Last week I had a return patient who was originally seen for anterior knee pain after a subluxation. He was a hot mess from my movement assessment and a lot of the focus was placed on improving kinematics and motor control at the hip, per SFMA breakouts and additional functional tests such as lat step down and drop landing. Long story short, he ended responding very well, was functional in all SFMA at D/C, and ended without pain and no difficulties with a week long hike on the Appalachian Trail. Couldn't be happier overall. Unfortunately, he came back nine months later with the same problem. He didn't mess it up with gym activity or long hikes but simply going down the stairs. I was really bummed because we built just good rapport that I felt like I let him down. And the crazy thing was that his movement was still good, everything was functional per SFMA (even for a stickler) and no imbalances found with FMS,etc. So what was I missing? Maybe some good ol fashion quad strengthening.
A systematic review on the need for Quadriceps (quad) strengthening for Patellofemoral pain (PFP) was released which found overall quad atrophy was shown to be present in those suffering with PFP when analyzed by imaging, supporting the rationale to add progressive resistance exercise for the quads. Maybe that's what I was missing, and what I have started applying to my patient for his second round of PT.
Here are three take home points, or applications, from this article:
1. Stop looking at the VMO
Although imaging demonstrates atrophy, three studies found girth measurements found NO difference. Examining the VMO muscle size had no validity. Additionally, you can't compare it to the contralateral limb because the uninvolved leg might be atrophied as well when compared to asymptomatic populations. Further, there was no imbalances in VMO/VL muscle size, just overall quad atrophy. Therefore, thinking just the VMO is weak is just plain wrong..and yet another reason we don't focus on isolating the VMO (add that on top of the fact you can't isolate the VMO and that we don't use the VMO in isolation but the whole quad in functional patterns).
And its just not looking at the VMO size that we can't accurately examine. This goes for examining the pull, the exact connection to the patella, etc. We can’t just trust our eyes. They will continue to deceive us. Here's one of many optical illusions to make my point:
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| In this tilt illusion, the lines in the centre of the image appear tilted counterclockwise, but they are actually vertical. Image adapted from University of Sydney image. |
It is plausible that knee pain causes inhibition over time of the quads, which leads to weakness.(more on how pain leads to atrophy and motor control deficits here). So it possible that atrophy developed after the onset of PFP and that PFP developed from overuse,etc. Meaning the pain that may have developed over time and not with one specific onset. Pain that may not be actively causing pain at the site but still there, like latent trigger points. Latent trigger points, that can be developed form overuse, have been shown to influence muscle activation patterns, which can result in poorer muscle coordination and balance.
“Treating latent MTPs in patients with musculoskeletal pain may not only decrease pain sensitivity and improve motor functions, but also prevent latent MTPs from transforming into active MTPs, and hence, prevent the development of pain syndromes.” Ge HY. So, treating latent trigger points can prevent possible quad atrophy seen with PFP as well as improve muscle activation patterns which may abolish the PFP!
3. Always add a little quad strengthening and a lot more when they don't have much hip or ankle issues.
“The findings that not all people with PFP have quad atrophy may help explain why some people with PFP respond more favorably to strengthening interventions than others.” It is possible that those without significant atrophy will respond more favorable to appropriate SFMA corrective exercise and motor control re-ed strategies. Unfortunately, I can't get all my patient’s quads images just to see how much quad re-ed I need to do. Therefore, applying some quad PRE will improve overall outcomes. In fact, similar outcomes from quad PRE and hip PRE interventions have been seen already.
As always, Ill always be looking to improve our outcomes from the newest and best research...as well as my mistakes. Thanks for reading.
