Allograft tissue irradiation and failure rate after anterior cruciate ligament reconstruction: A systematic review

Table 1 In vivo studies of non-irradiated and irradiated allograft tissue for anterior cruciate ligament reconstruction

Ref.	Year	Type of study	Graft type	Irradiation dose	No. of patients (at final follow-up/enrolled)	Male	Female	Average age (yr)	Follow-up length	Findings	Weaknesses
Rihn et al[26]	2006	Retrospective	BPTB - allograft	2.5 Mrad	39	27	12	44 ± 8.4	4.2 yr	Significant difference between irradiated allograft and allograft with laxity, Lachman, and pivot shift clunk	Age difference in populations
			BPTB - autograft	None	63	43	20	25.3 ± 9.3	4.6 yr	No significant difference on range of motion, effusion, IKDC, KT-1000 when adjusted for age, IKDC physical exam rating, and return to sport	No mention of temperature when irradiation performed
Rappé et al[18]	2007	Cohort	Achilles - allograft	2.0-2.5 Mrad	33/45	N/A	N/A	26 (ranage 14-59)	6 mo	Significantly more clincal failures in irradiated allograft vs non-irradiated allograft groups with failures occuring about 9 mo earlier in irradiated group (failure of graft = 5 mm or greater on KT-1000 compared to contralateral side, positive Lachman, or magnetic resonance imaging)	Large loss of follow-up in irradiated group
			Achilles - allograft	None	42/45			27 (range 14-57)			No mention of temperature when irradiation performed
Sun et al[22]	2009	Prospective, randomized	BPTB - allograft	2.5 Mrad	32/33	24	8	30.1 ± 6.1	31 mo (2% lost to follow-up)	Significant difference between irradiated allograft and autograft with greater laxity on KT-2000, side to side difference on KT-2000, pivot shift grade II or III, anterior drawer test grade II or III, and Lachman test grade II or III	No mention of temperature when irradiation performed
			BPTB - autograft	None	33/33	24	9	29.7 ± 7.2		No significant difference on overall IKDC, range of motion, Harner's vertical jump test, Daniel's one-leg hip test, subjective IKDC, Cincinnati knee score, Lysholm score, and Tegner score
Sun et al[23]	2009	Prospective, randomized	BPTB - allograft	2.5 Mrad	32	24	8	30.1 ± 6.1	31 mo (1% lost to follow-up - treatment group not mentioned)	Significant difference between irradiated allograft, non-irradiated allograft, and autograft with greater laxity on KT-2000, side to side difference on KT-2000, pivot shift grade II or III, anterior drawer test grade II or III, and Lachman test grade II or III	No mention of temperature when irradiation performed
			BPTB - allograft	None	34	22	12	31.8 ± 6.9
			BPTB - autograft	None	33	24	9	29.7 ± 7.2		No significant difference on overall IKDC, range of motion, Harner's vertical jump test, Daniel’s one-leg hip test, subjective IKDC, Cincinnati knee score, Lysholm score, and Tegner score
Sun et al[24]	2011	Prospective, randomized	Hamstring - allograft	2.5 Mrad	31/37	24	7	30.3 ± 7.9	42.2 mo (11% lost to follow-up)	Significant difference between irradiated allograft and autograft with greater laxity on KT-2000, side to side difference on KT-2000, pivot shift grade II or III, anterior drawer test grade II or III, and Lachman test grade II or III	No mention of temperature when irradiation performed
			Hamstring - autograft	None	36/38	28	8	30.9 ± 8.7		No significant difference on overall IKDC, range of motion, Harner's vertical jump test, Daniel's one-leg hip test, subjective IKDC, Cincinnati knee score, Lysholm score, and Tegner score
Sun et al[25]	2012	Prospective, randomized	Hamstring - allograft	2.5 Mrad	31/38	24	7	30.3 ± 7.9	42.5 mo (9.1% lost to follow-up)	Significant difference between irradiated allograft and non-irradiated allograft with greater laxity on KT-2000, side to side difference on KT-2000, pivot shift grade II or III, anterior drawer test grade II or III, and Lachman test grade II or III	No mention of temperature when irradiation performed
			Hamstring - allograft	None	38/39	31	7	31.7 ± 7.8		No significant difference on overall IKDC, range of motion, Harner's vertical jump test, Daniel's one-leg hip test, subjective IKDC, Cincinnati knee score, Lysholm score, and Tegner score

IKDC: International Knee Documentation Committee; BPTB: Bone patella tendon bone.

Table 2 In vitro studies of non-irradiated and irradiated allograft tissue for anterior cruciate ligament reconstruction

Ref.	Year	Type of study	Graft type	Irradiation dose	Temperautre when irradiated	No. of samples	Age (yr)	Findings
Balsly et al[9]	2008	Laboratory	BPTB - low dose	1.83-2.18 Mrad	- 20 °C to -50 °C	9	18-55	There was a significant difference for: (1) BPTB - tensile strength in the moderate dose irradiation vs control groups (2) Fascia lata - modulus of elasticity in the moderate dose irradiation vs control groups
			BPTB - moderate dose	2.4-2.85 Mrad		9
			BPTB - control	None	N/A	9 controls for low dose
						9 controls moderate dose
			Anterior Tibialis - low dose	1.83-2.18 Mrad	- 20 °C to -50 °C	10	23-64	No significant difference between the tensile strength and modulus of elasticity for all other groups for low dose irradiation vs control and moderate dose irradiation vs control (other than stated above)
			Anterior Tibialis - moderate dose	2.4-2.85 Mrad		10
			Anterior Tibialis - control	None	N/A	10 controls for low dose
						10 controls for moderate dose
			Semitendinosus - low dose	1.83-2.18 Mrad	- 20 °C to -50 °C	8	16-54
			Semitendinosus - moderate dose	2.4-2.85 Mrad		10
			Semitendinosus - control	None	N/A	10 controls for low dose
						10 controls for moderate dose
			Fascia Lata - low dose	1.83-2.18 Mrad	- 20 °C to -50 °C	10	19-48
			Fascia Lata - moderate dose	2.4-2.85 Mrad		10
			Fascia Lata - control	None	N/A	10 controls for low dose
						10 controls for moderate dose
Greaves et al[17]	2008	Laboratory	Tibialis - single strand irradiated (age < 45)	1.46-1.8 Mrad	Dry ice temperatures	10 irradiated	< 45	No significant difference in failure loads for irradiated vs non-irradiated for each of the three age groups (midsubstance failure = any rupture within graft substance, grip failure = slip from 1 of tendon grips exposing serrated portion of tendon)
			Tibialis - single strand non-irradiated (age < 45)			10 non-irradiated
			Tibialis - double strand irradiated (age < 45)			10 irradiated
			Tibialis - double strand non-irradiated (age < 45)			10 non-irradiated
			Tibialis - single strand irradiated (age 46-55)			13 irradiated	46-55
			Tibialis - single strand non-irradiated (age 46-55)			13 non-irradiated
			Tibialis - double strand irradiated (age 46-55)			10 irradiated
			Tibialis - double strand non-irradiated (age 46-55)			10 non-irradiated
			Tibialis - single strand irradiated (age 56-65)			10 irradiated	56-65
			Tibialis - single strand non-irradiated (age 56-65)			10 non-irradiated
			Tibialis - double strand irradiated (age 56-65)			10 irradiated
			Tibialis - double strand non-irradiated (age 56-65)			10 non-irradiated
Baldini et al[34]	2012	Laboratory	Tibialis	2.0-2.8 Mrad	Not reported	15	41.8	There were no significant difference in stiffness, failure to load, and failure stress between the irradiated vs non-irradiated groups
				None		12	47.4
Yanke et al[35]	2013	Laboratory	BPTB	1.0-1.2 Mrad	Not reported	10	52 ± 11	There was a significant difference in stiffness between the irradiated vs non-irradiated groups but none found in strain and elongation
				None		10

BPTB: Bone patella tendon bone.