Don’t Say Goodbye to Anatomic Total Shoulder Arthroplasty

Reverse total shoulder arthroplasty (rTSA) usage has eclipsed anatomic total shoulder arthroplasty (aTSA), since receiving approval from the U.S. Food and Drug Administration in 2003. It has become the most commonly performed shoulder arthroplasty procedure in the United States and now accounts for nearly 3 out of 4 shoulder replacements.

Despite the growing popularity of rTSA, largely driven by off-label use, Peter J. Evans, MD, PhD, Division Chair of Orthopaedic Surgery, Rehabilitation, and Sports Therapy for Cleveland Clinic in Florida, sees an enduring role for aTSA among certain patients with glenohumeral osteoarthritis (GHOA) and an intact rotator cuff, a position supported by postoperative patient-reported outcomes following primary TSA at Cleveland Clinic in Florida and Ohio.

Trends in total shoulder arthroplasty

The prevalence of shoulder arthroplasty in the United States has shown a marked increase in recent years, according to an analysis of Centers for Medicare and Medicaid Services data. Annual cases of primary TSA increased from 12,276 to 110,208 between 2000-2019, while revision TSA increased from 4,988 to 7,872 between 2015-2019.

Based on annual average growth rates of 12% for primary TSA and 14% for revision TSA, the projected demand for these surgeries by 2030 will be approximately 368,000 and 34,000, respectively. The study’s authors cite a number of possible reasons for this exponential increase in shoulder arthroplasty, from the aging population to positive clinical outcomes. They also point to the introduction of reverse shoulder replacement and the expanding indications for the procedure.

Reverse versus anatomic

Unlike conventional shoulder arthroplasty, which replicates a patient’s native anatomy, rTSA entails switching the joint alignment, placing the prosthetic socket at the head of the humerus and attaching the ball implant to the glenoid of the scapula. This allows the deltoid muscle to move the arm without the need of the rotator cuff. It is a better option for people with cuff tear arthropathy, a degenerative arthritis of the shoulder caused by rotator cuff damage.

“Historically, we had a whole segment of people with shoulder pain and poor function who did not have a good surgical option,” says Dr. Evans. “Now individuals with osteoarthritis and damaged rotator cuffs, who are not good candidates for anatomic shoulder replacement, are undergoing reverse shoulder replacement and experiencing very positive outcomes.”

A review of 2011-2020 utilization trends for aTSA and rTSA, using a large, national, multi-insurance administrative database, found the percent of shoulder replacements being performed with rTSA increased from 31.4% to 74.9%. Notably, this increase did not coincide with a decrease in aTSA volume, indicating an expansion of the overall TSA patient population.

Reverse TSA was originally approved for rotator cuff arthropathy or a previous failed joint replacement and later expanded to proximal humerus fractures for some reverse implants. An analysis of the American Academy of Orthopaedic Surgeons Shoulder and Elbow Registry (AAOS-SER), however, found off-label use of rTSA in 75.6% of cases between January 2015 to March 2021, including for OA without rotator cuff tear (RCT) and RCT without OA.

The researchers noted “implant manufacturers have expanded indications for rTSA without providing clinical data to support changing FDA approved indications for use,” and suggest indications should be formally expanded to reflect the published literature.

Mining patient-reported outcomes

Last year a team of researchers from Cleveland Clinic, including Dr. Evans, added to the literature with a study that looked at the associations of preoperative patient, disease-specific, and surgical factors with 1-year postoperative PENN Shoulder Score (PSS) in patients undergoing primary aTSA or rTSA for glenohumeral osteoarthritis (GHOA) or rotator cuff tear arthropathy (CTA).

They used Cleveland Clinic’s Outcomes Management and Evaluation (OME) database, a tool for the prospective collection of standardized shoulder arthroplasty data, including shoulder-specific validated baseline and 1-year patient-reported outcome measures (PROMs). Their analysis identified 1042 cases performed between February 2015 and August 2019 by Cleveland Clinic surgeons in Ohio and Florida. They were divided into three diagnosis-arthroplasty subgroups: GHOA-rTSA (n = 275, 26%), CTA-rTSA (n = 308, 30%), and GHOA-aTSA (n = 459, 44%).

“We believe this was the first study to prospectively investigate outcomes considering both diagnosis and arthroplasty type across the three commonly treated surgical groups,” states Dr. Evans. “We also controlled for 20 possible confounders with multivariable analysis.”

Key findings

The team reported that all PROMs showed statistically significant improvements postoperatively, with 89% of patients reaching an acceptable symptom state. Patients undergoing aTSA for GHOA demonstrated the highest PROM scores at 1-year follow-up while those undergoing rTSA for CTA had the lowest. Specifically, GHOA-aTSA predicted a 3.3-point higher 1-year PSS and CTA-rTSA a 4.9-point lower 1-year PSS (P< .001) when compared with GHOA-rTSA.

“What this tells us is that for patients with a good rotator cuff, anatomic replacement may be a superior approach,” says Dr. Evans. “In my practice, I’m seeing younger patients with intact rotator cuffs who are choosing joint replacement sooner in order to retain function and support active lifestyles. In these cases, conventional replacement offers a reliable primary solution that can restore motion without restrictions while preserving future revision options.”

Dr. Evans cautions, however, that while diagnosis-arthroplasty type was the strongest prognostic factor associated with 1-year PSS, several other factors impact patient outcomes. For example, the researchers observed a significant association of lower 1-year PSS with lower age, female sex, current smoking, chronic pain diagnosis, and worker’s compensation claim. They also noted that while the effects of some variables were small and perhaps not clinically significant in isolation, they occur in patients in combinations with additive effects, according to multivariable models.

“Ultimately, our goal is to improve preoperative patient counseling regarding the expected outcomes of shoulder arthroplasty by better understanding how patient, disease-specific, and surgical factors impact outcomes,” says Dr. Evans.