Table 6.

Follow-up variations in WOMAC score (mean [95% CI]) compared to baseline setting and stratified by radiological grade and therapy. All the estimates resulted by a quasi-randomization process obtained including propensity scores in the model for repeated measures (GEE model).

Timing x K-L grade	Hyaluronic acid 1,500–3,200 kDa	HYLAN G-F 20	Ctrls
Grade II
Baseline	62.5 [53.7 to 71.3]	62.4 [54.2 to 70.6]	59.8 [50.4 to 69.2]
1 mth vs. baseline	−12.8 [−17.9 to −7.7] p < 0.001	−14.3 [−19.4 to −9.2] p< < 0.001	−2.6 [−5.7 to 0.5] p = 0.100
6 mths vs. baseline	−17.7 [−25.0 to −10.4] p< < 0.001	−26.8 [−32.9 to −20.7] p< < 0.001	−0.6 [−2.8 to 1.6] p = 0.593
12 mths vs. baseline	−31.4 [−40.9 to −21.9] p< < 0.001	−30.9 [−38.2 to −23.6] p< < 0.001	+0.1 [1.3 to 0.0] p = 0.913
24 mths vs. baseline	−34.7 [−44.7 to −24.7] p< < 0.001	−35.9 [−43.4 to −28.4] p< < 0.001	+1.8 [1.8 to 1.0] p = 0.312
Grade III
Baseline	65.7 [57.3 to 74.1]	65.6 [57.7 to 73.5]	63.0 [55.2 to 70.8]
1 mth vs. baseline	−9.6 [−16.4 to −2.8] p = 0.009	−11.1 [−19.1 to −3.1] p = 0.010	0.6 [−6.0 to 7.2] p = 0.393
6 mths vs. baseline	−14.5 [−22.7 to −6.3] p = 0.001	−23.6 [−33.2 to −14.0] p< < 0.001	+2.6 [−3.3 to 8.5] p = 0.274
12 mths vs. baseline	−28.2 [−38.6 to −17.8] p< < 0.001	−27.7 [−37.4 to −18.0] p< < 0.001	−3.3 −9.5 to 2.9] p = 0.233
24 mths vs. baseline	−31.5 [−43.3 to −19.7] p< < 0.001	−32.7 [−41.1 to −24.3] p< < 0.001	+5.0 [−1.5 to 11.5] p = 0.129
Grade IV
Baseline	65.9 [57.1 to 74.7]	65.8 [59.1 to 72.5]	63.2 [55.5 to 70.9]
1 mth vs. baseline	−9.4 [−16.8 to −2.0] p = 0.019	−10.9 [−19.2 to −2.6] p = 0.014	+0.8 [−6.4 to 8.0] p = 0.389
6 mths vs. baseline	−14.3 [−23.1 to −5.5] p = 0.002	−23.4 [−33.0 to −13.8] p< < 0.001	+2.8 [−4.0 to 9.6] p = 0.287
12 mths vs. baseline	−28.0 [−38.3 to −17.7] p< < 0.001	−27.5 [−37.5 to −17.5] p< < 0.001	−3.1 [−10.1 to 3.9] p = 0.273
24 mths vs. baseline	−31.3 [−42.4 to −20.2] p< < 0.001	−32.5 [−42.6 to −22.4] p< < 0.001	+5.2 [−2.0 to 12.4] p = 0.145