Summary
For every positive test on the Beighton Score, the rate of second ACL injuries increased by 20% adjusted for RTS Tegner level and choice of autograft for primary ACL reconstruction within the first-year post-reconstruction.
Abstract
Background
Generalized joint hypermobility (GJH) is associated with an increased risk for a second anterior cruciate ligament (ACL) injury. Binary cut-offs are commonly used to diagnose GJH, but this may negatively influence patient classification and risk assessment.
Aim
To evaluate the rate of sustaining a second ACL injury in relation to the number of positive joint hypermobility tests on the Beighton Score.
Study design: Registry study.
Methods
Data from an ACL-rehabilitation-specific registry from Gothenburg was used. The study included patients aged = 15 years who underwent primary ipsilateral ACL reconstruction with either a hamstring tendon (HT) or bone-patellar tendon-bone (BPTB) autograft. The patients had a documented Beighton Score, engaged in knee-strenuous sports before injury, returned to sport (RTS) after the primary ACL reconstruction, and either experienced a second ACL injury or had = 1 year follow-up without injury. A multivariable Cox proportional hazard regression model was utilized to estimate the hazard ratio (HR) for a second ACL injury, considering the Beighton Score, adjusted for the Tegner Activity Scale (Tegner) score at RTS, and graft choice. Start point was time of RTS. End point for the primary analysis was one year after RTS, and for the secondary analysis the time of data extraction or time of second ACL injury.
Results
The study included 762 patients (mean age 23.8 ± 7.9 years, 50.9% female). The median Beighton Score was 1.0 (interquartile range (IQR) 3.0). The median follow-up period after RTS was 3.9 years (IQR: 2.8 years). Eighty-five patients (11.1%) sustained a second ACL injury, of which 45 (56.5%) graft ruptures, and the rest contralateral ACL injuries. The adjusted one-year HR for a second ACL injury increased 1.20 times for each positive Beighton Score (95% confidence interval [CI]: 1.07-1.35, p=0.002). The adjusted HR of a second ACL injury for the longest available time after RTS increased by 1.15 times for each positive joint hypermobility test on the Beighton Score (95% CI: 1.06-1.25, p<0.001).
Conclusion
For every positive test on the Beighton Score, the rate of second ACL injuries increased by 20% adjusted for RTS Tegner level and choice of autograft for primary ACL reconstruction within the first-year post-reconstruction. These findings suggest that clinicians should not exclusively rely on binary GJH classifications but should also consider the sheer number of hypermobile joints when assessing the risk of subsequent ACL injuries after RTS.