Randomized trial comparing suture button with single 3.5 mm syndesmotic screw for ankle syndesmosis injury: similar results at 2 years

Figures & data

Figure 1. CONSORT flowchart of the trial enrollment and analysis.

Figure 2. CT of injured ankle (upper panel) and uninjured ankle (lower panel) in a 20-year-old woman, 2 years after injury. Tibiofibular distance is measured on axial CT 1 cm proximal to the ankle joint. Distance measured anterior (A); central (C); and posterior (P).

Table 1. Patient characteristics at time of enrolment. Values are number of patients unless otherwise specified

Characteristic	SB (n = 55)	TS (n = 58)
Mean age (SD)	44 (15)	48 (14)
Male sex	35	30
Right side	32	26
Mean BMI (SD)	27 (5)	26 (4)
Medial malleolar fracture	14	19
Posterior malleolar fracture	37	31
Medial and posterior malleolar fracture	10	15
Maisonneuve fracture	26	20
Osteochondral damage of the talus	2 ^a	4
Intra-articular loose bodies	9 ^a	10
Temporary external fixator	7	2

^an = 54

Figure 3. AOFAS equivalence diagram. Blue area indicates margins of equivalence defined as the between-group difference of 10 points. Results at all time intervals are equivalent since the 95% CI lies wholly inside the margins.

Table 2. Primary and secondary outcome measures

Outcome measure	SB ^a		TS ^a		p-value
	n	score	n	score
AOFAS
6 weeks	54	67 (10)	52	66 (13)	0.7 ^c
6 months	53	87 (82–98)	54	88 (77–98)	1.0 ^b
1 years	53	93 (82–100)	52	90 (84–99)	0.5 ^b
2 years	48	97 (87–100)	47	97 (90–100)	0.7 ^b
MOXFQ
6 weeks	52	29 ((11)	48	31 (13)	0.4 ^c
6 months	55	14 (3–31)	53	14 (3–36)	0.7 ^b
1 year	52	5 (0–32)	51	6 (0–13)	0.9 ^b
2 years	48	5 (0–18)	47	3 (0–8)	0.2 ^b
OMA
1 year	53	90 (73–100)	52	90 (76–100)	0.4 ^b
2 years	47	90 (75–100)	45	100 (83–100)	0.2 ^b
VAS for pain during rest
6 weeks	53	1.0 (0–2)	49	1.0 (0–2)	0.9 ^b
6 months	54	0.0 (0–1)	54	0.0 (0–2)	0.1 ^b
1 year	53	0.0 (0–1)	52	0.0 (0–1)	0.5 ^b
2 years	48	0.0 (0–1)	47	0.0 (0–0)	0.6 ^b
VAS for pain during walking
6 weeks	53	2.0 (1–4)	49	3.0 (2–4)	0.3 ^b
6 months	54	1.0 (0–3)	54	1.0 (0–2)	0.8 ^b
1 year	53	1.0 (0–2)	52	1.0 (0–2)	0.9 ^b
2 years	48	0.0 (0–1)	47	0.0 (0–1)	0.2 ^b
VAS for pain at night
6 weeks	53	1.0 (0–2)	49	1.0 (0–3)	0.6 ^b
6 months	54	0.0 (0–0)	54	0.0 (0–1)	0.01 ^b
1 year	53	0.0 (0–0)	52	0.0 (0–0)	1.0 ^b
2 years	48	0.0 (0–1)	47	0.0 (0–0)	0.2 ^b
VAS for pain during daily activity
6 weeks	53	3.0 (2–6)	49	4.0 (2–7)	0.4 ^b
6 months	54	1.0 (0–3)	54	1.0 (0–2)	0.9 ^b
1 year	53	0.0 (0–2)	52	1.0 (0–2)	0.6 ^b
2 years	48	0.0 (0–29	47	0.0 (0–0)	0.03 ^b
EQ-5D index
6 weeks	53	0.7 (0.6–0.8)	53	0.7 (0.3–0.7)	0.1 ^b
6 months	54	0.8 (0.7–1.0)	54	0.8 (0.7–1.0)	0.9 ^b
1 year	53	1.0 (0.8–1.0)	52	1.0 (0.8–1.0)	1.0 ^b
2 years	48	1.0 (0.8–1.0)	47	1.0 (0.9–1.0)	0.3 ^b
EQ-5D VAS
6 weeks	52	73 (15)	51	63 (18)	0.004 ^c
6 months	53	89 (70–95)	54	80 (74–90)	0.2 ^b
1 year	52	85 (71–95)	52	88 (76–90)	0.6 ^b
2 year	48	85 (70–95)	45	90 (77–95)	0.6 ^b

^a For not normally distributed data values are given as median (IQR)

in parentheses and for normally distributed data as mean (SD).

^b Nonparametric (Mann–Whitney U) test.

^c 2-sided t-test for independent samples.

Table 5. Radiological results: difference measured in mm in tibiofibular distance at level of syndesmosis (1 cm proximal to the ankle joint) between injured and uninjured side. Values are mean (SD) or median (IQR) unless otherwise specified

Factor	SB		TS		Mean between-group difference (95% CI)	p-value ^a
	n	difference	n	difference
Difference in anterior distance
≤ 2 weeks	54	0.1 (1.9)	56	0.7 (1.8)	–0.5 (–1.2 to 0.2)	0.1
1 year	54	1.1 (2.0)	50	0.7 (1.8)	0.3 (–0.4 to 1.1)	0.4
2 years	46	0.9 (1.9)	45	0.7 (1.6)	0.2 (–0.5 to 1.0)	0.5
Difference in central distance
≤ 2 weeks	54	0.1 (1.2)	56	–0.7 (1.1)	0.2 (–0.2 to 0.6)	0.3
1 year	54	1.2 (1.9)	50	0.9 (1.4)	0.3 (–0.3 to 1.0)	0.3
2 years	46	1.4 (0.0–2.0)	45	1.0 (0.0–1.0)	0.7 (0.0 to 1.4)	0.2 ^b
Difference in posterior distance
≤ 2 weeks	54	–0.4 (2.2)	56	–0.6 (2.1)	0.2 (–0.6 to 1.0)	0.7
1 year	54	0.1 (1.8)	50	0.4 (1.8)	–0.3 (–1.0 to 0.4)	0.5
2 years	46	0.0 (2.3)	45	0.3 (2.0)	–0.4 (–1.2 to 0.5)	0.4

^aLevene’s test was used to assess equality of the variances. Statistical analysis was conducted using the 2-sided t-test for independent samples in normally distributed data;

otherwise the Mann–Whitney U-test was used.

^bThe Mann–Whitney U-test was used.