Sunday, February 26, 2023

Is It Easy To Return To Pivoting Sports After Articular Cartilage Surgery?

Picture from Upswinghealth
My receptionist has been complaining of left ankle pain, especially after her netball training. While treating her, I found out that her ankle injury was sustained a year ago while playing competitive netball. She's been training very hard as she's hoping to represent Singapore one day. 

She saw 3 physiotherapists concurrently last year, but none really treated her. They all just gave her exercises to do. 

After assessing her, I told her she may have an osteochondral injury (or articular cartilage injury) in her ankle. I also shared with her a recent article (Toyooka et al, 2023) on how successful athletes are, at returning to pivoting sports after articular cartilage surgeries.

The scoping review evaluated the following articular cartilage procedures: microfractureosteochondral autograft transplanation (OAT, or mosaicplasty,  harvested from one's own joint), osteochondral allograft (OCT, using a cadaveric graft) and autologous chondrocyte implantation (ACI, or autologous chondrocyte transplantation, ACT ). All of which have been written here previously.

16 studies fulfilled the ine inclusion criteria, of which 7 studies evaluated the microfracture technique alone. 44 to 83 percent managed to return to sport (RTS) after 6.2 to 10 months. 25-75 percent managed to return to their preinjury level. Average defect size was between 1.9-4.9 cm2

87-100 percent of athletes managed to RTS after their OAT or mosaicplasty surgery after 11.8 weeks to 6.5 months.. 67-93 percent managed to get back to their preinjury levels. Mean defect size varied from 1.34 to 2.9 cm2 (this is smaller than most OAT procedures that I've read previously).

For ACI, 33-96 percent managed to RTS 10.2 months after their surgery. 26-67 percent managed to return to their preinjury levels. Mean defect size ranged from 2.1 to 6.4 cm2. These athletes had also previously undergone an average up to 2.7 other surgeries.

The rate of RTS with the microfracture technique was not higher compared to other techniques in this review. This technique is usually the first-line treatment for articular cartilage injuries since it is relatively low cost and technical ease. Patients usually RTS within 9 months. The main disadvantage is that there is no restoration of hyaline cartilage. Fibrocartilage is formed after the procedure which may not tolerate pivoting sports. It is also not suitable for those with larger defect injuries. Defect sizes larger than 2 cm2 may not have good postoperative oucomes. 

Microfracture awls to puncture holes in the bone
The OAT or mosaicplasty techniques involve harvesting a bone plug with intact cartilage from the patient's joint in a non weight bearing area and transplanting that into the defect area. The main advantage of this technique is that it has high healing potential as a patient's own bone plug is used allowing the bone to integrate immediately. There may be some risk to donor site morbidity if too big bone plugs are taken (pictured below).

Harvesting the bone plugs in the knee
87-100 percent of athletes managed to return to pivoting sports after their OAT or mosaicplasty surgery after 11.8 weeks to 6.5 months in this review. 67-93 percent managed to get back to their preinjury levels. This suggest that the OAT  procedure may offer a good acceptable result for high demand athletes. Mean defect size varied from 1.34 to 2.9 cm2 (this is smaller than most OAT procedures that I've read previously) and smallest in this review.

ACI requires 2 surgeries to restore the damages done to the hyaline cartilage lining the joint, described in more detail in a previous post. For this review, 33-96 percent managed to RTS 10.2 months after their surgery. 26-67 percent managed to return to their preinjury levels in high demand pivoting athletes. Pivoting sports may have a lower RTS ate compared with other sports.

Mean defect size ranged from 2.1 to 6.4 cm2. These athletes had also previously undergone an average up to 2.7 other surgeries. This technique is used primarily with larger defects. However, it's limitations are requring 2 surgeries, high cost, open surgery and a very prolonged rehabilitation. 

Based on this review, the OAT procedure had the highest RTS rate in pivoting sports. They also returned to sport faster, especially when the defect size is small. For large defects, OCA and ACI may be considered with ACI preferred since OCA (caderveric) has many limitations like being expensive, limited in supply and restricted in many countries. Harvested bone plugs also need to be implanted within 14-21 days.

Most studies in this review reported high RTS rates although return to preinjury level was lower. RTS is a very critical variable and benchmark (to me) for patients who are athletes. These data can be used as a basis for selecting treatment options. 

Not only there are very few studies that only study athletes, the sports they compete in also vary. There was a tendency for RTS to be higher when the level the athletes were competing in were higher (especially professional), perhaps due to their access and compliance with rehab protocols, adaptibility to competition and for financial reasons.

Note that there was not enough data on the lesion size to decide between ACI and OAT. There were no significant difference in short term results between the two, although ACI outperformed the OAT in 10 year outcomes (in 2 studies).

Well, to my receptionist and other athletes reading this post, I hope this helps with your decision making should you need to consider the different options to return to your sport. It is definitely a long and winding road, with treacherous falls along the way while attempting your comeback, but it can be done.

Trust me, I've had 3 knee surgeries, a skull fracture and broke my back twice. You just need to be be persistent and never give up. Our team in our clinics have been patients before too and know how it feels like to be a patient and will be able to understand and do their utmost to help you.


Bentley G, Biant LC, Vijayan S et al (2012). Minimum ten-year Results Of A Prospective Randomised Study Of Autologous Chondrocyte Implantation Versus Mosaicplasty For Symptomatic Articular Cartilage Lesions Of The Knee. JBJS Br. 94: 504-509.

Biant L, Vijayan S, Macmull S et al (2012). Autologous Chondrocyte Implantation Versus Mosaicplasty For Symptomatic Articular Cartilage Defects In The Young Adult Knee: Ten Year Results Of A Prospective Randomised Comparison Study. Orthop Proc. 94-B: 122-22

Toyooka S, Moatshe G, Persson A et al (2023). Return To Pivoting Sports After Cartilage Repair Surgery Of The Knee: A Scoping Review. Cartilage. Pub online. DOI: 10.1177/194760352211414

Sunday, February 19, 2023

Steroid/ Cortisone Injections Significantly Increase Risk Of Tendon Tears

Picture from BuzzRx
I was asked to do a home visit for a patient who was having some pain in his hip 2 days ago. The patient hurt his knee last year while playing golf and the doctor he consulted did a steroid/ cortisone injection for him. His knee was better for a while but some of the pain came back a short while later. 

Perhaps my patient was not able to weight bear well on that right knee since then and subsequently that caused his right hip to act up. After assessing him, I found that his sore knee was not the main cause of his hip pain, but definitely a contributing factor. 

I shared an article (referenced below) that I just read just a few days ago with my patient and his family regarding steroid/ cortisone injections. There were 1025 patients with shoulder pain in that hospital study. 205 patients received a steroid/ cortisone while 820 did not (they acted as the control group).

Patients in that study who received a steroid/ cortisone injection (for their shoulder pain) significantly increased the risk of having a shoulder tendon tear by 7.44 times compared to those who did not receive a steroid/ cortisone injection! 

Those who had concurrent chronic liver disease were 3.25 times more likely to have a torn tendon while those who smoked by 2.4 times. Another reason to stop drinking and smoking too.

Since my patient is an avid golfer and still very active, I told him he definitely does not need to have any more steroid/ cortisone injections anywhere else on his body. There are high chances of degenerative changes in the surrounding areas where the steroid/ cortisone is injected.

Remember my true story when I used to work at the Singapore Sports Institute (formerly Singapore Sports Council). Back then, I used to treat the badminton players frequently and traveled with them on most of their training trips and competitions. (Ronald Susilo and I pictured below after he beat world number one Lin Dan at the Athens 2004 Olympics).
I'm more excited than Ronald
In 2006-2007, Ronald Susilo had on and off right elbow pain, in his playing arm. He was subsequently injected with steroids (cortisone) a few times to help with the pain so he could train and compete.

Tragedy struck at the 2007 SEA Games in Thailand. He tore a forearm muscle while playing at the Games. I was tasked with accompanying him back to Singapore for a visit to the surgeon to repair it.

I've accompanied Ronald for all his sporting surgeries. His shoulder in 2004, Achilles in 2005 and right forearm in 2007. These were his words to the operating surgeon, "Gino knows my body better than I, he's been around for all my operations."

As usual I was waiting outside the operating theater for Ronald when they operated on his forearm. The first words the surgeon said to me when he came out of the operating theatre was, "We found cortisone still in his arm." My interpretation was that he meant too much steroid/ cortisone had been injected into Ronald's forearm. That probably caused the muscle to tear. Just like what the study by Lin et al (2022) had found.

Yes, there would definitely be occasions where a steroid/ cortisone injection is needed.  However, speaking from personal experience, if you're an athlete or participating in sports regularly like my patient, please reconsider if your doctor suggests a steroid/ cortisone injection. There are definitely other ways to treat your pain/injury besides getting a steroid/ cortisone injection. You definitely do not want to risk tearing any muscle or tendon after that.


Lin CY, Huang SC, Tzou SJ et al (2022). A Positive Correlation Between Steroid Injections And Cuff Tendon Tears: A Cohort Study Using A Clinical Database. Int J Environ Res Pub Health. 19(8): 4520. DOI: 10.3390/ijerph19084520.

Sunday, February 12, 2023

New Evidence That Collagen May Help Your Tendons

Collagen liquid used in the study
I recently had quite a bit of pain in my right Achilles tendon. Besides getting Aized to treat me and wearing my Strassburg sock to sleep, I had to do some rehab as well. Running didn't hurt much, going down stairs was more painful.

Naturally my curiousity was piqued when a newly published study (Lee et al, 2023) on a group of elite female football players found a big improvement in tendon stiffness after taking collagen supplements 3 times a week. The study measured the properties of the patella tendon which connects the patella (kneecap) to the shin bone as this is a common injury site for female soccer players. Ultrasound and strength tests were measured before and after training.

Training consisted of on-field soccer practice, leg strengthening exercises and plyometrics.

The participants took 30 grams of hydrolyzed collagen (pictured above) 3 times a week immediately after training while the control group took a calorie- matched placebo drink. Both groups also took 500 milligrams of Vitamin C as it is thought to be necessary for the body to be able to use the collagen.

Results showed an increase in tendon stiffness. The stiffer tendons become, the more they stretch and the more energy they store. Stiffer tendons have shown to be associated with better running economy since they can recycle more energy from each stride.

The group taking the collagen had a significant 18 percent increase in tendon stiffness compared to the placebo's 8 percent gain. There were no differences in size or cross sectional area of the tendon, suggesting that the extra collagen ingested improved the microscopic structure of the tendon. There was also no differences in leg strength.

Remember Professor Keith Barr? I wrote about his gelatin collagen research in 2019. His research group from UC Davis published evidence suggesting that taking collagen plus Vitamin C enhances jump and squat performance but without significant change in leg stiffness (Lis et al, 2022).

Another published research (Jerger et al, 2022) found that taking collagen supplements daily boosted tendon cross sectional area, but did not improve tendon stiffness more than the placebo group.

Confused? Especially with each study mentioned above producing different results. Study protocols were different and this is actually good since it means that you do not have to follow one specific 'magic' protocol to get the benefits.

More research and details need to be worked out, as more studies are done, it will hopefully prove that tendons and ligaments can heal better than we think. So other than training your tendons and wearing your Strassburg sock when you sleep, collagen supplements may be something you want to try.


Jerger S, Centner C, Lauber B et al (2022). Effects Of Collagen Peptide Supplementation Combined With Resistance Training On Achilles Tendon Properties. Scan J Med Sci Sports. 32(7): 1131-1141. DOI: 10.1111.sms.14164

Lee J, Bridge JE, Clark DR et al (2023). Collagen Supplementation Augments Changes In Patella Tendon Properties In Female Soccer Players. Frontiers in Physiol. Vol 14. DOI: 10.3389/fphys.2023.108977

Lis DM, Jordan M, Lipuma T et al (2022). Collagen And Vitamin C Supplementation Increases Lower Limb Rate Force Development. Int J Sp Nutr Ex Metab. 32)2): 65-73. DOI: 10.1123/ijsnem.2020-0313

Sunday, February 5, 2023

Run Like A Snail To Go Fast?

I recently read a story about Alex Karp. Yes, that Alex Karp, who is the founder of Palantir Technologies, a tech company that specializes in data intelligence. Karp is 55 years old, but has 7 percent body fat! At his age, that is an extremely low level of body fat. That's the body fat level Michael Phelps had when he competed at the 2008 Beijing Olympics and won 8 gold medals.

Karp is a tech billionaire though, not a young Olympic gold medalist. He says he does not *diet nor starve himself. His fitness comes from 5 hours plus of cross country ski training a week.

What can we learn from Karp's training so that we too can benefit? Karp says he spends 90 percent of the time going at the speed of a snail! Whether you are running or cross country skiing, Karp advises going at the "slowest pace a human can run for as many hours as you can afford. And then once, preferably twice, a week, you're doing speed intervals."

Karp's training is all about sheer distance, just put in the miles he says. No speed or intensity, except when doing his intervals. He started training like this when the Covid pandemic hit. He was already in reasonably good shape before. But since he had lots of time, he became very disciplined about training in that format. He saw results after 18 months, and especially huge results after 36 months. 

Karp says he learned this training regime from athletes in Norway. Norway has won the most number of Winter Olympic medals for cross country skiing. Going slowly like a snail most of the time helps build a cardio base so that it allows you to go fast when you have to. Like when doing intervals or when racing. 

This form of training is also known as low intensity steady state training (LISS), the exact opposite of high intensity interval training (HIIT). LISS is the tortoise compared to HIIT's hare. When you go for a jog/ run, long walk, bike ride where you can easily hold a conversation, you are performing LISS. For those who need a number, this is usually between 50 to 65 percent of your maximum heart rate. 

Like HIIT, LISS can also help you burn fat, build endurance and increase exercise capacity. However the time you need to spend doing it to achieve those results is typically much longer. LISS can help you recover from those high intensity workouts while supporting your larger fitness goals. Exactly like what Karp is doing. 

For many of us who exercise and train, our hard sessions are not usually not hard enough and our easy (or recovery) sessions are not easy enough. This is why some athletes use a heart rate monitor (HRM) to train. This ensures that you know the correct intensities. Ben Pulham from Coached Fitness has been advocating training with a HRM for a long time. BUT, you have to really adhere to the readings, otherwise it will not be effective. With Singapore's climate, you really have to go a lot slower.

Yes HIIT can be super effective, but also incredibly stressful on the body. Do it too often and you'll increase your risk of overtraining and injury which will hinder your progress and shortchange your results. 

Alex Karp says it took him at least 18 months before he saw results. Can you be that patient? You have to, if you want results. If HIIT is a calorie scorcher, then LISS is a slow simmer where calories are still burned even if you don't emerge from your workouts drenched in sweat. 

Research also shows that those who engage in low intensity exercise are more likely to stick to their plan compared to those who attempt to accomplish the same goals in half the time with HIIT (Forster et al, 2015). The subjects found HIIT "less enjoyable".

Then, there's also the engagement factor. For some people, running, walking, cycling or swimming for a few minutes can feel endless. Me? I love the long, slow runs and rides.


Forster C, Farland CV, Guidotti F et al (2015). zthe Effects Of High Intensity Interval Training Vs Steady State Training In Aerobic And Aerobic Capacity. J Sp Sci Med. 14(4): 747-755. PMID: 26664271

*The biggest adjustment Karp made was dropping added sugar in his diet. He used to eat lots of chocolate, and had sugar in his coffee and tea. However, on special occasions and if he's traveling and finds a really nice Danish, he will eat it.