Shoulder surgeons are constantly weighing the pros and cons of anatomic total shoulder arthroplasty (aTSA) versus reverse total shoulder arthroplasty (rTSA) for primary glenohumeral osteoarthritis (GHOA) in patients with an intact rotator cuff. The trend toward rTSA has been explosive—it’s reliable, forgiving for bone loss, and great for older patients with comorbidities. But what about those “ideal” cases: no significant glenoid deformity (Walch A1 or B1), intact cuff, and relatively balanced shoulders? Is flipping to reverse an easy way out or should we be reconsidering anatomic arthroplasties?
This new multicenter study out of JSES tackles this head-on with a matched cohort analysis that controls for the usual confounders like age, sex, follow-up, Walch class, prior surgery, and preop motion/scores.1 They compared 155 aTSAs and 155 rTSAs using the Exactech Equinoxe system (medialized glenoid, lateralized humerus, 145° neck-shaft angle) at a mean 3.2-year follow-up. This is one of the cleanest, apples-to-apples comparisons to date, and the findings might make you think twice before defaulting to a reverse construct in straightforward cases.
Key Findings
Postoperative outcomes favor aTSA slightly: aTSA patients hit higher marks in abduction (146° vs. 133°, P < 0.001), internal rotation score (4.6 vs. 4.1, P = 0.004), external rotation (53° vs. 43°, P < 0.001), Constant score (73.6 vs. 70.5, P = 0.039), and SAS score (81.1 vs. 77.2, P = 0.002). These differences were statistically significant, but possibly not clinically meaningful. Both groups improved similarly in forward elevation, IR, ER, pain, function, Constant, ASES, and SAS, but aTSA gained more abduction (60° vs. 47° improvement, P = 0.024). This held up after multiple comparison adjustments. Complication rates were low and similar (both less than 4% and not significantly different) with aTSA issues of loosening and cuff tear and rTSA issues of acromial fracture and liner dissociation.
Clinically Meaningful Thresholds: Here’s where it gets actionable. Anatomic shoulder arthroplasty patients were more likely to achieve substantial clinical benefit (SCB) for abduction (78% vs. 64%, P = 0.034) and ER (61% vs. 45%, P = 0.034).
Anatomic (aTSA) vs. Reverse (rTSA) Study Outcomes
Comparison of 310 matched cases (155 each) for primary GHOA with intact rotator cuffs.
| Category | Anatomic (aTSA) | Reverse (rTSA) | Significance (P-value) |
|---|---|---|---|
| Abduction | 146° | 133° | P < 0.001 |
| External Rotation | 53° | 43° | P < 0.001 |
| Internal Rotation Score | 4.6 | 4.1 | P = 0.004 |
| Constant Score | 73.6 | 70.5 | P = 0.039 |
| SAS Score | 81.1 | 77.2 | P = 0.002 |
| SCB for Abduction | 78% | 64% | P = 0.034 |
| SCB for External Rotation | 61% | 45% | P = 0.034 |
| Complication Rate | < 4% (Loosening, Cuff tear) | < 4% (Fracture, Dissociation) | Not Significant |
Take Aways
In my experience, aTSA in these A1/B1 cases is still the reliable choice, with predictably excellent outcomes and motion with better rotation and quicker rehab. When the shoulder is substantially decentered, this study provides comfort for those considering rTSA in borderline case, but this comes at a cost of abduction and external rotation of the shoulder.
This is one of the cleanest apples-to-apples comparisons to date, and the findings might make you think twice before defaulting to a reverse construct in straightforward cases, but for cuff-intact OA without bone loss, aTSA remains the gold standard in my experience. For active patients in their 60s, aTSA predictably affords better ER/IR (e.g., golf swing, reaching behind back), but for 75+ with diabetes (higher in rTSA cohort here), rTSA’s reliability may tip the scales.
Conclusions
Patient counseling remains key when discussing shoulder arthroplasty. In A1/B1 glenoids with an intact cuff, in my opinion, we should be presuming the patient is a candidate for an anatomic arthroplasty. This may afford 10-15° more abduction/ER improvement which could be meaningful in an active, athletic population. Just because the reverse is exploding in popularity and patients come asking about it, does not mean it is one size fits all; the shoulder surgeon must be able to discern when an anatomic arthroplasty may be more beneficial for the patient.
References
- Hao KA, Elwell J, Wright TW, King JJ, Friedman RJ, Schoch BS. Exactech Equinoxe anatomic vs. reverse total shoulder arthroplasty for primary osteoarthritis with an intact rotator cuff in patients with no glenoid deformity. J Shoulder Elbow Surg. 2025 Oct;34(10):2385-2393. doi: 10.1016/j.jse.2025.01.038. Epub 2025 Feb 27. PMID: 40023476.