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RE: vmo

 
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RE: vmo - September 19, 2007 4:46:45 PM   
Bournephysio

 

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Joined: April 26, 2002
From: Montreal
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?Powers study concludes it does. That is what I have to go on for now. Do you have a paper (or papers) that would demonstrate otherwise??

No No No!!!! Again, a great example of why this kind of language does our profession a disservice. You, as a clinician, apparently have read this to mean that if the subject just rotates their hips, that the femur will rotate under the patella. Even ignoring the fact that what they did conclude is deeply flawed, they can?t conclude that the femur would rotate under the knee in this situation because they didn?t test it. The movements are so obviously different mechanically that you can?t even use their paper as support for this. If you need a paper to support this try Philosophiae Naturalis Principia Mathematica. You can?t break the laws of physics.

?Because of this, there is a 2 effect on petellofemoral and tibiofemoral positioning?

So what is the 2 effect? These things aren?t magic. Its basic high school physics. If it?s not the hip musculature it has to be something else. The biggest candidate is the patellar tendon and surrounding capsule. The only way this will change the position of the patella via the patellar tendon is with rotation of the tibia with respect to the femur.

?Your suspicion would be your opinion. I do think this would be a great next step for the authors to take in their research. I'd suspect it would change, but it's only both of our opinions as the research (as far as I know) has not been done to show which or us is more correct.?

Yes it?s my opinion but my opinion is backed by solid biomechanics (I could still be wrong). What is your opinion back by?

?PT's don't understand biomechanical terminology and convention; but it's a disservice to the PT profession because we describe something in a non-conventional way? I think it would do a biomechanic's profession a disservice by not sticking to common convention. But if PT's don't know any better, how can we abide by something we don't understand??

First, most of the biomechanics terminology used in this discussion has been basic first year PT stuff and most of the concepts are high school physics let alone from a PT biomechanics class. It does the PT profession a disservice to use vague, non-precise, meaningless language.

?Point is, the hypothesis of poor neuromuscular control at the hip being the 1 factor in "petellofemoral" pain may be incorrect - although not disproven yet - nitpicking "femur rotating" as a disservice to PT (again, maybe biomechanics) as a way to discredit this hypothesis in not valid.?

I never used ?nitpicking femur rotating? as a way to discredit this hypothesis. Not sure what you are reading.

Maybe I?ll get back to you later on my theories but I will leave you with this: Cartilage is aneural; therefore ?direct irritation? of the cartilage is not the source of pain. This does not mean that ?irritation? of the cartilage does not indirectly lead to nociception.

Sorry if my posts are condescending but if we are the ?movement specialists? we need to be able to understand and critically analyze biomechanics studies. Much of it is simple Newtonian mechanics that you learn in high school.

Doug

(in reply to jlharris)
Post #: 21
RE: vmo - September 19, 2007 11:14:47 PM   
jlharris


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quote:


...You, as a clinician, apparently have read this to mean that if the subject just rotates their hips...

No, I take it that, using real time MRI, in a weight bearing position, the patella remains stationary (to a point relative to the MRI) and the femoral groove moves medially.  You disagree, that's fine.  It seems you disagree more with the terminology used then what was actually found.

I think we agree more as to what is going on then our replies would indicate.  Although you still - for an unkown reason - hesitate to explain your working hypothesis of PFP origin or cause.

I don't think the pain is directly related to weak hip control but the biomechanical effects down the "chain" from it.  Particularly in regards to poor LE pronation control (or dynamic over pronation).  I don't think, IMO, that the pain is from the patella "rubbing" on the femoral groove, but most likely, the increased strain from obnormal forces on the patella tendon and/or infrapatella fat pad with lack of pronation control.

_____________________________

Jason L. Harris, PT, DPT
My PT Blog

(in reply to Bournephysio)
Post #: 22
RE: vmo - September 20, 2007 12:15:58 PM   
Sebastian Asselbergs

 

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Well, the primary culprit of PF pain is a sensitive nerve. Under stress of some kind. That is about as accurate an explanation as science can give us. After all, there is yet no evidence that poor alignment, weak muscles, or lumbar "malpositioning" or "stuckness" (my word....) a the direct originators of the pain.  As is abundantly clear in many patients whose "healthy and pain free" knee ( the other side) in the eval, shows awful alignment , awful foot mechanics, poor VMO control, or massive OA, or any combination of the above....   So why does the painful side become painful? With all the same findings....

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Mundi vult decipi

(in reply to jlharris)
Post #: 23
RE: vmo - September 20, 2007 6:55:13 PM   
Bournephysio

 

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Jason, Yes terminology is a factor but despite that I still don't believe that you understand the fundamentals of the study. Hip ir/horizontal add during a single leg squat is completely different than my example of just rotating your hip. The patella is not going to stay stationary in any reference frame (besides its own) during a squat. Now try and do a partial squat allowing your hips to ir. Now imaging where the patella would be if it remained stationary. It's just not going to happen.

Describing my working hypothesis would take much more time than I have wasted already on this thread. It is not a simple issue as Sebastian has alluded to. My entire PhD thesis is on biomechanics/mechanobiology of articular cartilage during loading in arthritic and normal cartilage and is just a tiny sliver of the whole story.

Doug

(in reply to Sebastian Asselbergs)
Post #: 24
RE: vmo - September 20, 2007 9:04:12 PM   
jlharris


Posts: 486
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From: Oregon
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Sorry for wasting your time Doug. Wish your wasted time could have given this community something to take to our patients to help them improve.

Thanks for the reply Sebastian.  I agree completely with you.  The quest seems to be finding what exactly is irratating those nocioceptors.  Cut me in if you ever find out.  Here is a recent study that makes everthing clearer (sarcasm):


The efficacy of treatment of different intervention programs for patellofemoral pain syndrome--a single blinded randomized clinical trial. Pilot study.
Avraham F, Aviv S, Ya'akobi P, Faran H, Fisher Z, Goldman Y, Neeman G, Carmeli E.

Raziel Physical Therapy Department, Clalit Health Services, Netanya, Israel.


Patello-femoral pain syndrome (PFPS) is a common knee joint disability. The integration of hip soft tissue regimens are not always emphasized, although current literature implies that there is a significant relationship between the two and there is a lack of randomized clinical trials to substantiate this relationship in clinical practice. A randomized controlled assessor blinded trial was designed to explore different rehabilitation programs related to PFPS. The study was conducted at RAZIEL institute of physical therapy, Netania, Israel with a total of 30 consecutive patients (mean age 35y), diagnosed with PFPS. All patients were randomly allocated into 3 groups. Group I conventional knee rehabilitation program. Included quadriceps strengthening and Trans Electric Neuromuscular Stimulation (TENS). Group II hip oriented rehabilitation program. included stretching, Hip external rotators strengthening and TENS. Group III a combination of the two above programs. Pain and function were documented on initial of the program and again 3 weeks later, on the completion. Pain was assessed by a numeric visual analogue scale (VAS); function was assessed by Patello-femoral joint evaluation scale (PFJES) (0-100 points). At end of trial, all groups showed significant improvements in VAS and PFJES (p<0.0001); these improvements did not vary significantly between the 3 groups. The conclusions were that the explored different rehabilitation programs showed a similar beneficial effect.

ScientificWorldJournal. 2007 Aug 24;7:1256-62.



Makes me think it's like LBP.  We aren't really sure what's wrong, so any specific treatment tends to result in similar outcomes with other different specific treatments.


< Message edited by jlharris -- September 20, 2007 9:07:55 PM >


_____________________________

Jason L. Harris, PT, DPT
My PT Blog

(in reply to Bournephysio)
Post #: 25
RE: Re: vmo - September 26, 2007 5:20:56 AM   
alodato

 

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Can't see the link, can you link it again.

(in reply to jlharris)
Post #: 26
RE: Re: vmo - September 26, 2007 2:04:28 PM   
jlharris


Posts: 486
Joined: April 13, 2006
From: Oregon
Status: offline
Another study that indicates PFP may be caused by tibiofemoral IR (pronation) and not patellar malalignment.

Patellofemoral Joint Contact Area Is Influenced by Tibiofemoral Rotation Alignment in Individuals Who Have Patellofemoral Pain
Gretchen B. Salsich, William H. Perman
DOI: 10.2519/jospt.2007.2589
STUDY DESIGN: Observational, cohort study. OBJECTIVES: To test the hypothesis that patellar alignment and tibiofemoral rotation alignment explain unique portions of variance in patellofemoral joint contact area in individuals with patellofemoral pain (PFP) and in pain-free control subjects. BACKGROUND: PFP has been proposed to result from increased patellofemoral joint stress due to decreased contact area. Patellar malalignment (lateral displacement and tilt) is believed to be the main contributor to decreased contact area. Recent studies suggest that transverse plane rotation of the femur and/or tibia may also contribute to decreased contact area. METHODS AND MEASURES: Twenty-one subjects with PFP (16 female, 5 male) and 21 pain-free subjects (14 female, 7 male) participated. Subjects underwent magnetic resonance imaging (MRI) with the knee in full extension and the quadriceps contracted. Measures of patellofemoral joint contact area, lateral patellar displacement, patellar tilt angle, tibiofemoral rotation angle, and patellar width were obtained. Hierarchical multiple regression analyses were performed for each group using contact area as the dependent variable. The order of independent variables was patellar width, patellar tilt angle, and tibiofemoral rotation angle. To avoid multicolinearity, lateral patellar displacement was not included. RESULTS: In the PFP group, patellar width and tibiofemoral rotation angle explained 46% of the variance in contact area. In pain-free subjects, patellar width was the only predictor of contact area, explaining 31% of its variance. Patellar tilt angle did not predict contact area in either group. CONCLUSION: Addressing factors that control tibiofemoral rotation may be indicated to increase contact area and reduce pain in individuals with PFP. Future studies should investigate the contributions of patellar alignment and tibiofemoral rotation to patellofemoral joint contact area at a variety of knee flexion angles.
J Orthop Sports Phys Ther. 2007;37(9):521-528, published online 12 July 2007. doi:10.2519/jospt.2007.2589
KEY WORDS: biomechanics, knee, MRI

Of course, the question of wether improving IR control would increase contact area is no where near answered.  Interesting nontheless.

_____________________________

Jason L. Harris, PT, DPT
My PT Blog

(in reply to alodato)
Post #: 27
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