Wednesday, June 22, 2016

Help! Both My Knuckles And My Knees Crack

Message from my patient
Have a look at my patient's reply in the WhatsApp message above when I asked about how her knee was. She came to see me earlier last week for "extreme pain" in her L knee. Couldn't run, couldn't jump.
Have a look at her battle scarred knees
I often get this question from my patients. "My knees keep popping or cracking when I squat, sit to stand etc. Is that a problem"?

I've also had patients ask me about knuckle cracking. Common urban legend suggest that too much knuckle cracking leads to arthritis of the hand joints. Worse still, there are also medical/ health professionals who will suggest that with the clicking/ grinding/ cracking in your joints, you have take glucosamine supplements to prevent osteoarthritis. Do not be fooled. You know my thoughts on glucosamine.

Well, let's settle this once and for all and set the record straight.

Within a joint, the joint space is filled with synovial fluid. The synovial fluid lubricates the joint. It also reduces friction in the joint when you move. There are also gases such as oxygen, nitrogen and carbon dioxide in the synovial fluid.

When you manipulate (crack or pop) a joint, you stretch out the space between the bones that make up that joint. This expanding space creates a negative pressure, causing the synovial fluid and gases to rush there. The larger bubbles collapse into microscopic bubbles, leading to that characteristic popping sound, and that's what you hear. The joint often feels better as the joint space is widened and the bones are repositioned better (*see reference I copied below from the article). The joint often has better range of motion too (see my patient's WhatsApp message above).

Do not mistake joint cracking/ popping or manipulation with joint crepitus. Joint crepitus feels a little like grinding you may hear/ feel when a bone moves against articular cartilage - the lining of the bones. Crepitus happens most often in the knees and has also been described as a crunching, grinding or popping sound. I often tell my patients that crepitus with no pain is usually harmless.

Many of my patients also confuse joint cracking with the snapping sound our tendons make when tendons slide between muscles or over bones. Tendons are like rubber bands stretched between muscles and bones to connect both of them. Hence, when a joint moves, the tendon snaps over the bone and can often make a popping or sliding sound. It's very common to hear these sounds in the knees and ankles when you go from sit to stand, squatting or walking up and down stairs.

There is no need to worry about these crunching, clicking, popping or sliding sounds unless they are accompanied by pain. Now you know.


deWeber K, Olszewski M and Ortolando R (2011). Knuckle Cracking And Hand Osteoarthritis. J Am Board Family Med. 24(2): 169-174. DOI: 10.3122/jabfm.2011.02.100156.

*During an attempt to crack a knuckle, the joint is manipulated by axial distraction, hyperflexion, hyperextension, or lateral deviation. This lengthens part or all of the joint space and greatly decreases intra-articular pressure, causing gases that have dissolved in the synovial fluid to form microscopic bubbles, which coalesce. When the joint space reaches its maximum distraction (up to 3 times its resting joint space distance), joint fluid rushes into the areas of negative pressure. The larger bubbles suddenly collapse into numerous microscopic bubbles, leading to the characteristic cracking sound. The maneuver leaves the joint space wider than it had been and synovial fluid more widely distributed. The stretching of joint ligaments required to produce the widened joint space also leaves the joint with greater range of motion. 

Thursday, June 16, 2016

Ankle Sprain? No, It's Cuboid Syndrome

R cuboid bone in the foot
I had a patient who came to our clinic today complaining of pain in the outside of his left foot. He thought he had sprained his ankle about 3 weeks ago while playing football barefoot. He rested, iced it  etc but it did not seem to get a lot better.

He then went to a Sports Doctor who diagnosed him with an ankle sprain and suggested that he see a Physiotherapist, which he did, but the one he saw did not make his ankle any better.

He still had most discomfort/ pain on the outer part of his left foot/ankle. Pain was worse during the push off phase of walking. He also couldn't run properly without pain.

However, his ankle proprioception (or joint position sense) was also not affected. Usually for ankle sprains, a patient's proprioception is usually worse on the affected side.

After a thorough assessment I found his ankle joint to be stable and free of pain. His pain increased on firm palpation of his left cuboid bone. The left cuboid also was sitting in a lower position compared to his right foot.

I explained to him that he did not sprain his ankle but instead there was probably a subluxation (or mild dislocation) in his cuboid bone. (I had actually seen two other cases of cuboid syndrome in the last few months).

The cuboid bone sits at the outer aspect of the mid foot and his connected to adjacent bones by strong connective tissue and ligaments (see picture above). During certain weight bearing activities like running, excessive forces placed on the cuboid bone (from the peroneal longus muscle especially) can sublux (or dislocate) the cuboid bone. This is exactly what happened to my patient. I've also seen this condition fairly frequently in ballet dancers that I've treated before.

How did I treat my patient? After the diagnosis, this is the easy part, or so I thought. I got him to lie on his tummy and gently tried to coax (or mobilise) his cuboid back into where it should be sitting. For some strange reason, it took a lot longer than I expected. My last two patients with cuboid syndromes had their cuboids back into position in less than five minutes.

It took me almost 20 minutes before my patient, his mother and I heard a loud click (of course I felt it with my hands too) suggesting I had relocated the bone.

I got my patient to stand up and try and he gave me a big smile after trying to walk and run. Job done, next patient waiting .....

Have a look at the reference below if you want to know more about cuboid syndrome.


Durall CJ (2011). Examination And Treatment Of Cuboid Syndrome. A Literature Review. Sports Health. 3(6): 514-519. DOI: 10.1177/1941738111405965.

Sunday, June 12, 2016

Which Drink Hydrates You Best?

Ever wondered which drink is best after a hard training session or race? I've written before that as a recovery drink, chocolate milk is as effective as Gatorade and even superior to Endurox.

Quite a few factors affect how quickly you pee out a certain drink. Drinks with more calories or electrolytes tend to stay in your system longer. How much you drink at a time also plays a part according to an article I read.

Researchers recruited 73 subjects to test 13 different drinks. Each subject tested water and three other beverages. At each session, the subjects drank a litre of the chosen beverage and collected their urine for the next four hours.

A "beverage hydration index" showed how much of that drink was retained after two hours compared to a litre of water.

Picture from American Journal of Clinical Nutrition

Looking at the picture above, you can see that a higher bar means more fluid retained. The dotted line represents twice the coefficient of variation away from water (meaning you can be real sure of a positive result).

The chart shows that milk stays longer in the body probably because of its calorie content. Milk and an oral rehydration solution (or sports drink, due to its calories and sodium) also stays in your system.

Personally, I was quite surprised that tea, coffee and beer did not seem to produce significantly more urine.

In fact coffee seems to have the lowest reading in the chart. The authors suggested that the diuretic properties of alcohol may be counterbalanced by its retention promoting calories (although another previous study that compared regular and alcohol free beer showed that regular beer drinkers had 12 percent more urine).

The authors also pointed out that larger doses of caffeine or alcohol may trigger more urine

Well, now you know not all drinks take the same time to reach your bladder. Choose your drinks wisely after your hard training session or race.


Maughan RJ, Watson P et al (2016). A Randomized Trial To Asess The Potential Of Different Beverages To Affect Hydration Of Different Beverages To Affect Hydration Status: Development Of A Beverage Hydration Index. Am J Clin Nutr. 103(3): 717-723. DOI: 10.3945/ajcn.115.114769.

Sunday, June 5, 2016

Drink It or Pour It?

Picture by richseow from Flickr
You've often seen the elite athletes pour water over their heads to cool themselves while racing. So is it really better to pour the water over your head on a really hot day or is it better to drink it?

Picture by richseow from Flickr
Well, here are some numbers obtained in the paper referenced below. In the article, kilojoules and calories are a measure of the energy dissipated as heat. The heat is produced as a by product of muscular exertion, which is powered by the energy from food.

Drinking a 250 mL cup of water at just above freezing ( 1 degree Celsius or 34 degress Fahrenheit) helps you get rid of 39 kJ of heat (about 9 calories).

If you drink a slushie that is half water and half ice, it's better as the ice can melt inside your body. A 250 mL slushie will get rid of 81 kJ of heat (or 19 calories).

Pouring a 250 mL cup of water on your head will get rid of 607 kJ (145 calories) if the water can be spread around your body surface so it all evaporates rather than dripping to the ground. Yes, evaporation is a great way of dissipating heat.

But, that's a very big "if" in my opinion as it's hard to pour a bottle over your head without spilling any water. although the authors suggested that even if you spill 85 percent of the water you still get more heat loss from pouring than from drinking the slushie.

Do take note that the water you pour over yourself has to evaporate. If it's a hot and super humid day like it always is in Singapore where your sweat is dripping like there's no tomorrow you won't have the water evaporating. Pouring cold water over your head probably makes your feel cooler (and hopefully better) for a while.

It works best when the weather is dry and breezy so that your sweat can evaporate. (Local runners who race overseas take note).

My suggestion would be to drink when you need and pour some cold water over your head and neck too to cool off if you don't mind your running shoes getting a little wet.

Best to be sure it is water and not a sports drink that you pour over yourself. Yes, I've accidentally poured 100 Plus over myself before when I was racing, so beware.


Morris N and Jay O (2016). To Drink Or To Pour: How Should Athletes Use Water To Cool Themselves? Temperature. 3(2): 191-194. DOI: 10.1080/23328940.1185206.