This study aimed to explore the factors influencing IG and CACL injury risks following ACLR, focusing on identifying sport-specific differences in injury rates.
This study included 1,055 patients who underwent isolated primary ACLR between 2008 and 2012 (541 female, 514 male; mean age, 24.0 ± 10.0 years; median pre-injury Tegner activity score, 8; mean BMI, 21.8 ± 0.5 kg/m²). The incidence of second ACL injuries and characteristics of patients who sustained IG or CACL reinjury were examined. The characteristics examined included age, sex, pre-injury Tegner activity score, preoperative period, timing of the second ACL injury, and sport type. The IG and CACL groups were compared using the chi-square test for categorical data and Student’s t-test or the Mann–Whitney U test for continuous data. The level of significance was determined at P 0.05.
IG and CACL ruptures occurred in 79 (7.5%; mean age, 18.8 ± 5.8 years) and 67 (6.4%; mean age, 20.1 ± 7.2 years) patients, respectively. No significant differences in age, sex, pre-injury Tegner activity score, or preoperative period were observed between the groups. The timing of second ACL injuries in the IG rupture group (median, 11.1 months) was significantly shorter than that in the CACL rupture group (median, 26.8 months). Among primary sports, the highest rate of second ACL injuries was observed in judo (18.1%), followed by basketball (15.4%), rugby football (15.3%), and handball (15.2%). Conversely, volleyball (10.1%) and soccer (9.0%) had lower rates. Handball had the highest IG rupture rate (10.6%), followed by judo (9.6%) and basketball (8.4%). Judo also had the highest incidence of CACL ruptures (8.4%), followed by rugby football (8.3%) and basketball (7.0%).
This study demonstrated that second ACL injury rates were higher in judo, basketball, rugby football, and handball than in volleyball and soccer. Moreover, CACL injury rates were higher in judo, rugby football, and basketball than in other sports, suggesting that the former sports may exert greater stress on the contralateral knee than other sports. Therefore, these sports require rehabilitation targeting both the operated and contralateral limbs to effectively reduce reinjury risk. Meanwhile, handball athletes, despite having a lower incidence of CACL injury, exhibited the highest IG rupture rate. Thus, targeted rehabilitation is crucial to improve knee stability and strength in the operated limb. Additionally, the earlier onset of IG injuries suggests that rehabilitation strategies should focus on knee function and the proper timing of return to sports to prevent early graft failure.
The findings of this study suggest that the risks of IG and CACL injuries depend on the type of sport, highlighting the need for rehabilitation approaches that target knee function and consider the specific injury risks associated with each sport.
Second ACL injury
sport type
