A comparison of femoral tunnel placement in ACL reconstruction using a 70° arthroscope through the anterolateral portal versus a 30° arthroscope through the anteromedial portal: a pilot 3D-CT study

Background: Graft malposition is a risk factor for failure of anterior cruciate ligament reconstruction. A 70° arthroscope improves visualisation of the medial wall of the lateral femoral condyle without switching portals. We investigated whether the use of this arthroscope affected the accuracy and precision of femoral tunnel placement. Methods: Fifty consecutive adult patients were recruited. Following one withdrawal and two exclusions, 47 patients (30 in group 1 (70° arthroscope), 17 in group 2 (30° arthroscope)) underwent three-dimensional computed tomography imaging using a grid-based system to measure tunnel position. Results: No difference was found in the accuracy or precision of tunnels (mean position: group 1 = 33.3 ± 6.0% deep-shallow, 27.2 ± 5.2% high-low; group 2 = 31.7 ± 6.9% deep-shallow, 29.0 ± 6.2% high-low; not significant). A post-hoc power analysis suggests a study of 106 patients would be required. Conclusions: This pilot study suggests that tunnel position is not affected by the arthroscope used. An appropriately powered study could investigate this finding alongside other potential benefits of using a 70° arthroscope for this procedure. Trial registration: ClinicalTrials.gov, NCT02816606. Registered on 28 June 2016.This article is freely available via Open Access. Click on the Publisher URL to access it via the publisher's site

Remnant preservation does not affect accuracy of tibial tunnel positioning in single-bundle ACL reconstruction

Purpose: Remnant preservation, in anterior cruciate ligament (ACL) reconstruction, has potential biological advantages. However, graft positioning remains vital to functional outcome and the prevention of failure. The aim of this study was to investigate the accuracy and precision of tibial tunnel positioning in remnant preservation single-bundle hamstring reconstruction. Methods: Fifty consecutive adult patients, with isolated ACL rupture, were recruited to a prospective study. Remnant preservation was performed in all cases where > 25% of the native ACL was present. Three-dimensional computer tomography was preformed 3-6 months post-operatively to assess tibial tunnel position (using a grid-based measurement). Accuracy and precision of this technique were assessed against published anatomical data in direct comparison with the group where remnant preservation could not be performed. Results: Two patients withdrew following surgery. In the remaining groups (31 remnant preservation; 17 non-remnant preservation), no difference was demonstrated in tunnel position (40.4 ± 6.7% (anterior-to-posterior) and 47.4 ± 1.5% (medial-to-lateral) vs. 38.8 ± 4.9% and 46.7 ± 1.5%, respectively; n.s.), accuracy (6.1% vs. 4.8%; n.s.) or precision (3.9% vs. 2.8%; n.s.). Conclusions: Remnant preservation can be safely performed without compromising tunnel position. Therefore, the potential benefits of this technique can be utilised, in clinical practice, without sacrificing the ability to optimize tibial tunnel positioning. Level of evidence: III.This article is available to RD&E staff via NHS OpenAthens. Click on the Publisher URL, and log in with NHS OpenAthens if prompted.published version, accepted version (12 month embargo