Variability in ACL Tunnel Placement Observational Clinical Study of Surgeon ACL Tunnel Variability
BACKGROUND:Multicenter and multisurgeon cohort studies on anterior cruciate ligament (ACL) reconstruction are becoming more common. Minimal information exists on intersurgeon and intrasurgeon variability in ACL tunnel placement.Purpose/ HYPOTHESIS:The purpose of this study was to analyze intersurgeon and intrasurgeon variability in ACL tunnel placement in a series of The Multicenter Orthopaedic Outcomes Network (MOON) ACL reconstruction patients and in a clinical cohort of ACL reconstruction patients. The hypothesis was that there would be minimal variability between surgeons in ACL tunnel placement. STUDY DESIGN:Cross-sectional study; Level of evidence, 3. METHODS:Seventy-eight patients who underwent ACL reconstruction by 8 surgeons had postoperative imaging with computed tomography, and ACL tunnel location and angulation were analyzed using 3-dimensional surface processing and measurement. Intersurgeon and intrasurgeon variability in ACL tunnel placement was analyzed. RESULTS:For intersurgeon variability, the range in mean ACL femoral tunnel depth between surgeons was 22%. For femoral tunnel height, there was a 19% range. Tibial tunnel location from anterior to posterior on the plateau had a 16% range in mean results. There was only a small range of 4% for mean tibial tunnel location from the medial to lateral dimension. For intrasurgeon variability, femoral tunnel depth demonstrated the largest ranges, and tibial tunnel location from medial to lateral on the plateau demonstrated the least variability. Overall, surgeons were relatively consistent within their own cases. Using applied measurement criteria, 85% of femoral tunnels and 90% of tibial tunnels fell within applied literature-based guidelines. Ninety-one percent of the axes of the femoral tunnels fell within the boundaries of the femoral footprint. CONCLUSION:The data demonstrate that surgeons performing ACL reconstructions are relatively consistent between each other. There is, however, variability of average tunnel placement up to 22% of mean condylar depth, likely reflecting the difference in individual surgeons' preferred tunnel locations. Individual surgeons are relatively consistent in their cases of ACL tunnels.
Available from: Brian R Wolf
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ABSTRACT: The purpose of this cadaveric study was to analyze variation in anterior cruciate ligament (ACL) tunnel placement between surgeons and the influence of preferred surgical technique and surgeon experience level using three-dimensional (3D) computed tomography (CT). In this study, 12 surgeons drilled ACL tunnels on six cadaveric knees each. Surgeons were divided by experience level and preferred surgical technique (two-incision [TI], medial portal [MP], and transtibial [TT]). ACL tunnel aperture locations were analyzed using 3D CT scans and compared with radiographic ACL footprint criteria. The femoral tunnel location from front to back within the notch demonstrated a range of means of 16% with the TI tunnels the furthest back. A range of means of only 5% was found for femoral tunnel low to high positions by technique. The anterior to posterior tibial tunnel measure demonstrated wider variation than the medial to lateral position. The mean tibial tunnel location drilled by TT surgeons was more posterior than surgeons using the other techniques. Overall, 82% of femoral tunnels and 78% of tibial tunnels met all radiographic measurement criteria. Slight (1-7%) differences in mean tunnel placement on the femur and tibia were found between experienced and new surgeons. The location of the femoral tunnel aperture in the front to back plane relative to the notch roof and the anterior to posterior position on the tibia were the most variable measures. Surgeon experience level did not appear to significantly affect tunnel location. This study provides background information that may be beneficial when evaluating multisurgeon and multicenter collaborative ACL studies.
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ABSTRACT: Intraoperative fluoroscopy has been proposed as a feasible method to improve the accuracy of anatomical tunnel positioning. However, it has so far not been determined, whether this technique reduces the variability of tunnel positioning in a clinical set-up. Therefore, the purpose of this study was to determine the variability of tunnel positions applying intraoperative fluoroscopy.
Femoral and tibial tunnel positions of 112 fluoroscopic ACL reconstruction cases were determined according to validated radiological measurement methods. Mean positions, standard deviations and ranges were calculated to determine the variability of the tunnel positions. Subgroup variability analysis was performed to analyse cases in which tunnel positions were corrected.
Applying intraoperative fluoroscopy, the variability of tunnel positions was found to be 3 % at the femur (range 15.4 %) and 2.3 % at the tibia (9.7 %). In 34 cases (30.0 %), non-satisfactory tunnel positions were identified and could be corrected achieving more accurate positions regarding to radiological parameters (14× femur, 16× tibia, 4× femur and tibia).
The results of the presented study indicate that intraoperative fluoroscopy allows to identify non-accurate tunnel positions regarding to radiological criteria. The determined low variability indicates that fluoroscopic-based ACL reconstruction can be recommended as a feasible, easy and effective adjunct that enables surgeons to create more consistent and reliable tunnel positions in ACL reconstruction. LEVEL OF EVIDENCE: IV.
Available from: Eirik Solheim
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ABSTRACT: Purpose To evaluate the effect of feedback from post-operative 3D CT in the learning process of placing the femoral graft tunnel anatomically using the anteromedial (AM)-portal technique in single-bundle anterior cruciate ligament (ACL) reconstruction. Methods An experienced knee surgeon converting from transtibial to AM-portal technique was offered post-operative feedback on tunnel placement. Three groups of patients were included: transtibial drilling, (AM1) anteromedial drilling without feedback and (AM2) anteromedial drilling with post-operative CT feedback. Intra-articular landmarks were used as the only guidance for tunnel placement. Tunnel position was compared to an ideal anatomical ACL position using the Bernard and Hertel grid and visual feedback was given on tunnel placements. The effect of feedback was measured as the distance from the anatomical centre, and spread of tunnel placements on post-operative CT performed feedback was initiated. Results When comparing the femoral tunnel placement to an ideal anatomical centre, there was an improvement in the mean tunnel position after (A) changing from a transtibial to an anatomical technique and a further improvement after (B) initializing the radiological feedback. There was a great variation of femoral tunnel localizations when initially only using intra-articular landmarks as guidance for tunnel placement—this variation, however, converged towards the anatomical centre throughout the feedback period and the AM2 group had a femoral tunnel closer (P = 0.001) to the anatomical centre than the AM1 group. Conclusions Post-operative 3D CT is effective in the learning process of placing femoral tunnels anatomically by giving post-operative feedback on tunnel placement. Bony landmarks and ACL remnants were found unreliable as the only guidance for femoral tunnel placement in the AM-portal technique—therefore, the use of an aid is recommended to reduce unwanted tunnel variations in a learning phase. Level of evidence Cohort Study, Level III.
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