Radiographic evaluation of osteoarthritis of the hip

Figures & data

Table 1. Inter-observer variation using the Kellgren and Lawrence (K&L) classification (number of hips)

K&L grades	Observer 2
	0	1	2	3	4	Total
Observer 1
0	44	0	0	0	0	44
1	5	0	0	1	0	6
2	1	1	0	1	0	3
3	0	0	1	2	0	3
4	0	0	0	1	4	5
Total	50	1	1	5	4	61

Long-term follow-up radiograph of a 44-year-old man where there was discrepancy between the observers in the assessment of the right hip. Using the minimum JSW method, observer 1 found no OA (a minimum JSW of 3.2 mm) whereas observer 2 found OA (a minimum JSW of 1.8 mm). Both observers found severe OA by Kellgren and Lawrence (grade 3) and Croft (grade 4).

Table 2. Inter-observer variation using the classification by Croft et al. (number of hips)

Croft grades	Observer 2
	0	1	2	3	4	5	Total
Observer 1
0	38	3	0	0	0	0	41
1	5	1	0	1	0	0	7
2	3	1	0	0	0	0	4
3	0	0	0	1	1	0	2
4	0	0	0	1	1	1	3
5	0	0	0	0	0	4	4
Total	46	5	0	3	2	5	61

Table 3. Inter-observer variation using the minimum joint space width (JSW) classification (number of hips)

JSW grades	Observer 2
	0	1	Total
Observer 1
0	51	1	52
1	1	8	9
Total	52	9	61

Table 4. Relationship between the minimum JSW classifications and the other classifications (observer 1, number of dysplastic hips)

JSW classification
	No OA	OA	Total
K&L
No OA	49	1	50
Mild OA	2	1	3
Severe OA	1	7	8
Total	52	9	61
Croft
No OA	47	1	48
Mild OA	4	2	6
Severe OA	1	6	7
Total	52	9	61

JSW: joint space width; OA: osteoarthritis.

Table 5. Reliability of inter- and intra-observer measurements using kappa statistics

			Kappa statistics
Authors	Method of grading	Grades	Intra-observer kappa coefficient	Inter-observer kappa coefficient	95% CI
Cerhan et al. 1995	K&L	2 (0–1 vs. 2–4)	0.84–0.92	0.50
Ingvarsson et al. 2000	K&L	2 (0–1 vs. 2–4)	0.76	0.60–0.65
Present study 2011	K&L	5	0.69	0.55	0.35–0.72
Present study 2011	K&L	3 (0–1, 2, and 3–4)		0.72	0.49–0.89
Croft et al. 1990	Croft	2 (0–2 vs. 3–5)	0.49	0.41
Croft et al. 1990	Croft	2 (0–3 vs. 4–5)	0.93	0.63
Present study 2011	Croft	3 (0–1, 2–3, and 4–5)		0.65	0.41–0.83
Croft et al. 1990	Min. JSW	2 (cutoff 2.5 mm)	0.81	0.70
Croft et al. 1990	Min. JSW	2 (cutoff 1.5 mm)	0.83	0.79
Present study 2011	Min. JSW	2 (cutoff 2.0 mm)	0.93	0.87	0.64–1.0

Cerhan JR, Wallace RB, El-Khoury Y, Moore TE, Long CR. Decreased survival with increasing prevalence of full-body, radiographically defined osteoarthrosis in women. Am J Epidemiol 1995; 141: 225-34.

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