Month: February 2012
The slump knee bend test is thought to have superiority over the prone knee bend test in differentiation between symptoms arising from neural vs. non-neural tissues because of the addition of the spinal flexion component. Until now not much research has been performed to examine the diagnostic value of this test.
In 2011, Trainor et al. looked at the diagnostic value of L4 nerve root compression in conjunction with other levels of nerve root compression through utilization of this test. MRI imaging was used as a gold standard for diagnosis.
How to perform:
- Subject is sidelying, slightly “cuddling” the underside leg (but not fully flexing it) with cervical and thoracic spines flexed.
- Investigator stands behind the subject supporting the upper leg to maintain a neutral hip position
- The subjects upper knee should flexed and hip extended to the point of evoked symptoms. If this point is not reached, hip extension and knee flexion should be ceased at the onset of firm resistance.
- Once symptoms are evoked, the subject is asked to extend their neck and the investigator monitors changes in symptoms and resistance to hip movement before ending the test. The results should be compared to nonsymptomatic side.
- Symptoms of stretching or discomfort on side tested
- Symptoms are felt in anterior thigh
- Normal symptoms may decrease in intensity or remain the same when cervical extension is performed
- ROM and normal symptoms response is same side-to-side
- All or part of the subjects reported symptoms are reproduced or increased during the test
- Provoked symptoms should diminish when the cervical spine is extended
- Associated symptoms (not subjects reported symptoms) are reproduced. If the associated symptoms are not in normal distribution and symptoms diminish when the cervical spine is extended, this is +. There must be evidence of asymmetry side-to-side.
- Onset of firm resistance is perceived to occur earlier in range during the testing procedure when once side is tested compared to the other. This may or may not be accompanied by symptom reproduction. There should be a decrease in resistance at the hip when extending the cervical spine.
Results: Sensitivity: 100%, Specificity: 83%, + predictive value: 67%, negative predictive value: 100%, + likelihood ratio: 6.0, – likelihood ratio: 0.
Read a case report about femoral nerve tension here by Dr. Erson Religioso.
Trainor K, Pinnington MA. Reliability and diagnostic validity of the slump knee bend neurodynamic test for upper/mid lumbar nerve root compression: a pilot study. Physiotherapy 2011: 97; 59-64.
By: Chad Cook PT, PhD, MBA, FAAOMPT
Last year, Charles Sheets and I published a paper titled “Clinical equipoise and personal equipoise: two necessary ingredients for reducing bias in manual therapy trials.” in the Journal of Manual and Manipulative Therapy. The focus of the paper was to inform the reader about the perils of failing to control for lack of personal equipoise in randomized controlled trials, and in a related sense, the hazards of an inappropriate study design that lacks clinical equipoise (in other words, the study was set up for one intervention to succeed over another). A true state of equipoise exists when one has no good basis for a choice between two or more care options. Violations of equipoise can occur in many forms and I’m thankful for the opportunity from Dr. Joe Brence to further discuss this important issue. My comments reflect my concerns of this issue and do not represent Charles Sheets’ thoughts; although his are very welcome.
Believability is a concept associated with face validity that allows one to determine, at “face” value, whether the results of a study truly have clinical merit. If a surgical team compared “conservative care” versus surgery, but provided a conservative intervention that was poorly defined, was not supported by clinical guidelines, or worse yet was called something such as exercise, manual therapy, or physical therapy, but was not provided by any experts in application of these interventions, most conservative-based clinicians would cry foul, and would suggest the intervention was biased and lacked equipoise. If a team of McKenzie-based clinicians provided a McKenzie (or MDT) approach versus a generic application of unsophisticated manual therapy care, one might also suggest bias. Further, because of assumed bias, sponsored interventions from device companies, equipment suppliers, or others who have a financial interest in the outcome, are often very difficult to publish. The authors of these studies are frequently required to report their vested interest in one side of the intervention. A recent paper published in JBJS in which I was senior author (Nunley et al. JBJS 2012) is a characteristic example of this challenge, since the primary author was also a paid consultant for the STAR total ankle replacement device company. We (the authors) were required to disclose our personal interests in the outcome of the trial, which indeed did favor the STAR device. I was able to disclose that I had no personal interests. Others were not.
The Commission on Publication Ethics (COPE) guidelines actually requires this disclosure for all publications and when this is absent, it is considered a strong enough reason to request retraction of the publication. A retraction is a “pulling” of the article from publication because of new information or because of ethics violations that were not disclosed at the time of publication. As stated by the COPE guidelines document “Retractions are also used to alert readers to cases of redundant publication (i.e. when authors present the same data in several publications), plagiarism, and/or failure to disclose a major competing interest likely to influence interpretations or recommendations”.
Recently, there have been a number of manual therapy studies that were designed by clinicians who have a personal interest in the success of one intervention over another. These clinicians have either a vested interest in the applications that are part of the interventional model because they provide instruction of these techniques in continuing education courses in which they profit from (although it may seem minimal, it is not); or because the tools are part of a philosophical approach or a decision tool that was designed from their efforts or efforts from those they were affiliated with. In nearly all cases, the bias is non-intentional and certainly not malicious. Nonetheless, in most cases, the comparative intervention (comparator) is designed in such a manner that it does not adequately represent clinical practice and in some cases, the same comparator is used despite the fact that it has been demonstrated to be ineffective in past clinical trials. It is my impression that these studies lack clinical and personal equipoise and require a disclosure of conflict of interest that is outlined within the COPE guidelines.
This concerns me greatly for a number of reasons. First, because the findings are not representative, and certainly, with the continued emphasis on “evidence based medicine” and the overt focus on publications as a source mechanism for ‘evidence’, we have the tendency to bias our future and advocate findings that reflect slanted papers. Second, I am concerned that new clinicians, passionate followers of selected manual therapy approaches, and in some occasions, seasoned clinicians, will be mislead because they lack expansive/formal research training with respect to study methodology. Certainly, once information is advocated within the clinical population, it takes years to diffuse its use, even after acknowledgement of its erroneous findings.
Since this is a Blog, and I’ve seen Blogs used quite effectively in the past to sway the masses, it’s my hope that you “Don’t always believe what you read”. And while I am not personally naming any papers or authors with respect to my concerns I’ve outlined, it’s very likely that if you suspect something screwy in a published paper, then you are probably accurate in your suspicions.
As always, my Sunday post has little to do with physical therapy and I find this important. I believe strongly in the science of physical therapy but also believe the art of human interaction is also important. I like make all of my clinical interactions as interesting as possible but wish I had the observational humor that Jim Gaffigan has. Watch his classic routine about “cake”.
In this months edition of Journal of Orthopedic and Sports Physical Therapy, Lankhorst et al performed a systematic review to examine which variables are correlated with the developement of patellofemoral pain syndrome (PFPS). PFPS is the most diagnosed condition of the knee in patients < 50 years old and its cause is thought to be multi-factorial. Past research has suggested that PFPS may be due to delayed onset timing of vasti muscles, structural abnormalities, muscle strength and kinematic variables, however, much of the conducted research has conflicting results as well as poor research design.
This study was performed to assess what we really know to be risk factors for this condition. Over 170 papers made it past the authors “title” screen, but when assessed for quality, only 7 made the cut. Out of these 7 papers, it appears that there are only two risk factors that have a positive predictive value for the development of PFPS. These include:
- Female Gender
- Having weak knee extensor strength (male and female)
Sorry ladies. This study indicates that there is still alot that we need to learn about this condition. I would be interested to examine the role of psychological variables on the influence of this pain. What do you think?
Lankhorst NE, Bierma-Zeinstra SMA, et al. Risk factors for patellofemoral pain syndrome JOSPT 2012: 42; 81-94.
Dr. Prizinski is a fellow in training at Sports Medicine of Atlanta . He is also an outpatient Physical Therapist in Pittsburgh, Pa and recorded this video as a guest lecturer for the cervical spine educational series hosted by Oakworks.