Osteoarthritis: Risk Factors and Radiography

00:00 So what causes osteoarthritis? this one's easy.

00:05 Despite being the most common, chronic, degenerative joint disease, afflicting nearly everybody over the age of 50, the etiology of osteoarthritis remains completely unknown.

00:16 We do, however, at least know some of its risk factors.

00:19 Anyone over the age of 65 has osteoarthritis and oftentimes it can start considerably earlier.

00:25 Female gender is a risk factor, any family history, prior joint trauma and certainly obesity by virtue of excess wear and tear on those joints.

00:34 In addition, osteoarthritis can be secondary to other disease processes like diabetes, hemochromatosis, acromegaly and even gout can cause osteoarthritic types of manifestations.

00:46 So, let's go back to our case for a moment and look for some key features.

00:50 We have an acute-on-chronic picture, very typical for osteoarthritis.

00:54 Worse after activity but morning stiffness lasting for less than 15 minutes.

00:59 Also, typical of osteoarthritis.

01:02 The swollen joint can happen as an acute synovitis on a backdrop of chronic osteoarthritis.

01:08 It's not common but it does certainly happen.

01:11 Bony enlargement of the knees due to these osteophytic growths around the pes is common especially on radiographs.

01:17 and the fact that you have tenderness on the medial joint line also supports that condition.

01:23 So, to recap: Classic features of osteoarthritis are those we had in our case.

01:28 A chronic disease with periodic flares, typically precipitated by increased activity.

01:33 You're also looking for asymmetric symptoms and with inexorable progression osteoarthritis of some joints can literally bring many people to their knees.

01:43 See what I did there? Now, it has a predilection for certain joints.

01:48 Like the knees, the hips, the lumbar spine and of course shown here on the left, the proximal interphalangeal and the distal interphalangeal joints of the fingers.

01:58 Classic physical exam findings as I alluded to are gonna be bony enlargement, a limited range of motion, varus deformity which means being somewhat bowlegged, crepitus by palpating the knee while moving it and of course, joint-line tenderness as I've mentioned.

02:14 So let's take a look at some of the common radiographic features of osteoarthritis.

02:18 The picture on the left here is a normal radiograph of a knee and the one on the right is somebody with severe osteoarthritis.

02:25 What you can see right off the bat, the first distinguishing feature is the joint space narrowing, particularly in the medial compartment of the knee.

02:32 In addition, you can see evidence of subchondral sclerosis which is that hyperlucent areas just on the tibial plateau.

02:39 There's evidence of subchondral cyst in there as well and osteophytes basically broaden the size of the knee relative to the size of the tibial plateau.