One of every eight primary total shoulder replacements required revision by 10 years - a causal analysis - augments/technology assistance

The 2024 Austrialian Orthopaedic Association National Joint Replacement Registry reports, "The cumulative percent revision of primary total conventional shoulder replacements for osteoarthritis is 12.7% at 10 years"  Instability/dislocation was the most common reason for revision (24%) followed by rotator cuff insufficiency (23%) and loosening (17%).

We obviously have room to improve our care of these patients. 

We must ask, "what might have been done differently to minimize this high revision risk for patients having elective shoulder arthroplasty for arthritis?"

These data are important because they are derived from all the shoulder arthroplasties performed for the national population, not from case series from individual surgeons or institutions. As a result they reflect the outcomes for all patients having arthroplasty by all surgeons in Australia. They provide a unique opportunity for Shoulder Arthroplasty Research (SAFR) causal modeling. 

The registry provides data on non-modifiable patient and shoulder factors (age, sex, ASA score, BMI, preperative shoulder pathoanatomy) and on surgeon-controlled variables (choice of implant, technique of component fixation, use of glenoid augments, size of implants, and technologies such as computer navigation and image derived instrumentation (IDI).

Here are some take-home points based on the remarkable AOA registry.

                                              Non-modifiable risk factors 

Younger age was significantly associated with a higher revision rate (older patients have a hazard ratio (HR) for revision of 0.47). Patients under 55 years of age had the highest revision rate.

Female sex was significantly associated with a higher revision rate (female patients have a 1.27 hazard ratio for revision)

Neither higher ASA score or higher BMI had a statistically significant relationship with revision rate (HRs 1.3 and 0.92, respectively).

Preoperative Walch pathoanatomy did not have significant relationship with revision rate. Importantly, and contrary to the belief of many surgeons, type B2 glenoids were not associated with an increased revision rate (in fact B2 glenoids had the lowest revision rate).

Surgeons can use these data in discussing the revision risk with patients considering elective shoulder arthroplasty for osteoarthritis. 

                                            Surgeon controlled, modifiable risk factors 

Cementless fixation was associated with a significantly higher revision rate than cemented or hybrid fixation (HR 3).

Modular metal backed components have a significantly higher revision rate than all-polyethylene components (HR 3).

Modular metal backed and non-modular metal-backed have significantly higher revision rates that glenoid components with a modified central peg (HR 4 and 2, respectively).

Arthroplasties with augmented glenoid components had a significantly higher risk of revision (HR 1.95).

The use of augments did not lower the rates of different types of failure for anatomic total shoulder performed for osteoarthritis.

The use of augmented glenoid components was associated with a significantly higher risk of revision for type A glenoids and did not lower the risk of revision for type B glenoids.

Arthroplasties in which short humeral stems were used had a lower long term risk of revision.

Arthroplasties in which smaller humeral heads were used were associated with higher rates of revision.

The use of technology assistance (computer navigation, image derived instrumentation (IDI)) was not associated with a decrease in the risk of revision. 

Comment:  The surgeon is the method; the surgeon must ask "what can I do to reduce the risk of revision for my patient?"

(1) The surgeon manages patient selection for surgery and the preoperative discussion with the patient, including the non-modifiable risk factors that increase the risk of revision (young age, female sex, preoperative rotator cuff status) as well as those that appear not to (ASA score, BMI, Walch classification).

(2) The surgeon selects and carries out the procedure in light of the factors that may increase revision risk (metal backed, cementless, and augmented glenoid components) and those that may decrease that risk (larger humeral head and short humeral stems).

(3) Apparently surgeons cannot depend on technology assistance (computer navigation, image derived instrumentation) to reduce the rate of total shoulder revision.

It's about making good choices

Lewis' Woodpecker

Tualatin, OR

2023

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).

Recent JBJS article on failures (51%) of anatomic total shoulder arthroplasties

Patients and surgeons are interested in the causes and prevention of shoulder arthroplasty failures. Failures can be viewed in terms of the characteristics of the surgeon, the patient, the shoulder, and type of failure. Regardless of the cause of the failure, it is the patient (not the surgeon or the implant company) that bears the consequences. Thus, in each case we should do our best to determine "what could have been done to prevent the failure experienced by the patient?" In this way, each failure - whether ours or someone else's - becomes a learning opportunity. At an early morning meeting in August 2025, a small group of shoulder surgeons took the first steps in developing a Shoulder Arthroplasty Failure Research (SAFR) program with the goal of learning from individual cases of arthroplasty failure.

The June, 2025 JBJS article, High Failure Rates of Polyethylene Glenoid Components in Stemless Anatomic Total Shoulder Arthroplasty for Primary and Secondary OA, is interesting to consider in this regard.  These components were used in this series

At a mean followup of 72 months, out of 197 patients, over half (101) had failures necessitating surgical revision, 86 because of glenoid component loosening. What might be done to prevent these failures? 

Left:  Intraoperative view following explantation of the polyethylene glenoid with a 4 x 2-cm bone defect. Right: Explanted components with severe glenoid wear and superior glenoid abrasion, with the pegs completely separated from the body of the glenoid component.

Is the problem (as the title might suggest) the use of a stemless humeral component with a polyethylene glenoid component (in which case failures could be avoided by using a stemmed humeral component)? 

Or is it the type of polyethylene glenoid component being used (in which case a different glenoid component design could be used)? 

Or is it the technique by which the glenoid component was inserted (in which case greater attention could be directed at the quality of glenoid component preparation, cementing and seating?). 

These three elements are surgeon-controlled variables (in contrast to patient age, sex, diagnosis, BMI, critical shoulder angle and lateral acromial angle, which were measured in this study but which are of lesser interest in that they are not modifiable by the surgeon). 

So...is the stemless humeral component or the glenoid component the problem? Prior studies of this glenoid component (with either stemless or stemmed humeral components) reported glenoid component loosening rates between 25% and 100% after 5 years when used with either stemless or stemmed humeral components: Univers II shoulder prosthesis: a multicenter, prospective randomized controlled trial and Radiologic midterm results of cemented and uncemented glenoid components in primary osteoarthritis of the shoulder: a matched pair analysis. Perhaps failure could be avoided with a different glenoid component.

Or...might the technique of glenoid component insertion be an issue?

In this 6 week postoperative x-ray from the article there is cement between the back of the glenoid component and the glenoid bone (yellow arrows).  Cement in this location can crack and displace leaving the component unsupported. 

This problem can be avoided by placing the component directly on the properly reamed glenoid bone without interposed cement as shown below.

The other issue shown on this x-ray is the large amount of bone in the glenoid vault surrounding the pegs (red arrow) that prevents bone ingrowth around them.

This problem can be avoided by careful preparation of the glenoid bone with good carpentry so that bone ingrowth is enabled.

Perhaps the risk of failure could be reduced using a different insertion technique

As shown below, this patient experienced glenoid component failure

How could this failure have been prevented?

Comment: This is an example of the type of analysis that we hope to carry out in the Shoulder Arthroplasty Failure Research program. Stay tuned!

Looking to make wise choices

Barred Owl

Union Bay Natural Area

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).