Still Think It's The Thigh Muscles?

I have seen many patients who have had an anterior cruciate ligament (ACL) tear over the years.  Some patients chose not to go under the knife but most had reconstruction done. ALL of them were taught to focus their strengthening on their quadriceps (or thigh) muscles.

So not surprising that a recently published study by Alzobi et al (2026) found that patients who did not opt for surgery exhibited progressive hamstring muscle atrophy.

A total of 1,207 thighs were examined. There were 92 with ACL tears and the other 1,115 acted as controls. The average age of the subject group was 61± 9 years.

Over 4 years, the ACL deficit thighs were smaller by an average of 28.18 mm, all due to progressive hamstring atrophy. The differences ranged from 13.92 to 42.43 mm smaller. The sartorius muscle also atrophied by an average of 3.02 mm.

There were no significant differences in the quadriceps or adductor cross sectional area. hamstring force was decreased significantly whereas quadriceps force showed no significant change.

The researchers concluded that muscle deterioration occurred in the posterior thigh muscles (hamstrings) with minimal changes in the front thigh muscles (quadriceps) over time. And for ACL deficient knees, it is really important to target long term rehabilitation strategies focusing on hamstring preservation. 

We already know that one of the reasons women sustained ACL tears is that their hamstrings were significantly weaker than their quadriceps muscle strength.

If you have been reading our previous blog articles, you already know that the quadriceps (thigh muscles) and gastrocnemius (calf muscles) increases load on the ACL due to anterior shearing forces at the tibia (shin bone). This is especially so when the knee is straightened (Maniar et al, 2022).

The hamstrings and soleus (deeper calf muscles) help to unload the ACL by generating posterior tibial shearing forces (Maniar et al, 2022).

So for those of you who have torn your ACL, whether or not you choose to go for surgery, make sure you focus on your hamstrings and soleus muscles instead.

References

Alzobi O, Mohajer B, Fleuriscar J et al (2026). Thigh Muscle Changes In The ACL-Deficient Knee: A 4-Year Lonitudinal MRI Study of 1,207 Patients. JBJS Am. 108(3): 219-226. DOI: 10.2106/JBJS.25.0064

Maniar N, Cole MH, Bryant AL et al (2022). Muscle Force Contributions To Anterior Cruciate Ligament Loading Sports Med. DOI: 10.1007/s40279-022-016743

Quads And Squats

We saw a few patients who tore their Anterior Cruciate ligament (ACL) in our clinic this past week. I have written many articles on the ACL before. Once you've torn your ACL, it usually takes 9 to 12 months before you can return to your sport, not to mention the financial cost. 

I came across an interesting article summarizing the evidence of the relationship between muscle forces acting on the ACL. This is important since muscles around the knee can increase and decrease the strain and mechanical loads on the ACL. This presents opportunities for preventive intenventions. 

Subsequently, our staff had interesting discussions regarding that article (referenced at the end of this post). The article demonstrated the forces acting on the knee joint and what can cause injuries there, specifically, what can hurt the ACL. 

The article reviewed muscle and and ACL loads during knee bending as well as weight bearing tasks like walking, lunging, landing, jumping and sidestep cutting.

Ready for the results? The quadriceps (thigh muscles) and gastrocnemius (calf muscles) increases load on the ACL due to anterior shearing forces at the tibial (shin bone). This is especially so when the knee is straightened.

The hamstrings and soleus (deeper calf muscles) helps to unload the ACL by generating posterior tibial shearing forces. For the hamstrings to 'protect' your ACL, your knee has to be bent at least 20 to 30 degrees.

R gluteus medius

The gluteus medius muscle was demonstated to consistently prevent the knee from collapsing inwards (knee valgus movement) and thus unloading the ACL, better than any other muscle.

Surprised? 

Patients who have been been told to strengthen their quadriceps (especially after ACL reconstruction) were really surprised when we told them. Make sure you focus on your hamstrings and soleus muscles instead.

The muscle to rule them all is of course the gluteus medius. Our patients will now understand why we always ensure their gluteus medius muscle is strong to prevent knee pain, Achilles tendon and of course ACL injuries.

Now you know.

Reference

Maniar N, Cole MH, Bryant AL et al (2022). Muscle Force Contributions To Anterior Cruciate Ligament Loading Sports Med. DOI: 10.1007/s40279-022-016743

Let Us Help With An Online/ Video Consultation

I remember doing an video consultation a few years ago with a former patient of mine who left Singapore and relocated to Hong Kong. I treated his shoulder previously and he tore his Anterior Cruciate ligament (ACL) and had the reconstruction done in Hong Kong.

He was frustrated as he was not improving (as you can read from his iMessage to me above) and wanted my advice. I was very hesitant as I wondered how I can assess him physically without being there. I wondered if I could really be of help.

I told him that if I hadn't treated him before I would not have agreed to the video conference. Even though he insisted on paying, I didn't charge him for that video consultation.

In this particular consultation what really helped was that my patient already had his ACL reconstruction done. He was also able to describe his symptoms in detail. So what the patient tells us can perhaps replace the assessment tests we need to do. We can then guide the patient through the session if we need them to do any active movements or tests.

Why am I writing about tele/ video consultations here? Well, these are unprecedented times. On 3rd April 2020, our Prime Minister went on national TV and announced the implementation of a "circuit breaker" to minimize the further spread of COVID-19.

In line with the new policies set out by our government, our clinics will be closed from Tuesday 7th April to 4th May 2020, both dates inclusive. We will reopen as soon as we are able to do so.

We understand and support this temporary closure as it is in the best interest of our community. We all need to do our part to make this work to overcome this pandemic.

We will be available for tele/ video consultations during this period of closure.

If you’re a patient at Physio Solutions, please contact  +65 9297 9641.

If you’re a patient at Sports Solutions, please contact +65 9112 5326. 

Despite my doubts and hesitation wondering whether online/ video consultations will help, my patient thought it was "super helpful" if I may quote him from his message above. Again, he asked me to bill him, but I did not. He actually felt much improvement from what I taught him and subsequently came back to Singapore to see me 3 times for his knee.

Never Give Up!

Chapeau to  Ronald Susilo. This guy just keeps on going and going. After suffering many potential badminton career ending injuries while at the top of his game, he has always managed to bounce back.

After winning the Japan Open Grand Prix and then beating World Number One Lin Dan at the 2004 Athens Olympics with a torn shoulder labrum, he went under the knife.

More heartbreak followed after coming back from that when he tore his achilles tendon at the World Badminton Championships in 2005.

Yet he persisted. Tragedy again at the 2007 Sea Games when he tore his right forearm muscles playing against Vietnam. Again he managed to bounce back and we went to our second consecutive Olympics together in Beijing in 2008.

His wife sent him to Sports Solutions in this 

Even after retiring from national duty, he kept playing after he started coaching. And subsequently ruptured his patella tendon while tearing his ACL and medial meniscus at the same time. He needed 2 operations after this. Attaching the patella tendon first before repairing the ACL almost a year later.

And now this right shoulder again .....

Well, Ronald we've done this together too many times before. But I know you'll be back once more. You can do this!! Want to be a champion? Passion for the sport and persistence is what you'll need. Lots of it.

In the picture below, you see me celebrating and more excited than Ronald Susilo himself after he defeated Lin Dan in the 2004 Athens Olympics.

Yes, I used to sit on court with him and his coach every time he played.

How Gelatin (Jell-O) May Help Healing

Home made soursop flavoured

I came across Professor Keith Barr's work on ligaments, tendons and how they heal etc and was amazed that gelatin may hold the secret to recovering from many ligament and tendon injuries.

Professor Baar and his colleagues at UC Davis have been growing "engineered ligaments" in the university lab, subjecting them to all sorts of loads/ abuse) to understand what factors affect injury risk and healing. They may also have found how to train and feed (yes, you read correctly) connective tissue like ligaments, tendons, bones and cartilage.

We've always thought that connective tissue does not heal well. But Professor Baar's "engineered ligaments" grown from remnants of ruptured ACL's collected during reconstructive surgeries showed that it may not be totally true.

When ligaments are "exercised" by movement/ stretching, they respond by forming new collagen fibers (these are the building blocks for new ligaments and tendons). However, this process peaks in about ten minutes and begins to switch off if exercise is continued. Exercising for three hours may be good for your heart and muscles, but not great at all for your tendons, ligaments and other connective tissue.

The "engineered" ligaments also respond to proline, an amino acid. Professor Baar found that best way to ingest proline was taking gelatin. Their study showed that blood test of participants in a skipping rope test for six minutes, three times a day doubled the rate of collagen growth. When the participants consumed 15 grams of gelatin with Vitamin C an hour before each skipping rope session, collagen growth doubled again.

Now, I'm not asking all of you to run out and buy all the gelatin you can get, cook and eat it an hour before doing the specific exercises you need. Skeptics among you readers (myself included) will probably scoff at the idea of eating gelatin and hoping that it will specifically go to strengthen the injured ligaments and tendons in your body.

Professor Baar himself has said that as word of his research spreads, some athletes may develop unrealistic expectations. Eating gelatin without doing the specific strengthening exercises to help new collagen fibers grow in the stressed areas is one. The optimal exercises will depend on what type of connective tissue you're trying to strengthen.

For the injured and non injured athletes that are reading this, I've read that hydrolyzed collagen powder is easier to use compared to gelatin as it does not require boiling and cooling down. It also seems to be equally effective for tendons based on preliminary research in Professor Baar's lab.

For those of you who torn your ACL fully, no amount of gelatin plus specific exercises would help. This is more for patients who have strained (not totally torn) ligaments and tendons.


References

Lis DS and Barr K (2018). Effects Of Different Vitamin C-enriched Collagen Derivatives On Collagen Synthesis. Int J Sp Nutr Ex. DOI: 10.1123/ijsnem.2018-0385

Shaw G, Lee-Barthel A et al (2017). Vitamin C-enriched Gelatin Supplementation Before Intermittent Activity Augments Collagen Synthesis. Am J Clin Nutrition. 105(1): 136-143. DOI: 10.3945/ajcn.116.138594.

*picture by Smabs Sputzer (1956-2017) from Flickr

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. And you definitely don't need to ingest any glucosamine too.


Reference

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.

black and white version

How Effective Is Your Knee Brace?

Assortment of soft knee braces from the Holland Village Guardian

How many of you have seen runners run past with a knee sleeve/ brace on? That's what I always look out for! But that's me and that's what I always do, watching people move and see if there's anything wrong or different.

I've also seen so many of my patients walk in to our clinic with a self prescribed over the counter soft neoprene knee sleeve/ brace. Often, they are asked by the doctors they see to wear a brace.

Often prescribed by doctors

I always ask the patients why they have the sleeve/ brace on. Some will say the brace helps with their pain or it makes their knee feel less wobbly. They usually reply that they feel a little more secure with the sleeve / brace. Most, however are not sure if the sleeve/ brace works.

Let me explain what the differences are. Braces that are stiff and rigid are usually made from plastic, aluminium or carbon fibre. They usually restrict joint movement by physically pressing against the bones of the knee to provide firm external support.

My patient in his rigid knee brace 

While the rigid knee brace can help restrict or limit movement, there is a definite downside  to using them. Have a look at my patient who had a tibial plateau fracture and a partially torn anterior cruciate ligament (ACL).

Check out the rigid brace

See the difference in thigh girth?

Since knee movement is often limited and restricted, the load is often transmitted to the ankle, hip and lower back. Often I end up treating them for the back pain too.

The softer neoprene type sleeves usually will not be able to provide the same mechanical support as they are much softer and do not have any rigid structural support. Neoprene sleeves generally help the wearer by increasing proprioception (or joint position sense) much like the high cut shoes basketball players wear to give themselves more awareness of their ankles to prevent ankle sprains. It is believed that improved proprioception around a knee joint can help stability by improving balance.

However, a 2012 published study of people with knee arthritis found no significant improvements in balance with the use of a neoprene knee sleeve.

There is also very little evidence that knee supports worn prophylactically on healthy knees protect active people against knee injuries.

Granted, knee supports/ braces are usually less expensive or as invasive against knee operations to treat injuries or even arthritis so so people will try them before resorting to surgery.

Some specialized knee supports may help to take pressure off the knee joint while walking and especially during exercise. My patient (in the picture below) intends to use her brace when she goes back to wake boarding and skiing after her injury. Of course I added that proper rehabilitation is important too. Such braces may also be able to help patients with knee arthritis remain active and put off surgery at least for a while.

All ready for action

As explained above, rigid knee braces (but not sleeves) may help after some knee injuries. They are often prescribed by doctors after a patient suffers a torn medial or lateral collateral ligament (LCL). MCL's and LCL's tends to heal fairly well without surgery provided there is no further strain/ injury to the knee for the first 6-8 weeks after the initial injury.

Bracing can be effective when you know what injury you have and the structures involved as a brace can be matched effectively to your needs.

My MCL taping- "Much better than any brace" says my patient

I always prefer to tape compared to using a brace though. As I always say to my patients, I can customize the taping according to their needs and it always fits better than any brace they buy.

So don't just go and buy a sleeve/ brace.


Reference

Collins AT, Blackburn JT et al (2012). The Assessment Of Postural Control With Stochastic Resonance Electrical Stimulation And A Neoprene Knee Sleeve In The Osteoarthritic Knee. Arch Phys Med Rehab. 93(7): 1123.1128. DOI: 10.1016/j.apmr.2011.12.006.

*Big thank you's to all my patients who allowed me to take pictures or sent me pictures.

Muscle Wasting Occurs Quickly

Check out the difference in size.

Have a look at my patient's legs in the picture above. See the difference in size? Can you guess how quickly it happened?

My patient fell while skiing in Japan and the doctor there said she tore her medial collateral ligament (MCL). She was prescribed crutches, a huge brace and came back in a wheelchair.

There was definite swelling around her knee and I taped it to reduce the swelling of course and promptly taught her how to walk without the crutches and wheelchair.

2 days. that's how quickly the muscle atrophy took place.

Later an MRI confirmed she tore her MCL as well as her anterior cruciate ligament (ACL) as well.

Running Injuries? Blame Your Genes?

Chromosome by Hey Paul Studios from Flickr

All right, it's finally been proven, some people are more prone to injury than others. So says a newly published article from the British Journal of Sports Medicine.

The researchers found evidence from family and genetic studies that DNA sequence variants (together with non-genetic factors) can increase your risk for tendon and ligament injuries. This is for both exercise-associated and occupational-associated acute and chronic injuries to tendons and ligaments.

Although research at this stage is still preliminary, there have been specific gene variants found (COL5A1 gene) that are less likely (58 percent less) to cause Achilles tendinopathy (degenerative change in the tendon).

A different gene (COL1A1) is associated with ACL (anterior cruciate ligament) and Achilles tendon ruptures (September et al, 2009).

In fact, several other genes have been associated with injuries ranging from carpal tunnel to tennis elbow.

The common link among these genes is that they affect collagen fibrils structure. Collagen fibrils are the basic structural building block for tendons, ligaments and other connective tissue including fascia. In simple terms, some Achilles tendons are built better than others.

So what do you do with this information then? Athletes and coaches beware, especially when there are now many genetic tests marketed for self testing promising to reveal potential injury susceptibilities.

The researchers reported that such tests should be requested by an appropriately qualified healthcare professional since results need to be interpreted together with certain clinical indicators and other lifestyle factors.

Personally I'm fairly sceptical about such over the counter/ online genetic tests that you can purchase to do a self test on whether you're more prone to injury.

Will knowing that really change your training habits? As a previously compulsive competitive athlete, I trained as hard as I could handle and more without getting injured. Knowing I'm say, 10-20 percent more likely to get a tendon injury will not alter my day to day training. On the contrary, because I've been training hard for so long (previously), I know what injuries I'm prone to because I've already had them previously.

Hmmm, maybe from now I'll ask my patients whether they have a family history of tendon or ligament injuries instead. (Standard practice for Physiotherapists is asking patients if they have any family history of hypertension, heart diseases and cancer etc).


Reference

Collins M, September AV and Posthumus M (2015). Biological Variation In Musculoskeletal Injuries: Current Knowledge, Future Research And Practical Limitations. BJSM. DOI: 10.1136/bjsports-2015-095180.

September AV, Cook J et al (2009). Variants Within The COL5A1 Gene Are Associated With Achilles Tendinopathy In Two Populations. BJSM. 43: 357-365. DOI: 10.1136/bjsm.2008.048793.