing is less about reconstructing humeral anatomy and more about care of the glenoid side of the arthritic glenohumeral joint.

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Ream and Run for Shoulder Arthritis - is wear an issue? - research foundation 5

We know that shoulder arthritis affects both sides of the joint as shown below.

 This alters the normal load distribution (below left) to one of load concentration and progressive wear (below right)

Simply replacing the humeral head (ball of the shoulder joint) alone, does not address the glenoid wear and can be associated with progressive glenoid wear.

The ream and run procedure restores the glenoid surface to a concentric concavity.

We wanted to know if there was wear of the glenoid bone after this procedure. Shoulder fellows Mercer and Saltzman developed a method for documenting the position of the humeral head center relative to the scapula on standardized plain radiographs that can answer this question. In this method, standardized templates (shown below) are placed over the x-rays to track the position of the center of the head of the humerus.

They used this method in assessing glenoid wear at a minimum of two years after hemiarthroplasty with concentric glenoid reaming. They found that the average wear rate was minimal: the movement of the head center towards the scapula was less than 0.4 mm per year.

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