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Symptomatic knee disorders in floor layers and graphic designers. A cross-sectional study

Lilli Kirkeskov Jensen1*, Søren Rytter2 and Jens Peter Bonde1

Author Affiliations

1 Department of Occupational and Environmental Medicine, Bispebjerg Hospital, Bispebjerg Bakke 23, Copenhagen, DK 2400, NV, Denmark

2 Department of Orthopaedic Surgery, Hospital Unit West, Lægårdvej 12, Holstebro, DK 7500, Denmark

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BMC Musculoskeletal Disorders 2012, 13:188  doi:10.1186/1471-2474-13-188

Published: 25 September 2012



Previous studies have described an increased risk of developing tibio-femoral osteoarthritis (TF OA), meniscal tears and bursitis among those with a trade as floor layers. The purpose of this study was to analyse symptomatic knee disorders among floor layers that were highly exposed to kneeling work tasks compared to graphic designers without knee-demanding work tasks.


Data on the Knee injury and Osteoarthritis Outcome Score (KOOS) were collected by questionnaires. In total 134 floor layers and 120 graphic designers had a bilateral radiographic knee examination to detect TF OA and patella-femoral (PF) OA. A random sample of 92 floor layers and 49 graphic designers had Magnetic Resonance Imaging (MRI) of both knees to examine meniscal tears. Means of the subscales of KOOS were compared by analysis of variance. The risk ratio of symptomatic knee disorders defined as a combination of radiological detected knee OA or MRI-detected meniscal tears combined with a low KOOS score was estimated by logistic regression in floor layers with 95% confidence interval (CI) and adjusted for age, body mass index, traumas, and knee-straining sports activities. Symptomatic knee OA or meniscal tears were defined as a combination of low KOOS-scores and radiographic or MRI pathology.


Symptomatic TF and medial meniscal tears were found in floor layers compared to graphic designers with odds ratios 2.6 (95%CI 0.99-6.9) and 2.04 (95% CI 0.77-5.5), respectively. There were no differences in PF OA. Floor layers scored significantly lower on all KOOS subscales compared to graphic designers. Significantly lower scores on the KOOS subscales were also found for radiographic TF and PF OA regardless of trade but not for meniscal tears.


The study showed an overall increased risk of developing symptomatic TF OA in a group of floor layers with a substantial amount of kneeling work positions. Prevention would be appropriate to reduce the proportion of kneeling postures e.g. by working with tools used from a standing working position.

Epidemiology; Occupational; Knee; Osteoarthritis; KOOS