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).
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.
- Preventing the runners knee issue (mega-adsens.blogspot.com)
- Exercise and Arthritis (pharmacyupdates.wordpress.com)
- Jogging – How To Gain Maximum Benefits From Healthy Exercise (dietnewsinfo.com)