Purpose: It was the aim to assess the influence of synovial sheath disruption on early failure of primary anterior cruciate ligament (ACL) repair. It was hypothesized that more-part ACL tears with disruption of the synovial sheath are associated with a higher risk of failure after primary ACL repair.
Methods: A cohort study was conducted comprising patients with primal ACL tears undergoing primary ACL repair and dynamic intraligamentary stabilization (DIS). The patients were stratified into three groups: A-one-part rupture with intact synovial membrane (n = 50), B-two-part ruptures resultant to separation of the ACL into two main bundles with synovial membrane tearing (n = 52) and C-more parts involving multilacerated ruptures with membrane disruption (n = 22). Failure was defined as a retear or residual laxity (anterior posterior translation > 5 mm compared to healthy knee). Adjustment for potential risk factors was performed using a multivariate logistic-regression model.
Results: The overall failure rate was 17.7% throughout the mean follow-up period of 2.3 ± 0.8 years. The failure rate in patients with one-part ACL tears with an intact synovial membrane was 4% (n = 2) (Group A), which was significantly lower than the failure rates in groups B and C, 26.9% (n = 14) (p = 0.001) and 27.3% (n = 6) (p = 0.003), respectively. Disruption of the synovial sheath in two- or more-part tears was identified as an independent factor influencing treatment failure in primary ACL repair (OR 8.9; 95% CI 2.0-40.0).
Conclusion: The integrity of the ACL bundles and synovial sheath is a factor that influences the success of ACL repair. This needs to be considered intra-operatively when deciding about repair.
Level of evidence: IV.
Keywords: ACL repair; Anterior cruciate ligament; Ligamys; Proximal ACL; Proximal tear; Reconstruction; Rupture; Suture; Tears.