Background

A rupture of the surgically reconstructed anterior cruciate ligament (ACL) is a definitive treatment failure and has serious consequences for an athlete’s career, life and health. Several factors, including age, sex, time to return to sport (RTS), activity level and graft type, have been associated with an ACL re-rupture, but more knowledge of rehabilitation-specific outcomes linked to an ACL re-rupture is warranted.

Purpose

The purpose of this study was to determine the psychological characteristics and outcomes of patients who suffered an early ACL re-rupture after their primary ACL reconstruction and cross-sectionally to compare them with a matched cohort of patients who underwent primary ACL reconstruction without sustaining a re-injury during the first 2 years after primary ACL reconstruction.

Methods

Data for quadriceps and hamstring strength, three hop tests and answers to standardized patient-reported outcomes (PROs) were extracted from a rehabilitation-specific registry. Data for 36 patients suffering a re-rupture were identified and patients were matched in terms of sex, age and activity level with 108 patients not suffering a re-rupture within 2 years of primary ACL reconstruction. Outcomes between groups were compared 10 weeks and 4, 8 and 12 months after the index reconstruction. For comparisons of mean values, a t-test was used. For the comparison of proportions, a chi-square test was used. Delta (differences; ?) and confidence intervals (CI) were reported.

Results

Of the 36 included patients suffering an ACL re-rupture, 21 (58%) suffered the ACL re-rupture within the first 12 months and 15 (42%) between 12 and 24 months after their primary ACL reconstruction. Patients suffering a re-rupture had greater psychological readiness to RTS, higher knee-related self-efficacy and returned to a more knee-strenuous sport, 8 to 12 months after primary ACL reconstruction, compared with the matched group. There were no differences in terms of muscle strength between the groups. Furthermore, there was no difference in the proportion of patients passing a cut-off of Limb Symmetry Index = 90% in all five tests of muscle function at any follow-up between patients who sustained an ACL re-rupture and patients who did not.

Conclusion

A stronger psychological profile can characterize patients who sustain an ACL re-rupture within 2 years of the primary reconstruction. Continued and regular assessments, alongside the careful interpretation of outcomes in patients after ACL reconstruction, may help identify patients at risk of a second ACL injury.