Cochrane in CORR: Shoulder Replacement Surgery For Osteoarthritis And Rotator Cuff Tear Arthropathy
These authors point out that the demand for shoulder arthroplasty is projected to rise by more than 750% by 2030 in the United States, a growth rate exceeding that for hip and knee replacements. Osteoarthritis is reported as the primary diagnosis in 34% to 72% of patients and rotator cuff tear arthropathy in 4% to 21%.
Despite the rise in diagnosis of shoulder OA, rotator cuff tear arthropathy, and shoulder arthroplasties performed, they found no clear consensus regarding the best type of replacement when it comes to managing these shoulder conditions, nor enough data on the harms in order to fully appreciate the risks and benefits of each type of surgery.
They summarized a recent Cochrane review and metaanalysis "Shoulder replacement surgery for osteoarthritis and rotator cuff tear arthropathy" that evaluated all randomized controlled trials (20 studies; 1105 shoulders) of shoulder replacement surgery in adults with OA of the shoulder, including rotator cuff tear arthropathy.
This study concluded that total shoulder arthroplasty did not provide a clinically important advantage over hemiarthroplasty in terms of patient reported pain, function, nor adverse effects; however, the evidence on this topic was of low quality.
Out of the 20 studies included, none compared reverse shoulder arthroplasty to another type of shoulder arthroplasty despite the rise in the number of reverse shoulder arthroplasty being performed.
Only three studies that compared total shoulder arthroplasty to stemmed humeral hemiarthroplasty for OA were eligible for pooling and meta-analysis.
While these studies suggested statistical differences in improvements in pain and function, these differences fell below the accepted minimal clinically important difference (MCID).
They emphasize that patients perceive the magnitude of improvement (the effect size) rather than the p value - statistically significant difference is not the same as clinically significant difference.
Effect sizes below the MCID may not be large enough for patients to care about, and regardless of p values, such small effects should not justify surgical choices.
This Cochrane review found that total shoulder arthroplasty did not provide a clinically important benefit over hemiarthroplasty in terms of patient-reported pain or function. The evidence on this topic was of low quality.
The durations of follow-up were insufficient to show whether total shoulder arthroplasty or hemiarthroplasty was associated with increased or decreased risk of harm. This deficiency could change conclusions in either direction. On one hand, the glenoid component is more likely to loosen than is the humeral component (a fact that favors hemiarthroplasty); by contrast, cartilage wear and increases in pain over time sometimes occur in patients with hemiarthroplasties (which might favor total shoulder replacement over time).
The authors state that given the substantial difference in complexity and risk associated with implanting a total shoulder replacement, until or unless those future studies deliver in that way, the best-available (albeit relatively low quality) evidence we have suggests that hemiarthroplasty is as good in terms of improving pain and function, which is a finding that cuts against the current dominant paradigm.
Comment: The options for managing glenohumeral osteoarthritis are increasing each year, with variations on the humeral side (standard stem, short stem, stemless) and variations on the genoid side (no glenoid surgery, glenoid reaming, all-polyethylene, metal backed, hybrid, augmented, inset), reverse vs anatomic, as well as the approaches to preoperative planning (plain films vs 3D CT planning with patient specific instrumentation). Currently there is insufficient guidance from the published literature to guide the surgeon in deciding the best approach for each patient.
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