Comparing anatomic and reverse total shoulders: are revision rates/survivorship the appropriate outcome measures?

"The most functional patients after an anatomic total shoulder are more functional

than the most functional patients after a reverse total shoulder. 

The least functional patients after an anatomic total shoulder are more functional

than the least functional patients after a reverse total shoulder. "

The clinically relevant outcome measure for shoulder arthroplasty is the patients' ability to regain the shoulder functions of importance to them (see Shoulder joint replacement arthroplasty - what outcomes do patients care about?). Large population-based registries are often used to assess patient outcomes, but these commonly rely on revision rates (did the patient have another surgery on the shoulder) and "survivorship" (was the original implant changed at the time of revision?).

Revision rates and survivorship are commonly used to compare anatomic and reverse total shoulder outcomes, although rarely are the patients having the two procedures matched for age, sex, diagnosis, health, and pathoanatomy (cuff status, version, decentering).

An important consideration when evaluating revision rates/survivorship is the ability of a revision operation to safely address the mode of failure,  i.e. how much function and function is the patient likely to regain after the revision and what are the risks of complications?

Most of the important causes of failed anatomic total shoulder - such as rotator cuff failure and glenoid component loosening - can be safely and effectively revised either to a revision anatomic or to a reverse total shoulder. By contrast, some of the most important causes of failed reverse total shoulder - such as acromial/spine fractures, instability, baseplate failure, humeral bone loss, and neurologic injury - can be difficult to revise safely and effectively. 

The decision to revise a failed shoulder arthroplasty is based on (1) the surgeon's identification of a problem that can be safely and effectively addressed by revision and (2) the patient's willingness to undergo a revision procedure. 

Thus, the revision rate is not an indication of the clinical failure rate for patients having a shoulder arthroplasty.

These points are recognized by the authors of the article below: "Reverse total shoulder replacement had the lowest revision rate at mid-term follow-up. Given the limitations of using revision as a primary endpoint foroutcome, the results of this study should be considered with caution in clinical practice. RTSA has fewer revision options compared with the other classes of shoulder arthroplasty, which may confound the results. If RTSA is considered by surgeons in the primary setting to treat young patients with osteoarthritis, consideration should be given at surgery to mitigate the higher risk of early dislocation in the first 2 years postoperatively."

Survivorship of shoulder arthroplasty in young patients with osteoarthritis: an analysis of the Australian Orthopaedic Association National Joint Replacement Registry assessed the survivorship and reasons for revision of shoulder arthroplasties in patients aged <55 years with a primary diagnosis of osteoarthritis using data on 1564 patients from a large national arthroplasty registry. The cumulative percent revision for anatomic total shoulders (ATSA) was 6.4% at two years and 10.1% at five years. The cumulative percent revision for reverse total shoulders (RTSA) was 3.1% at two years and 5.5% at five years. 

Of note, the durations of followup were substantially shorter for the RTSA patients (mean 3.5 yrs, median 2.6 yrs) than for the ATSA patients (mean 6.2 yrs, median 5.8). So 5 year followup was only available on about half of the patients.

The diagnoses thought by surgeons to be amenable to revision are shown below. 

This study does not present data on the clinical failures that did not come to revision.

A similar study, The lifetime revision risk of primary anatomic and reverse total shoulder arthroplasty sought to estimate a patient’s lifetime revision risk based on registry of 4346 primary anatomic shoulders (ATSA) and 7384 reverse (RTSA) total shoulders.

Lifetime revision risk was highest in the youngest age group (46-50 years) at 35.8% for aTSA and 30.9% for RTSA.

Females reported higher lifetime revision risk for each age group in the ATSA cohort whereas males reported higher lifetime revision risk for each group in the RTSA cohort.

Younger patients (51-55 years) were at an 11-fold increased risk of lifetime revision for rTSA and 8-fold increased risk of lifetime revision ATSA compared to older patients (81-85 years).

The diagnoses thought by surgeons to be amenable to revision are shown below. 

This study does not present data on the clinical failures that did not come to revision.

The authors of Incidence of primary anatomic and reverse total shoulder arthroplasty in patients less than 50 years of age and high early revision risk sought to investigate the incidence of primary anatomic total shoulder and reverse total shoulder, rate of revision within 1 year, and the associated economic burden in 509 patients younger than 50 years identified in a national private insurance database.

The one year revision rate was 3.1% for anatomic and 6.8% for reverse total shoulders,

The authors of Similar rates of revision surgery following primary anatomic compared with reverse shoulder arthroplasty in patients aged 70 years or older with glenohumeral osteoarthritis: a cohort study of 3791 patients sought to determine whether there was a difference in outcomes in patients aged 70 years who received RTSA (n=685) vs. ATSA  (n=3106) for glenohumeral osteoarthritis with an intact cuff using data from a US integrated health care system’s shoulder arthroplasty registry. The mean age was 75.8 years;  43.4% of patients were men. 

After accounting for confounders, they observed no significant difference in all-cause

revision risk for RTSA vs. ATSA.

The most common reason for revision following aTSA was for rotator cuff tear (54.0%); the next most common reasons were dislocation (26.4%) and glenoid component loosening (14.9%).

The most common reason for revision following RTSA was glenoid component loosening (40.0%, followed by dislocation (20.0%) and periprosthetic fracture (20.0%). 

Again, it is apparent that revision of an ATSA for cuff tear, dislocation or glenoid component loosening is likely to be more straightforward than revision of RTSA for baseplate failure, dislocation or periprosthetic fracture. Furthermore this study did not capture the rates of other major RTSA complications that may not be suitable for revision, such as acromial/scapular spine fracture, humeral bone deficiency, and neurologic injury.

Anatomic versus reverse total shoulder arthroplasty: usage trends and perioperative outcomes evaluated patient revision rates and medical complications for  ATSA (n = 57,680) and RTSA (n = 90,551) from the PearlDiver database after 1:1 patient matching  based on age, sex, and Elixhauser-Comorbidity Index.

Patients undergoing RTSA were older, more likely to be female, and had higher ECI. 

After matching for these criteria, 33,582 were available from each of the ATSA and RTSA cohorts. Of these matched  patients, no difference was observed on multivariable analysis with regard to overall revision rates between the two groups. 

Matched patients undergoing RTSA were at significantly greater risk for transfusion, wound dehiscence, any adverse event, sepsis, acute kidney infection, pneumonia, urinary tract infection, and severe adverse events.  

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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).

Revision cuff surgery - is dermal matrix allograft of greater value than a smooth and move?

Outcomes of arthroscopic revision rotator cuff repair with acellular human dermal matrix allograft augmentation

These authors studied patient-reported outcomes and failure rate of patients who underwent revision arthroscopic rotator cuff repair augmented with acellular human dermal matrix (AHDM) allograft for repairable retears. 28 patients had minimum 2 year clinical followup but only 13 had postoperative imaging by MRI or ultrasound - four of these had retears. Three patients had another revision surgery.  Only 6 patients had both preoperative and postoperative outcome scores. In these the ASES score improved from 56 to 85 (P = .03) and the SANE score improved from 42 to 76 (P = .03).

The cost of the dermal matrix allograft is not mentioned in this paper.

Comment: The data presented in this paper do not enable the reader to see the value of dermal matrix allograft - the change in scores is available for less that 25% of the cases and less than 50% had post operative imaging of the cuff. 

This paper needs to be viewed in light of the results of a much larger series of patients having irreparable cuff tears treated without attempting to re-establish tendon continuity:

Treatment of irreparable cuff tears with smoothing of the humeroscapular motion interface without acromioplasty

These authors sought to determine whether shoulders with irreparable rotator cuff tears and retained active elevation can be durably improved using a conservative surgical procedure that smoothes the interface between the proximal humeral convexity and the concave undersurface of the coracoacromial arch followed by immediate range of motion exercises.

They reviewed 151 patients with a mean age of 63.4 (range 40–90) years at a mean of 7.3 (range 2–19) years after this surgery.

In 77 shoulders with previously unrepaired irreparable tears, simple shoulder test (SST) scores improved from an average of 4.6 (range 0–12) to 8.5 (range 1–12) (p < 0.001). Fifty-four patients (70%) improved by at least the minimally clinically important difference (MCID) of 2 SST points. For 74 shoulders with irreparable failed prior repairs, SST scores improved from 4.0 (range 0–11) to 7.5 (range 0–12) (p < 0.001). Fifty-four patients (73%) improved by the MCID of 2 SST points.

These authors concluded that smoothing of the humeroscapular interface can improve symptomatic shoulders with irreparable cuff tears and retained active elevation. This conservative procedure offers an alternative to more complex procedures in the management of irreparable rotator cuff tears.

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