Table 2.

Frequency of Kellgren-Lawrence (K-L) grades (0–IV) and location of pain (knee only, hip only, knee and hip, neither knee nor hip) over time per cluster of radiographic knee osteoarthritis.

	Severe, n = 17			Bone Density, n = 113			Early, n = 110			Late, n = 69			No, n = 108
	T0	T2y	T5y	T0	T2y	T5y	T0	T2y	T5y	T0	T2y	T5y	T0	T2y	T5y
K-L^†, %
0	38	29	26	74	69	35	86	78	57	88	77	40	83	79	64
I	35	35	35	22	24	43	10	16	27	10	20	47	15	17	30
II	24	29	18	4	6	20	3	4	12	2	3	10	2	3	6
III	3	6	15	0	1	2	0	1	4	0	0	2	0	1	0
IV	0	0	6	0	0	1	0	0	0	0	0	0	0	0	0
Pain^††, %
Knee only	71	70	53	44	32	29	40	32	30	30	31	27	34	28	21
Knee and hip	24	12	35	42	38	40	41	46	39	33	37	41	49	33	29
Hip only	5	0	0	14	13	13	19	13	13	36	23	17	17	14	6
Neither knee nor hip	—^*	18	12	—^*	17	18	—^*	8	18	—^*	9	15	—^*	25	44

↵† K-L: percentage of knees, taking into account the left and right knee of participants within cluster (e.g., 17 participants in Severe cluster for a total of 34 knees).
↵†† Pain: reflects whether an individual experiences pain in, e.g., any knee (1 or both).
↵* Participants with neither knee nor hip pain were not included in the CHECK study. T0: baseline; T2y: 2-year followup; T5y: 5-year followup.