Low infection rates after 34,361 intramedullary nail operations in 55 low- and middle-income countries

Figures & data

Table 1. Number of femur and tibia SIGN nail operations, follow–up, and infection rates by country in the SOSD in October 2010

Country		Nails	Follow-up			Infected
	Bone	N	n	%	(95% CI)	%	(95% CI)
Afghanistan	Femur	893	138	16	(13–18)	1.6	(0.8–2.4)
	Tibia	698	109	16	(13–18)	1.7	(0.7–2.7)
Bangladesh	Femur	1,111	299	27	(24–30)	1.2	(0.6–1.8)
	Tibia	211	48	23	(17–28)	4.7	(1.8–7.6)
Belarus	Femur	28	1	4	(0–11)	0.0	(0.0–0.0)
	Tibia	150	5	3	(0.4–6)	0.0	(0.0–0.0)
Bhutan	Femur	39	8	21	(8–33)	2.6	(0.0–7.6)
	Tibia	126	29	23	(16–30)	1.6	(0.0–3.8)
Cambodia	Femur	2,478	550	22	(21–24)	0.7	(0.4–1.0)
	Tibia	1,587	275	17	(15–19)	0.6	(0.2–1.0)
Cameroon	Femur	309	35	11	(8–15)	0.3	(0.0–0.9)
	Tibia	116	12	10	(5–16)	1.7	(0.0–4.1)
Dominican Republic	Femur	847	22	3	(2–4)	0.5	(0.0–1.0)
	Tibia	168	4	2	(0.1–5)	0.0	(0.0–0.0)
Egypt	Femur	47	4	9	(1–17)	0.0	(0.0–0.0)
	Tibia	120	9	8	(3–12)	0.0	(0.0–0.0)
Ethiopia	Femur	347	142	41	(36–46)	1.7	(0.4–3.1)
	Tibia	139	52	37	(29–45)	2.9	(0.1–5.7)
Guatemala	Femur	320	10	3	(1–5)	0.3	(0.0–0.9)
	Tibia	200	8	4	(1–7)	1.5	(0.0–3.2)
Haiti	Femur	297	37	13	(9–16)	0.7	(0.0–1.7)
	Tibia	90	1	1	(0–3)	0.0	(0.0–0.0)
India	Femur	348	12	3	(2–5)	0.3	(0.0–0.9)
	Tibia	652	22	3	(2–5)	0.2	(0.0–0.5)
Indonesia	Femur	434	57	13	(10–16)	0.0	(0.0–0.0)
	Tibia	239	37	16	(11–20)	0.0	(0.0–0.0)
Iran	Femur	223	0	0	(0–0)	0.0	(0.0–0.0)
	Tibia	254	1	0.4	(0–1)	0.0	(0.0–0.0)
Iraq	Femur	137	69	50	(42–59)	0.7	(0.0–2.1)
	Tibia	71	38	54	(42–65)	8.5	(2.0–15)
Kenya	Femur	1,849	250	14	(12–15)	0.8	(0.4–1.2)
	Tibia	742	169	23	(20–26)	3.2	(1.9–4.5)
Malawi	Femur	236	46	20	(15–25)	1.3	(0.0–2.8)
	Tibia	66	10	15	(7–24)	1.5	(0.0–4.4)
Mongolia	Femur	229	9	4	(1–6)	0.9	(0.0–2.1)
	Tibia	306	12	4	(1–6)	0.3	(0.0–0.9)
Mozambique	Femur	131	11	8	(4–13)	0.8	(0.0–2.3)
	Tibia	12	1	8	(0–24)	0.0	(0.0–0.0)
Myanmar	Femur	1,508	343	23	(21–25)	0.7	(0.3–1.1)
	Tibia	1,234	232	19	(17–21)	1.1	(0.5–1.7)
Nepal	Femur	624	251	40	(36–44)	1.0	(0.2–1.8)
	Tibia	909	435	48	(45–51)	3.0	(1.9–4.1)
Nicaragua	Femur	165	12	7	(3–11)	0.0	(0.0–0.0)
	Tibia	238	18	7	(4–11)	0.0	(0.0–0.0)
Niger	Femur	122	16	13	(7–19)	0.0	(0.0–0.0)
	Tibia	43	6	14	(4–24)	0.0	(0.0–0.0)
Nigeria	Femur	412	49	12	(9–15)	0.0	(0.0–0.0)
	Tibia	147	23	16	(10–22)	0.0	(0.0–0.0)
Pakistan	Femur	1,493	313	21	(19–23)	0.9	(0.4–1.4)
	Tibia	1,187	203	17	(15–19)	1.2	(0.6–1.8)
Philippines	Femur	1,295	367	28	(26–31)	0.6	(0.2–1.0)
	Tibia	450	130	29	(25–33)	1.8	(0.6–3.0)
Russian Federation	Femur	380	56	15	(11–18)	0.3	(0.0–0.9)
	Tibia	420	49	12	(9–15)	0.0	(0.0–0.0)
South Africa	Femur	169	4	2	(0.1–5)	0.6	(0.0–1.8)
	Tibia	20	0	0	(0–0)	0.0	(0.0–0.0)
Swaziland	Femur	128	13	10	(5–15)	0.8	(0.0–2.3)
	Tibia	108	9	8	(3–14)	1.9	(0.0–4.5)
Tanzania	Femur	1,206	462	38	(36–41)	0.7	(0.2–1.2)
	Tibia	297	116	39	(34–45)	2.0	(0.4–3.6)
Thailand	Femur	91	25	28	(18–37)	0.0	(0.0–0.0)
	Tibia	72	8	11	(4–18)	1.4	(0.0–4.1)
Uganda	Femur	909	295	33	(30–36)	0.8	(0.2–1.4)
	Tibia	147	28	19	(13–25)	0.7	(0.0–2.1)
Vietnam	Femur	1,609	29	2	(1–3)	0.1	(0.0–0.3)
	Tibia	2,105	29	1	(1–2)	0.0	(0.0–0.0)
Countries with n < 100 ^a	Femur	393	99	25	(21–30)	0.8	(0.0–1.7)
	Tibia	230	62	27	(21–33)	4.3	(1.7–6.9)
Total	Femur	20,807	4,034	19.4	(18.9–19.9)	0.7	(0.6–0.8)
	Tibia	13,554	2,190	16.2	(15.6–16.8)	1.2	(1.0–1.4)
Total: femur andtibia combined		34,361	6,224	18.1	(17.7–18.5)	0.9	(0.8–1.0)

The 95% confidence intervals are based on linear calculations based on approximations to the normal distribution.

^a To reduce the size of the table, all countries with less than 100 registered cases are grouped together.

Table 2. Total number of SIGN nails and follow-up according to sex, geographic region, and income level of country

Region / income level ^a	Total no.	No. of women (%)	Total no. followed up (%)	No. of females followed up (%)	p-value ^b
Africa	8,146	1,815 (22.3)	1,811 (22.3)	403 (22.3)	1.0
Asia	23,484	3,828 (16.3)	4,207 (17.9)	785 (18.7)	< 0.001
Latin America	2,552	390 (15.3)	200 (7.8)	26 (12.5)	0.3
Europe	179	64 (34.6)	6 (3.4)	1	0.7 ^c
Low-income	18,152	3,496 (19.3)	4,365 (24.1)	889 (20.4)	0.03
Lower middle-income	13,391	2,032 (15.2)	1,645 (12.3)	283 (17.2)	0.01
Higher middle-income	2,818	567 (20.1)	214 (7.6)	42 (19.6)	0.9
Total SOSD	34,361	6,095 (17.7)	6,224 (18.1)	1,214 (19.9)	< 0.001

^a Income level as defined by the World Bank 2009.

^b Chi-square test, gender against follow-up.

^c Fisher's exact test.

Table 3. Follow-up for each age group compared to the < 20-year age group

Age group	n	Follow-up (%)	p-value ^a
< 20 years	4,237	824 (19.4)	< 0.001 ^b
20–29 years	11,645	2,161 (18.6)	0.2
30–39 years	7,770	1,510 (19.4)	1.0
40–49 years	4,940	902 (18.3)	0.2
50–59 years	2,823	451 (16.0)	< 0.001
≥ 60 years	2,946	376 (12.8)	< 0.001
Total	34,361	6,224 (18.1)

^a logistic regression.

^b overall test.

Figure 1. Poisson regression analysis. Pattern of follow-up rate over time for femur and tibia fractures in the SOSD. The color band signifies the 80% range of values between countries.

Figure 2. Poisson regression analysis. Pattern of infection rate for femur and tibia fractures over time in the SOSD. The color band signifies the 80% range of values between countries.

Figure 3. Follow-up rate plotted against log change in the infection rate. The curve is based on a generalized additive regression model (gam). Dotted lines represent 95% CI. With follow-up over 5%, there is very little increase in infection rate and the curve is consequently nearly horizontal. Short vertical lines on x-axis represent observations in different countries.