Table 1

Details of patient populations, follow-up duration, time from primary to revision ACL reconstruction, objective outcomes at final follow-up (objective IKDC, difference of laxity between indexed and healthy knee and pivot-shift test) and return to sport outcomes for each study

Authors and year	Patients	Follow-up duration	Age at revision ACL reconstruction (ACLR)	Time from primary to revision ACL reconstruction (ACLR)	Final IKDC	Final laxity	Final pivot-shift n (%)	Return to sport n (%)
Noyes and Barber-Westin (1996)21	65	3.5 years	25 years	NA	NA	3.4±4.8 mm	34 (52%) negative	51 (79%) Return to sport
						30 (53%) <3 mm	24 (37%) grade I
						17 (30%) 3–5.5 mm	4 (6%) grade II
						10 (17%) >5.5 mm	3 (5%) grade III
	22	2.3 years	27 years	NA	NA	1.9±4.4 mm	12 (60%) negative	16 (80%) Return to sport
						12 (66%) <3 mm	7 (35%) grade I
						3 (17%) 3–5.5 mm	1 (5%) grade II
						3 (17%) >5.5 mm	0 (0%) grade III
Johnson et al (1996)22	25	2.3 years	25 years	30 months	NA	3.7±3.5 mm	20 (80%) negative—grade I	22 (88%) Return to sport
	22 M/3F					5 (20%) <2.5 mm	5 (20%) grade II
						11 (44%) 3–5 mm	0 (0%) grade III
						9 (36%) 5.5–10 mm
Noyes and Barber-Westin (2001)23	52 knees	2.8 years	27 years	NA	NA	2.2±4.9 mm	NA	40 (72%) Return to sport
	51 patients
O'Shea and Shelbourne (2002)12	11	4.1 years	24 years	71 months	NA	1.6±1.2 mm	NA	11 (100%) Return to sport
						11 (100%) <3 mm		5.1±2.2 weeks to light sports
								5.4±1.5 months to full sport
Taggart et al (2004)24	20	3.4 years	30 years	49 months	NA	3 (15%) <1 mm	3 (15%) negative	8 (40%) Same pre-injury sport level
	14 M/6F					5 (25%) 1–3 mm	9 (45%) grade I	6 (30%) Lower level
						5 (25%) 3–5 mm	4 (20%) grade II
						7 (35%) >5 mm	4 (20%) grade III
Carson et al (2004)25	43	Minimum 2 years	NA	NA	NA	2.9 mm	37 (86%) negative	12 (28%) Sport without limitation
						20 (47%) <3 mm		20 (46%) Sport with limitation
						13 (30%) 3–4 mm
						6 (14%) 4–5 mm
						4 (9%) >5 mm
O'Neill (2004)26	48	7.5 years	33 years	60 months	20 (42%) A	10 (21%) 0 mm	NA	36 (75%) Same pre-injury sport level
	28 M/20F				20 (42%) B	22 (46%) 0–2 mm		21 (44%) High impact activities
					6 (12%) C	3 (6%) 2–3 mm
					2 (4%) D	10 (21%) 3–5 mm
						3 (6%) >5 mm
Grossman et al (2005)10	29	5.6 years	30.2 years	56 months	17 (58%) A	2.8 mm	27 (93%) negative	20 (68%) Same pre-injury sport level
	22 M/7F				8 (28%) B		2 (7%) grade I
					4 (14%) C		0 (0%) grade II
					0 (0%) D		0 (0%) grade III
Thomas et al (2005)13	49	6.2 years	35.4 years	NA	12 (24%) A	1.9±2.4 mm	43 (88%) negative	0 (0%) Same pre-injury sport level
	37 M/12F				28 (58%) B	46 (94%) 0–2 mm	5 (10%) grade I
					8 (16%) C	1 (2%) 3–4 mm	1 (2%) grade II
					1 (2%) D	2 (4%) >5 mm	0 (0%) grade III
Ferretti et al (2006)27	28	5.0 years	34 years	60 months	15 (53%) A	2.5±1.8 mm	15 (54%) negative	6 (20%) Same pre-injury sport level
					11 (39%) B	20 (71%) 0–3 mm	11 (39%) grade I	9 (30%) Lower level
					2 (8%) C	6 (21%) 3–5 mm	2 (7%) grade II	30 (100%) Return to sport
					0 (0%) D	2 (8%) >5 mm	0 (0%) grade III
Garofalo et al (2006)28	28	4.2 years	27 years	26 months	5 (18%) A	3.1±2.0 mm	21 (75%) negative	26 (93%) Same pre-injury sport level
	16 M/12F				21 (75%) B	18 (65%) <3 mm	7 (25%) grade I	18 (64%) High competitive
					2 (7%) C	9 (32%) 3–5 mm	0 (0%) grade II	6 (21%) Recreational
					0 (0%) D	1 (3%) 6–10 mm	0 (0%) grade III	2 (7%) Light sport
						0 (0%) >10 mm
Noyes and Barber-Westin (2006)29	21	4.1 years	33 years	NA	5 (24%) A	2.1±2.2 mm	10 (48%) negative	15 (71%) Return to sport
	15 M/6F				11 (52%) B	8 (38%) <3 mm	7 (33%) grade I
					3 (14%) C	7 (33%) 3–5 mm	3 (14%) grade II
					2 (10%) D	4 (19%) >5 mm	1 (5%) grade III
Salmon et al (2006)30	50	7.4 years	27 years	36 months	33 (73%) A/B	2.5 mm	31 (69%) negative	26 (58%) Return to level I-II activity
					12 (27%) C/D	17 (50%) <3 mm	14 (31%) grade I
						17 (50%) 3–5 mm	0 (0%) grade II
						0 (0%) >5 mm	0 (0%) grade III
Battaglia et al (2007)31	63	6.1 years	31 years	61 months	NA	3.9±2.4 mm	NA	42 (66%) Return to sport
	36 M/27F					30 (48%) <3 mm
						20 (31%) 3–5 mm
						10 (21%) >5 mm
Denti et al (2008)32	60	3.5 years	31 years	NA	18 (36%) A	28 (56%) <3 mm	NA	47 (78%) Same pre-injury sport level
					23 (46%) B	17 (34%) 3–5 mm		8 (14%) Lower level
					9 (18%) C	5 (10%) 6–10 mm		30 (50%) High competitive activities
					0 (0%) D	0 (0%) >10 mm
Diamantopoulos et al (2008)33	107	6.0 years	39 years	60 months	79 (74%) A	0.9±1.1 mm (KT)	79 (74%) negative	39 (36%) Same pre-injury sport level
	64 M/43F				17 (16%) B		17 (16%) grade I
					11 (10%) C		11 (10%) grade II
					0 (0%) D		0 (0%) grade III
Wegrzyn et al (2009)34	10	3.2 years	30 years	26 months	4 (40%) A	1.3±1.9 mm	NA	1st revision:
	8 M/2F				5 (50%) B	9 (90%)<5 mm		5 (50%) Same pre-injury sport level
					1 (10%) C	1 (10%) >5 mm		4 (40%) Lower level
					0 (0%) D
								2nd revision:
								2 (20%) Same pre-injury sport level
								4 (40%) Lower level
Muneta et al (2010)35	21	3.3 years	27 years	NA	NA	1.7±1.8 mm	14 (78%) negative	13 (76%) Same pre-injury sport level
	14 M/7F						3 (17%) grade I	18 (86%) Return to sport
							1 (5%) grade II
							0 (0%) grade III
Reinhardt et al (2012)36	21	3.0 years	16.9 years	NA	NA	NA	20 (95%) negative	11 (52%) Same pre-injury sport level
							1 (5%) grade I	20 (95%) Return to sport
							0 (0%) grade II
							0 (0%) grade III
Franceschi et al (2013)37	30	6.8 years	29.1 years	34 months	27 (90%) A/B	3.1 mm	25 (83%) Negative	20 (67%) Same pre-injury sport level
	19 M/11F				3 (10%) C		5 (17%) grade I	7 (25%) Lower activity
					0 (0%) D		0 (0%) grade II
							0 (0%) grade III
Gifstad et al (2013)11	56	7.5 years	26.5 years	38 months	NA	3.3±2.7 mm	45 (80%) negative—grade I	7 (13%) Same pre-injury sport level
	25 M/31F					28 (52%) <3 mm	11 (20%) grade II-III
						17 (23%) 3–5 mm
						8 (15%) >5 mm
Buda et al (2013)38	24	3.3 years	NA	NA	4 (17%) A	3.1±1.1 mm	4 (17%) negative	17 (71%) Same pre-injury sport level
	24 M/0F				16 (67%) B		18 (75%) grade I	3 (13%) Lower level
					2 (8%) C		2 (8%) grade II
					2 (8%) D		0 (0%) grade III
Shelbourne et al (2014)39	259	7.2 years	22.4 years	NA	NA	2.3±1.8 mm	NA	178 (69%) Same pre-injury sport level

Pre-injury level is referred to the initial injury before primary ACL reconstruction. Values are expressed as the mean or absolute number and percentage, according to variable.
F, females; M, males; IKDC, International Knee Documentation Committee; NA, not applicable.