Michael Fu, MD
Journal Club is a recurring series where we highlight the latest orthopedic shoulder research, and discuss potential applications and ramifications for our patients.
Title
Prospective, Blinded, Randomized Controlled Trial of Stemless Versus Stemmed Humeral Components in Anatomic Total Shoulder Arthroplasty: Results at Short-Term Follow-up
Authors
J. Michael Wiater, MD , Jonathan C. Levy, MD, Stephen A. Wright, MD, Stephen F. Brockmeier, MD, Thomas R. Duquin, MD, Jonathan O. Wright, MD, Timothy P. Codd, MD
Journal
The Journal of Bone and Joint Surgery. 2020 Sep 28. 10.2106/JBJS.19.01478.
Abstract
Background
Stemless humeral components for anatomic total shoulder arthroplasty (aTSA) have several reported potential benefits compared with stemmed implants. However, we are aware of no Level-I, randomized controlled trials (RCTs) that have compared stemless implants with stemmed implants in patients managed with aTSA. We sought to directly compare the short-term clinical and radiographic outcomes of stemless and stemmed implants to determine if the stemless implant is noninferior to the stemmed implant.
Methods
We performed a prospective, multicenter, single-blinded RCT comparing stemless and short-stemmed implants in patients managed with aTSA. Range-of-motion measurements and American Shoulder and Elbow Surgeons (ASES), Single Assessment Numeric Evaluation (SANE), and Constant scores were obtained at multiple time points. Device-related complications were recorded. Radiographic evaluation for evidence of loosening, fractures, dislocation, or other component complications was performed. Statistical analysis for noninferiority was performed at 2 years of follow-up for 3 primary end points: ASES score, absence of device-related complications, and radiographic signs of loosening. All other data were compared between cohorts at all time points as secondary measures.
Results
Two hundred and sixty-five shoulders (including 176 shoulders in male patients and 89 shoulders in female patients) were randomized and received the allocated treatment. The mean age of the patients (and standard deviation) was 62.6 ± 9.3 years, and 99% of the shoulders had a primary diagnosis of osteoarthritis. At 2 years, the mean ASES score was 92.5 ± 14.9 for the stemless cohort and 92.2 ± 13.5 for the stemmed cohort (p value for noninferiority test, <0.0001), the proportion of shoulders without device-related complications was 92% (107 of 116) for the stemless cohort and 93% (114 of 123) for the stemmed cohort (p value for noninferiority test, 0.0063), and no shoulder in either cohort had radiographic signs of loosening. Range-of-motion measurements and ASES, SANE, and Constant scores did not differ significantly between cohorts at any time point within the 2-year follow-up.
Conclusions
At 2 years of follow-up, the safety and effectiveness of the stemless humeral implant were noninferior to those of the stemmed humeral implant in patients managed with aTSA for the treatment of osteoarthritis. These short-term results are promising given the potential benefits of stemless designs over traditional, stemmed humeral components.
Level of Evidence
Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.
Discussion
As shoulder replacement technology continues to evolve and improve, humeral implant stems have trended toward being smaller and smaller over time. More recently, “stemless” humeral implants have been developed, which I was trained to use during my fellowship at Midwest Orthopaedics at Rush in Chicago. To me, there are four main benefits of stemless humeral implants: 1) it removes significantly less bone than traditional stemmed implants, which means more of your native bone is preserved, 2) if the shoulder replacement fails and it needs to be revised for whatever reason, a stemless implant is much easier to remove than a stemmed implant, 3) if there is pre-existing bone deformity due to a prior fracture, for example, a stemless implant is more easily accommodated by the abnormal anatomy compared to a stemmed implant, and 4) if the patient were to unfortunately fall on the shoulder after shoulder replacement, a fracture around a stemless implant would be much easier to treat than a fracture around a larger stem.
One potential concern with stemless implants is a fear of loosening, as there is less surface area for bony ingrowth and no apposition against the humeral shaft. However, stemless implants now have a medium-term track record in the United States, and the rates of loosening have not been found to be higher than stemmed implants. The track record with stemless implants was excellent during our experience in Chicago.
In this current prospective, randomized study comparing stemless and stemmed total shoulder replacement, Dr. Wiater and his team found that at 2 years after surgery, there was no difference in patient-reported outcomes between the groups. The rate of implant-related complications was the same between the groups as well. Finally, no loosening was seen in either group in this study.
This paper is an important contribution to the growing evidence in favor of stemless humeral implants. In my practice, the implant choice is specific to each patient, as there is not a one-size-fits-all solution. Anatomic total shoulder arthroplasty with a stemless humeral implant may be a good option that we would discuss during your pre-surgical consultation.
About the Author
Dr. Michael Fu is an orthopedic surgeon and shoulder specialist at the Hospital for Special Surgery (HSS), the No. 1 hospital for orthopedics as ranked by U.S. News & World Report. Dr. Fu treats the entire spectrum of shoulder conditions, including rotator cuff tears, shoulder instability, and shoulder arthritis. Dr. Fu was educated at Columbia University and Yale School of Medicine, followed by orthopedic surgery residency at HSS and sports medicine & shoulder surgery fellowship at Rush University Medical Center in Chicago. He has been a team physician for the Chicago Bulls, Chicago White Sox, DePaul University, and NYC’s PSAL.
Disclaimer: All materials presented on this website are the opinions of Dr. Michael Fu and any guest writers, and should not be construed as medical advice. Each patient’s specific condition is different, and a comprehensive medical assessment requires a full medical history, physical exam, and review of diagnostic imaging. If you would like to seek the opinion of Dr. Michael Fu for your specific case, we recommend contacting our office to make an appointment.