Table 3.

The associations between patterns of knee pain and self-report of difficulty performing activities of daily living on the individual items of the Knee Injury and Osteoarthritis Outcome Score (KOOS) Activities of Daily Living subscale.^ab

Function in Daily Living Subscale	Patellofemoral Pain vs. Tibiofemoral Pain†	Combined Pain vs. Tibiofemoral Pain†	Combined Pain vs. Patellofemoral Pain†
Difficulty when going down stairs
Odds Ratio (95% CI)	0.89 (0.67, 1.18)	1.48 (1.10, 1.99)*	1.67 (1.17, 2.37)*
Group Percentages	18.3% vs. 20.5%	28.4% vs. 20.5%	28.4% vs. 18.3%
Difficulty when going up stairs
Odds Ratio (95% CI)	1.12 (0.86, 1.45)	1.92 (1.45, 2.54)*	1.71 (1.24, 2.38)*
Group Percentages	25.1% vs. 22.5%	37.1% vs. 22.5%	37.1% vs. 25.1%
Difficulty when getting up from a sitting position
Odds Ratio (95% CI)	1.04 (0.79, 1.37)	1.66 (1.23, 2.23)*	1.60 (1.13, 2.26)*
Group Percentages	20.7% vs. 19.5%	30.1% vs. 19.5%	30.1% vs. 20.7%
Difficulty when standing
Odds Ratio (95% CI)	0.62 (0.42, 0.92)*	1.34 (0.93, 1.93)	2.14 (1.35, 3.41)*
Group Percentages	7.4% vs. 10.2%	14.8% vs. 10.2%	14.8% vs. 7.4%
Difficulty when bending to the floor
Odds Ratio (95% CI)	0.98 (0.75, 1.28)	1.48 (1.11, 1.99)*	1.51 (1.07, 2.13)*
Group Percentages	25.4% vs. 25.7%	35.5% vs. 25.7%	35.5% vs. 25.4%
Difficulty when walking on a flat surface
Odds Ratio (95% CI)	0.78 (0.53, 1.17)	1.20 (0.81, 1.78)	1.54 (0.95, 2.49)
Group Percentages	7.1% vs. 8.8%	11.9% vs. 8.8%	11.9% vs. 7.1%
Difficulty when getting in or out of the car
Odds Ratio (95% CI)	1.13 (0.85, 1.49)	1.57 (1.16, 2.12)*	1.39 (0.98, 1.98)
Group Percentages	20.8% vs. 18.5%	28.4% vs. 18.5%	28.4% vs. 20.8%
Difficulty when going shopping
Odds Ratio (95% CI)	0.80 (0.55, 1.15)	1.52 (1.06, 2.18)*	1.90 (1.22, 2.96)*
Group Percentages	10.2% vs. 11.3%	18.6% vs. 11.3%	18.6% vs. 10.2%
Difficulty when putting on socks or stockings
Odds Ratio (95% CI)	0.83 (0.57, 1.21)	1.19 (0.81, 1.74)	1.43 (0.90, 2.27)
Group Percentages	9.2% vs. 10.4%	13.6% vs. 10.4%	13.6% vs. 9.2%
Difficulty when getting out of bed
Odds Ratio (95% CI)	0.63 (0.20, 1.97)	2.45 (0.95, 6.33)	3.90 (1.11, 13.72)*
Group Percentages	12.9% vs. 11.8%	18.9% vs. 11.8%	18.9% vs. 12.9%
Difficulty when taking off your socks or stockings
Odds Ratio (95% CI)	0.93 (0.63, 1.38)	1.30 (0.87, 1.94)	1.39 (0.86, 2.25)
Group Percentages	8.5% vs. 8.6%	12.5% vs. 8.6%	12.5% vs. 8.5%
Difficulty when lying in bed
Odds Ratio (95% CI)	0.65 (0.42, 1.00)	1.24 (0.82, 1.87)	1.91 (1.13, 3.21)*
Group Percentages	5.5% vs. 7.8%	10.6% vs. 7.8%	10.6% vs. 5.5%
Difficulty when getting in or out of the bathtub
Odds Ratio (95% CI)	1.03 (0.68, 1.56)	1.43 (0.92, 2.22)	1.39 (0.83, 2.34)
Group Percentages	13.2% vs. 11.6%	18.9% vs. 11.6%	18.9% vs. 13.2%
Difficulty when sitting
Odds Ratio (95% CI)	0.90 (0.58, 1.38)	1.10 (0.70, 1.71)	1.22 (0.72, 2.09)
Group Percentages	6.2% vs. 6.9%	8.8% vs. 6.9%	8.8% vs. 6.2%
Difficulty when getting on or off the toilet
Odds Ratio (95% CI)	1.38 (0.97, 1.97)	1.82 (1.26, 2.63)*	1.32 (0.86, 2.02)
Group Percentages	13.2% vs. 9.8%	18.9% vs. 9.8%	18.9% vs. 13.2%
Difficulty with heavy household chores
Odds Ratio (95% CI)	1.04 (0.78, 1.39)	1.61 (1.18, 2.21)*	1.55 (1.08, 2.24)*
Group Percentages	20.9% vs. 19.3%	29.4% vs. 19.3%	29.4% vs. 20.9%
Difficulty with light household chores
Odds Ratio (95% CI)	0.95 (0.63, 1.43)	1.69 (1.13, 2.52)*	1.78 (1.10, 2.88)*
Group Percentages	8.4% vs. 7.6%	13.9% vs. 7.6%	13.9% vs. 8.4%

^aGeneralized linear mixed models adjusted for age, gender, race, body mass index, clinical center, and radiographic disease severity.

^bThe sample sizes are slightly different for different outcomes due to missing values.

^†Reference group for comparisons

^*Significantly different than the reference group (P < 0.05).

CI = confidence interval