Posterior cruciate ligament repair in acute knee instabilities with internal bracing: midterm follow up for clinical and kinematic results

Abstract

Abstract Background: Injuries of the PCL are comparably rare. They occur with or without accompanying injuries of the knee and frequently occur in multi-ligament knee instability. Internal bracing is a recent treatment option for acute PCL tears. For low-grade instability, a conservative therapy is recommended while severe instability in multi-ligament injuries is mostly addressed by surgical reconstruction. Recent evaluations of internal bracing demonstrate good options for both isolated ligamentous and multiligamentous injuries. The aim of this study was to assess general outcomes in joint function and stability as well as activity and quality of life by clinical examination and functional gait analysis. Methods: A total of 19 patients were examined after internal bracing of an acute II/III° PCL- injury between 2017 and 2021. Included were patients with MRI-proven unilateral PCL tear. In addition to clinical tests for mobility and posterior drawer test, a IMU based kinematic gait analysis was performed. Further IKDC-Score, TAS and Lysholm Score were examined. Regular stress radiographs of both knee joints were included for further evaluation. Results: Follow-up examination took place after 29.40 ± 10.47 months. The mean ROM of the injured knee showed 0.79° ± 1,9° for extension and 138,4° ± 3,4° for flexion. In gait and walking analysis, no significant movement restrictions for either knee joint remained. IKDC amounted to 53,2 ± 4,2% after injury and 91.7 ± 7,4% at follow-up. The Lysholm Score was 95.5% ± 8,3%. The TAS showed no significant difference (5,5 ± 1.30 pt pre-injury and 5,2 ± 1.2 pt at follow-up). The mean difference of posterior tibial translation reached 2,5 ± 1,5 mm in clinical examination and demonstrated significant difference to the healthy side. 1 patient needed revision surgery by complete PCL- reconstruction due to grade II-Instability postoperative but no other complications occurred. Conclusions: Internal bracing can offer good treatment for acute grade II and grade III PCL-instabilities, especially when further meniscal or ligamentous injuries require surgical repair. Despite the limited evidence-based results and applications to date, restoration of joint mobility and a minor residual posterior tibial translation can be confirmed. Results for everyday and sports activities are comparable with conservative and established surgical procedures.