Fate of the Young Patient Undergoing Anterior Cruciate Ligament Reconstruction: Exploring the High Re-Injury Rate

OBJECTIVES: Younger age has been increasingly recognised as a risk factor for ACL graft rupture and contralateral ACL injury following ACL reconstruction. The purpose of the study was to evaluate the re-injury rate and explore factors that might be associated with increased risk. METHODS: In this observational study, a cohort of 362 consecutive patients was identified from patients undergoing primary ACL reconstruction by a single surgeon form December 2004 to February 2012. Patients were under 20 years at the time of surgery and had a normal contralateral knee. The incidence of subsequent ACL injuries (graft rupture or contralateral ACL injury) was determined at a mean follow up time of 5 years (range 3-10). For further analysis the group was divided according to gender and age: under 18 or 18-19 at the time of surgery RESULTS: The overall follow up rate was 89% (40/362 patients were unable to be contacted). Graft ruptures occurred in 60 patients (16.6%) at an average time of 1.9 years. Almost half (47%) occurred within the first postoperative year. The graft rupture rate was significantly higher in males (19.5%) than females (11.1%). The rupture rate in the youngest males (under 18) was the highest at 25.4%, which was significantly higher than females of the same age (11.7%) and males over 18 years (12.7%). Of the early graft ruptures, 75% occurred in the under 18 group. Contralateral ACL injuries occurred in 57 patients (15.7) at a longer average time of 3.7 years. There were no gender or age differences for contralateral ACL injuries. There were 4 patients who had a graft rupture as well as a contralateral ACL injury; therefore the total number of patients who had at least one further ACL injury subsequent to the primary surgery was 113 (31.2%). CONCLUSION: The high rate of subsequent ACL injury in younger patients was confirmed. Early graft ruptures are more prevalent in the very young and gender differences are more apparent for graft rupture, where the youngest males are at high risk. The high incidence of multiple ACL injuries in such a young cohort is concerning for future knee health.