Episode Transcript
[00:00:03] Speaker A: Welcome to your Cases on Hold, a JBJS podcast hosted by Antonia Chen and Andrew Stonefield.
[00:00:10] Speaker B: Here we discuss the science of each issue of JBJS with an additional dose of entertainment and pop culture.
[00:00:17] Speaker A: Take us with you in the gym, on the commute, or most certainly whenever your case is on.
[00:00:28] Speaker B: Welcome back to another episode of your cases on hold, number 96. This is the end of 2025.
Almost made it to the end and ready for a start of a new year. I'm Antonia Chen, Executive editor at jbjs, and I have here.
[00:00:46] Speaker A: I am Andrew Schoenfeld, Associate editor for Methods. I work in the back. I see no smiles.
[00:00:53] Speaker B: Well, I'm smiling at you right now. So you're getting one now.
[00:00:56] Speaker A: Because the year is over.
[00:00:58] Speaker B: The year is over. So you know, it's a time for celebration, a time for reflection. I'm going to reflect on the end of the season. It's a time of gift giving, and so what better thing to do than give the gift of jbjs? Learning so many things to learn through jbjs. Multiple different pathways. Clinical classrooms is great. Not just for residents, not just for trainees. But the clinical classroom is actually really good for attendings as well too. So jbjs clinical classroom, give it as a gift. You'll make people happy.
As usual, the opinions of this podcast are our own. Do not reflect JBGS in any way, shape or form. And without further ado, we're going to start with top of the pile. Medical Malpractice Litigation, Orthopedic Surgery in the United States. Risk Factors, Outcomes and Strategies for Navigating Lawsuits. Prevention and Reform by Bufadel et al. This is the lead article Right out the Gate.
Heads, Hands and Heart by Aretz. It's permanently free.
Is it enough? Disclosures of Medical Industry Payments, Orthopedic Surgery Journal Editors and the need for Transparencies by Riddle.
Human Carpentry. Exploring the Parallels between orthopedic surgery and Woodworking by Jane.
The Urgent need for musculoskeletal Risk Research in youth. Concussion Protocols by Hyde.
A New Angle and Outcomes. Introducing the win Ratio to Orthopedic Research by Bhavosky. It's a highlight and there's a commentary on it as well.
What's new in Musculoskeletos? Cultural Basic Science by Bahani. It's permanently free.
And appreciation 2025 by Clark. It's also permanently free. It's our end of the year tribute to all those who contribute to jbjs. So thank you for all of you who are listening first for listening and two, if you contribute to jbjs, we'd like to thank you for that as well.
Marvin Tile, MD, FRCS 1933-20.
It's a tribute. It's also permanently free.
We're gonna start off with the headlines. Dr. Schoenfeld, please tell us about Bezothermin Alpha RHBMP6 administration in Lumbar interbody fusion surgery using a posterior approach. A randomized double blinded placebo controlled phase 2 study by Lee et al. There's a commentary, a highlight and it's free for 30 days.
[00:03:15] Speaker A: Yes, absolutely. So this research, as you mentioned, was done by Dr. Wei Xi Li and colleagues, including some colleagues from California and researchers in Croatia and in Canada as well. Dr. Lee was a research fellow at the same time that I was a clinical fellow at MGH many decades ago.
Good to see him continuing on his research trajectory.
This is a study that is a report of a randomized trial looking at novel osteoconductive and osteoinductive therapies. Which is the Bizio termin alpha used in posterior based lumbar interbody fusion, either transforaminal lumbar interbody or posterior lumbar interbody fusion, the so called TLIF or PLIF. This is a recombinant human bone morphogenetic protein BMP6.
The more common is BMP2 which does have it is widely used in spine and has been for several decades now. But it's not without some challenges.
This study evaluated safety and preliminary efficacy of biziotermin carried by autologous blood coagulum termed ABC in the article in patients undergoing a lumbar interbody fusion. This is single level elective lumbar interbody fusion. There were six clinical trial sites in China and they were randomized 1 to 1 to 1 to placebo 0.25 milligrams of bizioturmin or 0.5 milligrams and then followed for one year.
[00:05:04] Speaker A: The BMP6 is mixed with autologous blood coagulum as a carrier and it's introduced into the inner body area during the surgery.
It has higher specific osteogenic activity than the more conventional BMP2 and it's anticipated to cause fewer complications.
BMP2 can result in heterotopic ossification. It can result in nerve irritation.
There are some problems with sometimes increased swelling seroma formation.
The patients in this study underwent TLIF or PLIF at the surgeon's choice.
This had pedicle screw fixation.
They Prepared the disc space and then 1 millimeter of the intervention, whether it was placebo or the dosing of bizioturmin, was prepared and put anteriorly. Then the disc space was packed with local autogenous bone graft. They put in the interbody spacer and then the remaining two mls were applied into the disc space and then bracewear was required for three months after surgery, which is a little bit different than how we conventionally most people would manage a one level instrumented fusion. But nonetheless it is a choice that is not unknown.
So at six months, the success rates for the three groups were 60%, 74% and 80%. 60% for the placebo, 74% for the low dose and 80% for the high dose of the BMP6. At 12 months, 91% of placebo patients, 90% of the low dose and 100% of the high dose group had achieved radiographic fusion.
They reported nonunion in two patients in the placebo group and two patients in the low dose group at 12 months.
Their conclusion is that this is safe and well tolerated during posterior based single level lumbar interbody fusion. And then they speak to some preliminary efficacy in improving clinical outcomes, which I think is a fairly weak conclusion, certainly within their sample size, which was 63 patients, 21, 20 and 22 in each of the different cohorts, 21 in placebo, 20 in the low dose and 22 in the high dose.
So I would consider this more of a, it is a randomized design, but it's more of a pilot study. It's very small numbers when you're talking about safety and efficacy. When we're thinking about the things that you see with BMPs, heterotopic ossification, infection due to seroma, sterile or otherwise, that then get seated, things of that nature, postoperative radiculitis and neuritis, even though those are known to occur, they're not especially common. You're talking about 5%, 2%, 1% rates.
And so when you have just 63 patients in total, I don't, you know, the fact that none of those things happened doesn't necessarily mean that they won't happen.
Further, when anything is a hundred percent, nothing is never, and nothing is always even, just solely and entirely due to the potentialities for chance to inform things. So when they say there's 100% fusion rate with the high dose physiothermin, that's unlikely to hold up if you started applying this in much larger numbers. So an interesting study that suggests the potential for further research.
BMP2 is very expensive and restricted in certain areas in terms of how it can be applied.
I'm sure that would be the case here as well. The placebo group did quite well in terms of their fusion at 91%.
I don't know if the costs in these types of patients are fully justified. When you get into the added cost of these types of biologics and their use as supplements and adjuncts to standard interbody fusion, would you use this?
No, I think that we do quite well with what we have right now for interbody fusions. There are certain high risk patients where you're going to need some additional assistance in terms of enhancing the proclivity for fusion. I think this is just very preliminary data.
I think the BMPs in general are known to have a certain type of complication profile. I think if you did this in larger numbers you'd probably see more of that.
[00:10:01] Speaker B: All right, good to know.
Interesting studies but practical applicability Whole new thing.
My next article is also a question about practical applicability, but an interesting topic. Post operative abstinence restores osteointegration impaired by ethanol consumption in a murine tibial implant model by Doring et al. There's a visual summary of this as well. There are plenty of studies looking at the effect of alcohol consumption on bone health. Previous studies have shown that alcohol can increase osteoporosis and negatively affect fracture repair. This potentially could affect the ability of an implant to ingrow into a bony bed. However, some of the clinical studies have inconclusive results with regards to osseointegration of implants with regards to alcohol consumptions and the effect of alcohol consumption on implant oscegration.
This study was looking at ethanol consumption and implant osteointegration using micro ct, histology and pull out testing. They used a mirroring model of ethanol use disorder. How did they do so well? What did it ask? First they asked if ethanol consumption impaired osteointegration and the strength of the bone implant interface in a load bearing tibial implant mirror model. And to what extent does postoperative ethanol abscess influenced osteo integration? I think that was the biggest differentiating factor of the study is that there was an abstinence factor of it.
There were adult male mice that were randomly assigned into three groups. Note there were no female mice, it was just male mice.
Control had 25, ethanol had 20 and abstinence had 22. Control group got water throughout the whole course. They lived a boring life but they got water. The Whole time. The ethanol group had ethanol water throughout the entire study period.
3 months pre op and 4 weeks post op. And then the abstinence group got ethanol for the 12 weeks prior to surgery, but then had no ethanol after surgery. So the abstinence didn't come before surgery. The abstinence only came up for four weeks after surgery.
The concentration for the ethanol and abstinence group was 10% for the first six weeks and then increased to 15% for the remaining six weeks. So they wanted more alcohol or they gave them more alcohol during that time frame. Now, they didn't actually quantify how much alcohol that they took. Remember the alcohol was in their water, whether or not they drank it. They clearly had to drink something because also they would have no hydration. But they did quantify the amount of alcohol that they had. So during surgery, what did they use for their osteointegrative substance? It was a titanium alloy with the porous stem, so it allowed for osteointegration. And there's a smooth top that articulated with femoral condyles. This is a load bearing implant. The ACL was excised, Both mendici were resected. They used a bur to remove the top 300 micrometers of the tibial plateau. And there was a 0.9 millimeter hole that was drilled into the medullary canal. And the stem was then press fit into the medullary canal until it's flush with the proximal tibia. So a little bit of partial knee replacement, tired tibia. For this murine model, osseointegration again was used by micro ct, biomechanical pull out tests and histological analysis.
What happened? Mice in the ethanol group had reduced peri implant bone formation compared to control mice. They had a lower bone volume fraction and this is both on histology and micro ct. Ethanol mice also had a higher percentage of fibrotic tissue area.
Biomechanic testing demonstrated a weaker bone implant interface in the ethanol group compared to controls and this is measured by the maximum failure load and work to failure.
In contrast, abstinence or post operative abstinence restored the peri implant formation measured by bone volume and total volume and bone implant interface strength to levels similar to those in the control group. As the maximum failure load after abstinence was significantly higher than mice who continued ethanol consumption and they were comparable to the control group. What's this conclusion from this murin model?
If you take ethanol consumption for 12 weeks prior to it and you continue it for four weeks afterwards, it can potentially compromise implant osteoagration in mice. Again looking at the formation of bone based on volume.
That said, if you abstain, meaning you stop alcohol and you don't drink it, four weeks after surgery, it can recover the peri implant bone formation and interface strength. So is this translatable to clinical research? Hard to say. Remember this only concluded male mice patients or these mice were only followed for four weeks, which is not a long, long time if you're talking about osteo integration. I always tell patients it takes at least six to eight weeks to really get it. The beginning of the integration and bone turnover is constant. So is four weeks enough? Can we translate this to clinical practice and say, you know, if you're drinking alcohol, at least stop by the day of surgery and make sure that you decrease that so you can get ingrowth of your cementless implants. Whether it be a hip, knee or whatever, the cementless parts are there. But a longer timeframe of follow up would be interesting to really see the osteointegration. But it was interesting the preliminary results and see that you can make this a modifiable risk factor.
[00:15:08] Speaker A: So the first thing I would say is that when you look at their clinical relevance, their clinical relevance is future clinical studies are needed to assess the impact of preoperative postoperative abstinence, which is that's not actually the clinical relevant. Like you could have said that without the benefit of this study. And it's not the clinical relevance, the clinical relevance is that this is suggesting that there is some negative impact of ethanol. I think that part you can take away from this. What you can't really say and what isn't translatable is what's the timeline? Because mice are not people and their physiology is entirely different, you can't set any definitive timelines. I think it makes sense that by not consuming alcohol in any time period in perioperatively, you're going to likely improve the environment, the physiology and the patient's physical status for recovery across the board. And things that go beyond the bone even. I mean, definitely food for thought and something very interesting. I don't think you can create any testable or clinically applicable guidelines from this. However, as it stands right now.
[00:16:23] Speaker B: Agreed. More to come, I guess.
Anyway, so next one is looking at a randomized controlled trial of a conventional versus modular dual mobility bearing. Are serum metal levels of concern by Debinetti et al. There's an infographic and it's free for 30 days.
This is a study out of Rush based on the concern that if you do modular dual mobility, can there be increased levels of metal ions? Why do they happen? There's potential, what they call tribal corrosion at the interface between the cobalt column acetabular liner. So whenever you do mobility, at least historically, you would put this liner in there and the liner itself would be made of cobalt chromium through a cobalt alloy. And you put every shell out there is titanium. So you put dissimilar metals together and by doing so you can actually create metal corrosion.
And so is this a concern for patients? If you do get metallosis, you can have neurologic cardiac other implications. People will say the metal on metal scare. People did not use it because of women in childbearing age, for example, because metal can cross the placenta border.
So the question remains whether or not the junction between this modular cobalt ally liner and the alloy liner and the titanium shell can lead to clinically relevant increases in cobalt and chromium levels. So the purpose of the study was to evaluate these levels and they included titanium. So cobalt chromium titanium levels in patients have a total hip arthroplasty with a conventional total hip replacement compared to dual mobility bearing. This was a randomized controlled trial. The secondary aim was to compare prom score between the two cohorts and these included SF12, the Harris Hip score and the HIP Disability and Osteoarthritis outcome score, or jr, which is the HOOSH jr, the SANE score and the UCLA activity score. So there's a lot of outcome measures that were evaluated.
The key factor here, at least in my mind, is not all dual mobilities are made the same. So they made a very good point here that those who got the conventional versus the dual mobility had the same basis or basic implant. So what they used was the G7 acetabulous shell and a taper locked femoral stem by Zimmer Biomet. They used computerized random number generator to assign patients to either the conventional modular dual mobility. They both got a ceramic femoral head and patients were blinded prior to surgery. Two fellowship trained arthroplasty surgeons did all the surgeries through a posterior approach. So there was uniformity in that cold and chromium levels were measured preoperatively and annually at one through five years. Postoperatively, 53 patients were enrolled and randomized. But at the end of it, there were only 41 patients who were included in the analysis, which we'll talk about in a little bit. The authors state that the two cohorts didn't really differ in terms of demographics, but I feel like the percentages were quite different. So in the conventional bearing one, meaning non dual ability, 76% of the patients were white and then the split of male female was pretty equal. 48% male and 52% female. However, in the dual mobility cohort, 86% of the patients were white, but 79% of the patients were male and 21% were female. I would think that if it was a randomized controlled trial, those would have been divvied out. And typically patients will say that maybe in a young, active, flexible female they're more likely to do dual mobility. But here the dual mobilities were much less women. An a priori power analysis determined that 20 patients per cohort were needed to detect a 0.35 nanograms per milliliter difference in serum cobalt levels using a standard deviation of 0.31, 90% power and alpha 0.5 to account for a 30% drop rate. That's why they had a target enrollment of 52 patients. I will say that think of that number 0.35 detective difference. That difference is a pretty large difference when it comes to these serum levels. So again, remember, we only have 41 patients who are randomized, 24 with the modular dual mobility and and 17 were conventional and the minimum follow of two years at both one and two years postoperatively. Serum cobalt chromium titanium levels did not really differ between groups. However, in the dual mobility cohort the serum cobalt levels increased significantly at one and two years postoperatively compared to preoperatively. However, there was no significant difference in serum cobalt levels between one and two years postoperatively within the dual mobility group. Serum chromium levels also changed significantly within dual mobility cohorts at both one and two years postoperatively, with the one year postoperative value significantly greater than the two year value.
In the conventional group, serum cobalt levels increased significantly from preoperative to one year, but there was not really a difference between one and two years and there were no significant changes in serum chromamine levels. There's really no issues with titanium. Titanium and this titanium did kind of follow the levels there, but not to the levels of cobalt and chromium. Neither patient in the cohort had cobalt or chromium levels of greater than 1.0 nanograms per milliliter and no patient had a serum cobalt level outside the reference ranges. There were statistical differences in proms at the two year follow up. For a Harris HIP score, dual mobility was higher and Hoosh jr, where again, dual mobility was higher.
However, they did not meet dual. The minimally clinically important difference.
There were no intraoperative or postoperative surgically related complications in either of the two cohorts and no implant showed radiographic evidence of loosening. All patients had retained the primary components at the minimum follow up of two years, including the patients who had received metal iron blood draws outside the study window. There were no significant difference between one and two years in these patients. Both conventional durability.
There was an elevation in cobalt and chromium, which is known in this dual mobility cohort because of the mismatching of metals, but the threshold did not go above 1 nanogram per milliliters. Again, this is a small sample size. Remember, the sample size calculation was calculated on a difference of 0.35 which we didn't reach here, between groups. The difference between sex, even though it was randomized, was concerning.
The study is a randomized study. It does look at serum levels, it does look at it prospectively, but I'm not sure it's necessarily saying to people, you know, go ahead and do these constructs per se. I'd love to know your thoughts are.
[00:22:41] Speaker A: Yeah, I thought the finding where they comment suggesting accelerated metal release during an initial run in tribal corrosion or bedding in interval that then decreases or becomes more negligible over time.
I thought that was interesting. I'm more interested in your thoughts because polyethylene just seems to work so well.
We keep trying to like find things it seems that do better, but it seems like you can approximate but. But never really exceed. Is that a fair calculation?
[00:23:15] Speaker B: I mean, if you think of durability, durability has polyethylene in it too. So you have the line or you poly. So polyethylene is always a good thing to have, I'd say. I mean dual mobility came onto the market for decreasing dislocation risk. And so I think polyethylene is still king or queen, whichever way you're going to look at it. Now, that said, polyethylene is meant to adapt to different size heads and there are systems out there that have 36, 40, 44 heads. You're talking about a pretty big head. And so does it add to the same benefit of dual mobility? I think it really depends on your cup size. They did note that as a restriction though, if the cup size was under 48, they couldn't include them in the study because there was no dual mobility. That was for that cup size. But you're right, polyethylene works and total hips work really well. I think it was a big flare where dual mobility was used by a lot of people. For every primary case, they were scared of dislocation. As we've done more technology and put cups and implants in places that reduce the dislocation risk, do we need to have as much dual mobility? I think the use of dual mobility has decreased. Personally, I use dual mobility more in revision settings than I do anything else and not the primary setting. So this is just good information to know. There was a huge scare with the metal and metal implants. And so, you know, patients do ask, they're like, oh, if I do get a doability, what's it going to look like for my metal levels? And you can say here in the small study of patients that it didn't exceed a clinical significant threshold potentially. But elevated metals can still wreak havoc other ways.
[00:24:47] Speaker A: And then, you know, with the ceramic femoral heads, there's, there's the squeaking issue. And they can crack, right?
[00:24:55] Speaker B: If it's ceramic to ceramic, that's the key factor. So you do ceramic to poly. As you say, it's pretty nice. Now I will say this is the second generation of ceramic that's out now. It is much harder and much tougher and stronger than the last generation. So it's very few cracking, very few issues there.
[00:25:11] Speaker A: Okay, great.
[00:25:13] Speaker B: All right, honorable mentions.
Five year radiographic and clinical outcomes of pyrocarbon hemiarthoplasty for glenohumeral arthritis and osteonecrosis by Griswold et al. It's permanently free. This study looked at the progression of humeral head medialization in patients who underwent pyrocarbon hemiarthoplasty and patients who underwent this procedure with greater than 60 months of follow up were included in this prospective study. This study found at five years that this pyrocarbon hemiatoplasty is a reliable procedure for treating glenohumeral joint disease and it demonstrates excellent clinical outcomes and stabilized glenoefology in the majority of patients between the two year and intermediate follow up of five years and finally normalization of subchondral bone density patterns after surgical treatment for capitellar osteochondritis desiccants. A qualitative analysis by Miyamura et al and there's a commentary on this capitella, osteochondritis dissecans or OCD is a common is common adolescents who are throwing athletes. However, the relationship between bone density and clinical outcomes after OCD treatment is not well known.
This included 51 male ethnic Japanese patients who had capitellar OCDs that were treated surgically. They looked at the relative bone densities as proportions in the distal humerus, radial head, proximal ulna and they're compared in preoperative, postoperative and contralateral elbows at the respective anatomic sub regions. The surgical treatment of Capitella OCD was found in the study to effectively restore the subchondral bone density distribution to normal patients. Regard to the level of normal patients, regardless of the surgical technique that was done, patterns in the subchondral bone density in the regions were comparable between the reconstruction and preservation groups across all conditions. Improvements in Timmerman Andrew scores correlated moderately with bone density normalization at the lesion site and surrounding sclerotic bone, providing quantitative evidence supporting the efficacy of surgical intervention of these advanced OCDs. So in your athletes please go ahead to use them. It's been useful.
Thanks so much for dialing in again. Happy New Year. Happy whatever you celebrate. Happy New Year everyone and we will see you in 2026.
[00:27:23] Speaker A: It'll be another new Year but your case will still be on hold. Can guarantee.
