PCPs Diagnosing Osteoarthritis of the Knee

Peter L. Salgo, MD: When we talk about this, you folks see it every day. You actually see it at the endpoint. I feel a certain sympathy for the folks out there, in the real world, who are in their offices—the frontline physicians. They see all-comers. First, there’s a pregnant woman. Next, there’s somebody with strep throat. Next, comes somebody who says, “I can only walk 18 holes a day.” What do the frontline doctors need to know? What is the take-away message on diagnosing and caring for this?

Richard Iorio, MD: Normally, we like to see something. Then, we like to treat it. Or, we like to refer to a specialist, for definitive treatment. Unfortunately, in osteoarthritis, that treatment is going to span a large amount of the life expectancy of that patient. So, when they’re first diagnosed, if they exhibit the symptoms that Paul was speaking about—they have discomfort, or stiffness, or pain, or disability associated with an activity—we need to rule out the other problems that could be associated with that—inflammatory arthritides, etc. Those are done with some simple lab tests. But if an X-ray is taken and osteoarthritis is seen on the X-ray (the typical spur formation, narrowing of the joint space, deformity of the limb alignment), and the primary care doctor, or the frontline doctor, can treat that patient with simple, conservative measures—physical therapy, over-the-counter anti-inflammatory drugs, ice, heat, small braces, etc—that’s great. If the patient needs more than that, they should refer them to an orthopedic surgeon, a rheumatologist, or a specialist in osteoarthritis who can decide if further imaging is necessary. Most imaging is only necessary if they have another set of problems, such as instability.

Paul Lachiewicz, MD: Peter, I’d like to emphasize what Rich said. Often, we see patients referred (from a primary care physician), with MRI scans. They have not had plain radiographs. One take-home message to the primary care physicians who are watching this is, if you’re going to order some imaging, get a standing X-ray first.

Richard Iorio, MD: A weight-bearing X-ray. Correct.

Paul Lachiewicz, MD: Yes.

Peter Salgo, MD: Why?

Paul Lachiewicz, MD: Because, sometimes you won’t pick up narrowing of the cartilage of the knee joint in a supine or non—weight-bearing film.

Andrew Spitzer, MD: I would even push that 1 step further. In my practice, I actually get single leg weight-bearing X-rays. Because, unless you’re a kangaroo, you walk on 1 leg at a time. The bottom line is, that’s the physiologic functional test that you can do, very easily, to know what’s happening with your patient.

Peter Salgo, MD: As I understand this, if you take the load off of the joint, then the joint can get a little larger?

Paul Lachiewicz, MD: It can. In advanced osteoarthritis of the knee, if it’s bone on bone, I’m not sure the non—weight-bearing X-rays are going to be a lot different. It’s very interesting. I don’t know what it’s like in the Northeast, but, in the South, most of the internists are not even ordering X-rays. They’re referring the patient on.

Peter Salgo, MD: Does that make any sense?

Richard Iorio, MD: It depends on the insurance model, right? It depends on whether they’re in a capitated system or some sort of a system that dissuades them from spending any more money.

Peter Salgo, MD: Let’s take money off the table. Clinically, does it make sense to not get an X-ray, and to say, “Oh, your knee hurts? Go there.”

Andrew Spitzer, MD: The rationale is that you have 30 seconds to make a decision, as a primary care physician. You have a patient with knee pain. You want to get the maximum amount of information from a single test. Unfortunately, when you get a MRI, it’s like looking at an elephant under a microscope. Until you pan out and say, “OK, what are we really looking at here,” with a plain X-ray, and with a good physical examination, you don’t really have a sense as to what to do with all of that information that you get with a MRI. That’s the problem, whether it’s economic, or intellectual, or clinical, that we find ourselves in when a patient presents with a MRI but no basic information.

Paul Lachiewicz, MD: For the primary care physicians, if they’re pushed, if the patient is not that disabled, maybe they can just go on to the nonsurgical treatments that we’re going to talk about, first. Then, if that patient doesn’t respond, and he or she calls the office again, get an X-ray and refer.

Richard Iorio, MD: Part of the issue with getting the advanced imaging before you get the primary indicated imaging is that there are a number of diagnoses associated with a MRI and with osteoarthritis of the knee that may not need to be treated as the primary issue.

Paul Lachiewicz, MD: Absolutely.

Richard Iorio, MD: For example, a MRI may show a meniscal tear. It may show degeneration of the anterior cruciate ligament. It may show cartilage damage. It may show loose bodies. If the patient doesn’t have symptoms associated with those diagnoses, they’re not going to need surgical intervention. But once that diagnosis is told to the patient without context, it becomes a real issue. And the internist isn’t really capable of making that clinical decision. For example, every single osteoarthritic knee, after a time, has a torn meniscus. All of them—whether it’s degenerative or not. The trick here, and what we get paid to do, every day, is to figure out which of those symptomatic ones need treatment in a different way. That’s a very difficult decision.

Peter Salgo, MD: So, again, it comes back to being a doctor and not a technician. The MRI, in my experience, is a great tool. It sees everything. But, sometimes everything is not what you need. Or, to quote Dr. McCoy, “I’m just an old country doctor, Jim.” Maybe I just need a good X-ray, or a good history, and physical.

Andrew Spitzer, MD: Contextualizing the information that you get from any clinical study, or any clinical exam is really what it’s all about. It really goes back to basics and the introduction to clinical medicine. Take a history. Do a physical exam. You’ll be able to make the diagnosis 85% of the time. An X-ray is confirmatory. You don’t really need to go beyond that, in a primary care setting. I feel bad for the primary care physicians, because 50% of patients with knee osteoarthritis are treated in that space. But, by the time they get done with their 15-minute appointment, talking about hypertension, and diabetes, and cardiovascular disease, and risk modification, they have got their hand on the door and the patient says, “By the way, my knee has been bothering me.” Well, it’s either a MRI or some Tylenol.

Paul Lachiewicz, MD: Right. But, sometimes the primary care physicians are under pressure. The patient says, “I want a MRI.” They saw that on Law and Order. “A patient had a MRI, so I need one.” Then, they come to the surgeon and say, “I need arthroscopic surgery because my MRI showed ‘that.’” So, again, I think the take-home message for the primary care physician is, resist the pressure to order a MRI before a radiograph.

Transcript edited for clarity.