Why arthritis occurs?

Are joint injury, sport activity, physical activity, obesity or occupational activities predictors for osteoarthritis? A systematic review

Richard et al, 2013. Journal of Orthopaedic & Sports Physical Therapy.


To identify if joint injury, physical activity, obesity and occupational activity are risk factors for osteoarthritis (OA) of the knee, hip and ankle in all age groups.


OA affects up to 10% of men and 18% of women over the age of 60.  The study aimed to support and inform the physiotherapy management of individuals following the onset of OA.


The authors performed a systematic review of 12 databases.  A total of 1294 studies were identified through title review.  Eight reviewers assessed study quality using a data extraction form.  Overall 43 articles were included in the meta-analysis, all of which which all met a strict inclusion criteria.  Of the 43 studies: 10 were cross sectional, 12 were case studies, 17 were cohort, 2 were longitudinal and 2 were reportedly case series.

Inclusion Criteria

Studies had to show original data, investigate one of the afore-mentioned risk factors, one of the outcomes had to be OA and there had to be an analytic component to the design.  The age range of participants ranged from 20-95 years.


Overall, joint injury, obesity and physically demanding occupational activity were all associated with increased risk of OA to the hip and knee.  Previous menisectomy (with or without ACL ligament injury) was also heavily linked to knee joint OA. The meta-analysis was however met with mixed results. While some studies concluded that certain predictors were closely linked to the onset of OA, others studies examining the same factor proved inconclusive.

Main Findings within each category:

Sporting activity:

  • Team sports (prior to age 45), soccer, gymnastics (females) & kung fu were all most associated with knee OA.
  • Soccer, gymnastics, (females) track & field and racket sports were all most associated with hip OA.
  • Volleyball was most associated with ankle OA.

Physical activity:

  • Out of the 5 studies included, increased physical activity was found to be protective for knee & hip OA in 1 study, but found to be a risk factor in the 4 others.
  • The main finding was that exercise in early adult life was shown to be a risk factor for knee OA.


  • A total of 13 studies looked at obesity as a risk factor.
  • All demonstrated an increased risk of knee and hip O.A in the overweight population.
  • Results were inconclusive as to whether obesity affected joints unilaterally or bilaterally.
  • 4 of the 13 studies were cross-sectional and were unable to determine a relationship as to whether weight gain pre-dated or followed the onset of OA.
  • The authors acknowledged the possibility for an inverse relationship between OA and weight gain, in that patients with OA may adopt a more sedentary lifestyle due to pain and subsequently gain more weight.

Occupational activity:

  • The finding from all 9 studies concurred that professions involving heavy lifting, squatting, kneeling, working in cramped space, climbing stairs, floor activities or higher physical demands were more likely to lead to lower limb OA. 


  1. There was a paucity of evidence for the risk factors in OA of the ankle.
  2. Some of the studies included were not published in peer review journals, i.e, were dissertations.
  3. In examining occupational activity, most of the study participants examined were male.
  4. Injuries from previous trauma were all self reported.
  5. Recall bias may have been a factor as some participants were asked to report previous sporting activity.
  6. Sporting exposure time and intensity and level were seldom measured.
  7. Many of the studies examined multiple risk factors within 1 study group, making the accuracy of the result difficult to measure without a control for potential confounders.
  8. Factors such as genetics and diet were not taken into consideration and are difficult to control over the longer study time-frames.

Implications for our clinical practice

As physiotherapists we are often asked by patients if they should stop or modify their activities.  Early identification of individuals at risk of OA provides an opportunity for physiotherapy management and lifestyle interventions to modify risk related behaviour.  This may include advice on posture, work ergonomics, exercise, diet and lifestyle.  In addition to our clinical experience, studies such as this add an evidence based component to validate and influence the advice we give.

Further Study

Further high quality studies such as cohort studies are required to minimise potential bias when examining the relationship between physical risk factors and OA.

Thank you for reading, if you have any questions please email me at annika.williams@kenphysio.com


Senior Physiotherapist


Share this: