Do higher case volumes make us safer and more effective surgeons?

I've always held that "the surgeon is the method", meaning that considering all of the variables that might affect the outcome of a given surgery for a given problem, the most important is the person making the decisions, carrying out the procedure, and analyzing the results = the surgeon. As surgeons we are engaged in the constant pursuit of learning to achieve better outcomes for our patients. We hope, as the saying goes, that experience is the great teacher and that practice makes us better at our art. But as we'll see below, the number of repetitions is not the only thing that matters.

My friend JP Warner pointed to this article, Higher Surgeon Volume is Associated With a Lower Rate of Subsequent Revision Procedures After Total Shoulder Arthroplasty: A National Analysis, the authors of which assessed the association between increasing surgeon volume and decreasing rate of revision for anatomic (aTSA) and reverse (rTSA) shoulder arthroplasty using the Centers for Medicare and Medicaid Services (CMS) fee-for-service inpatient and outpatient claims data from 2015 through 2021. 

They found that in comparison to an arthroplasty case volume of <4 per year, an annual surgeon case volume of

 ≥ 10 aTSAs was associated with a 27% decreased odds of a revision within 2 years

≥ 29 aTSAs was associated with a 33% decreased odds of a revision within 2 years

An annual surgeon volume of ≥ 29 rTSAs was associated with a 26% decreased odds of a revision within 2 years.

The figure below shows the trend line for revisions as function of surgeon case volume.

There are several interesting observations to be made on this graph: 

(1) the downward trend appears to continue out to surgeons performing over 100 shoulder arthroplasties per year, No end in sight for the effect.

(2) the effect of case volume on revision rate appears relative continuous: there is no obvious inflection point after which the volume effect starts to level off, 

(3) there is wide scatter in the data, indicating that there are factors other than annual case volume that are driving a surgeon's revision rate (some lower volume surgeons have lower revision rates than some higher volume surgeons).

So questions arise: 

(1) which is more important, the number of cases / year or the lifetime total number of cases ("how many do you do" vs "how many have you done")?

(2) how does a patient learn a surgeon's case volume? 

(3) how important should case volume be in a patient's choice of surgeon (e.g. how far should the patient travel or how much more should they be willing to pay to be cared for by a higher volume surgeon)?  

(4) what factors account for the high variability shown in this chart (note especially the three surgeon outliers at the top with over twice the average revision rate even though they're in the "high volume" category)? Should the patient be more concerned about the volume or the revision rate of their potential surgeon?

(5) if a large percentage of patients select their surgeon on volume, how do low volume surgeons become high volume surgeons? 

(6) is it experience (the number of cases) that is the determinant of revision rate?

In his books Noise a Flaw in Human Judgment and Thinking Fast and Slow Daniel Kahneman emphasized that experience does not automatically improve the outcome.  Over time, experienced surgeons may gain increased confidence but not necessarily increased competence, a phenomenon Kahneman calls the illusion of validity. Instead it is learning that leads to better outcomes. Learning, in turn, comes from quality, timely and accurate feedback. If a surgeon routinely takes and analyzes postoperative x-rays, she or he can learn how well the preoperative plan was executed - becoming smarter with each case. That's pretty easy to do. What's harder is to study each case that required revision to learn what went wrong - this is harder because the revision is delayed and memory fades. 

Each failure is a learning opportunity not to be passed up. Through the experience of studying the factors associated with each revision, the surgeon can reduce the risk of revisions in the future. There is safety in numbers, but its not the only thing that counts.

Dunlins Ocean Shores 2020

While there is safety in numbers, the peregrine falcon can usually cause an adverse event for one of them.

You can support cutting edge shoulder research that is leading to better care for patients with shoulder problems, click on this link

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).

A complex revision of an infected reverse total shoulder

A 45 year old right handed active man had a Simple Shoulder Test score of 4/12. His x-rays revealed severe capsulorrhaphy arthropathy with posterior dislocation of right shoulder after a Putti Platt procedure for shoulder instability performed many years earlier.

At surgery he was found to have massive humeral and glenoid deformity with severe posterior glenoid erosion and malformation of the humeral head with posterior capsular laxity and anterior capsular contracture. His surgery was a humeral hemiarthroplasty with subscapularis lengthening. His post operative film is shown here.

                                       

However, the humeral head again became posteriorly unstable. A year later he had an open reduction of the posteriorly dislocated shoulder with anterior release, prosthetic head removal, posterior cortical iliac autograft of the glenoid with screw fixation, posterior soft tissue reconstruction, and reinsertion of hemiarthroplasty head. However, on testing the range of motion of the shoulder at surgery, the securely fixed bone graft fragmented requiring removal of the graft and screws and insertion of a reverse total shoulder. His postoperative film is shown here.

                                                  

Three years later he represented with pain in his shoulder that started with golfing. He had no clinical evidence of infection. His x-rays showed humeral osteolysis and subsidence

 

He then had a primary exchange revision of reverse total shoulder arthroplasty to a long stemmed humeral component and a new glenoid component at which time six cultures were obtained before antibiotics were administered. At this procedure there was a substantial amount of membrane and granulomatous tissue from the glenoid and from the humeral medullary canal. There was no cloudy fluid and no purulence.

His histology showed gram-positive rods and up to 40 white blood cells per high power field on frozen section. The patient’s final pathology eventually returned “synovial tissue with multiple foci of dense neutrophilic infiltrates (greater than five neutrophils per high power microscopic field using a 40 X objective in at least five separate microscopic fields) in a background of prominent plasmacytic inflammation and hemosiderin-laden macrophages.” He was placed on a six-week course of IV vancomycin and rifampin, which was changed to ceftriaxone to better cover Propionibacterium after the culture results were final at 3 weeks.

His culture results were as follows:
Glenoid Membrane No. 1: 2+ Propionibacterium
Glenoid Membrane No. 2: 1+ Propionibacterium
Fluid Right Glenoid: 1+ Propionibacterium
Humeral Membrane No.1: 1 colony Propionibacterium
Humeral Membrane No. 2: 1+ Propionibacterium
Humeral Membrane  No. 3 One colony Propionibacterium

He remained on oral Augmentin for a year.

Today six years after his most recent revision he plays tennis (tossing the ball with his right hand serving with his left), skis gentle slopes, and runs for fitness. His Simple Shoulder Test responses are 8/12:
1: Is your shoulder comfortable with your arm at rest by your side?: Yes
2: Does your shoulder allow you to sleep comfortably?: Yes
3: Can you reach the small of your back to tuck in your shirt with your hand?: Yes
4: Can you place your hand behind your head with the elbow straight out to the side?: Yes
5: Can you place a coin on a shelf at the level of your shoulder without bending your elbow?: Yes
6: Can you lift one pound (a full pint container) to the level of your shoulder without bending your elbow?: Yes
7: Can you lift eight pounds (a full gallon container) to the level of your shoulder without bending your elbow?: No
8: Can you carry twenty pounds at your side with this extremity?: Yes
9: Do you think you can toss a softball under-hand twenty yards with this extremity?: No
10: Do you think you can toss a softball over-hand twenty yards with this extremity?: No
11: Can you wash the back of your opposite shoulder with this extremity?: No
12: Would your shoulder allow you to work full-time at your regular job?: Yes

His x-rays today continue to show stable component fixation.

 

Comment: This case reveals the challenges of severe capsulorrhaphy arthropathy with posterior instability as well as the substantially delayed insidious presentation of osteolysis associated with Propionibacterium.

===
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

To see the topics covered in this Blog, click here

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.

To see other similar posts, click on the label of interest below.