Category Archives: Running

Causes of Knee Osteoarthritis.


Knee (Photo credit: mariandy_gizfel)

I have talked about the extraordinary and disturbing number of knee joints that are being replaced by artificial joints. There are 600,000 knee replacements every year in the US at a yearly cost of $9 Billion. They have doubled over the last decade. (OECD iLibrary 2011). They are expected to double again in the UK over the next 2 decades! (Lancet 380:1768 2012).

Age is a factor. 70% of those 65+ show radiological evidence of osteoarthritis in at least one knee or hip joint. (J. Orthop. Res. 7:15 2012)

But one of the major causative factors is obesity. 69% of knee operations may be attributed to obesity in Croatia (Ljec. Vjesn. 131:22 2009). If all overweight and obese people were to reduce weight by only 5Kg., or until their  BMI was within the normal range, 24% of OA knee surgical cases could be avoided.! (Int. J. Obes. Relat. Metab. Disord. 25(5):622 2001). Some surgeons do not operate until the patient has reduced his BMI. A BMI of 40 is considered inoperable!

Another major cause of osteoarthritis of the knee, which is rarely discussed, is inactivity. The synovial fluid of the joints is viscous and cannot function unless the joint is put under pressure. 40% of men with knee osteoarthritis are couch potatoes (Northwestern Univ. News Aug. 2011). Lower extremity muscle weakness is a risk factor for knee osteoarthritis (Arthrit. & Rheum. 41(11):1951 1998). Low muscle strength is strongly associated with knee pain, (Ann. Rheum. Dis. 57:588 1998) and muscle weakness may be an im portant factor in the pathogenesis of osteoarthritis. (Rheum. Dis. Clin. N. Am. 25(2):283 1999).  Such patients require not only rehabilitation after the operation  but “prehabilitation”, to increase necessary muscle strength,  before the operation!

Age-standardised disability-adjusted life year...

Age-standardised disability-adjusted life year (DALY) rates from Osteoarthritis by country (per 100,000 inhabitants). (Photo credit: Wikipedia)

Man is the most destructive animal that has ever existed on the planet and efforts are being made to protect animal and plant species. However there seems little effort to protect the human species from the man made destruction of human health.

We are already at a point where we have to be treated to give us sufficient minimal health in order that we can be treated.


Jumper’s and Runner’s Knee

English: Medial view of the knee showing anato...

English: Medial view of the knee showing anatomical features. (Photo credit: Wikipedia)

In my one of my previous blogs the content referred to the dramatic increase knee replacements, mainly due to osteoarthritis, which creates a huge burden on health systems.

The causes are multifactorial, which include previous injury, obesity and possibly genetic influences. (Dr. Sofat, RFS Newsletter 46:4 2013).

Age is also a factor with the majority of people over 60 showing evidence of osteoarthritis in at least one joint. At over 65 (a shocking) 70% of hips or knees show radiological evidence of osteoarthritis! (J. Orthop. Res. 7:15 2012)

But the increased number of knee replacements cannot be explained by population growth and obesity epidemic alone. The recent increase is likely to be related to the growing prevalence of sport-related knee injuries. (J. Bone Joint Surg. Am. 94(3):201 2012)

Injury:   An injury in younger years can lead to osteoarthritis in later years. Kneeling for long periods can cause injury. Housemaid’s Knee (Bursitis), (swelling in front of the kneecap) or Clergyman’s Knee, (swelling below the kneecap), seem to be relatively harmless (Mailonline May 2013).

Jumper’s Knee:  Jumping causes sudden pressure to the knee joint of 9-11 times body weight.  20% of jumping athletes have Jumper’s Knee (Performance, June 2009). In volleyball the prevalence of jumper’s knee is high, up to 40-50%!  Symptoms increase slowly and are often unreported especially as athletes with tendon pain perform substantially better in jump tests compared to asymptomatic controls!  “Jumper’s Knee Paradox”. (B.J.S.M. 47(8):503 2012)

Runner’s Knee: Whereas in jumper’s knee, high stresses on the knee are the main causative factor, runner’s knee is caused by repeated micro-trauma. (Angelfire March 2002).    25-65% of runners suffer from runner’s knee. There is a significant increase with increasing duration per week, but training pace has no impact on the incidence of chronic knee lesions. (Eur. J. Radiol. 58:286 2006).  In Singapore up to 50% of runners have runner’s knee (HealthXchange).  However, long distance running per se does not increase the risk of osteoarthritis. (J. Am. Osteopath. Ass. 106(6):342 2006).

English: Jogging at Cranny Good for your healt...

English: Jogging at Cranny Good for your health, but sore on the joints. (Photo credit: Wikipedia)

Jogging is excellent and popular exercise, but decades of jogging especially after 50 can cause problems. Not only overuse, but muscular imbalance can be a source of injury. (Walk Jog Run May 2012).  Cross training has been seen to be beneficial as prevention of injury.   Barefoot running reduces joint movement and work done at the knee and may provide potential benefits for the management of knee pain and injury. (Br. J. Sports Med. 47:387 2013)

It is unfortunate that sport related knee injuries are too often ignored, thus compounding the damage.  While the percentage of jumpers and runners that develop jumper’s knee or runner’s knee are disturbing and sport related knee injuries are on the increase, early injuries, although important, are nevertheless not the major cause of knee osteoarthritis in later life.

A New Profession? Try Orthopaedic Surgeon.

Total Knee replacement : AP view (Xray).

Total Knee replacement : AP view (Xray). (Photo credit: Wikipedia)

Should you consider a new profession then an orthopaedic surgeon specializing in knee replacements could be a very good idea. Consider the facts:

There was an extraordinary 400% increase in the number of total knee replacements from 1971 to 2003 as compared to an increase of (only) 55% in the number of hip replacements in the same period!

The number of primary knee replacements are expected to increase nearly 8 times from 450,000 to 3.48 million by 2030! But that is not all.  An increasing number of the artificial joints will have to be replaced or “revised”. From 2005 to 2030 it is estimated that the increase in revisions of total knee replacements will come to an amazing 600% compared to hip replacement revisions of (only) 137%!  (Renaissance Orthopaedics Jan. 2008).


More and more younger patients are involved. In 1999, 30% of knee replacements were for those under 65. In 2008 the number was already 41%.  There is a higher rate of failure and earlier revisions in younger patients. (Am. Acad. Orth. Surg. Now April 2012).  After only 5 years, 8% of the replacements in the under 55 age group had failed! (Acta Orthop. 81(4):413 2010).

What are we doing to our knees?  Overweight and obesity obviously put more strain on the knees. But population growth and obesity cannot explain the rapid growth of total knee replacements in the last decade ( J. Bone Joint Surg. 94(3):201 2012). The major causes seem uncertain.

Almost certain seems to be the expected shortfall of orthopaedic surgeons which is projected to be so dramatic that  by 2016, 72%  of those patients that require total knee replacements  will, (in the US), be unable to obtain them! (AAOS Ann. Meeting 2009)


Participants in the 2010 Boston Marathon in We...

Participants in the 2010 Boston Marathon in Wellesley, just after the halfway mark (Photo credit: Wikipedia)

Although the Boston Marathon was marred by tragedy the Boston and London Marathons were glorious symbols of human endurance, determination, and perseverance.

Participation at a Marathon requires training of about 4 months prior to the event. With a peak of less than 56km per week training there seems to be a risk of some heart damage or dysfunction. Intensive training is really necessary.

Although deaths have been recorded, the number is relatively small at 1:50,000 (J. Am. Coll. Cardiol. 28(2):428 1996) and is comparable to athletics at 1:43,000 (Nat. Coll. Athletic Ass.). Women have a far lower risk of death at 1:200,000 at Marathons. (B.M.J. 47:68 2013).

However those participants with a sickle cell trait are at risk, as they have a 37 times higher death rate (Br. J. Sports Med. 46:325 2012). The average age of death was 41.   ( B.M.J. 335:1275 2007).  The oldest recorded death was at about 57.

Thus it seems that, in spite of the fact that many runners were found to be positive for the Troponin test after the race which usually indicates myocardial infarction, the old and very old Marathon participants seem to be statistically almost risk free!

While the record is just over 2hrs, most participants aim for about 4hrs.  The oldest record holders are Mr Singh at 100 at 8hrs 11mins and Ms Burrill at 92 with 9hrs 53mins. To keep going for 8-10 hours in extreme old age is truly amazing. The old that complete a marathon have exceptional endurance and extraordinary determination.

Should we, in old age, emulate and follow their example as has been suggested by some physicians?

I personally think not, in spite of the fact that risks seem to be minimal. The first runner’s source of energy is glycogen (carbohydrate). Lipids (fat) become the primary source of fuel once the glycogen stores are depleted. This is followed by glucogenisis whereby calories are made available from protein by extracting amino-acids from muscle tissue (Med. Sci. in Sports & Exercise 19:179 1987). Thus during the last phase of the Marathon, muscle protein breaks down (Adv. Nutr. & Human Met. 5th ed. 2009). In other words not only fat but muscle tissue is broken down during a Marathon.

It should be no surprise that the Marathon elite look “like matchstick men”, lacking fat and muscle mass.  Muscle glycogen depletion also causes (temporary) stress on the immune system. Given sufficient time the loss of muscle mass in the young can be compensated by hypertrophy exercises. But due to reduced protein synthesis this is extremely difficult in old age. Sarcopenia or the loss of muscle mass is the major cause of disability in old age.

As participation in a Marathon causes the loss of muscle mass and weakening of the immune system at the same time, it does not sound like something that can be universally recommended for the aged runner.