Episode Transcript
[00:00:02] Speaker A: Welcome to your Cases on Hold, the JVGS podcast, hosted by Andrew Schoenfeld and Aisha Adkeen.
[00:00:08] Speaker B: Here we discuss the best of what each issue of JBJS has to offer with the usual dose of entertainment and pop culture.
[00:00:16] Speaker A: Take us with you in the gym, on the commute, and as ever, whenever your case is on hold.
Welcome back, everyone, to your Case is on hold, episode 103.
It is April 7th. If you're listening, on the day we drop for the April 8 issue of the Journal, we are coming at you with the best and the most interesting research in the landscape today, published in the Journal of Bone and Joint Surgery. For those regular listeners, you know that what you're going to hear on this podcast are my opinions and those of my colleague, and not the opinions of the editor in chief or legal requirements as far as the board of trustees, the other constituent editors, or the staff of JBGS are concerned. This episode of JBGs is brought to you by the Miller Review Course.
Definitely. If you are going to be taking part one of the board exam or part two of the board exam or maintenance of certification or the written exam for recertification, you want to attend the Miller Review course. It is simply unparalleled in terms of the degree and extent of orthopedic education that you get in a very, very short period of time. A little bit amount of your time goes a very long way when you are wanting to do board prep or actually, honestly, I think it's like a great thing to go to just to catch up on where things are in the field. If you're in a very niche area or you're, you're just not keeping up with stuff, it helps to touch base every once in a while because as we know from this kind of research, the landscape of orthopedic science changes very rapidly. So I think it's good for everybody if you can take advantage of it and then please do so. Before we get into what we're presenting, you need to know who we are. Why don't you tell the listeners who you are?
[00:02:31] Speaker B: Aisha yeah, hi, I'm Aisha Abdeen. I'm an arthroplasty surgeon and chief of the Division of Hip and Knee Arthroplasty at Boston Medical center. And I'm also an associate professor of Orthopedic surgery at Boston University.
[00:02:45] Speaker A: I am Andrew Schoenfeld, professor of Orthopedic Surgery at Harvard Medical School and Vice Chair of Education at Mass General Brigham.
Getting into what's in the top of the pile we have Enhancing Patient Comprehension in Orthopedic Surgery, the Explain Framework for Surgeon Patient Communication by Hirschfeld, Hablas Ingles by Khalil. That's permanently free Obstacles to Spine Surgery in Limited Resource Environments by Sabali. Then the report of the 2025 Austrian Swiss German Traveling Fellowship by Scheidt and colleagues. Then we have Weighted Weight bearing radiographs of the foot and ankle by Panch Bobby.
That's what's in the top of the pile. We're now going to move into the headlines. My headline is Bracing Outcomes and Risk of Curve Progression and in Adolescents with Idiopathic Scoliosis and Autism Spectrum Disorder by Amaral and Colleagues. There is a comment, a visual summary. It's 30 days free and it's also one of the issue highlights. I thought this was really a very interesting study, very well done and underexplored area for sure.
So really good work from the team at the Texas Children's Hospital and Baylor College of Medicine, University of Iowa Hospitals and Clinics, Houston Methodist, Wayne State University and Connecticut Children's Medical Center. A nice multi center effort on that front.
Certainly in the current climate and health care environment, people are more sensitive to conditions such as autism spectrum disorder and the fact that it is a spectrum disorder and is recognized in varying degrees of penetration across a segment of the population to a greater degree than it has in the past.
As a result of that, these authors theorize, and I do believe it's true that more pediatric orthopedic surgeons or spine surgeons who deal with spinal deformity, will be coming into contact with young individuals and adolescents who have diagnosis of autism or autism on the autism spectrum.
And it is of course a spectrum disorder and there are varying degrees of effects. But amongst segments of the population with that diagnosis, the use of bracing for adolescent idiopathic scoliosis, which is the primary mainstay of non operative treatment, can absolutely be very challenging.
Some of individuals on the autism spectrum have difficulties with stimulation, so the actual wearing of the brace or changes to their previously expected regimen of daily activities, they don't necessarily handle a disruption to that especially well. So as variegated as the individuals on the autism spectrum scale can be, there can be variegated responses. Some of what they mentioned here in the report would be outbursts, just refusal to wear the brace probably being the most significant and materially damaging as far as the risks of progression. Because we do know in adolescent idiopathic scoliosis that essentially the duration of wear is one of the biggest predictors towards effectively managing the curve. That's kind of a classic Oite question. So you don't just get the Miller review course stuff here, you get the Oite tips as well.
Tell your friends, make sure everyone is listening.
[00:06:39] Speaker B: That's right.
[00:06:40] Speaker A: But brace effectiveness is dose dependent and greater adherence has been shown to reduce curve progression. So in individuals with autism spectrum disorder, which they abbreviate as asd, and I'll for convenience use that abbreviation going forward, sensory and communication challenges can impair brace adherence.
In their study, they want to evaluate the impact of the diagnosis of ASD on outcomes with bracewear.
Just full disclosure.
I think that the study was done in an interesting way. I think that the findings are very meaningful and potentially impactful.
But from a methodology standpoint, I do have to. I do feel that it's necessary for the, if only for the listeners to understand a few things because they do make some casual references and in science words mean things. And I think it's better to be very deliberate and exact about terminology that you use so there's not confusion.
And if I had to pull the coattails of the authors on this particular paper, the area in which I really feel it's necessary is in their use of their description of the analytic approach because not only in some respects is a little bit confusing, but also they use terms that don't necessarily apply in this context. So this is obviously a retrospective study. They're talking about patients who were treated for adolescent idiopathic scoliosis between 2011 and 2024.
But then they've got essentially, for all intents purposes, 58 patients with ASD.
And you know, a simple approach would be that is your predictor and the rest of the cohort is the rest of the cohort and you do a regression analysis. And I don't think there would really be a problem doing that. But they wanted to engage in a matching process, which you certainly can do. But the need for it isn't especially well substantiated. They say that patients with ASD were matched 1 to 2 to randomly selected controls who did not have ASD but otherwise met study criteria from an institutional database with use of greedy nearest neighbor matching without replacement based on the braced calc estimated probabilities of success.
They're matching based on a determination of the likelihood that they're going to have a major curve of less than 45 degrees at skeletal maturity.
And so people hear matching, they start to think about causal inference testing. This is obviously not a causal inference approach. They're just trying to find controls for these patients, but you could adjust for confounding factors between the groups in a regression. So I'm not sure that the matching procedure adds any greater degree of erudition to this, to this paper. And then they start talking about intent to treat sensitivity analyses. And this is where they really, I think, kind of diverged from the conceptual lane.
So intention to treat analyses really apply to randomized trials.
And even in the setting of randomized trials, particularly when you're talking about orthopedic surgery, it's very hard to conceptually wrap your head around them.
Just as a little bit of a segue here, intention to treat principles come out of the randomized trials primarily in the setting of medication use.
There it makes much more sense if somebody was randomized to a cholesterol medication and they took the cholesterol medication for seven days and then stopped when they were supposed to use it for, say, 90 days.
The intention to treat principle basically relies on the fact that, well, maybe they got really good effects in those seven days. You have no way of knowing. So you have to handle that individual like they did take the medication, even though they didn't follow it to the fullest extent of the trial regulation. And that's where intention to treat principles come from. It's much harder in orthopedics, where you essentially have a specific, or any surgery, really, where you have a specific intervention.
And we saw this in the SPORT trial within spine, that's probably one of the most glaring examples of it, where patients who were randomized to have surgery but didn't want surgery and didn't have it done were still analyzed in the surgical cohort, which just makes absolutely no sense. Like, how are you going to.
Right. Like, it's not like they got a little bit of the surgery. They got seven. Seven minutes of surgery. Yeah, they just did get the surgery. And so intention to treat principles.
I understand what. What they're doing here is they said that they want to include patients with ASD who met the criteria for the brace, but discontinued treatment before 12 months or maybe didn't get the brace at all.
So you shouldn't call it. You should call it something else. I'm not sure it's even a sensitivity analysis because at the end of the day, you know that the patients who are not using the brace at all, based on the AIs literature, are just not going to do as well. So I don't know what that really proves that you have this group of patients who are anticipated to do even worse than your regular cohort of patients and you just throw them in there, what do you expect you're going to find? Like they're, the cohort is going to look worse with the inclusion of these individuals.
[00:12:51] Speaker B: Yeah, exactly right.
[00:12:53] Speaker A: So ultimately at the, you know, what did they conclude? They found that the ASD group had a higher post treatment curve magnitude than the non ASD group. A greater proportion of patients in the ASD group reached the surgical threshold, 40% versus 20%. That's quite profound. Or, or had curve progression greater than 6 degrees or had surgery recommended or performed.
And in their multivariable analysis they found that ASD had over a threefold increase in the odds of progression to surgical threshold.
And the other factors, noncompliance, greater pretreatment curve magnitude, have face validity based on the prior literature.
So ultimately the conclusions are, you know, in this cohort of patients, ASD adds an additional layer of challenge, maybe an independent risk factor for brace failure. Although I would say it's probably more mediated as they say by the. It's not ASD itself, it's whether or not they're willing to tolerate or use the brace.
And someone who doesn't want to use the brace, let's just say they have like, I know it's, it's not, it's not cool to use the term opposition defiant disorder anymore. I don't believe amongst the psychology psychiatry folks. But you know what I'm getting at? Someone who doesn't have ASD but doesn't want to wear the brace because they're just that kind of teenager. I don't know, whatever. They're probably going to do just as poorly as someone who, the reason why they can't tolerate the braces because they have asd. It isn't anything about they ASD itself. I thought it was a novel question. I think they could have gotten at the same answers by doing just a standard regression approach and not having to get into the matching and the intention to treat and you know, there's a lot of moving pieces and parts in terms of their analytic approach that I think is, makes it a little bit more complex than it probably needs to be. But at, at the end of the day, overall I, I think it, it, it was interesting and important work for, for sure.
So I don't know if you have any thoughts from.
[00:15:10] Speaker B: Yeah, I mean I thought this was very methodologically sound and they had very meaningful results. You know, as with all of the non arthroplasty papers, I always learned something. I learned, you know, in particular on this One about the braced calculator online, I thought that was pretty cool that there's an online aid for patients to determine their risk of curve progression.
You know, I think it's compelling that the that ASD increase the odds of of curve progression more than threefold.
But I think it's tempered by the fact that bracing actually does work in 60% of their patients. Bracing worked in the ASD population. And so I mean, I guess the extent to which this would change or sort of clinical management is minimal, but I think it really does help in the realm of shared decision making. Right. So when you're treating patients with ASD in the setting of adolescent idiopathic scoliosis, probably tailor your approach to the patient and their specific needs based on their severity of asd. So I thought it was very, very informative on that basis.
[00:16:08] Speaker A: Yeah. And can, you know, literature is good when it can increase sensitivity to a particular condition or raise awareness. So really leading the field on that front in this particular question.
Your headline is Medial Unicompartmental versus Tony arthroplasty in the treatment of isolated anteromedial knee osteoarthritis. Two year results from a double blinded multicenter randomized trial of 350 patients by Mortenson and colleagues. It's the lead article for this issue. There is a comment, an infographic, and it's permanently free. That's the. Your case is on hold. Perfecta.
[00:16:48] Speaker B: That's right. Seems like we're staying in our respective lanes today. You with the spine case and me with the arthroplasty. This is a multicenter double blinded superiority randomized control trial.
It was performed at 10 centers arthroplasty centers in Denmark and the goal was to compare total knee arthroplasty versus unicompartmental arthroplasty for the treatment of isolated anteromedial knee oa, which they acronymized as amoa. The primary outcome measure was the average improvement of the Oxford Knee Society score over two years analyzed by an intention to treat and this is a more of an appropriate study to apply the intention to treat model.
Secondary outcomes included multiple other proms, including the Forgotten Joint Score, the COOS Score, the SF36 Bodily Pain Score. Other secondary outcomes included range of motion, revision, non revision reoperation, such as manipulation under anesthesia and death.
The study adhered to the consort statement for RCTs. The inclusion criteria were severe AMOA confirmed radiographically. They don't say much more about their radiographic inclusion criteria nor examination of the joint exclusion were non Danish citizenship, language barriers, psychiatric disorders, substance abuse, severe systemic disease, inflammatory arthritis, knee instability, lateral OA and major deficits in range of motion. I think it's interesting that no comment was made on indications such as patellofemoral arthritis or for soft tissue contractures, but I'll talk about that a little bit later.
Also, it seemed a little peculiar at first that patients had to be Danish citizens, but it was likely because all participating hospitals were public tax finance hospitals providing free access to public care for all citizens. That's also an interesting difference between the US where we have public hospitals such as where I work, where citizenship is not exactly something we're aware of. In the patient care space, the patients were randomized one to one and blinded. The patients were blinded for the first entire post operative year and they were followed for two years in total. And the analysis was conducted by a blinded senior statistical analysis and so therefore the study was considered double blinded.
The randomization was done with a software that was also used to send automated questionnaires and reminders which the authors felt led to a high response rate.
Another interesting point was the patients in the unicompartmental group all had the same implant design, brand and fixation type. They all had an Oxford mobile bearing implant which was press fit. However, the total knee arthroplasty on the other hand had any brand based on surgeon preference with a cemented cruciate retaining implant. So there was more variation in implant type in the total knee arthroplasty group.
The post op protocols were based on local institutional practices of each of the 10 institutions.
To promote a pragmatic design, an intention to treat analysis was performed and secondary outcomes were analyzed with a Bonferroni sequential gatekeeping procedure.
Subgroup analysis was performed for BMI and age and rates of revision and mortality were reported using the Boschloo test. I hadn't heard of that one before. Kind of fun to say. Bosch Lu I had to look it up. Apparently it's a more powerful unconditional exact test for 2 by 2 tables in comparison to. Probably the one that more people are familiar with is a Fisher exact test. And we're not sure if you had as our stats grew. Any thoughts? It was somewhat new for me anyway.
[00:20:16] Speaker A: New to me as well.
[00:20:18] Speaker B: So patients were enrolled. They had surgery between September 2017 and 2021. There were 1,219 patients screened, of which 176 were ineligible and 693 declined leaving 350 patients 62% of those who declined did so on the basis that they did not want a total knee replacement and exclusively wanted a uni. So I thought that was interesting too.
There were 177 patients in the uni group and 173 in the total knee arthroplasty group. In the group that had been assigned to uka, eight of them underwent total knee arthroplasty due to contraindications to UNI compartmental knee arthroplasty. However, the authors did not specify what those reasons were, presumably disease in the lateral compartment, but it wasn't exactly defined.
For the primary outcome measure, the Oxford Knee Score, which is a 12 item patient reported scale for assessing knee symptoms, function and pain. The mean improvement over the two years was 3.5 points greater for the UNI compartmental group rather than the total knee arthroplasties. While this was statistically significant, this fell short of the clinically meaningful difference or the MCID, which is 4 to 5 points for this metric.
Clinically meaningful differences in favor of medial unicompartmental arthroplasty were observed for the Forgotten joint score.
Range of motion was also better in the UNI group and the KOOS score for symptoms.
Also the SF36 for bodily pain and between group differences were greatest in the first year and then they diminished in year two.
Sequential gatekeeping confirmed significance while controlling for type one error.
At 12 months it was found that reoperations occurred in 2.3% of the UKA group and in 6.9% of the total knee arthroplasty group, and that was significant. And nine of the 12 patients in the total knee arthroplasty group underwent a manipulation under anesthesia so that was larger in the total knee group versus the uni group.
Revisions occurred in 2.8% and 4.0% of patients in the unicompartmental and total knee arthroplasty groups, respectively, and there was no significant difference in death rate between the two groups.
Patient satisfaction was higher after unicompartmental than total knee arthroplasty, especially early on.
Blinding was maintained in 89% of patients or 88.7% of patients during the first year, and their missing data was very minimal, less than 5%.
The hospital stay was less than three nights for all patients, but it was shorter in the unicompartmental knee group.
The study I thought was conducted with very rigorous sound methodology.
The authors compared their methodology to a similar trial called the topcat or the total or partial knee arthroplasty trial which found no differences at five years in Oxford Knee Society score. But they point out the TOPCAT trial was not blinded and indications varied between surgeons. One of the main concerns with this study was there are really no guardrails on indication in any way. And it's true that surgeons are moving away from the classic Cozen and Scott criteria. You know, defined in 1989, a patient age more than 60, low demand lifestyle, no inflammatory arthritis, minimal angular deformity, minimal flexion contracture and an intact ACL, and no patellofemoral arthritis. So even though we're going away from those criteria, there's still varying degrees of deformity and severity and soft tissue contracture. So it seems it's almost implausible that the very severe deformities could be treated as equally with a medial uni as they could with a total knee or arthroplasty as someone with really mild wear in the medial joint space. So I think there may be some apples and oranges here that we're not able to really hone in on in the way that they describe the outcomes. Historically, patients younger than 60 had a higher likelihood of revision than older patients. And as with heavier patients, the study, the authors did do a subgroup analysis on the basis of age and bmi, but it wasn't very in depth. They sort of compared patients over the age of 70 with those younger than the age of 70 and, and with BMI less than 30 or over. So it's kind of very broad strokes and did not find much of a difference.
If you read the fine print on Table one, the paper, you'll see that the majority of the patients were younger than 70 and the majority of the patients had a bmi less than 30. So that may not reflect populations in all areas in all hospitals.
Ultimately, the take home here is that unis outperformed total knee arthroplasties in the first two years, most notably in the first 12 months after surgery for medial and osteoarthritis of the knee. With respect to most patient reported outcomes, range of motion and the likelihood of a manipulation under anesthesia, this is meaningful.
However, the main goal in arthroplasty, I would contend, is long term pain relief and implant durability.
So ultimately, this paper is not going to change my clinical indications for a total knee arthroplasty versus a medial uni. However, most long term evidence shows 10 year survival of unis to be lower than that of total knee arthroplasty. So I'm really weighting the 10 year data on this particular cohort. And I think that longer term follow up would have more of an impact on clinical decision making in this particular instance. Amber, what are your thoughts?
[00:25:42] Speaker A: So a few things I think it very well done from a randomized trial, like the methodology, the messaging, all that great.
I think you already touched on several of the points that I was thinking about in terms of the broader reach in clinical application.
One thing my impression was that after the surgery, the patients knew what they had. They knew if they had an MUK or total knee, right?
[00:26:08] Speaker B: No, they didn't. That's what's crazy. They didn't know. And of course the surgeons knew, but they weren't the investigators. The investigator didn't know. And they did the incision in a way that in the medial arthrotomy. So that the patients didn't know. And they said for one whole year, 80, almost 89% of them remained blinded in the first year.
[00:26:28] Speaker A: Okay, right, right, right, right. So let me ask you this. And these are some conversations that I had with Antonia, of course, because arthroplasty was her domain as well on earlier episodes.
This is for isolated anterior medial knee osteoarthritis. And I will say, you know, we talked about Kaiser Soze paradigm in the past. I think this is a Kaiser Soze paper. I could totally see on the oite or part one of the boards, they're being like patient presents.
They're showing you imaging or whatever it is, but they basically make it clear that lateral patellofemoral, they're all good.
What's the best surgery.
And those who do not select MUKA will suffer the consequences.
I can see that, I can totally see that. But I agree, and so correct me if I'm wrong on this, but for patients who are of a larger body habit, it's bmi. There is some concern about doing just a unicompartmental. Right?
[00:27:32] Speaker B: Yes. And that gets back to those Kozan Scott criteria. Right. So over 90 kilograms was a concern.
Higher demand patients. So by definition younger patients, although that's subject to debate now. And all of those criteria are being debated, which is why this is a hot topic. But I would be more interested in stratification of were there any outliers. And they really kept their sort of demographics tight because the majority, more than 60% of the patients actually had a BMI of less than 30 in this group. In both groups.
[00:28:06] Speaker A: I don't see a lot of patients with BMIs under 30 in my right. And, and so how much this is really Broadly applicable to the US demographic or different states and things like that I think is open to question. And then the other part is, you know, in this situation, what they're not looking at is like you said, the long term durability of the implant. And in, in some populations they're willing to sacrifice a smaller thing up front as a value proposition against needing another surgery maybe sometime down the road versus like I just want to have one procedure and then not have to worry about more surgery in the future. So those are considerations that you can't really have in this, in this environment. This is just a randomized trial. Not just randomized trial. But those parameters don't get considered in randomized trial.
[00:29:02] Speaker B: Absolutely.
[00:29:04] Speaker A: All right, so moving on to the your cases on hold featurette. This is physical activity and four year radiographic medial joint space loss in knee osteoarthritis.
A joint model analysis. This is by psy and colleagues with a comment and a highlight and 30 days free.
Just missed the perfecta on that front.
I don't know about you, but when I started reading this, I had to read it several times.
It was complex to say the least.
And you know, for the interested reader, when we get the articles that JBGS is publishing, we kind of look through things to select what's going to be the your case on hold featurette and what's available for other things.
And as I was reading this, I was like, I wish we had gone with the article that you just presented, Mortensen for the featurette. And I was like, why am I doing this? Oh man.
So I think it's an interesting study and the concept is really interesting, but it is just there are so many layers. It is like reading a Clive Barker novel.
Like, are you see, are you in the matrix on this? Like, I mean, this is like they wanted to assess the role of physical activity in knee osteoarthritis progression as conventionally defined by joint space loss. So they had over 1800 patients from the Osteoarthritis initiative and they measured physical activity with the physical activity scale for the elderly and then categorize that as low, moderate or high. And then they're measuring the joint space loss defined as a reduction in joint space width of greater than 0.7 millimeters stratified by baseline, Kellgren, Lawrence Grade.
And then sort of looking out on this, this data set which is collected, you know, independently of These authors, over 48 month time interval and all that is great. Like you read that part, good to go. But then when you get into the statistical analysis section, it is, there is just so many moving pieces and parts, so many comparisons.
The pay score with residuals, the proportional hazards with residuals.
Incidentally, Schoenfeld residuals, not me, I don't get any.
[00:31:51] Speaker B: That was my question.
[00:31:54] Speaker A: I don't get any royalties off of the Schoenfeld.
The interaction between the physical activity and the Kellgren Lawrence grade. Then they apply two types of the proportional hazard models to examine the association of baseline physical activity and joint space loss. And the first one has a cluster term and then the second one has a penalized cubic spline.
And like, I mean I'm thinking like, if I'm not getting it, like other people are just, they're going to read like three sentences of the methods and maybe just like, okay, whatever, what did they find? Which is a valid question in this context and, and very nuanced. So in patients with Kellgren Lawrence 2 grade, moderate physical activity was associated with reduced joint space loss risk compared with low physical activity.
Then patients with the KL3 grade, increasing physical activity in their continuous modeling was associated with increased joint space loss risk. However, their like findings, while it is statistically significant, the hazard ratio is like basically one point. If you rounded it to, if you just limited it to two significant digits after the decimal, there's no impact, it's 1.00, which is the null.
So the rate of change of physical activity over time did not significantly influence progression. And their conclusions is basically that moderate or high physical activity did not increase the four year joint space loss risk in patients with KL grade two, the lower grade. So fine. However, they have the caveat that high, higher current physical activity was associated with higher joint space loss in patients with KL grade 3, highlighting the need for further research on the complex impact of physical activity and osteoarthritis. They postulate that their findings would help clinicians identify subgroups that might benefit from tailored physical activity recommendations informing value based care and personalized osteoarthritis management.
And that part is probably the part that I would put on hold more definitively.
So this is, it is a longitudinal study, but it's also a cross sectional study if you're considering it's 48 months over the course of the lifetime of a patient.
And we're basically like ignoring everything that these individuals have been doing or have done over the course of whatever time it was preceding the time where the study started. So I mean those who, this is a, a very common paradigm where like you look at These, you know, Kellgren Lawrence Grade is an artificial construct. Like, the knee doesn't know what it's. Kellgren Lawrence Grade is like. Like, this is a construct that we use to help us interpret and communicate findings. Yeah. Front. Right. It was not, you know, created at the beginning of the world as some type of immutable employee. Right. So the difference between what is a KL grade two in someone who is 65 versus someone who has a KL grade three when they're 45, those are very. Those knees have lived very different lives.
[00:35:11] Speaker B: 100%. Yep.
[00:35:14] Speaker A: And then saying that, like, that individual if they're doing more activity, or this individual if they're doing less activity, there are just so many, like. It's an interesting study, but I don't believe any of these findings at the end of the day, for all of these reasons are really clinically informative. I would. I wouldn't tell a patient, you know, not that I treat people for knee problems in my practice, but, you know, as a corollary, if someone had grade four degenerative disc disease with the same kind of findings versus Grade two, I wouldn't tell the grade four person, do less activity, because it's just going to make your situation worse. Right.
[00:35:52] Speaker B: It's so counterintuitive.
Yeah. I mean, I. I'm happy that you felt the same way. Actually, I felt very similar after reading this. To me, it felt like War and Peace because you keep going back. What was that? What was that pathway? What was that story and all the characters? So, yeah, it was. It was convoluted. But, I mean, I have to hand it to the authors. It's a really tough time topic and it's an interesting premise. Right. The notion that physical activity can cause OA to progress seems to be something that patients anyway, especially lay people, tend to believe at face value. I can't count the number of times that patients say to me, you know, yeah, doc, my knees are all worn out because of X, Y or Z that I did when I was 20 or over the years of recreational sports that they've been engaged in over the course of a lifetime. So, you know, we know that obesity is directly related. We know that our sedentary lifestyle may contribute to our OA progression by way of obesity. We speculate there might be some genetic link, but we don't know what it is. But the notion that moderate exercise causes osteoarthritis progression is kind of scary and also fascinating. It's never been definitively proven, so I think it's a topic worthy of study, but it's really a hard one to study well.
It's also one of the things I had issue with. It's really hard to measure true differences in joint space from one radiograph to the next. Different angles, error of measurement, parallax.
The authors were measuring a difference of 0.7 millimeters on an X ray, which I would argue is really difficult to measure accurately. Patient reported activity is also questionable in terms of reliability because there might be overestimation, underestimation and also some recall bias of the patient's activity.
I even teach the residents as well that the KL classification is what we have and we use it, but it's inherently subjective. It does have a lot of inter observer reliability, unreliability as well as intra observer reliability. So for instance I might call something a grade 2 on an X ray and then at a later stage considered a three. And so there's not a whole lot of reliability within those two stages. Specifically more reliability between 0 and 4. But between 2 and 3 which comprise the entire group of patients in the study. It's really different to distinguish between those in the first place.
And I think as you've mentioned there findings were quite fragile in terms of the differences. So I certainly wouldn't change my practice and tell patients with a grade 3 OA that they should be less active, particularly in the context of moderate activity. So for me this case still remains on hold.
[00:38:19] Speaker A: Perfect. All right, that's two for two on that front.
Next we're going to move into the honorable mentions. We have sex based differences in cell types and gene expression within the anterior cruciate ligament by Garcia and and colleagues with a comment and this is permanently free, so you don't have to take my word for it. You can check it out yourself. The authors hypothesize that cellular differences in human progenitor cells contribute to the higher ACL tear risk observed in females. They had ACL samples collected from four male and five female patients undergoing ACL reconstruction. They discovered sex based differences very interesting in all of the native cell types within the acl.
In particular, they identified the fibroblast progenitor like cells from female patients and found that these expressed genes associated with dysregulation and degradation of collagen more highly than those progenitor cells in male patients. They speculated that the differential gene expression among this TPP3 positive progenitor like cells provides a possible target population for studying with a menace injury and regeneration and also provides evidence of specific genes that could be therapeutically targeted in the future to strengthen the ACL and or reduce the risk of rupture, particularly among female athletes.
That is about all the time that we have. We'll try to do better next time. If you like what you heard, like, subscribe. Hit the notification bell.
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Jumanji. We're doing Jumanji next episode.
[00:40:36] Speaker B: Love it. Thanks everyone.
