The goal of shoulder arthroplasty is to improve comfort and function for a variety of degenerative conditions. Over the past two decades, the prevalence of shoulder arthroplasty has increased dramatically, and the proportion of reverse shoulder replacements has now surpassed anatomic shoulder replacements accounting for 70-80% of the market.
As the indications for shoulder replacement have evolved and the implants have been engineered to address common modes of failure, so too has the profile of potential complications, both short-term and long-term, that may afflict patients undergoing these procedures.
Shoulder surgeons who engage an increasingly complex array of clinical problems must understand the factors that may negatively impact results and lead to a higher risk of complications. A better understanding of risk factors will help not only educate patients about potential adverse outcomes, but it also leads to improved ways to mitigate complications by addressing the root cause(s) where possible.
A better understanding of risk factors will help to educate patients about potential adverse outcomes and leads to improved ways to mitigate complications by addressing the root cause(s) when possible.
Aibinder and colleagues were able to leverage the data from a large multinational clinical registry of anatomic and reverse shoulder arthroplasty to determine risk factors for complications and revision surgery.1 Although based on a single implant design, this registry uses a standardized data collection method across centers and provides long-term follow-up on large cohorts that provide for robust analysis of both patient-specific and implant-specific risk factors for intraoperative or post-operative complications.
Interestingly, while intraoperative complication rates did not differ between ATSA and RTSA, post-operatively ATSA patients had nearly double the revision rate of 5.7% vs 2.4%. Principle complications for ASTA included subscapularis failure and aseptic glenoid loosening, while those for RTSA included acromial/scapular spine fracture reactions and instability.
Risk factors for complications intraoperatively included female gender and prior shoulder replacement surgery, while those for post-operative complications included younger age, prior shoulder surgery, and inflammatory arthritis. Implant-related risk factors for revision shoulder replacement surgery included increased retroversion, larger humeral liner offset, and larger glenosphere.
These findings may indicate more difficult underlying pathology that required implant configurations creating more lateralization and distalization to achieve stability. The use of augmented baseplates and glenoids was associated with greater intraoperative complications as was increased operative time. All of these suggest that as the complexity of the case increases, so too do the potential risks for adverse outcomes.
A key finding across this study, and one that has been reported in other outcome studies of RTSA, is the association of prior surgery with risk poor outcomes.1 In the current study, prior surgery was an independent risk factor for intraoperative and post-operative complications and revision surgery. This suggests that surgeons must carefully consider this variable when counseling patients about arthroplasty and consider the implications of the prior surgery on the reconstruction complexity both with regard to bone and soft tissue.
Another key finding of this study, though one that requires longer term follow-up to confirm, is that the revision rate of RTSA is now less than that of ATSA which is counter to what people initially predicted as RTSA started increasing in utilization. While this is a testament to the utility and durability of RTSA, it must also be noted that the specific complications of acromial/scapular spine fractures and instability can be very difficult to treat.
As our planning and navigation tools become ever more sophisticated and may eventually be able to include information on bone density and fracture risk, the hope is that we will be able to reduce the incidence of these problems by leveraging data to improve patient outcomes.
- Aibinder W, Schoch B, Parsons M, Watling J, Ko JK, Gobbato B, Throckmorton T, Routman H, Fan W, Simmons C, Roche C. Risk factors for complications and revision surgery after anatomic and reverse total shoulder arthroplasty. J Shoulder Elbow Surg. 2021 Nov;30(11):e689-e701. doi: 10.1016/j.jse.2021.04.029. Epub 2021 May 5.
Moby Parsons, MD, practices at the Knee, Hip and Shoulder Center in Portsmouth, N.H., and is a member of the ExactechGPS® design team. He trained at the University of Pittsburgh where he performed a research fellowship in shoulder surgery; his clinical research on tendon transfers won the Neer Award. Dr. Parsons received fellowship training at the University of Washington and University of New South Wales. He is a founding member of the New England Shoulder and Elbow Surgeons and a regional leader in shoulder surgery, including outpatient shoulder arthroplasty.
For additional content on leveraging data for shoulder arthroplasty, read our blog post titled The Power of Data Collection. To access our library of resources for tools and techniques that can improve patient outcomes, visit the landing page of our Innovations Blog.