Category Archives: Musculoskeletal System

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.


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)