This week’s Orthopaedic Crossfire® debate was part of the 19th Annual Current Concepts in Joint Replacement® (CCJR®), Spring meeting, which took place in Las Vegas. This week’s topic is “OA in a 60-Year-Old: Stemless Trumps Stemmed Implants.” For is Anthony A. Romeo, M.D., Rothman Orthopaedic Institute, New York, New York. Opposing is Frank A. Cordasco, M.D., Hospital for Special Surgery, New York, New York. Moderating is Thomas S. Thornhill, M.D., Harvard Medical School, Boston, Massachusetts.
Dr. Romeo: I’m going to take the side that stemless trumps a stemmed implant. And I want to bring you from where many of you are into where you’re going to be in the next few years.
We know that the goals of shoulder replacement are to alleviate pain, improve motion and improve function. We’ve learned how to do this very effectively with our modern-day concepts of best exposure and anatomic reconstruction (particularly with regards to the humeral head), restore the glenohumeral relationships and then fixation.
Really the break-through for many is when we realize the relationship of head height to radius of curvature is fixed. When we followed that principle, our results improved. We’ve learned what we really need to fix that head in the right spot. Long stem. Short stem and now, stemless.
There is some basic science to suggest that less metal inside of the canal can change the forces around the shoulder and may be able to favorably affect the stress shielding that occurs at the proximal end of the humerus. The smaller or less stem you use the more favorable it is. (Razfar, et al., J Shoulder Elbow Surg 2015).
We’ve seen this when we’ve looked at whether it’s a long stem or a short stem—our longer stem implants typically fit below the metaphysis and therefore they stress-shield the metaphysis whereas the shorter stems seem to be able to maintain that bone. (Denard, et al., J Shoulder Elbow Surg 2018)
There are different short stem designs on the market. We looked at one system with greater than 2-year outcomes, no revision. The radiolucent lines were minimized and we’re very happy with the overall outcomes and the functions that the patients had with this type of implant. (Romeo, et al., J Shoulder Elbow Surg 2018)
But there have been some reports of stress shielding being quite dramatic. In fact, up to 80% have had significant calcar loss of bone. (Schnetzke, et al., J Shoulder Elbow Surg 2015) So, you have to be careful because short stem implants are not all the same and you have to take a careful look at the results that are coming together.
Why would you use a stemless shoulder arthroplasty? To preserve the bone and have an anatomic reconstruction of the head, which is the primary principle to follow through with. Glenoid replacement is easier as opposed to trying to do a surface replacement where the head stays in your way. You don’t have to worry about malalignment of the humeral shaft in a post-traumatic case. There’s decreased blood loss. And probably less pain in many of these patients.
As we start going to outpatient shoulder arthroplasty, we look very carefully at some of the things that will favor this, the loss of blood plays a role so we can minimize that. Reduce their pain. Reduce the amount of dissection or bone injury that we have. All this plays a significant role. (Leroux, et al., J Shoulder Elbow Surg 2016)
