Ideal total elbow replacement remains elusive
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After the development of total hip arthroplasty in the 1970s, orthopedists continued to push surgical innovations to develop total joint replacement in other extremities.
Despite the progress made with knee and shoulder replacements, elbow replacement continued to lag.
Source: Carla Morrey
“The main reason for the poor success rate of the early implants in the early ‘70s was because the design of implants had not matured enough to recognize the need to clearly understand the kinematics and the biomechanics of the [elbow] joint,” Bernard F. Morrey, MD, FAOA, clinical professor in the department of orthopedics at The University of Texas Health Science Center at San Antonio, told Healio | Orthopedics Today. “As the failure rates increased, the need to better understand the normal function of the joint increased.”
But even with advancements in bearing surfaces, implant designs and surgical technique, some surgeons fear elbow replacement still may have a long way to go.
“I do not think we have an implant that provides all the desired characteristics of joint replacement,” Morrey said. “The ultimate gold standard would be an implant that can be implanted by a broad spectrum of upper extremity surgeons [and have] a low complication rate and a high reproducibility rate – one in which the patient would have fewer limitations or restrictions and less likely to wear at a premature rate.”
Restore elbow kinematics
While the traditional gold standard in the United States for total elbow arthroplasty has been a cemented linked implant with a semi-constrained bearing system, sources who spoke with Healio | Orthopedics Today said it is limited by aseptic loosening and wear. But some of the potential for early aseptic loosening can be mitigated by restoring natural elbow kinematics, according to Matthew A. Butler, MD, hand and upper extremity surgeon at Hospital for Special Surgery.
“The closer that we can replicate the normal anatomy, the less load is going to be absorbed by the implant and it should preserve the longevity of the implant. Even though the gold standard is a linked system, our goal should still be to get as close as possible to restoring normal arc of motion and kinematics,” Butler told Healio | Orthopedics Today.
Although restoring the natural kinematics of an elbow should be the target of an elbow arthroplasty, the pathological nature of many elbow cases can make it challenging, according to Matthew L. Ramsey, MD, shoulder and elbow surgeon at the Rothman Orthopaedic Institute.
“It is important to be as anatomic as you can be within whatever your implant allows,” Ramsey, a Healio | Orthopedics Today Editorial Board Member, said. “The tricky part is in some of these [cases] where the anatomy of the articulation is so pathologic, there is a lot of disruption to the normal geometry of the joint. In those scenarios, even though it would be wonderful to reestablish a more normal kinematic pattern, that can be difficult because of the soft tissue envelope that you are putting the implant into is not anatomic.”
Soft tissue preservation
Similar to restoring normal elbow kinematics, Butler said preserving the soft tissues in the elbow may help “preserve the bearings and decrease or slow the progression of aseptic loosening.”
According to Akin Cil, MD, Rex L. Diveley Professor and chair of the department of orthopedic surgery at the University of Missouri-Kansas City, when soft tissue was not preserved in older surgical techniques, a lot of bone would be excised and tissues released, leading to a 5- to 10-year survival of approximately 65%.
“It is a dismal survival for a total joint replacement,” Cil told Healio | Orthopedics Today. “You cannot accept that for a hip, you cannot accept that for a knee, you cannot accept that for a shoulder, but you are accepting it for an elbow.”
Ramsey said surgeons should preserve the soft tissue envelope at the flexor pronator attachment, common extensor mechanism and the triceps, which can lead to devastating outcomes if compromised.
“If you lose the triceps somewhere along the way or early on, it is a devastating problem,” Ramsey said. “Not only because functionally they cannot extend the elbow, but it compromises the integrity of your soft tissue sleeve to prevent soft tissue breakdown and infection. This operation, primarily, is a soft tissue procedure. You need to manage the tissues in order for the implant to function the way it needs to function without complication.”
Implant, polyethylene design
The evolution of implant designs and bearing surfaces has more recently improved elbow arthroplasty, according to Joaquin Sanchez-Sotelo, MD, PhD, chair of the division of shoulder and elbow surgery at the Mayo Clinic.
“[Bearing surfaces and implant designs] have evolved substantially, mostly in terms of the geometry of the joint portion itself,” Sanchez-Sotelo told Healio | Orthopedics Today. “When the Coonrad/Morrey (Zimmer Biomet) was designed, it was a metallic cylinder inside a channel of polyethylene. That creates a fair amount of what we call ‘edge loading.’ Certain new elbow implants all have a joint that is more of a round type of articulation, and that decreases edge loading.”
Butler said advances in polyethylene have also improved the wear characteristics of the polyethylene component, which is part of the moving articulation of the elbow prosthesis.
“We have also seen some of the polyethylene components getting thicker over time for that same reason,” Butler said.
However, since the number of patients who need an elbow replacement is less than that of patients who need hip or knee replacements, Sanchez-Sotelo said companies that design replacement components may be less likely to invest resources into elbow implants.
“There may be companies that have access to high-quality polyethylene, but if it is limited, they are going to prioritize placing that polyethylene in the hip and knee implants because they are better business decisions and will bring in more income. There is an element of business in medicine that we cannot forget about,” he said.
Despite these advancements, according to Cil, “None of them seem to be perfect.”
“It is hard to replicate the whole motion of the elbow because even if you think that it is a hinge, it is not a cylindrical hinge in the elbow. It is asymmetric, and so there is some rotation while there is flexion and extension,” Cil said. “That is the main reason bushings are getting loaded because you are trying to get a three-dimensional structure and think about it two-dimensionally and recreate a hinge just to prevent it from dislocating.”
Infection
In addition to loosening and wear, one of the most common and devastating complications that has thwarted some of the progress in elbow arthroplasty is infection, according to Morrey.
“The elbow is more prone to infection,” Morrey said. “The indications for the elbow are rheumatoid or inflammatory arthritis or posttraumatic conditions, both of which are known to inherently have an increased complication of infection.”
In addition, Sanchez-Sotelo said the elbow can be more prone to infection due to the subcutaneous nature of the elbow joint.
“In the shoulder, for example, the surrounding muscle envelope is big, so if you have a skin problem, there is muscle underneath. At the elbow, as soon as you have some issues with the skin, you are in the joint,” Sanchez-Sotelo said.
According to Ramsey, elbow surgeons will need to enhance their knowledge of infection before it can be curbed.
“We need to get a better and clearer understanding of infection,” Ramsey told Healio | Orthopedics Today. “The two big areas that need a lot more attention are how we manage infection and how we manage bone loss. They often come together, so they are not always in isolation. Getting a better feel for those issues would be enormously valuable.”
Mechanical failure
Another complication of total elbow arthroplasty is mechanical failure, according to Sanchez-Sotelo.
“We typically counsel patients after elbow replacement to be careful with weightlifting,” Sanchez-Sotelo said. “But at least 80% of our patients perform activities that were not recommended because people have to have a life. Imagine that you are at home, and it is snowing. You have to get out of your house, and if you are alone with no one else there to shovel, you are going to do it.”
According to Cil, the best method for preventing mechanical failure may be improving patient counseling.
“We all give restrictions to our patients, and we know that they are not following our instructions,” Cil said. “Maybe with wearable technology, we can understand what their needs are and then we can consult them better. I would like to see more advice on how we can advise our patients not to use the elbow in positions that are not conducive to long-term survival for the elbow replacement. Patient-reported outcomes are usually limited. We want to understand more about our patients so that we can talk to them in a patient-centered and patient-specific manner.”
Cementless fixation
As surgeons continue to improve implant design for the elbow, Ramsey said the ideal method of implant fixation is another ongoing debate in total elbow arthroplasty.
“The standard is cemented fixation and we have certainly gotten better at doing it, but most of us who do enough elbow replacement would argue that there is something sorely missing with an all-cemented implant over the long haul,” Ramsey said. “The controversy still exists: Is cementless fixation possible in the elbow and, if possible, is it something that will supplant cemented fixation?”
Sanchez-Sotelo said that while he is optimistic about the potential of cementless fixation, there are concerns regarding the feasibility of current implementation.
“We need a change in how the implants are designed because for an implant to be applied cementless, the implant has to fit the geometry on the inner canal of the bones perfectly, and the way implants are designed now, if you were to fit a stem perfectly in the canal, the joint would not land where it is supposed to be,” Sanchez-Sotelo said. “There is a need for a completely different design, where the relationship between the stem portion and the joint portion of the components is modified.”
Even if a cementless implant is designed for the elbow, it would not be used for every patient, according to Sanchez-Sotelo.
“There are patients with such poor bone quality that if we were to use a cementless implant, it probably would not work,” he said. “There will always be a need for cemented fixation in some patients.”
Future directions
Overall, the modern elbow surgeon has a great deal of work still to do when it comes to total elbow arthroplasty, according to Ramsey.
“We need more people who are interested in doing it,” Ramsey said. “One of the reasons I like upper extremity surgery in general is that there is still a lot of work to be done, and the challenges are immense. We need people to be engaged in continuing to try to push us forward. It is important.”
According to Sanchez-Sotelo, improvements in education may push elbow arthroplasty forward.
“Elbow replacement is not common, and as such, trainees do not get to see them often,” Sanchez-Sotelo said. “In total knee, residents participate in so many by the time they graduate from their programs, they know how to do it — an elbow, not so much. We need to continue working on education so that more surgeons around the world can do a perfect job with elbow replacement.”
With the increase in the prevalence of acute traumatic elbow fractures, Morrey said traumatologists should also be equipped to replace an elbow when needed.
“The one thing I would like to see going forward is the ability of a patient who has suffered elbow trauma to either have the traumatic components fixed, or if that is not possible, replaced by the same surgeon,” Morrey said. “The way it is now, traumatologists fix fractures. They do not replace. But they do [replace] at the hip, and they do at the shoulder. The traumatologists have to be in a position to replace the joint if it needs it, and to fix it if they can. My formula is: Fix it if you can, replace it if you must.”
- References:
- Booker SJ, et al. Shoulder Elbow. 2017;doi:10.1177/1758573216682479.
- Gibbs CM, et al. J Hand Surg Glob Online. 2023;doi:10.1016/j.jhsg.2022.12.008.
- Iwamoto T, et al. JSES Int. 2023;doi:10.1016/j.jseint.2023.10.005.
- Kohls MR, et al. Hand (NY). 2023;doi:10.1177/15589447231209066.
- Prki A, et al. World J Orthop. 2016;doi:10.5312/wjo.v7.i1.44.
- Robertson ED, et al. J Shoulder Elbow Surg. 2024;doi:10.1016/j.jse.2023.07.037.
- For more information:
- Matthew A. Butler, MD, of Hospital for Special Surgery, can be reached at rennichr@hss.edu.
- Akin Cil, MD, of the University of Missouri-Kansas City, can be reached at akin.cil@uhkc.org.
- Bernard F. Morrey, MD, FAOA, of the University of Texas Health Science Center at San Antonio, can be reached at morrey.bernard@mayo.edu.
- Matthew L. Ramsey, MD, of the Rothman Orthopaedic Institute, can be reached at matthewramseymd@gmail.com.
- Joaquin Sanchez-Sotelo, MD, PhD, of the Mayo Clinic, can be reached at madson.rhoda@mayo.edu.
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