Occupational physical loading tasks and knee osteoarthritis: a review of the evidence.
Purpose : To perform a systematic review with best evidence synthesis examining the literature on the relationship between occupational loading tasks and knee osteoarthritis (OA).


METHODS
Two databases were searched to identify articles published between 1946 and April, 2011. Eligible studies were those that (1) included adults reporting on their employment history; (2) measured individuals' exposure to work-related activities with heavy loading in the knee joint; and (3) identified presence of knee OA (determined by X-ray), cartilage defects associated with knee OA (identified by magnetic resonance imaging), or joint replacement surgery.


RESULTS
A total of 32 articles from 31 studies met the inclusion criteria. We found moderate evidence that combined heavy lifting and kneeling is a risk factor for knee OA, with odds ratios (OR) varying from 1.8 to 7.9, and limited evidence for heavy lifting (OR=1.4-7.3), kneeling (OR=1.5-6.9), stair climbing (OR=1.6-5.1), and occupational groups (OR=1.4-4.7) as risk factors. When examined by sex, moderate level evidence of knee OA was found in men; however, the evidence in women was limited.


CONCLUSIONS
Further high-quality prospective studies are warranted to provide further evidence on the role of occupational loading tasks in knee OA, particularly in women.
School of Population and Public Health.
Allison M
AM
Ezzat
Department of Physical Therapy, University of British Columbia, Vancouver ; Arthritis Research Centre of Canada, Richmond, B.C.
Linda C
LC
Li
knee joint; occupational diseases; occupations; osteoarthritis