Flexible reamers create comparable anterior cruciate ligament reconstruction femoral tunnels without the hyperflexion required with rigid reamers: 3D-CT analysis of tunnel morphology in a randomised clinical trial

Abstract

Purpose The hyperflexion required for femoral tunnel drilling in anterior cruciate ligament reconstruction can be challenging in patients with increased body habitus or musculature. Whilst allowing femoral tunnel creation without hyperflexion, additional benefits of flexible reamers have been proposed in terms of tunnel dimensions. The purpose of this study was to examine whether these theoretical benefits are seen in a clinical study. Methods Fifty adult patients (with isolated anterior cruciate ligament rupture) were randomised to reconstruction with either flexible or rigid femoral reamers. Femoral tunnel drilling was performed at 100° flexion (flexible system) or maximal hyperflexion (rigid system). Otherwise, the procedure was standardised. Femoral tunnel measurements were performed by a consultant musculoskeletal radiologist who was blinded to the method of femoral drilling. Tunnel position, length and angles (axial and coronal) were measured alongside aperture shape and exit point using three‐dimensional computed tomography 3–6 months post‐operatively. Results With no difference in tunnel position, tunnel length was found to increase with the use of the flexible system (37.8 ± 3.7 vs 35.0 ± 4.4 mm; p = 0.024). In addition, the exit point and fixation device were more anterior on the lateral femur using the flexible reamers (p = 0.016). No difference was seen in either tunnel angles or aperture shape. One case of incomplete posterior blow‐out was seen in each of the study groups. Conclusions This comparative study shows that flexible reamers can reproduce a desired femoral tunnel position with only small improvements of no clinical relevance. As this can be achieved without hyperflexing the knee, these systems can be used for all patients (even when hyperflexion is a challenge). Level of evidence I.

Comparing the Use of Flexible and Rigid Reaming Systems Through an Anteromedial Portal for Femoral Tunnel Creation During Anterior Cruciate Ligament Reconstruction: A Systematic Review

“…Eight included studies 9 , 15 , 16 , 20 , 21 , 23 , 33 , 35 quantified femoral tunnel positioning by utilizing radiologic parameters. No studies reported any significant difference in the intra-articular femoral tunnel aperture location.…”

“…No studies reported any significant difference in the intra-articular femoral tunnel aperture location. 15 , 16 , 20 , 36 Table 3 illustrates a comparison of 6 studies that reported femoral tunnel positioning in the frontal, coronal, sagittal, or axial plane. 15 , 20 , 21 , 23 , 33 , 35 Two out of 3 studies 15 , 33 , 35 reported a significant difference in tunnel positioning in the sagittal plane, with AM-FR resulting in greater tunnel anteversion in these studies ( Figure 3 ).…”

“…Cadaveric studies examining the distances to surrounding ligaments and neurovascular structures, femoral tunnel length, and posterior femoral cortical wall breakage were included because they reported anatomic findings relevant to surgical risk and clinical outcome. 15 , 16 , 20 , 21 , 30 , 33 , 36 Studies were excluded if they were not available in full-text through MEDLINE (PubMed) or were not available in the English language. Similarly, studies that only concentrated on describing surgical technique were excluded from this review.…”

“… 31 The global ideal score for comparative studies using the MINORS scale is 24. 31 Methodological quality was also assessed for 1 included randomized controlled trial (Kosy et al 20 ) using the Jadad scale, which has an ideal score of 5. 13 Two independent reviewers (T.E.M., A.J.I.)…”

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

“…Patients were recruited as part of a published study comparing flexible and rigid femoral tunnel reamers [6]. Ethical review board approval was additionally received, prior to study commencement, for the present analysis (study number 16/SW/0080).…”