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Dealing with Knee Problems

Medical Director
The Orthopaedic Centre


Dr David Su, Medical Director at The Orthopaedic Centre, shares the common causes of chronic knee pain and other knee problems like knee osteoarthritis and Anterior cruciate ligament (ACL) tears.

Chronic knee pain for people below 45 is commonly caused by overdoing and overuse from sports. As for those above 45, the common cause is age-related wear and tear leading to degenerative knee conditions. Three common knee pain problems are Patellofemoral Pain Syndrome (runner’s knee), knee osteoarthritis and knee ligament and cartilage injuries.

Runner’s knee happens when the kneecap is misaligned and rubs against the lower end of the femur. This is often caused by repetitive stress on the knees due to an excessive running or cycling routine. Dr David Su recommended that runners incorporate cross-training in their fitness routine to get a good mix of load on joints and muscles. Some supplements can help to stimulate the formation and repair of the cartilage or keep it from deteriorating.

Knee osteoarthritis, which is the wearing away of the knee cartilage, is the most common form of knee arthritis. There is no cure for this degenerative disease but there are ways to decelerate the cartilage erosion. Shedding 5kg of weight, especially for those who are overweight, can reduce knee pain by 50%. Knee joint injections like hyaluronic acid and platelet rich plasma (PRP) therapy are common temporary measures as well.

ACL tear is the most common ligament injury, especially for soccer players. Physical therapy is often used to restore the knee. However, orthopaedic specialists may advise for ACL reconstruction in the case of complete ACL tears.

DR Kannan
Senior Consultant
Centre for Foot and Ankle Surgery, Singapore

Article 1: Anterior (Front) knee pain

Q: I am a weekend warrior, I run a few hours to burn calories. Recently during my run, I developed pain at the front of the knee. The pain was very sharp and severe. What should I do? Any recommendations? Can I still run?

Anterior knee pain amongst runners and athletes is very common. It is sometimes referred to as “runner’s knee”. It is a symptom that should not be taken lightly or neglected. Being a “weekend warrior”, it is even more important to pay attention to this symptom as your muscles, tendons and ligaments may not be as well conditioned as that of an active professional athlete.

There are several structures in the front of the knee, the most prominent of which is the patellar bone. This is also sometimes referred to as the kneecap. A tendon called the quadriceps tendon attaches above the patella & a tendon called the patellar tendon attaches below the patella. The patella glides in the front of the knee over the knee bone called the femur, making up the patella-femoral joint.

As we run the muscles contract and move the kneecap in the front of the femur. If our thigh muscles are weak, the pull on this quadriceps tendon is not strong and the kneecap is not able to glide well in the front of the femur. This abnormal gliding can give rise to mechanical knee pain as the patella knocks abnormally on the femur causing pain. Similarly the tendons above and below the knee cap could be inflamed from overuse causing pain. This is known as a tendinosis.

The structures within the knee like the menisci or the cruciate ligaments could also be injured to give the sharp pain. The most common structure to be injured within the knee is the meniscus. The meniscus is a type of cushion that protects the cartilage within the knee during impact. When we accidently twist the knee or land awkwardly while running, its possible for the meniscus to be injured. Sometimes the cartilage on the patella gets injured and the cartilage injury can cause severe pain, especially if there has been repetitive injury to the kneecap. The cartilage over the patella-femoral joint becomes thinned out and that condition is known as chondromalacia. However a cartilage injury of the patellar is uncommon.

It is best to seek an expert medical opinion with an orthopedic surgeon if the knee pain persists. Once a ligament or meniscal knee injury has been ruled out, physiotherapy can be started to strengthen the muscles. A structured physiotherapy program is useful to return a person to sports. Some patients do very well with knee taping and by changing their running pattern. Occasionally if there is structural damage to the knee and when physiotherapy has failed, surgery may be necessary. Knee surgery is usually done via arthroscopic (keyhole) surgery and there is minimal downtime following surgery.

 Knee Injury

Visual adapted from: , last assessed 20th Mar 2018

Dr Tan Chyn Hong
Shoulder Knee Elbow
The Orthopaedic Centre
TMBBS (Singapore), MRCS (Edinburgh),
MMED (Ortho), FRCS (Edinburgh)

Article 1:

Seek Early Treatment for Your Knee 

Knee pain is the most common problem in patients that Dr Tan sees. He recalls seeing a 69-year-old patient who was asking if there were any other alternatives to total knee replacement surgery for his condition. However, his knee arthritis was already too severe for other treatments to work.

The alternatives to total knee replacement surgery this patient had asked about can be broadly termed as knee preservation surgery. Knee preservation surgery primarily uses minimally invasive keyhole techniques to preserve vital knee components.

The vital components that determine the knee’s functionality include the menisci, cartilage and ligament:

  • The menisci are the two crescent-shaped fibrous cartilages that stabilize and reduce impact to the knee joint. They can be surgically regenerated or partially removed, instead of entirely removed, if damaged. Studies have found that removing the menisci entirely would result in easier onset of knee arthritis.
  • The cartilage is the tissue covering the bone end that lubricates the knee joint and reduce any impact. Any cartilage damage should be treated immediately to prevent its progression to a point where the cartilage can no longer be surgically regenerated.

Seeking early treatment is key to the viability of knee preservation surgery. No alternatives to total knee replacement would be available if the knee arthritis or other conditions gets too severe.

Consultant Orthopaedic Surgeon
MBBS (London), MRCS (Edin),
M.Med (Orth), FRCS (Orth & Trauma)


"Doctor, can I still run now that I have developed osteoarthritis in the knees?" This is a common question I get when I tell my patients the "bad news" that they have arthritis in their knees. Running has become a very popular form of exercise here in Singapore in recent years.1 More and more people are taking up the sport, including long distance running like marathons.1 Runners do not like to stop running. Let us see how we can manage our running desires when we have arthritis in the knees.

"Does running cause osteoarthritis in the knees?"
Running, just like any form of exercise is generally good for our health.2 It helps to improve our blood pressure and reduce the risk of heart disease. It also helps to control obesity and boots weight loss amongst others.3,4 There is no evidence that moderate amount of running contributes to the development of arthritis in the knees.5 The more common causes of arthritis in the knees are due to a genetic predisposition, previous injuries to the knees and being overweight.6,7 If you have close family members such as your parents or siblings with arthritis, there is a good chance that you will too.8,9 If you have had an injury to your knee such as an ACL (anterior cruciate ligament) tear or a tear of the meniscus, the risk of developing arthritis in the knee can go up to as high as 50%.10,11 Being overweight or obese can increase the risk of developing osteoarthritis in the knees 3-fold.12 In someone who is otherwise well and heathy, there is no reason to quit running and head for the swimming pool!

"What is osteoarthritis?"
Arthritis is inflammation in the joints. The knee is the most commonly affected joint in the body and osteoarthritis is one of the most common types of arthritis.13 Osteoarthritis is a degenerative condition where it happens most often in people 50yrs of age or older. It is commonly known as "wear and tear" arthritis and therefore its misconception with running as a causative factor. In osteoarthritis, the cartilage in the knee joint breaks down, causing the symptoms of:14,15

  • Pain and swelling
  • Stiffness
  • Deformity
  • Reduction in function

"How does arthritis in the knees affect runners?"
For someone who has arthritis in the knees, he or she can suffer from pain due to inflammation, stiffness and a sensation of weakness or instability.15 It is generally accepted that low impact activities such as swimming or walking are more suitable forms of exercise.16,17 Running is considered a "high impact" activity and is usually discouraged.17

However, all is not lost! Should you suffer from milder forms of arthritis, it can be fair to "listen to your knee" and let the pain in your knee determine how much and how far you can run. Running at a pace and distance that is comfortable for your knees is important.18,19 As arthritis often waxes and wanes, many runners back off when the pain in the knee is bad and resume running when the pain improves. It is important to have on a good pair of running shoes and run on a treadmill instead of on concrete. The running track on the treadmill is designed to absorb some of the impact from the running and is therefore more forgiving to the knees. For a regular runner, it is important to change the pair of running shoes regularly. A good rule of thumb is to change a pair of shoes after 500km or at about 6 months of use.19

"Is running good for someone who suffers from arthritis in the knees? And can I continue running when I have arthritis?"
Evidence in the medical literature indicates that with a good rehabilitative programme which combines stretching, strengthening exercises both of the lower limbs and the core muscles can enable someone with mild osteoarthritis in the knees to be able to continue with sports without significant harmful effects.20,21 Careful supervision with your doctor and the physiotherapist is important.21 Doing cross training type exercises such as cycling and swimming in between runs are also particularly helpful.22 Heavy load, high impact activities is still a clear No-No! So, marathon running is definitely out!19

It is important to remember that every individual's situation is different. If you have any concerns about arthritis or your joint health, please see a health professional for advice and treatment specific to your needs.


  1. Tan CM, et al. Medical planning for mass-participation running events: A 3-year review of a half-marathon in Singapore. BMC Public Health. 2014;14:1109.
  2. Hespanhol Junior LC, et al. Meta-Analyses of the effects of habitual running on indices of health in physically inactive adults. Sports Med. 2015;45(10):1455–1468.
  3. Williams PT. Relationship of running intensity to hypertension, hypercholesterolemia, and diabetes. Med Sci Sports Exerc. 2008;40(10):1740–1748.
  4. Shipway R, Holloway I. Running free: Embracing a healthy lifestyle through distance running. Perspect Public Health. 2010;130(6):270–276.
  5. Bosomworth NJ. Exercise and knee osteoarthritis: Benefit or hazard? Can Fam Physician. 2009;55(9):871–878.
  6. Heidari B. Knee osteoarthritis prevalence, risk factors, pathogenesis and features: Part I. Caspian J Intern Med. 2011;2(2):205–212.
  7. Jiang L, et al. Obesity, osteoarthritis and genetic risk: The rs182052 polymorphism in the ADIPOQ gene is potentially associated with risk of knee osteoarthritis. Bone Joint Res. 2018;7(7):494–500.
  8. Lespasio MJ, et al. Knee osteoarthritis: A primer. Perm J 2017;21:16–183.
  9. Neame R, et al. Genetic risk of knee osteoarthritis: A sibling study. Ann Rheum Dis. 2004;63(9):1022–1027.
  10. Paschos NK. Anterior cruciate ligament reconstruction and knee osteoarthritis. World J Orthop. 2017;8(3):212–217.
  11. Ratzlaff CF, et al. Prevention of injury-related knee osteoarthritis: Opportunities for the primary and secondary prevention of knee osteoarthritis. Arthritis Res Ther. 2010;2(4):215.
  12. Salih S and Sutton P. Obesity, knee osteoarthritis and knee arthroplasty: A review. BMC Sports Sci Med Rehabil. 2013;5:25.
  13. Hunter DJ, Felson DT. Osteoarthritis. BMJ. 2006;332(7542):639–642.
  14. Hunter DJ, Bierma-Zeinstra S. Osteoarthritis. Lancet. 2019;393(10182):1745–1759.
  15. Hunter DJ, et al. The symptoms of OA and the genesis of pain. Rheum Dis Clin North Am. 2008;34(3):623–643.
  16. Geneen LJ, et al. Physical activity and exercise for chronic pain in adults: An overview of Cochrane reviews. Cochrane Database Syst Rev. 2017;2017(4):CD011279.
  17. Hunter DJ and Eckstein F. Exercise and osteoarthritis. J Anat. 2009;214(2):197–207.
  18. Van der Worp M P, et al. Injuries in runners: A systematic review on risk factors and sex differences. PLoS One. 2005;10(2):e0114937.
  19. The Straits Times. Ask the ST Run Expert Knee-joint Pain and Osteoarthritis. Available from: Accessed on 22 April 2020.
  20. Abdel-aziemv AA, et al. Effect of a physiotherapy rehabilitation program on knee osteoarthritis in patients with different pain intensities. Journal of Physical Therapy Science. 2018;30(2):307–312.
  21. Bhatia D, et al. Current interventions in the management of knee osteoarthritis. J Pharm Bioallied Sci. 2013;5(1):30–38.
  22. Alkatan M, Baker JR, Machin DR, et al. Improved function and reduced pain after swimming and cycling training in patients with osteoarthritis. J Rheumatol. 2016;43(3):666–672.

Senior Consultant
Orthopaedic Surgeon
MBBS (NUS), MMed (Singapore) FRCSEd (Orth), FACS

Subspecialties in Joint Reconstruction,
Sports Orthopaedics, Fracture Surgery


The Knee
The knee joint, the largest and complex joint of the human body, takes an enormous amount of pressure for even simple day-to-day activities. For example, when climbing stairs or running, each knee joint may absorb three times the body weight. This is one reason why the knee joint is prone to experiencing wear-and-tear, called osteoarthritis. This refers to progressive damage of the cartilage, excruciating pain, restricted movement and reduced quality-of-life.

Knee Injuries
Injuries are the other quite common issues that are associated with knee problems. Some of the problems which are associated include conditions such as anterior cruciate ligament (ACL) tears, medial collateral ligament (MCL) tears, meniscus tears, cartilage injuries and patella dislocations. A lot of people, e.g. skilled sportspersons, sustain ACL tears due to activities such as football, basketball and skiing. An ACL tear, in a young patient, is best treated with surgery to reconstruct a new ACL, therefore giving the patient a good knee for the years to come.

Dr Ang Chia Liang is an orthopaedic surgeon with more than 17 years of experience in the field of orthopaedics (please click on the link to know more: Dr Ang Chia Liang | Centurion Orthopaedic Centre). In his clinical practise, he uses the patient’s hamstring tendons to make a new ACL, thus ensuring the best clinical outcome.

A tissue-healing stimulant injection is useful for injuries with delayed healing, which further stimulates healing in injured tissues.

Osteoarthritis Treatment
The treatment methods for early osteoarthritis include medications, self-therapy exercises and viscosupplementation (e.g. Hylan GF-20). In suitable cases, Hylan GF-20 can give effective pain relief that lasts for 12 months or more. Doctors use information from patients’ symptoms, examinations, X-rays and sometimes MRI to determine patients’ suitability for Hylan GF-20.

Glucosamine and collagen can help in reducing pain and maintaining the joint in early stages.

More advanced stages may require bone marrow concentrate injection, arthroscopic surgery to reconstruct cartilage or knee replacement surgery.

Symptoms of Knee Problems
Common symptoms of knee problems include:

  • The occurrence of severe pain on prolonged walking or standing
  • The occurrence of pain, especially, when the person gets up after sitting for a prolonged time
  • Hearing a sound of pop in the knee followed by swelling
  • Giving way or ‘weakness’ of the knee
  • Feeling movement inside the knee

Risk and Prevention
It is risky to ignore persistent pain. For example, many patients who regularly run report that they have had knee pains after running for a short period of time. They may have ignored it as they felt they could still run. However, by ignoring it, the pain can intensify and stop them running, which in turn promts them to consult a doctor. Sometimes, by this stage, the cartilage would have been damaged significantly, requiring a more advanced treatment method such as keyhole surgery. In general, ignoring the persistent pain for a month or longer period of time is dangerous and may lead to more severe injuries. Hence, consulting a doctor in the early stage is effective and highly recommended to prevent significant damage to the knee.


  1. Lim JB, Ang CL, Pang HN. Acetabular prosthetic protrusio after bipolar hemi-arthroplasty of the hip: case report and review of the literature. J Orthop Case Rep. 2016;6(3):28–31.
  2. Zhu M, Ang CL, Yeo SJ, et al. Minimally invasive computer-assisted total knee arthroplasty compared with conventional total knee arthroplasty: A prospective 9-year follow-up. J Arthroplasty. 2016;31(5):1000–4.
  3. Ho SWL, Ang CL, Ding CSL, et al. Necrotizing fasciitis caused by Cryptococcus gattii. Am J Orthop. 2015;44(12):E517–E522.
  4. Ang CL, Yeo SJ. Quality of cementation in conventional versus minimally invasive total knee arthroplasty. J Orthop Surg (Hong Kong). 2016;24(1):7–11.
  5. Teo EY, Ang CL, Sathappan SS. A variant of patellar clunk syndrome after bilateral total knee arthroplasty: clinical manifestations and arthroscopic images. Orthop Surg. 2014;6(4):326–8.
  6. Ang CL, Foo LS. Multiple locations of nerve compression: an unusual cause of persistent lower limb paresthesia. J Foot Ankle Surg. 2014;53(6):763–7.
  7. Ang CL, Fook S, Chia SL, et al. Unconstrained arthroplasty in type II valgus knees: posterior stabilized or cruciate retaining? Knee Surg Sports Traumatol Arthrosc. 2014;22:666–73.
  8. Ang CL, Phak-Boon Tow B, Fook S, et al. Minimally invasive compared with open lumbar laminotomy: No functional benefits at 6 or 24 months after surgery. Spine J. 2015;15(8):1705–12.
  9. Ang CL, Lim YJ. Recurrent admissions for diabetic foot complications. Malays Orthop J. 2013;7(3):21–6.
  10. Ang CL, Foo LS, Sun S, et al. Positive ProbeTecTM tests in fresh specimens from malignant musculoskeletal tumours: a case series. Orthop Surg. 2013;5(1):29–32.