The role of computer assisted navigation in revision surgery for failed anterior cruciate ligament reconstruction of the knee: A continuous series of 52 cases

Abstract

IntroductionThe causes of failure of anterior cruciate ligament (ACL) reconstruction mainly involve incorrect tunnel positioning. There is no intraoperative tool allowing the surgeon to test graft biomechanics and to confirm that the new graft is in an optimal position. HypothesisControl is improved with computer assisted navigation. Material and methodsIn this retrospective study, revision ACL reconstruction was performed with a new autologous graft in a continuous series of 52 failed ACL reconstructions. A computer assisted navigation system was used intraoperatively in all knees. Evaluation with this system confirmed the position of old and new tunnels as well as intraoperative laxity. ResultsEvaluation of tunnel position based on traditional radiological criteria found in the literature significantly underestimated graft biomechanics: 69% of the cases presented with unfavorable graft ansiometry (mean: 13±2.2mm) while the correct position of the tibial tunnel was identified in 64% of cases on radiography and the femoral tunnel in 48%. All new grafts were optimally positioned by the computer assisted navigation system with a mean isometery of 3.2 (±0.7) mm. Comparative pre- and postoperative evaluation of laxity showed a statistically significant improvement (P<0.001): preoperative and postoperative Lachman test: 10.5±2mm and 3±0.5, respectively; global rotational laxity: 24±5° and 37±7° respectively. ConclusionThe use of a computer assisted navigation system allows optimal positioning of the graft as well as a predictive assessment of laxity. Type of studyLevel IV, retrospective cohort study.