Diagnosis and Implant Type Drive Patient Outcomes in Shoulder Replacement Surgery

Conventional anatomic total shoulder arthroplasty (TSA) still has a place in patient care and should not be widely substituted with reverse TSA (rTSA), suggests a Cleveland Clinic study on patient-reported outcomes of shoulder replacement surgery.

As shoulder replacement surgery has evolved over the past four decades, rTSA has gone from a newer experimental technique to the most common type of shoulder replacement worldwide. Initially intended only for patients with rotator cuff tear arthropathy, rTSA now makes up approximately 70% of shoulder replacements in the U.S., including for patients with glenohumeral osteoarthritis.

“There’s been a lot of debate about whether reverse replacement is as good as anatomic replacement,” says Eric Ricchetti, MD, an orthopaedic surgeon specializing in shoulder surgery at Cleveland Clinic. “Some papers have shown that the procedures are basically equivalent, particularly for patients with intact rotator cuffs. However, these papers have studied relatively small groups of patients with less advanced statistical analysis.”

Enter Cleveland Clinic’s orthopaedic Outcomes Management and Evaluation (OME) database, which collects data from patients having elective shoulder, hip and knee surgeries. The database has collected nearly 100% of baseline data from Cleveland Clinic arthroplasty patients before surgery and approximately 70%-80% of patient-reported data at one-year follow-up, making the database a powerful tool for studying orthopaedic surgeries and their outcomes.

“Some orthopaedic surgeons argue that one implant type is generally better than the other, but it’s not that straightforward,” Dr. Ricchetti says. “There are many factors at play — factors that can overlap.”

To untangle the interaction of these factors, Dr. Ricchetti and colleagues studied the wealth of data in the OME database and published the most comprehensive study to date on short-term patient-reported outcomes of shoulder replacement surgery. According to the study published in the Journal of Shoulder and Elbow Surgery, the biggest driver of one-year outcomes of shoulder replacement surgery is a combination of diagnosis and implant type.

Top 3 factors that influence outcome

The researchers prospectively studied more than 1,000 (n = 1,042) patients who had primary shoulder replacement at Cleveland Clinic between 2015 and 2019:

• 275 (26%) rTSAs for glenohumeral osteoarthritis
• 308 (30%) rTSAs for rotator cuff tear arthropathy
• 459 (44%) anatomic TSAs for glenohumeral osteoarthritis

They reviewed the Penn Shoulder Scores (pain, function, satisfaction and total scores) reported by patients before and one year after surgery, and evaluated which patient, disease-specific and surgical factors most impacted the scores. The Penn Shoulder Score is a validated, shoulder-specific outcome tool using a scale of 0 to 100. Higher scores indicate better shoulder function, lower pain and higher satisfaction.

“Most research on this topic has assessed only a few predictive factors at a time, often in smaller cohorts of patients,” Dr. Ricchetti says. “We controlled for 20 predictive factors in over 1,000 patients and conducted a multivariable statistical analysis to rank factors in order of importance to outcome.”

Average Penn Shoulder Scores significantly improved one year after surgery for patients in all three treatment groups. However, certain preoperative factors were associated with lower scores, including younger age, female sex, current smoking, chronic pain diagnosis and history of prior surgery on the operative shoulder.

The factors that most strongly impacted Penn Shoulder Scores one year after surgery, ranked by importance, were:

1. Combined diagnosis and arthroplasty type. Relative to patients undergoing rTSA for glenohumeral osteoarthritis, scores were higher for patients who underwent anatomic TSA for glenohumeral osteoarthritis and lower for patients who underwent rTSA for rotator cuff tear arthropathy.
2. Baseline mental health status. Penn Shoulder Scores were higher in patients who had better preoperative mental health, as measured by scores on the Veterans RAND 12-Item Health Survey mental component summary.
3. Insurance status. Relative to patients with private insurance, Penn Shoulder Scores were substantially lower for patients who had workers’ compensation insurance.

Anatomic TSA performs best for patients with glenohumeral osteoarthritis and an intact rotator cuff

“Patients who had anatomic TSA for glenohumeral osteoarthritis reported the highest Penn Shoulder Scores one year after surgery when controlling for a large number of other patient, disease and surgical factors — higher than the other categories of patients, including those who had rTSA for glenohumeral osteoarthritis,” Dr. Ricchetti says.

In addition, the study further supports that patients with rotator cuff tear arthropathy report worse outcomes after shoulder replacement surgery. It’s known in medical literature that patients with rotator cuff tears have slightly worse outcomes after rTSA, likely because they don’t have the same strength and function as patients with intact rotator cuffs. The data from Cleveland Clinic’s OME database affirmed this finding in the largest cohort to date.

When focusing on patients with glenohumeral osteoarthritis and intact rotator cuffs, medical literature hasn’t clearly shown that one type of TSA is better than another. The complex analysis by Dr. Ricchetti and colleagues is the first to reveal that anatomic TSA performs better than rTSA for these patients.

“The conventional anatomic replacement puts the implant in the normal position of the joint,” Dr. Ricchetti says. “The reverse replacement switches the position of the ball and socket, so the movement may not be as natural as with a conventional replacement. In particular, the published literature shows that patients with reverse shoulder replacements have less internal rotation motion than patients with conventional replacements. The more natural motion after a conventional replacement may be why patients are more satisfied with their shoulder after that procedure.”

Diagnosis should direct surgical technique

Reverse TSAs, which have boomed in popularity in the past decade, may be the best option for some patients — particularly those with rotator cuff tears or those with more severe glenoid bone loss — but not for all.

“Conventional TSAs still can provide optimal outcomes,” Dr. Ricchetti says. “We should think twice about performing rTSAs in every patient and indicate patients based on the status of their rotator cuff and severity of bone loss. Reverse TSAs may not be preferable for all patients with intact rotator cuffs.”

Consider the right implant for each diagnosis, he says.

Based on this study, the research team developed an online tool to help predict Penn Shoulder Scores one year after primary TSA. To use this tool during presurgical counseling with your patients, see https://riskcalc.org/Predicting1YearPROMSAfterTotalShoulderArthroplasty.