The Ream and Run - how much of an issue is glenoid wear? pyrocarbon vs. chrome cobalt?

Management of glenohumeral arthritis in young and active patients with arthroplasty is a hot topic because of more difficult shoulder pathology, high patient expectations, and, in the case of anatomic total shoulder arthroplasty, long-term risks of glenoid component wear, loosening, osteolysis, and challenging revision surgery. 

For this reason, there is interest amoung young/active patients in a glenohumeral arthroplasty - such as the ream and run - that does not involve a prosthetic glenoid component. The ream and run is a glenohumeral arthroplasty for patients who wish to avoid the risks and limitations associated with a polyethylene glenoid component. In this procedure the glenoid articular surface is conservatively reamed to a single concavity without attempting to modify glenoid version. A chrome/cobalt humeral head prosthesis is selected with a diameter of curvature 2 mm smaller than that of the reamed glenoid surface and that provides a good balance of glenohumeral mobility and stability.

The authors of Characterizing Glenoid Wear after Hemiarthroplasty with Concentric Glenoid Reaming: A Study of 113 Arthroplasties at a Mean of 6.7 Years Followup sought to characterize the amount and rate of glenoid wear and its association with patient-reported outcomes. Patients prospectively enrolled in a shoulder arthroplasty database were included if they had a ream and run procedure, minimum four year clinical and radiographic followup and comparable radiographs.  Medialization was determined by measuring the position of the prosthetic humeral head center relative to a line drawn through the lateral edge of the acromion and parallel with the glenoid face. 

These measurements were compared between radiographs obtained immediately after surgery and at followup, the difference reflecting the amount of medialization: minimal/mild (≤5mm), moderate (between >5mm and ≤10mm) and substantial (>10mm). 

Included patients had an average age of 59 years, 92% were male, 81% had primary osteoarthritis.

The mean preoperative SST score of 5.3 out of 12 improved to 9.9 out of 12 postoperatively (P <.001). 81.5% of the patients were clinically significantly improved (i.e. surpassed the minimal clinically important difference for the SST). 

Comparable radiographs of 113 shoulders with a mean radiographic follow-up of 6.7 years were analyzed. Minimal/mild glenoid wear was noted in 92 (81%) patients, moderate wear in 15 (13%), and severe wear in 6 (5%). The mean total glenoid wear was 2.9 ± 4.3 mm. Based on linear modeling, the glenoid wear rate was calculated at 0.3mm per year. The majority of glenoid wear occurred in the first four years after the ream and run arthroplasty and plateaued thereafter.  

Multivariable analysis revealed that younger patients were at greater risk for moderate or severe glenoid wear.

Comparing clinical outcomes among patients with minimal/mild glenoid wear to those with moderate/severe wear, no differences were noted in SST scores, change in SST scores, VAS scores, or change in VAS scores.

Are the data different for pyrocarbon hemiarthroplasty?

Recently there has been interest in the use of a pyrocarbon humeral head rather than a chrome cobalt humeral head in the hope that this bearing surface would have a lower rate of glenoid wear. 

The authors of Pyrocarbon hemiprostheses show little glenoid erosion and good clinical function at 5.5 years of follow-up: found that the mean medial glenoid erosion measured 1.4 mm at an average of 5.5 years of follow-up. In the first year, 0.8 mm of erosion was observed, significantly more than the average erosion of  0.3 mm per year. This is the same rate of wear as noted in the study above using the chrome cobalt humeral head. There was no correlation between erosion and clinical outcome.

The authors of Pyrocarbon humeral heads for hemishoulder arthroplasty grant satisfactory clinical scores with minimal glenoid erosion at 5-9 years of follow-up did not measure the amount of medialization; rather they classified it as shown below.

At 2-4 years, progression of glenoid erosion was noted in 6 patients (16%), compared with immediate postoperative radiographs (1 from none to mild and 5 from mild to moderate).When comparing erosion at 2-4 years to that at 5-9 years, 10 shoulders exhibited progression of glenoid erosion by 1 grade (n = 9) or 2 grades (n = 1). Stratifying patients by glenoid erosion revealed no significant differences in clinical outcome at first follow-up or second follow-up.

The authors of B2 and B3 glenoid osteoarthirtis: outcomes of corrective and concentric (C2) reaming of the glenoid combined with pyrocarbon hemiarthroplasty examined 41 shoulders with osteoarthritis and B2 and B3 glenoid pathoanatomy having corrective reaming of the glenoid and a pyrocarbon humeral hemiarthroplasty. The authors did not correlate clinical outcome with erosion rate. At an average follow up of 4.5 years , CT scan measurements showed that the average total medialization was 3.7  mm (2.0  mm due to reaming and 1.7  mm due to erosion). Note that the average rate of erosion was 1.7 mm / 4.5 years or 0.38 mm/year. This is the same rate of wear as noted in the study above using the chrome cobalt humeral head. 

Conclusion: 

The available literature does not provide evidence that

(1) the rate of glenoid erosion is different for pyrocarbon humeral heads in comparison to cobalt chrome humeral heads

(2) wear rate is clinically significantly correlated with clinical outcome

We can conclude that the use of humeral hemiarthroplasty combined with reaming (that either accepts or attempts to correct glenoid version) is a topic of great interest, especially for patients who wish to avoid the risks and limitations of a glenoid component.  Comparison of outcomes between cobalt chrome and alternate bearing surfaces (pyrocarbon or ceramic) will require thoughtful clinical research that controls for the many confounding variables.

What difference does the head make?

White headed woodpecker

Sleeping Lady

Leavenworth Washington

May 2025

Follow on twitter/X: https://x.com/RickMatsen
Follow on facebook: https://www.facebook.com/shoulder.arthritis
Follow on LinkedIn: https://www.linkedin.com/in/rick-matsen-88b1a8133/

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).

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?

===

Consultation for those who live a distance away from Seattle.

Click here to see the new Shoulder Arthritis Book.

Click here to see the new Rotator Cuff Book

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 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'


See from which cities our patients come.

See the countries from which our readers come on this post.

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.

---

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 including:shoulder arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty,  and rotator cuff surgery.

See from which cities our patients come.

See the countries from which our readers come on this post. 

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.

--

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 including:shoulder arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty,  and rotator cuff surgery.

See from which cities our patients come.

See the countries from which our readers come on this post.

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.

--

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

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.

See the countries from which our readers come on this post.