Diagnostic Palpation, is it a skill, an art or an illusion?

The Sports Physio / May 5, 2014

This blog is a talk I did recently at the University Sports and Exercise Medicine Conference 2014 in Birmingham on the role of diagnostic palpation. As usual it's a little controversial in places and highlights some big questions and doubts over the common claims that many therapists think they can make with palpation tests. I'm also not entirely sure how a 20 minute presentation transfers into blog format so please let me know, its a fairly long piece, so grab a cuppa or a beer first, put your feet up and enjoy!

Before I get started, let me make it clear that we are not discussing or debating the THERAPEUTIC effects of palpation or touch, we are only looking at palpation in its DIAGNOSTIC capacity and seeing if it stands up to scrutiny to some of the claims and diagnoses made by many in the musculoskeletal industry.

Now as a physiotherapist you won’t be that surprised to hear me say, I palpate people, and I use palpation both diagnostically and therapeutically. I palpate a wide variety of people from the old to the young, the fit to the not so fit, I’ve poked them, I’ve prodded them, I’ve pressed them and pulled them in all sorts of ways, in all sorts of positions and in some weird and wonderful places.

Now before this starts to sound like a dodgy confession at a self-help group for ‘Palpators Annoymonous’ let me explain where I am going with this ramble, what I’m trying to get across, is that I’ve palpated a lot of people in my career, in fact, I estimate that I’ve palpated about 25,000 people so far and that’s a conservative estimate, so I think I can confidently say that I’ve have had plenty of experience in palpation!

So as an experienced palpater you would assume that I could reliably feel the difference between a stiff and a loose joint, that I can easily distinguish a tight and tense muscle from soft and relaxed one, that I can readily feel scar tissue, adhesions and muscle knots with ease, and finally you would assume that my surface anatomy land marking is second to none and that I can feel if a structure is in its correct position or not.

Well, you may be surprised to hear me say that I can’t do any of those things and if you think you can or others can, then I’m afraid you are mistaken!

It’s a common and widely held misconception by many in the healthcare profession and by the general public that us therapists can detect things with our hands and fingers that mere mortals cannot, that we have some kind of mystical extra sensory perception when it comes to palpating things.

Many therapists believe they can develop these mystical powers of palpation through training, practice and experience.This belief starts off very early on in most therapists training, with tutors instructing students to practice palpation techniques in some weird and wonderful ways. For example, in my first year as a physio student I was told by my tutor to practice feeling for a single strand of hair underneath a sheet newspaper, I was told to gradually add one page at a time until I could feel it through the whole paper, I kid you not, this I was lead to believe would improve my sensitivity to touch, and I have heard many others with similar stories.

This type of training, indoctrination and exposure to ridiculous claims of palpation does leave many therapists believing that they can achieve these super human powers of palpation that when realistically examined are beyond the realms of common sense, and more importantly beyond any evidence base, and it’s a problem that continues to grow within the therapy industry. For example, I must get, at least half a dozen patients each week telling me that they have had another therapist tell them they have felt knots in their muscles, or that they have felt excessive tightness in their iliotibial band, or upper trapezius muscle, or that they have found a stiff vertebral joint, and the most annoying and worrying description I hear on a regular basis is that some, so-called healthcare professional, tells a patient that something is out-of-place or alignment such as a subluxed sacroiliac joint.

Well these are all classic examples of palpation pareidolia a term I was first introduced to thanks to Paul Ingram via his excellent blog here http://saveyourself.ca/articles/palpatory-pareidolia.php

Pareidolia for those who are unfamiliar with the term, is a type of illusion or misperception involving a vague or obscure stimulus, which is then perceived as something clear and distinct, it is usually used to describe visual illusions rather than tactile ones…

Such as seeing a face on the surface of Mars which is just a collection of hills and rocks

Or seeing a Disney elephant cartoon character in a cloud shape

Or even a religious icons face burnt into your toast first thing in the morning

Or perhaps seeing that religious icon in even more unusual places…

But all joking aside, in musculoskeletal medicine and therapy the phenomenon of palpatory pareidolia can be strong and it can give a therapist a sense that they can feel and palpate something that the literature and evidence tells us we cannot with any degree of reliability or validity. This palpation pareidolia then results in high levels of misdiagnosis, and directs treatments down wrong and ineffectual pathways, it adds nothing but confusion and misinformation for our patients, and can extended periods of pain and dysfunction for them, the exact opposite of what we should be trying to achieve.

Now that’s not to say all diagnostic palpation within musculoskeletal medicine is an illusion or unreliable, far from it. There are many good examples of reliable and accurate diagnostic palpation tests.

For example a recent paper by Hutchison 2012 looked at 10 clinical tests used to diagnose Achilles tendinopathy, and they found only direct palpation of the tendon or calcaneus together with the location of pain was sufficiently reliable and accurate to confirm a diagnosis of tendinopathy

Also Bachmann in 2004 published a paper in the BMJ on the effectiveness of the Ottawa Ankle Guidelines, these use amongst other criteria, palpation testing of the ankle malleoli, the base of the 5th metatarsal and navicular bones in those who have suffered an ankle sprain. These tests have been found to be very reliable for ruling in or out suspected fractures, and has helped reduce the number of unnecessary radiographs in A & E departments by up to 40%, great, this is diagnostic palpation working at its best.

And there are a host of other papers that I could carry on presenting that show diagnostic palpation does have an important, reliable and validated role in musculoskeletal medicine and therapy, such as joint line palpation of the knee to assess for meniscal issues, or palpating the acromioclavicular joint for suspected problems here, but, all these palpation tests have one thing in common…

Pain… They all use ‘pain’ as a response, either a lack of it or by provoking it.

When it comes to using palpation for other diagnostic purposes such as assessing joint stiffness, or soft tissue tightness without pain to guide us, then I’m afraid this is when the literature does NOT support many of our claims and highlights high levels of variability, and unreliability.

For example, let’s first look at a common diagnostic palpation tool used by every therapist I know, including myself, that of spinal motion testing, this is where a therapist applies downward pressure to a spinal segment, to feel for stiffness and quality of movement, and of course to also assess for pain, but if we put pain to one side and just look at this test for assessing stiffness.

Now I’m not going to get into the debate about IF spine segmental stiffness produces pains and problems, and I’m also not going to dwell on the research that shows that our reliability to accurately locate individual lumbar vertebra is also highly questionable, instead let’s just look at if a therapist can tell if a spinal segment is too stiff or not.

Well the major obstacle here, and always will be, is the high variability in forces applied by individual therapists when performing these tests, meaning what feels stiff for one therapist, won’t be for the next

This variability in forces applied was first demonstrated by Harms and Bader in 1997, (which are two great names for physio researchers by the way) they assessed the forces applied by 30 experienced physios as they performed a series of mobilisations to the lumbar spine, including one where they were asked to press the spinal segment to what they thought was its end of range. As you can see the difference in forces applied is vast, with some only pressing as little as 100N and others pressing up to 3 ½ times harder, to up to 350N, this clearly means those pressing with higher forces won’t interpret that spine is as stiff as those pressing with lower forces.

And there have been many other studies since this one looking at the forces applied by therapists during spinal motion palpation tests and these were collated in a literature review by Snodgrass 2006, and although there are differences in study design, methodology, and areas of the spine palpated, making direct comparison difficult, there is again clear evidence of the high variability in forces applied by therapists when assessing spinal stiffness

They also concluded that the forces varied greatly between therapists, and this may be due to differences in levels of experience, with physio students and newly qualified therapists pressing with much lower forces and with higher levels of variability, whereas more experienced therapists pressed harder and slightly more consistently, perhaps showing that there is a learning curve and some skill acquisition in spinal motion palpation, however the conclusions are still damming in that there is no reliability in using spinal motion palpation to assess for stiffness anywhere in the spine. They also conclude that there is vast differences in individual stiffness from person to person, and as we don't know what is 'normal' stiffness we cannot make any assumptions as to what is too stiff or not.

So take high variability in forces applied by therapists, combined with vast differences in individual spinal stiffness, this makes any interpretation of stiffness felt highly unreliable and based on nothing more than individual interpretation alone!

Now please understand I’m not to saying we should stop pressing down on spines, and I’m not saying spinal manipulation doesn’t alleviate back pains or improve function, it does, for some, a little bit, there are studies that show it does, just about… But we just cannot press a spinal segment and use it to tell a patient, or anyone else that its too stiff or not.

So if we can’t diagnose stiffness in the spine with palpation how about diagnostic palpation tests for soft tissues? Therapists often palpate soft tissues feeling for tension, tightness, lumps, bumps and again those knots I mentioned earlier, but how reliable are we in finding these elusive muscle knots?

Muscle knots and taut bands are commonly referred to as ‘Trigger Points’ and there is now a huge industry built up around the training, education and treatment of them. Trigger Points where first described by the US physicians Janet Travell and David Simons back in the 1960’s, they described palpable knots and taut bands that can be felt within muscles throughout the body and hypothesised that these are local areas of sustained muscular contraction and hypertoncity that cause pain either locally or referred elsewhere.

These trigger points are thought to be caused by insult to the muscle fibres either directly from trauma, or indirectly from repetitive overload from sustained postures, positions or repetitive activity. This trauma is then thought to releases substances such as histamine, serotonin, kinnins etc. which activate nocioceptors and so cause adverse reflex muscle contractions.

To treat trigger points Travell and Simons advocate the use of tissue stretch, pulling or direct sustained pressure to them, and many now use the method of Dry Needling to treat them. So to effectively treat Trigger Points we need to be able to reliably find them, and herein lies a major hurdle and obstacle for the Trigger Point theory, because when blinded, and pain is not reported, no one, and I mean no one, can find these muscle knots or taut bands with palpation testing!

For example, there is a little known study conducted by Fred Wolfe back in 1992 in which he invited the world’s leading experts in trigger points, including David Simons, to partake in a blinded randomised study, to try and locate trigger points in three groups, those already diagnosed with them, a group with fibromyalgia and a healthy control group.

Unfortunately for the Trigger Point experts it was an unmitigated failure, simply put there was no reliability or consistency in using palpation testing to locate these muscle knots or taut bands when blinded, they only found them in 18% of the diagnosed group, and actually found them just as much in the healthy control group, and remember these where the best trigger point palpaters in the world!

However much to Wolfe’s dismay and objections the study was fluffed up, a positive spin woven into it, and it was eventually published quietly and soon forgotten about, it is rarely seen or cited, and so the Trigger Point machine happily rolled on and on….

But there is a growing evidence base that supports Wolfe’s study, with a number of systematic reviews such as Hsieh in 2000 looking at inter examiner reliability for finding Trigger Points in the trunk and lower limb and finding none in novices and then only marginally reliable in trained therapists.

Next Myburgh in 2006 did a systematic review and found many poor quality studies and that establishing reproducibility of Trigger Points is generally poor.

Then Lucas in 2009 did another systematic review who concludes that using the current proposed criteria, feeling for knots, taut bands or local twitch or jump responses in trigger point assessment is unreliable.

Now again please don't misunderstand me in saying that I don’t believe in finding or treating sore spots found in and around the body, and again I don’t won’t get into the debate on WHAT these sore spots are when we press and palpate them, that’s for another talk, just to say, that I don’t think they are as described by Travell or Simons, nor do I think we palpate them or treat them as reliably or specifically as many think they do.

So we can’t reliably palpate for spinal stiffness, nor can we for muscle knots or taut bands, so finally how about using palpation tests to diagnose for things that are in or out of position.

Well palpating for obvious structural deformity after trauma in sports medicine is obviously very useful, if sometimes clearly not needed as with this poor chap, but what about the use of diagnostic palpation to check for other more subtle structural positional defects that are commonly thought to cause pain and dysfunction.

The classic area this is routinely done for is in the assessment of the pelvis, in particular that of the sacroiliac joint. Now the sacroiliac joint is so full of myths and misconceptions within the manual therapy world it is the grand daddy of palpation pareidolia, and a source of constant annoyance and eye rolling for me.

The sacroiliac joint is thought to be a common source of pain and dysfunction by many therapists if it's not positioned correctly or if it's moving to much or too little, and that it not only causes problems around the pelvis or back but also much further afield. Now again I’m not going to get into the debate about IF the sacroiliac joint does or does NOT cause these issues, but rather if we can palpate it diagnostically and reliably

To check for a sacroiliac joints position many therapists will commonly palpate for the bony landmarks of the anterior and posterior superior iliac spines (ASIS/PSIS) in a standing position, if the ASIS is too low then the pelvis is thought to be too anteriorly rotated, or if the ASIS is too high then it’s thought to be too posteriorly rotated so causing excessive stresses, strains and overload elsewhere.

Now if we conveniently ignore the issues around the accuracy and reliability of finding these bony landmarks, especially in some of our more adipose challenged or muscular athletes, and instead look at the other often overlooked issue when using bony landmarks to assess structural position, that of the impossibility of interpreting any difference in position due to normal bony anatomical structural variances.

Preece did a nice little study looking at just this, he dissected 30 pelvic cadavers, and measured the angles between the ASIS and PSIS, and found there was high levels of variability between the angles, ranging from 0 degrees up to 23 degrees so making any clinical test that uses these landmarks unreliable.

The other common illusion around diagnostic palpation of the sacroiliac joint is that therapists think they can feel it move too much or too little, and so decide if it’s too stiff or too loose, however the credibility of palpating a sacroiliac joint move, and I use the word move here very, very loosely, as it’s only a few millimetres at best, under layers of tissue, ligaments and muscles is simply ridiculous, and yet this practice is still used and taught widely.

There are many good quality studies that show terrible inter and intra reliability and validity for these sacroiliac joint movement tests such as Riddle in 2002, with the kappa scores of these tests being extremely poor

And then Robinson in 2006 who found the kappa values now in the minus figures for these same tests, so why these diagnostic palpation practices around the SIJ are still in wide-spread use is baffling, it’s nothing more than palpatory pareidolia at its worst.

So I hope that I have very briefly demonstrated that diagnostic palpation in musculoskeletal medicine does have a useful and important role, but, these tests all rely on pain provocation.

I also hope that I have raised your awareness a little, that within the in the world of musculoskeletal therapy a lot of diagnostic palpation tests have some ridiculous, far-fetched and un-evidenced claims, and I hope the next time you hear a therapist explaining to you or a patient that they have felt a stiff spine, or a that a sacroiliac joint is not moving properly, or even that they have felt a knot in a muscle you will remember the role that palpation pareidolia plays.

As always thanks for reading