. 2014 Mar 19;7:21. doi: 10.1186/1757-1146-7-21

Table 2.

Included studies in qualitative synthesis

Author, year	Study type	Participants	Follow up	Sample size	Measurement of CAI	Epidemiology of CAI- prevalence/distribution
Hiller *et al. 2008* [17]	Prospective cohort	Adolescent dancers 14.2 ± 1.8 yrs	13 months	116	Ankle instability (CAIT)	36% of all dancers unstable
					Ankle instability (CAIT)	71% of sprainers unstable
					Ankle joint laxity (mod ant draw)	37% right, 47% left ankles moderate to very lax
					Self report	50% of total had history of sprain
						22% of total had history of ≥2 sprains
						38 sprains were sustained by 33 participants
						Incidence of sprains 0.21/1000 hours of dancing
Hollwarth *et al. 1985* [19]	Retrospective	Patients with high ankle sprain, severe trauma for inclusion	6 yrs	96	Subjective complaints; rolling over, pain, swelling, meterosensitivity	31.3% subjective complaints
		16 (range: 9–21) yrs			X-ray (AP and lateral) injured side, talar tilt stress x-ray both sides	17.7% ligament avulsions
					Ligament stiffness, pain during supination or palpation of, fibular ligaments or syndesmosis	38.5% “pathologic clinical findings”
					Abnormal talar tilt (> 5 deg)	42% abnormal
Marchi *et al. 1999* [20]	Prospective cohort	Patients with moderate to severe ankle injury 6–15 yrs. 26 female (48%)	3 yrs	220	Medical report of objective (limited joint mobility, pain on pressure, axial deviations, weakness, or shortening of a limb) and subjective (pain at rest or during exercise, sense of unsteadiness, or paraesthesia) symptoms	42% had objective or subjective symptoms (3 yrs follow up)
Marchi *et al. 1999* [20]	Prospective cohort		12 yrs	54		23% had permanent symptoms (Risk ratio: 1.79, p = 0.10) (12 yrs follow up)
Soderman *et al. 2001* [21]	Prospective cohort	Adolescent female soccer players 15.9 ± 2.1 (range: 14–19) yrs	1 season	153	Medical report of re-injuries	56% of sprainers had recurrent sprain
Steffen *et al. 2008* [22]	Prospective cohort	Female soccer players 15.4 ± 0.8 (range: 14–16) yrs	-	1430	Self report of sprain history	Players with previous ankle injury (PI) more likely to sustain new ankle injury than those without (NH) (Rate ratio = 1.2 [1.1; 1.3] p < .001).
					FAOS	92.0 ± 11.3 (PI), 97.3 ± 6.0 (NH) mean difference: −5.3 (95% CI = −6.0 to −4.5)
					Pain	62.8 ± 11.1 (PI), 68.2 ± 9.7 (NH) mean difference: −5.4 (95% CI = −6.3 to −4.5)
					Symptoms	96.3 ± 7.5 (PI), 98.7 ± 4.2 (NH) mean difference: −2.3 (95% CI = −2.9 to −1.8)
					Activities of daily living	89.0 ± 16.2 (PI), 96.3 ± 8.4 (NH) mean difference: −7.3 (95%CI = −8.4 to −6.2)
					Sport and recreation function	71.3 ± 12.4 (PI), 76.3 ± 10.0 (NH) mean difference: −5.0 (95% CI = −5.9 to −4.0)
					Ankle-related quality of life	411.5 ± 46.8 (PI), and 436.7 ± 26.8 (NH) mean difference: −25.2
					Ankle-related quality of life	(95% CI = −28.5 to −21.9)
Swenson *et al. 2009* [23]	Descriptive epidemiology study	High school students	-	100 high schools 13755 injuries	Medical report of re-injury	Ankle most frequently diagnosed site for recurrent injury in basketball (boys: 58.4%, girls: 43.6%), volleyball (42.7%), soccer (boys: 34.8%, girls: 37.2%), football (29.8%), softball (26.3%), and wrestling (20.1%)
						28% of all recurrent injuries were ankle injuries
						More recurrent (28%) than new ankle injuries (19%) (Injury Proportion Ratio = 1.47; 95% CI, 1.31-1.65)
Timm *et al. 2005* [24]	Prospective cohort	Emergency department patients with ankle injury	6 weeks	199	Medical report of:
		Emergency department patients with ankle injury			Pain with activity	24 (34%) OW, 14 (15%) NW, RR = 2.25 (95% CI = 1.25-4.02)
		Range: 8–18 yrs			Persistent swelling and/or weakness	22 (31%) OW, 12 (13%) NW, RR = 2.40 (95% CI = 1.28-4.52)
		Range: 8–18 yrs			Re-injury	17 (24%) OW, 14 (15%) NW, RR = 1.60 (95% CI = 0.84-3.01)
		OW mean age = 13.9 yrs	6 months	171	Pain with activity	19 (41%) OW, 19 (16%) NW, RR = 2.57 (95% CI = 1.50-4.39)
		NW mean age = 13.5 years.			Persistent swelling and/or weakness	16 (34%) OW, 18 (15%) NW, RR = 2.28 (95% CI = 1.28-4.08)
					Re-injury	12 (26%) OW, 19 (16%) NW, RR = 1.62 (95% CI = 0.86-3.06)
					Re-injury	31 (44%) of OW had persistent ankle symptoms at 6 months compared with 24 (26%) NW (RR, 1.70; 95% CI, 1.10-2.61)
Tyler *et al. 2006* [25]	Cohort study	Male high school football players	3 seasons	152	Medical report of sprain history	50 (33%) had history of previous ankle sprain 15 non-contact ankle sprains were incurred. Of the 11 players who had a previous ankle sprain and sustained a noncontact sprain in this study, 9 (82%) injured the same ankle (incidence 2.1)
Weir & Watson 1996[26]	Prospective cohort	Physical education students	1 yr	266	Self report of injuries	230 injuries were incurred. The most common injuries were ankle sprains.
Weir & Watson 1996[26]	Prospective cohort	Males (56%): 14.3 ± 0.85 (range: 12–15) yrs	1 yr	266	Self report of injuries	7 overuse injuries of the ankle were incurred. 100% of overuse injuries of the ankle were re-injuries.
		Females: 14.1 ± 0.90 (range: 12–15) yrs

KEY: CAI = Chronic Ankle Instability, CAIT = Cumberland Ankle Instability Tool, FAOS = Foot and Ankle Outcome Score, Mod ant drawer = modified anterior drawer test, OW = Children who are Overweight (≥85^th BMI percentile), NW = children who are of Normal Weight (<BMI 85^th percentile).