The natural history of Perthes' disease

Figures & data

Table 1. Relationship between the Catterall classification and the lateral pillar classification (number of patients)

Catterall classification	Lateral pillar classification			Total
	group A	group B	group C
Group 1	5	4	0	9
Group 2	3	25	0	28
Group 3	0	74	10	84
Group 4	0	21	70	91
Total	8	124	80	212

Table 2. Femoral head cover (%) of the normal hip at the time of diagnosis, and after 1, 3, and 5 years

Time	Femoral head cover
	Age < 6.0 years			Age > 6.0 years
	Mean	SD	LL	Mean	SD	LL
At diagnosis	98	7.4	83	96	6.1	84
1-year follow-up	98	6.2	86	95	5.5	84
3-year follow-up	96	5.9	84	94	7.8	78
5-year follow-up	93	6.6	80	92	7.4	77

LL: Lower limit of normal range (mean – 2 SD)

Table 3. Femoral head cover (%) of the hip with Perthes' disease at the time of diagnosis, and after 1, 3, and 5 years, according to age (years) and degree of femoral head necrosis

	Femoral head cover
	Catterall groups 1 and 2				Catterall groups 3 and 4
	Age < 6.0		Age > 6.0		Age < 6.0		Age > 6.0
Time	Mean	SD	Mean	SD	Mean	SD	Mean	SD
At diagnosis	93	7.6	93	9.8	94	12	87	12
1-year follow-up	92	8.7	92	8.7	83	11	78	7.2
3-year follow-up	89	9.8	^a		79	9.7	75	9.5
5-year follow-up	89	8.7	88	5.8	79	11	76	9.6

^a only 2 patients.

Table 4. Radiographic 5-year outcome (modified Stulberg classification) in relation to the Catterall classification and lateral pillar classification

	Radiographic outcome
	Good		Fair		Poor
Classification	n	%	n	%	n	%
Catterall
Group 1	9	100	0	0	0	0
Group 2	23	82	5	18	0	0
Group 3	56	67	24	29	4	4
Group 4	26	29	31	34	34	37
Lateral pillar
Group A	8	100	0	0	0	0
Group B	85	68	28	23	11	9
Group C	21	26	32	40	27	34

n: number of patients; %: percentage of patients.

Figure 1. A 7-year-old girl with Perthes' disease of the left hip. She had symptoms for 1 month before diagnosis (pain and limping gait). A and B. At 1-year follow-up, showing Perthes' disease classified as Catterall group 3 and lateral pillar group B. C. At 5-year follow-up, showing good radiographic outcome with spherical femoral head.

Table 5. Radiographic 5-year outcome (modified Stulberg classification) in relation to age and femoral head affection in patients with more than 50% femoral head necrosis

	Radiographic outcome
Femoral head affection	Age < 6.0 years						Age > 6.0 years
	Good		Fair		Poor		Good		Fair		Poor
	n	%	n	%	n	%	n	%	n	%	n	%
Catterall
Group 3	40	70	15	26	2	4	16	59	9	33	2	7
Group 4	25	37	26	39	16	24	1	4	5	21	18	75
Lateral pillar
Group B	45	68	14	21	7	11	16	55	9	31	4	14
Group C	20	34	27	47	11	19	1	5	5	23	16	72

n: number of patients; %: percentage of patients.

Figure 2. A 9-year-old boy with Perthes' disease of the left hip. He had had pain in his left knee and limping for 2 months prior to diagnosis. A and B. At the time of diagnosis, showing Perthes' disease classified as Catterall group 4 and lateral pillar group C. C. At 5-year follow-up, showing poor radiographic outcome with flattened left femoral head.

Table 6. Radiographic 5-year outcome in relation to age at diagnosis in children with total femoral head involvement (Catterall group 4)

Age at diagnosis (year)	Radiographic outcome
	Good		Fair		Poor		Total
	n	%	n	%	n	%	n
< 4	16	41	18	46	5	13	39
4.0–5.9	9	32	8	29	11	39	28
6.0–7.9	1	6	3	19	12	75	16
> 8.0	0	0	2	25	6	75	8

n: number of patients; %: percentage of patients.

Table 7. Radiographic 5-year outcome (modified Stulberg classification) according to the number of risk factors and age at diagnosis in patients with more than 50% femoral head necrosis

	Radiographic outcome (modified Stulberg classification)
	Age < 6.0 years (n = 124)						Age > 6.0 years (n = 51)
Number of risk factors ^a	Good		Fair		Poor		Good		Fair		Poor
	n	%	n	%	n	%	n	%	n	%	n	%
0	30	79	7	18	1	3
1	15	65	6	26	2	9	10	67	4	27	1	7
2	15	35	18	43	9	21	7	64	3	27	1	9
3	5	24	10	48	6	28	0	0	6	43	8	57
4							0	0	1	9	10	91

^a Risk factors: Catterall group 4, lateral pillar group C, age over 6.0 years, and femoral head cover of < 80%.