Graft tensioning in anterior cruciate ligament reconstruction

Abstract

BackgroundAnterior cruciate ligament reconstruction (ACLR) is an effective procedure for restoring stability and function. Being a technically demanding procedure, patient outcomes are highly dependent on numerous surgical factors, which are critical for success. The application of tension to the graft prior to tibial fixation is one such factor and is considered essential for the restoration of joint stability, normal knee biomechanics, graft revascularisation and patient function. In applying tension, a key factor is the amount of force applied to the graft. However, the method of applying the tension, position of the knee during tensioning, properties of the graft material, tunnel placement and graft fixation device can all influence the effect that graft tension has on outcomes. Despite the reported importance of graft tension there has been limited empirical evidence defining the best tensioning practice for restoring patient outcome post ACLR. AimsThe goal of this program of research was to explore the effect that different aspects of graft tensioning has on patient function post ACLR. To address the aims of the thesis, three studies were conducted. The first study was a systematic review aimed at examining if a particular amount of tension results in better functional outcomes post ACLR. The second study aimed to compare the effect of two methods of applying graft tension on patient function post ACLR. The study used a prospective randomised controlled trial to compare manual tensioning with the use of a tensioning device. The third study aimed to define current graft tensioning practices and explore the factors that influence surgical decision making. A national survey of Australian orthopaedic surgeons was conducted to achieve the aims of the study. ResultsThe systematic review (study one) revealed that a medium graft tension of 79N to 90N produced the least side-to-side difference (STSD) in anterior posterior (AP) tibial translation as measured by a KT-1000 when compared to tensions <79 or >90N. However, the heterogeneous use of functional outcomes inhibited the ability to draw conclusions on other patient specific functional outcomes.Furthermore, the review highlighted the lack of high quality studies, which also failed to discuss other aspects of graft tension such as the method of applying tension.iii Building on the findings of study one, the second study undertook a RCT to compare the functional outcomes of applying 80N of force with a tensioning device (TD) (n=10) to a manual tensioning method (MT) (n=13) using an estimated force described as a sustained maximum one handed pull.Patients were assessed at pre-surgery and two weeks, three months, six months and 12 months post Based on the findings of study one, tensioning between 79N and 90N appeared to improve the restoration of joint stability, when compared to higher and lower tensions. However, no effect on patient function within 24 months post surgery was apparent. Furthermore, study two observed that tension did not appear to have an...