citation: Testa EJ, Glass E, Ames A, Swanson DP, Polisetty TS, Cannon DJ, Le K, Bowler A, Levy JC, Jawa A, Kirsch JM. Indication matters: Effect of indication on clinical outcome following reverse total shoulder arthroplasty-a multicenter study. J Shoulder Elbow Surg. 2024 Jun;33(6):1235-1242. doi: 10.1016/j.jse.2023.09.033. Epub 2023 Nov 7. PMID: 37944747.
What are the factors that influence outcome after reverse total shoulder replacement?
While surgical factors including surgeon volume and experience, implant features, patient variables (age, body mass index, comorbidities) are all critical for consideration, we should also be looking at the underlying diagnosis the patient carries as means of predicting the individual outcome. This was nicely shown in this large multicenter retrospective cohort of 625 patients undergoing reverse total shoulder replacement for three common diagnoses: glenohumeral osteoarthritis with intact rotator cuff (GHOA), rotator cuff tear arthropathy (CTA), and massive rotator cuff tear without arthritis (MCT). Notably, GHOA had better functional results and patient reported outcomes than those with CTA or MCT. GHOA afforded patients with a reverse prosthesis the greatest improvements in external and internal rotation, best forward elevation, and highest outcome scores including ASES, MCID, and SCB.
Specifically, with an average follow-up of 33.4 months, the GHOA group had superior ASES scores in comparison with CTA and MCT (86 vs 77 vs 76 respectively), SANE scores (86 vs 77 vs 74 respectively), as well as improvement in external and internal rotation. Residual pain was least in the GHOA group at 0.0 (although all on average had 0.0 pain in analysis). Interestingly, patients with MCT and CTA had surprisingly similar outcomes and pain results, even though these two diagnoses represent different time points on the spectrum of the same disease process. Even more interesting, postoperative external rotation was 7 degrees higher in the MCT group than the CTA group. Complication rates were low in all groups but acromial stress fractures were relatively higher with CTA (4.9%) than GHOA (1%) or MCT (1.3%).
My first take home message of this study is that massive cuff tears without arthritis remain a valid indication for reverse arthroplasty.
I believe this represents an evolution in thinking from historically using the reverse implant only very far into the cuff arthropathy disease process to using it earlier when arthritis hasn’t yet set in. In fact, in using the reverse prosthesis for massive tears (no arthritis) earlier in the disease may be protective in preserving external rotation as well as preventing complications such as acromial stress fracture in this study, which are both worse when the disease worsens to cuff arthropathy. When the clinician is faced with a discussion with a massive cuff tear patient regarding options including controversial salvage procedures such as arthroscopic subacromial balloon or superior capsular reconstruction, this data suggests there may not be a large benefit of continued waiting, and he or she may consider offering reverse arthroplasty earlier in the conversation.
The study does not help the surgeon choose between anatomic and reverse arthroplasty for patients with cuff intact OA. In fact, all we know was the decision to use the reverse in this group was made “at the surgeon’s discretion” in patients with “type B2 or B3 glenoids”. What we can reliably glean from this study, however, is that the use of the reverse prosthesis for this group is a very valid decision, with excellent pain, function, and outcome scores, which is consistent with my clinical experience. This too represents an evolution of thinking regarding indications for the reverse, as not more than a few years ago more surgeons were pushing the anatomic implant even for severely worn and eroded glenoids. I think this data underscores that anatomic arthroplasty is becoming the exception rather than the rule for advanced GHOA, as we really should be using it for those with central glenoid wear patterns, high activity status, and better preoperative function. Once these variables become compromised, we are increasingly confident knowing the reverse is an excellent choice.
This study is a good example of how pooled cohorts of patients taken from disparate geographies can allow us to obtain clinically meaningful conclusions about decision making, even when the data is reviewed in a retrospective cohort (Level III) fashion. While the present study looked at a lateralized glenosphere (DJO) design, the results about indicating patients for reverse arthroplasty based on preoperative diagnosis is reasonably generalizable. We increasingly know that reverse arthroplasty is a predictable, durable, and reliable options for patients with massive irreparable cuff tears as well as arthritis, and not just for cuff arthropathy. This information will confirm our decision to continue to increase the utilization for reverse arthroplasty going forward.