The anterior cruciate ligament (ACL) injuries are common, 100,000 to 200,000 cases per year in the U.S.A1,2.
The status of the menisci influences clinical results after ACL reconstruction1. The reported incidence of meniscal tears ranges from 16% to 82% in acute ACL injuries and up to 96% in chronic injuries3.

Pike et al4, demonstrated that an increase between ACL injury and time to surgery, presents a higher incidence of meniscal injuries, with a risk of 1% per month of delay, this being greater for the medial meniscus, with an increase from 8 to 19% when treatment is postponed between 6-12 weeks, Even though other authors like Stone et al5, found that delayed reconstruction (greater than 90 days) was not associated with an increased risk of meniscal injuries.

We studied 321 patients between 2004 and 2020. 255(79.4%) males, 66(20.6%) females. Mean age of 37 years (range 14-65). Mean time from injury to surgery was 15.05 months.

86(26.79%) of all ACL injuries were isolated, 224(69.78%) were associated with meniscal injuries.

Of the 224 patients with associated ACL and meniscal injury, 106(47.3%) were medial meniscus, 65(29%) lateral meniscus, and 53(23.7%) both menisci.

Type of tear, 93(33.6%) were degenerative, 78(28.2%) longitudinal, 56(20.2%) bucket handle, and 50(18%) transverse.

Of the 159 medial meniscus injuries, 52(32.7%) were degenerative, 45(28.3%) longitudinal, 40(25.1%) bucket handle, and 22(13.9%) transverse.
For the 118 lateral meniscus, 41(34.7%) were degenerative, 33(28%) longitudinal, 28(23.7%) transverse, and 16(13.6%) bucket handle.

Tear location, 60.3%(167) were posterior horn and body, 22.7%(63) anterior horn and body, and mid-body in 17%(47).

Medial meniscus location, 92(57.8%) were posterior horn and body, 40(25.2%) anterior horn and body, and 27(17%) body.
Lateral meniscus location, 75(63.5%) were posterior horn and body, 23(19.5%) anterior horn and body, and 20(17%) body.

Of the total 321 patients, 202(62.9%) had a record of the injury date. 147(72.8%) underwent surgery after 3 months (group A), and 55(27.2%) within the first 3 months (group B).

Group A (147 patients). 105 patients (71.4%), presented 130 meniscal injuries. 51(48.6%) were medial meniscus, 29(27.6%) lateral meniscus, and 25 both menisci (23.8%).

Location, 87(66.9%) posterior horn and body, 26(20%) anterior horn and body, and 17(13.1%) body.
Injury type, 48(37%) degenerative, 38(29.2%) longitudinal, 28(21.5%) bucket handle, and 16(12.3%) transverse.

Group B (55 patients). 32 patients (58.2%), presented 41 meniscal injuries. 14(43.8%) were medial meniscus, 9(28.1%) lateral meniscus, and 9(28.1%) both menisci.

Location, 23(56%) posterior horn and body, 9(22%) anterior horn and body, and 9(22%) body.
Injury type, 14(34.2%) longitudinal, 13(31.7%) degenerative, 8(19.5%) bucket handle, and 6(14.6%) transverse.

Surgery after 3 months presents a tendency to meniscal tears (p=0.07), and in these patients, there is a higher probability of posterior horn tear (p = 0.006)(X2).

In conclusion, with this study, we support, the importance of early surgical treatment, to prevent injuries associated with ACL and improve the functional prognosis and return to previous physical activity. To our knowledge, there is no previous report in the literature for the Mexican population.