Morbidity from repetitive knee trauma in carpet and floor layers.

Carpet layers comprise less than 0.06% of the United States workforce yet they submit 6.2% of compensation claims for traumatic knee inflammation. Their work involves multiple sources of acute and chronic knee trauma including kneeling, pressure from sharp objects, and use of a device called a "knee kicker" to stretch wall to wall carpet. To characterise the knee morbidity in carpet layers and to identify occupational risk factors, a questionnaire was completed by 112 carpet and floor layers, 42 tile and terrazo setters, and 243 millwrights and bricklayers (MWBL). The MWBL comparison workers seldom kneel and do not use a knee kicker. Physical and xray examinations were conducted on a subset of 108 respondents to validate the questionnaire responses. Compared with the MWBL, carpet layers reported more frequent bursitis (20% v 6%), needle aspiration of knee fluid (32% v 6%), and skin infections of the knee (7% v 2%). A score indicating frequency of using the knee kicker was the only statistically significant predictor of bursitis, whereas the score for kneeling was one of several predictors of knee aspiration and skin infections of the knee. These data suggest that carpet and floor layers experience substantially more knee morbidity than other occupational groups, and that kneeling and use of the knee kicker are risk factors providing opportunities for prevention.