Not So Fast on That Knee Replacement

Here’s a short piece by the New York Times that’s well worth the read if, driven to desperation by pain and a bleak prognosis, you’re considering the ultimate in knee surgery: a total replacement of the joint.

You wouldn’t be alone -- far from it. More than 600,000 of the surgeries were performed in 2012. That’s a big jump from the 250,000 of 15 years ago. But what’s most interesting is where the most rapid growth is: among those 45 to 64 years old, who had triple the number of operations as before.

Are all these surgeries beneficial, especially among younger patients?

Researchers analyzing data from major studies found that people with really bad knees were helped by surgery. “Really bad” in this case means advanced arthritis: in other words, severe pain and impaired physical function, like an inability to climb stairs. But others with less serious arthritis saw only a very small benefit.

The upshot? According to Daniel Riddle, the professor of physical therapy and orthopedic surgery who led the studies:

If you do not have bone-on-bone arthritis, in which all of the cushioning cartilage in the knee is gone, think about consulting a physical therapist about exercise programs that could strengthen the joint, reducing pain and disability.

Amen. Surgery sometimes is the best option. But it’s often the best option when it’s the last option.

Three Reasons Why “Mistracking Kneecaps” Probably Isn’t the Reason for Your Pain

Last time I mentioned in passing an interesting Swedish study. It found clinical tests perceived no significant differences between subjects who had knee pain of unclear origin and a control group. So, in other words, the knee pain sufferers weren’t crooked or imbalanced in some way the control group was not.

Intrigued, I managed to locate the study (most are behind paywalls, but luckily, this one was not). It begins with a fairly broad discussion of patellofemoral pain syndrome that won me over with these two lines:

Some practitioners who find no identifiable cause to the pain use both the term PFPS as well as the term AKP (anterior knee pain), but the terms are best reserved to describe the patient who has yet to be evaluated. If no causative explanation for the pain is found, despite a thorough investigation, the term idiopathic anterior knee pain (IAKP) seems reasonable.

Yes, yes, yes! Let’s stop pretending PFPS is a real diagnosis. “Idiopathic anterior knee pain” is more honest and useful. Basically, it means “you have pain in the front of your knee and we don’t know why.”

There is another discussion section, at the report’s end, that is well worth perusing too. The researchers’ skepticism about catchall explanations for PFPS that cite mechanical abnormalities is virtually palpable.

Here are three big problems with the “oh, you’re crooked/imbalanced” line of thinking.

(1) There’s no accepted definition of what constitutes crooked in the first place -- or more precisely “meaningfully crooked” if you will, because I’m sure very small discrepancies in the length of someone's legs (or in whatever) wouldn’t be considered important even by diehard structuralists.

To make this more concrete: Say you believe patellar maltracking causes most cases of PFPS. Well, if a kneecap doesn’t track perfectly by 1/100th of a millimeter (the width of a thin hair), that’s not enough to be significant. But then, what is? 2 millimeters? 6? 10, 20? The fact is, no one has set forth an assertion on this that’s supported by clinical evidence. So we don’t even know what crooked is.

(2) Also we can’t measure it well anyway (a related, overlapping issue). The Swedish researchers report:

“Fitzgerald and McClure (1995) studied four different manual clinical tests for patellofemoral alignment where measurement reliability ranged from poor to fair ... they were unable to find a reliable clinical method for assessing alignment.”

So there’s no accepted definition of malalignment and no good way of measuring it anyway. But wait, it gets worse:

(3) “Fairbank, Pynsent, van Poortvliet and Phillips (1984) reported that in pain-free subjects, between 60% and 80% of the population fall into what is generally classed as lower extremity malalignment.”

So, even when someone does take a stab at defining malalignment, it turns out -- surprise -- that most of us who are pain-free share this “problem.” In that case, if almost everyone is crooked/imbalanced, what’s so special about it?

And the answer just may be: not much at all.