Preseason elimination impact on anterior cruciate ligament injury in the National Football League

Table 1 Cumulative anterior cruciate ligament tear count

Season	Total ACL tears	Percent difference	Teams impacted	P value1
Through four regular season games, excluding preseason
2020	14	+118.8%	11	0.039
2015-2019 average	6.4		5.8
Through four regular season games, including preseason injuries
2020	14	-18.6%	11	0.394
2015-2019 average	17.2		13.6
Through eight regular season games, including preseason injuries
2020	19	-16.7%	12	0.196
2015-2019 average	22.8		16.0
Through eight games played, regular or preseason
2020	19	+10.5%	12	0.600
2015-2019 average	17.2		13.6

¹P value calculated using Chi-squared analysis. Bold indicated statistical significance.

ACL: Anterior cruciate ligament.

Table 2 Week by week comparison of cumulative anterior cruciate ligament tear rate for the first 8 games played

	Year	Total injuries	Total games	Rate	RR	95%CI	P value
Game 1	2020	3	16	0.188	1.071	0.348-3.302	0.904
	2015-2019	14	80	0.175
Game 2	2020	10	32	0.313	1.724	0.937-3.174	0.08
	2015-2019	29	160	0.181
Game 3	2020	13	48	0.271	1.477	0.865-2.524	0.153
	2015-2019	44	240	0.183
Game 4	2020	14	63	0.222	1.317	0.781-2.22	0.301
	2015-2019	54	320	0.169
Game 5	2020	15	77	0.195	1.237	0.745-2.055	0.412
	2015-2019	63	400	0.158
Game 6	2020	17	91	0.187	1.338	0.826-2.169	0.237
	2015-2019	67	480	0.140
Game 7	2020	19	105	0.181	1.333	0.844-2.107	0.218
	2015-2019	76	560	0.136
Game 8	2020	19	119	0.160	1.181	0.748-1.864	0.476
	2015-2019	86	636	0.135

RR: Relative risk; CI: Confidence interval.