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Treatment of Common Knee Problems

The knee is a complex joint, a tri-compartmental, diarthrodial, synovial-type hinge joint. Two weight-bearing articulations comprise the concave condyles of the femur, which rest on the flatter tibial plateau. In the knee their congruence and stability is maintained by fibrocartilaginous structures on each side; the menisci. In the intercondylar notch are two broad collagenous structures, the cruciate ligaments which not only prevent A-P translocation but also serve to deliver some proprioceptive information.

Our approach in the clinic as we try to say, "Where does it hurt? Why does it hurt there?" sometimes itís very simple. We take a history and a physical examination and get the answer right away, or so the story is supposed to go. Actually our clinical exercise is merely a set of guesses in which we try to get down to some possible anatomic explanations for the pain and some possible notions about the processes that might be modified. In fact, the number of historical features that seem to have some weight in classic training about diagnosis really may not tell us much. For instance, locking; which is supposed to be quite indicative of a meniscal derangement, was looked at among hundreds and hundreds of possible symptoms in a systematic way. In normal knees and knees that underwent arthroscopy and had these derangements shown and locking was not predictive of a torn meniscus. A buckling, for instance, was not indicative of a cruciate ligament.

The second common pattern is genu varus, also accompanied in this case by medial tibial rotation, hip abduction and compensatory pronation at the foot. Iím sure we are all used to seeing both of these painful conditions resting in the middle of both of these arrangements.

Now to look at the knee itself. This illustration depicts the expected path of the patella during knee motion. It moves vertically between flexion and extension and we expect it to move in a smooth, sinusoidal path. We will be addressing patellar tracking in the upcoming vignettes, however it is important that we all recognize that cases and cases of diagnosed patellofemoral pain, patellar abnormalities actually appear in only about half of the cases, so itís not a universal problem. Of course, the quadriceps. Books are written on the quadriceps. We only have one picture. A central focus in any knee discussion is the quadriceps.

In summary, when we look at the knee, we need to keep in mind that the knee connects two long lever arms and is affected by local, proximal and distal events. It depends on soft tissue, not bony configurations, for stability and also for the mobility that we need. It is full of complex joints and relationships. There are actually 14 muscles that control the knee; six act only at the knee but seven also act at the hip and this is often forgotten, but wonít be today. And one also at the ankle. So thinking about the knee and the kinetic chain as a closed kinetic chain, which we see here, where there is at least partial weight-bearing and the feet are in contact with a weight-bearing surface. Whether itís a closed kinetic chain or an open kinetic chain, which we see here, and although many people discuss what is an open kinetic chain, I think when you can see the soles of their feet itís pretty much assured that you are talking about an open kinetic chain. But whatever the case, open or closed kinetic chain, what we need to remember is that we must consider the knee in terms not only of what it does and where it is, but also as a response to forces and conditions in its environment.

Our thought was that she had anterior knee pain that was exertion related. Once upon a time this would have been put under the umbrella of chondromalacia patella, a term that fortunately is just about dead. There are conditions in which the patellofemoral articular cartilage degeneration is an important part of the process. This patient has a more advanced case of it. Itís a process that you canít see well on an A-P x-ray, perhaps in the lateral. But with prolonged patellofemoral mis-articulation there can be fairly severe patellofemoral osteoarthritis develop, with this person with lateral subluxation. She has worn a new groove in her trochlear sulcus and has a large osteophyte. Other consideration for her, but was probably ruled out by the physical examination, was patellar tendonitis and that is largely made by physical examination looking for tenderness at the tibial tuberosity.

Another intraarticular anatomic process that she might have going on is a problem with the fat pad. This is a shot looking down from the suprapatellar pouch, underneath the patella, trochlear groove below, patella above.

Another intraarticular structure that could be deranged here is the synovial plica, I mentioned in the physical examination. If you reach down with your thumb medial to your patella and rub back and forth, a good three-fourths of you should be able to feel something twanging there. This is one of the few prospective orthopedic surgery studies involving arthroscopy in which patients with persistent pain and medial plica and arthroscopy were randomized to either have it resected to simply lavaged. The dark line on top are the folks that were resected and it denoted their likelihood to preserve a good or excellent result.

Probably what we are seeing here, and what our bottom line would be is that people with fairly good lower extremities very often start to have a problem when the increase in activity or demand outstrips the conditioning of the neuromusculature and they need time to back off a little bit and get in condition and get in shape for what they are doing.

And from the physicians point of view, aside from being grateful for a successful physical therapy intervention, it also reminds us that many of the spots that seem to be sources of pain and pathologic are in fact just merely showing the effects of disordered biomechanics, which are maybe a temporary disorder and can corrected by specific exercise interventions.

Our next patient is a little more typical for us rheumatologists. This is knee pain in a 55-year-old farmer who is at the point of increasing pain in his right knee over the past six months. He also says it is stiff and weak. He is having trouble getting up and down on equipment, sometimes hard to put on shoes and boots and hurts worse the day after any extra activity.

Now for the rheumatologist this is maybe a no-brainer. This is a person who has a sore knee. Probably itís osteoarthritis. He has a small effusion, he is not bad off elsewhere. Your first step might be local therapy for local disease, perhaps a corticosteroid injection. Indeed, most rheumatologists use corticosteroid injections for OA. Some quite a bit. In fact, if you get right down to it, is there data to support the use of this? It actually is a bit hard to come by, nevertheless we have, despite the lack of data, our daily practice reinforces that these are generally effective interventions for patients with knee OA, effusions and pain.

So we use corticosteroids. We generally give them intraarticularly. And the patients very often do feel better, sometimes for quite a while. But, are there other ways to do it? Well, yes. This is from an article from down under by Sanbrook that looked at whether it matters that you inject into the joint. In fact others have found that we donít always hit the joint.

There are other local therapies for local disease and had he been resistant about having an injection, we could go back to some that have been on the drug store counter for years, and some more that may be coming out, although all those rubs on the drug store counter are usually combinations of counter-irritants that produce local warmth and dilatation merely with Ö sometimes with some coolness as well. The salicylates that are there mainly to induce local warmth also can achieve therapeutic tissue levels, so Aspercreme produces aspirin levels in the joint, basically. Capsaicin - thatís been around for a long time.

Here we see some common tender points and all the places they correspond to. This is the enthesis of the tibial fibular joint, the insertion Ö the origin and insertion of the medial collateral ligament, later collateral ligament, insertion of the quadriceps muscle onto the superior popliteal patella, the medial synovial plica, sometimes there are lateral plica, joint line, tibial tuberosity for parapatellar insertion. In the back we have some other insertion sites, joint line and popliteus muscle.

Other cultures pay attention to tender points about the knee and modify them in different ways. Notice how Ling Lang Kwan _ corresponds quite well to the pes anserine tender point. There is growing literature on the use of acupuncture in the treatment of osteoarthritis knee pain. The latest coming out of Baltimore published earlier this year, in which they took eight of these spots - and I confess, I donít know which eight, but these are at least four - and subjected half their group to acupuncture treatments twice a week for eight weeks, and their control group was a similar group of patients with knee OA and pain who went about their conventional therapy with the same number of follow-up visits. So they had some observational effect. Certainly the acupuncture people had quite a significant reduction in their pain scores.