Sunday, February 12, 2023

The value of anatomic and reverse total shoulder arthroplasty - changes with time and with how it's measured.

The value of shoulder arthroplasty is commonly defined as the benefit of the procedure to the patient divided by the costs associated with the procedure. "Benefit" is commonly measured as the preoperative to postoperative change in patient self-assessed comfort and function. "Costs" potentially include the expenses of the preoperative work-up, the implant, the hospital care, the postoperative care and the complications.

The authors of Longitudinal Analysis of Shoulder Arthroplasty Utilization, Clinical Outcomes, and Value: a Comparative Assessment of Changes in Improvement Over 15 Years with a Single Platform Shoulder Prosthesis conducted a longitudinal analysis of their extensive experience with anatomic (aTSA) and reverse total shoulder (rTSA) using a single shoulder arthroplasty prosthesis (Equinoxe; Exactech, Inc) with the goal of quantifying changes in clinical outcomes, cost, and value, associated with the introduction and adoption of new shoulder arthroplasty technologies.


They observed a dramatic increase in rTSA utilization over the 15-year study period.
In 2007 rTSA accounted for 19% of the prostheses compared to 57% aTSA.
In 2021 rTSA accounted for 76% of the prostheses compared to 14% aTSA

This article provides a wealth of data about these patients and their outcomes. The two tables below contain data extracted from the paper along with one type of calculation of value - the amount of improvement in SST score divided by $1,000 of implant cost.

For patients receiving anatomic total shoulders, the age at the time of surgery was less for more recent procedures while the % of male patients and the % of patients with primary osteoarthritis increased. The cost of the implants was stable as was the postoperative SST; however the preoperative SST scores indicated a higher degree of comfort and function in more recently operated patients. The result is that the benefit expressed as the SST improvement per $1,000 prosthesis cost was less for patients having more recent surgery.



For patients receiving reverse total shoulders, the age at the time of surgery was less for more recent procedures while the % of male patients and the % of patients with primary osteoarthritis increased. The cost of the implant was less for more recent procedures. While the postoperative SST scores were constant, the preoperative SST scores indicated a higher degree of comfort and function in more recently operated patients. As a result, the SST improvement per $1,000 remained essentially constant over time.



This paper uses a different outcome measure than that shown above: the percent of patients reaching the "ceiling" for various scores. As shown below, this approach shows improved outcomes in more recent surgeries for most of the scales. However, since this metric does not include the effect of higher preoperative scores in more recent surgeries (as shown in the tables above) it does not reflect the benefit of the procedure in terms of improvement in comfort and function.



The authors point out that implant pricing is negotiated by the vendor and the hospital. These negotiations are commonly associated with non-disclosure agreements. Since the implant cost is an important component of the denominator of the value equation, these negotiations may lead to different results for different hospitals and different implants.

CT-based preoperative planning was initiated in 2016 and was used in 93% of primary aTSA cases and 83% of primary rTSA cases by 2021. Use of CT-based preoperative planning was associated with a dramatic increase in the use of augmented glenoids, such that by 2018 augmented components were used in the majority of primary rTSAs and aTSAs.

Hybrid aTSA glenoids were introduced in 2011; by 2020 they were used in 100% of primary aTSAs in 2020. In this study overall 54% of the glenoids were hybrid and 46% were traditional cemented peg/keel glenoids.

Overall 76% of the antomic glenoids were nonaugmented and 24% were augmented. The rTSAs included 56% standard baseplates and 44% augmented baseplate.

The use of short humeral stems for rTSA and aTSA and the use of stemless humeral components in aTSA increased dramatically over the period of this study. Overall 8% of the aTSAs and 17% of the rTSAs used short humeral stems and 5% of the aTSAs used stemless humeral components.

The value of these technologies is not assessed in this study. The paper does not provide a comparison of the clinical outcomes achieved without and with CT-based preoperative planning, without and with augmented glenoid components, without and with hybrid aTSA glenoids, or without and with short stemmed or stemless humeral components.

It is apparent that many factors may go into the calculus of value, including patient age, sex, diagnosis, preoperative comfort and function, use or non use of technologies, implant design, and the negotiated implant cost. These authors appear to have the volume of carefully characterized patients that would enable an enlightening multivariate analysis of the factors affecting value for this prosthesis system.

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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).