A delay in surgery of greater than three months was the only predictive factor of the need for an additional procedure after ACL reconstruction in younger patients, according to Justin T. Newman, M.D. from the University of Colorado. In his retrospective chart review of 272 consecutive patients who had ACL reconstruction during a seven year period at a large tertiary pediatric center, those who were more than three months out from time of surgery were 4.75 times more likely to require another procedure, a figure that jumped to nearly eight times more likely for another procedure at more than five months from surgery. Sixty six of patients were younger than 14 years.

The overall incidence rate of a second ACL injury within 24 months after ACL reconstruction and return to sport is nearly 6 times greater than that in healthy control participants. The rate of injury within 24 months of return to sport for female athletes in the ACL reconstruction group also is 5 times greater than that for female controls. These data support the hypothesis that in the 24 months after ACL reconstruction and return to sport, patients are at a greater risk to suffer a subsequent ACL injury compared with young athletes without a history of ACL injuries. In addition, the contralateral limb of female patients appears at greater risk.