Magnitude and meaningfulness of change in SF-36 scores in four types of orthopedic surgery

Table 5 Change in SF-36 subscales across study groups

	Norm 95%CI^¶	Total hip replacement (controls)				Total hip replacement (patients)				Total knee replacement				Arthroscopic partial meniscectomy				Anterior cruciate ligament reconstruction
		SEM*	MDC^#		ΔM (SD)	SEM	MDC		ΔM (SD)	SEM	MDC		ΔM (SD)	SEM	MDC		ΔM (SD)	SEM	MDC		ΔM (SD)
			Ind	Grp			Ind	Grp			Ind	Grp			Ind	Grp			Ind	Grp
PF	12	12	34	5	-2 (12)	18	49	4	27 (23)	15	41	6	29 (17)	16	45	6	15 (23)	14	40	6	34 (21)
RP	23	21	57	10	-2 (26)	33	91	8	33 (33)	30	84	12	35 (34)	32	88	11	27 (45)	29	81	12	50 (30)
BP	15	15	41	6	-3 (16)	20	54	5	37 (23)	19	51	7	36 (27)	17	46	6	20 (24)	17	48	7	31 (22)
GH	18	13	36	6	-4 (13)	14	39	4	0 (17)	13	35	5	3 (14)	10	27	3	-3 (14)	11	31	5	2 (12)
VT	16	12	34	6	-2 (14)	16	44	4	17 (20)	18	50	7	16 (22)	14	39	5	9 (20)	12	34	5	11 (14)
SF	26	17	48	7	-3 (21)	19	53	5	19 (24)	19	52	7	14 (25)	14	38	5	1 (19)	17	46	7	19 (26)
RE	28	28	79	14	3 (31)	35	97	9	25 (43)	34	94	14	24 (47)	27	74	9	9 (38)	28	78	11	30 (43)
MH	24	12	33	5	-3 (14)	15	40	4	12 (17)	14	39	6	8 (18)	12	33	4	5 (17)	12	34	5	12 (17)

Note: ^¶ 95%CI for population-based normative scores on SF-36 subscales [36].
* SEM (Standard error of measurement) = √within subjects variance; Derived from ANOVA model with 'time of follow-up' as the within subjects factor.
# MDC_ind (Minimal detectable change at individual level) = 1.96*√2*SEM; MDC_grp (Minimal detectable change at group level) = (1.96*√2*SEM)/√n.
PF = Physical Functioning, RP = Role Physical, BP = Bodily Pain, GH = General Health, VT = Vitality, SF = Social Functioning, RE = Role Emotional, MH = Mental Health.

ISSN: 1477-7525