Improved results of ACL primary repair in one-part tears with intact synovial coverage

PurposeIt 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.MethodsA 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: Aone-part rupture with intact synovial membrane (n=50), Btwo-part ruptures resultant to separation of the ACL into two main bundles with synovial membrane tearing (n=52) and Cmore parts involving multilacerated ruptures with membrane disruption (n=22). Failure was defined as a retear or residual laxity (anterior posterior translation>5mm compared to healthy knee). Adjustment for potential risk factors was performed using a multivariate logistic-regression model.ResultsThe overall failure rate was 17.7% throughout the mean follow-up period of 2.30.8years. 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 thefailure 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 sheathin 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).ConclusionThe 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 evidenceIV.