Friday, August 10, 2018

Fat Pad Most Painful In The Knee?

I had a patient who came to our clinic recently complaining that his MRI showed that his patella (knee cap) cartilage had "worn out" completely but he didn't have any pain prior to that. He had actually gone to do his MRI under his doctor's insistence for investigating something else.

His  MRI results was like in his words "opening a can of worms" telling him what's wrong with his knees and perhaps that's why he started having pain after that.

After his ranting, I had to explain very thoroughly about the structures in our knees that cause the most pain. The information I gave him was derived from an article published quite a while ago in the American Journal of Sports Medicine but still very relevant today.

The doctors in that study came up with a simple method to document the various sensations felt inside a single subject's knees one week apart. Right knee first, followed by the left a week later. (Note that the subject had no prior knee pain).

They would arthroscopically poke/ palpate (using a specially built spring loaded device) different structures inside the knee while video recording the procedure and record what the subject's response was. Force used was between 0 to 500 grams. All this done without intra articular anesthesia. Ouch! That must really hurt.

The doctors only injected local anesthesia at the portal site (incision). The first author inspected both knees arthroscopically. He asked the patient when he poked at different structures and graded the sensation as follows (0) no sensation; (1) was non painful awareness; (2) slight discomfort; (3) moderate discomfort and (4) severe pain. This was done with with a modifier of either accurate spatial localization (A) or poor spatial localization (B).

Ready for the results? They were exactly the same for both knees. Even though it was done one week apart.

Palpation of the patellar articular cartilage in the three under surfaces (central ridge, medial and lateral facets) resulted in no sensation, or a 0 score, even with a strongest force of 500 grams. Palpation of the odd facets elicited a score of 1B. Asymptomatic grade II or III chondromalacia (wearing out) of the central ridge was identified on both patellas of the subject!

Palpation of the articular cartilage surfaces of the femoral condyles, trochlea, and tibial plateaus at 500 g of force universally produced a sensation of 1B to 2B.

The sensation from the meniscus ranged from 1B on the inner rim of the meniscus to to 3B near the capsular margin.

Sensation from the  cruciate liagaments (Anterior, posterior cruciate ligaments) range from 1-2B in the mid-portion of the ligaments and 3-4B at the insertion sites.

Palpation of the suprapatellar pouch, capsule, and the medial and lateral retinacula produced a score of 3A to 4A (moderate to severe localized pain) at relatively low levels of force (about 100 g).

The most painful structures were the anterior synovium of the knee, the fat pad and the joint capsule - 4A.

The human knee can be very complex, especially our patellofemoral joint (patella and the femur). The three asymnetrical surfaces on the underside of the patella (or knee cap) has to work together with the femur as it accepts, transfers and dissipates loads between the bones.

We know from previous research that various structures in the knee send neurosensory signals (or messages) to the brain. It is theses signals that result in us feeling pain.

Even though my patient's patella cartilage had worn out (just like the subject) there shouldn't be any pain there as articular cartilage doesn't have any nerve supply. No nerve endings means it is unable to detect pain.

Even the ACL and meniscus wasn't really that sensitive to the poking. This observation may provide an explanation for the often poor localization of structural damage that many patients experience with a cruciate ligament or meniscal injury.

Now you know, worn out articular cartilage doesn't cause you pain. The pain you have is likely to come from other structures.


SF Dye, GL Vaupel and CC Dye (1998). Conscious Neurosensory Mapping Of The Internal Structures Of The Human Knee Without Intraarticular Anesthesia. AM J Sp Med. 26(6): 773-777. DOI: 10.1177/03635465980260060601.

Wednesday, August 1, 2018

PS Sim - Winner Of The Cameron Ultra-Trail 100 Km Race

Picture from PS Sim
PS kindly agreed to not remain anonymous anymore so I can finally write here that she is the runner who won the Cameron Ultra-Train 100 km race despite having plantar fasciitis (for the past six months at least). She came back to our clinic today to allow me to finish assessing her and treat the cause of her pain.

Actually, after my previous post, I've had questions from some readers already asking me what I did for PS and her plantar fasciitis.

Here's a summary of what I did for those asking. No ultrasound, no ESWT (shock wave) needed, no orthotics and no other gimmicks.

Just plain old accurate body reading and thorough assessment after the body reading pointed to clues around her hips being one of the main reasons to her pain in her plantar fascia. Other contributing factors also suggest that changing shoes and her foot type may have triggered it.

So, of course I started treating her hip first and also taught her what to do to prevent it from recurring. She needs to work at this still for the time being.

 I wrote in my last session with her that I only had time to treat parts of her foot along her Superficial Back Line (SBL) and The Spiral Line.
Superficial Back Line

I did more work on her SBL and also treated fascia along her Superficial Front Line today. After that I had to change her pelvic rotation and suggested she may want to try taping her foot (in case she was planning on starting training again).

Happy to discuss if anyone has questions.
Spiral Line
Congrats to PS once again for a race well won and to Melvin for winning PS.

Sunday, July 29, 2018

Patient With Plantar Fasciitis Who Saw Me 3 Days Ago Won 100 km Race

My patient who had been having plantar fasciitis came to see me 3 days ago in the clinic just won the 100  km Cameron Ultra-Trail race.

It was quite a last minute request and I could only fit her in for a 30 minute session during my lunch break (new cases usually have an hour's appointment in our clinic).

Have a look at our WhatsApp exchange.

Not bad for half an hour's work. Now at least I get a full hour to sort it out properly next week. What did I do to treat her? Let me review her case when I next see her and I'll do a follow up post if I find something interesting.

Saturday, July 21, 2018

My Patient Was Told He "Just" Tore His Lateral Meniscus

Maybe it's not so obvious from just the picture above. But when I looked at my patient's legs, they were the first clue I received that perhaps there was something more than meets the eye.

He had gone on a skiing holiday in Whistler in March earlier this year and suffered a fall. After being brought to the physiotherapy clinic on site, they just gave him a knee brace and told him that he tore his lateral meniscus and that it will recover in a month or two. He actually felt fine after a few days of resting and thought he recovered fully after returning to New York where he's studying.

Two months later, when he tried to play tennis once, his right knee "gave way" and he had a very sharp pain for a few seconds. That actually subsided quite quickly too. Similarly on another occasion when he had a kick around game of football with his friends, his knee collapsed again.

He then mentioned that he wasn't confident about running, playing sport with his knee since even it seems to him that he'd recovered.

From what he told me, I immediately suspected he'd tore his Anterior Cruciate Ligament (ACL). Not wanting to "scare" him at first, I didn't say anything to my patient I went through all the ligament and joint testing thoroughly.

After checking his patellofemoral and tibia femoral joints, I did the Lachman's test, Reverse Pivot Shift test and the Anterior Drawer Test for the knee and they were all positive. (I seldom get a positive result for the Anterior Drawer Test but for him there was pain and a big difference in laxity compared to his other leg).

My patient was very shocked when I told him that he'd torn his ACL based on my assessment findings. He wasn't very convinced at first until I explained to him what I found based on his history, the positive orthopedic tests (and the fact that the physiotherapist in Whistler didn't actually examine him). Later he added that no wonder his knee never felt quite right after the skiing trip and now he knew the reason for it.
From my patient
He later went to see his general practitioner doctor and got a referral for a MRI scan and he later messaged me the result as you can see in the picture above.

After some consideration, he decided to do his ACL reconstruction yesterday in Singapore instead doing it elsewhere. Here's the picture he sent me upon discharge from hospital today.
Picture from my patient
It's not the the first time I have a patient who tore his ACL but the previous doctor/ medical practitioner/ physiotherapist they went to first missed it.

Please make sure whoever you see for your knee pain assesses your knee thoroughly.

Saturday, July 14, 2018

They're Not Spitting, It's Carb Rinsing

Helps with penalty taking?
Last couple of days before the end of the Russia 2018 World Cup and if you've been watching the football matches, you've noticed all the rinsing and/or spitting some of the football players do nearing the end of the match. Particularly before the penalty kicks so that their performance won't decline. 
Yes, the players seem to be taking a long swig from the water bottles and then they expel all the contents instead. The players are actually "carb rinsing".

I've written about this "rinse and spit" way back in 2010. It definitely works. Yes, us runners and triathletes have done this for a long time before the footballers caught on. If  you live in Singapore, you'll know that how it feels racing in our super hot and humid climate. Not everyone can handle eating a Power bar or gel and it's worse when you drink too much because you'll end up feeling bloated. And once you feel bloated, it's gonna be real difficult to run fast.

How does it work? It involves "tricking" the brain a little. Exercise physiologists explain that receptors in our mouth send signals to our brain (reward and pleasure areas) suggesting that more energy is on the way so our muscles can push a little harder and there should not be any reason to feel tired.
Ronaldo does it too
Research suggest that carb rinsing works better when the fluids are swished around the mouth for at least five to ten seconds, the longer the better so that more oral receptors come into contact with the carbohydrates in the drink.

Please take note that there needs to be actual carbohydrates in the drink that you use and carb rinsing cannot sustain you for an indefinite period. You still need to eat or drink actual carbohydrates as your body's muscles become depleted of glycogen. 

It seems to work best for intense exercise lasting between 30 mins and and hour so perhaps rinsing your mouth and then actually swallowing some of it for best results if your races are longer.


Currell K, Conway and Jeukendrup AE (2009). Carbohydrate Ingestion Improves Performance Of A New Reliable Test Of Soccer. Int J Sp Nutr Ex Metab. 19(1): 34-46.

Phillips Sm, Sproule J and Turner AP (2011). Carbohydrate Ingestion During Team Games Exercise: Current Knowledge And Areas For Future Investigation. Sports Med. 41: 559-585.

Rollo I, Williams C et al (2008). The Influence Of Carbohydrate Mouth Rinse On Self-selected Speeds During A 30-minute Treadmill Run. Int J Sp Nutr Ex Metab. 18(6): 585-600.

Sunday, July 8, 2018

Influence Of Maximalist Running Shoes On Biomechanics

My patient's new running shoes
I had a runner come in to our clinic today. After finishing the Boston marathon in April recently, he had been taking it easy. But since his next race is the New York marathon later on 4th November this year, he started training again just this past week.

After asking the necessary questions regarding his training, I then noticed he was wearing a new pair of maximalist  running shoes. He'd bought it after running Boston as it was a lot cheaper there than in Singapore.

My patient thought that the mega cushioned maximalist shoes would help protect him from the pounding that comes with the running (since he's in excess of 6 feet). 

It was then really fortunate that I'd recently just read an article on the influence of maximalist running shoes on running biomechanics.
Women's NB 880

In that study, researchers had 15 female runners tested by running 5 km on two occasions on a treadmill. Each time, their running biomechanics were analysed before and after running in a pair of "traditional" New Balance (NB) 880 which had a heel height of 35 millimetres and forefoot height of 34 mm versus a Hoka One One Bondi 4 (4l mm heel, 34 mm forefoot height). 
Hoka One One Bondi 4
It is important to note here that the runners were more accustomed to shoes like the NB than the Hokas.

Before reading the article, it seemed logical to me to expect the plush mega cushioned shoes would be more supportive for the tested runners.

However, runners in that study had greater vertical loading rates (the speed at which impact forces affect the body) and peak impact forces (maximum amount of force incurred at one time) in the Hokas than the NB shoes. Meaning, when the runners wore the more cushioned Hokas, the bodies absorbed more of the impact forces of running and in less time. While wearing the regular NB shoes, the impact forces of each step were lower and more evenly spread over time.

The authors noted that even though all the tested runners were assessed to be heel strikers, the higher impact forces while wearing the Hokas cannot be totally attributed to a change in foot strike pattern. In other studies, running in mega cushioned shoes result in runners landing with stiffer knees, resulting in higher impact forces.

Another point to note is that the runners in this study were new to maximalist shoes. I don't know about you, for me, if I get a new shoe to run in (or new tennis racket or any new equipment), my body takes a while to get used to it and run efficiently with it. (Note: even my wife who got a new iPhone X previously took a while before she liked it).

Previously, when minimalist running shoes were more popular caution was advised when trying those shoes. This study suggest such caution if your new running shoes have significantly more cushioning than your previous.

It will be interesting to note what happens to the impact forces when you get used to the maximalist running shoes. The authors of this study are now conducting follow up research on the same runners. The runners are monitored by starting with 20 percent of the weekly mileage in the Hokas, and adding 20 percent the next week and so on.

As I've suggested before, it's probably wiser if you have a few different pair of running shoes so that you can rotate your running shoes to minimize your risk of injury. Now, which runner can resist getting another pair of running shoes to run in?


Pollard CD Ter Har JA et al (2018). Influence Of Maximal Running Shoes On Biomechanics Before And After A 5k Run. Orth J Sp Med. 6(6): 2325967118775720. DOI: 10.1177/2325967118775720.

Friday, June 29, 2018

Popliteus Is The Problem, Not Baker's Cyst

Back of L leg
I had a patient who came to our clinic this past week complaining of pain in the back of her knee. She looked at her symptoms online and thought she had a Baker's cyst. One look at it and I told her not a chance of it being a Baker's cyst.

After examining her knee carefully, I told her it was her popliteus muscle bothering her.

Here's some background information about my patient. She was about 13 months post ACL (anterior cruciate ligament) surgery, back to weight training, running and training two to three times a week for netball.

Now, as far as I remember, every single patient who've undergone an ACL reconstruction I've treated have had a problem with their popliteus muscle at some point or other.

The popliteus muscle is triangular in shape sitting at the back of the knee. It starts on the lateral femoral condyle (posterior, outer part) of the femur (thigh bone) and the lateral meniscus. It then runs down and across the back of the knee joint to finish on the posteromedial (inner) part of the tibial (shin bone).
R popliteus
The muscle limits excessive internal and external tibial rotation. It helps straighten your knee from full extension by rotating the tibial internally. It also "pulls" the lateral meniscus out of the way during knee bending to prevent too much compressive forces from the femur of the tibial so you don't tear your lateral meniscus.

The poplitues muscle is very seldom the main cause of the problem. There is usually a problem with other stabilizing strutcures in that posterior lateral corner of the knee. It is often hurt because of compensating mechanisms related to that. Such has hip rotator weakness that transmits excessive forces towards the knee. Also, hamstring weakness with hip, knee pivoting movements, which are extremely common in netball.

Consider that most ACL reconstructions for patients now are done usually using the hamstring grafts so the hamstring is consistently weaker thus causing the injury/ strain to the popilteus muscle.

Treating the poplitues muscle for my patient was the easy part. I got her pain free at the end of the session. Ensuring the pain does not come back is trickier.

She needed to address the weakness in her hip stabilizers and hamstrings to prevent the problem from coming back. And that will take some effort on her part.