Summary

Well placed femoral tunnels in patients operated within 3 months of the injury gave best PROM's and stability.

Abstract

Introduction

Femur and tibia tunnel positions are important determinants on the success of ACL surgery. The ideal tunnel position is where the native ACL was attached. There are very few studies using 3D CT scan for tunnel position and their effect on patient reported outcome measures (PROM’s), stability, and activity levels using one constant technique. We studied the effect of tunnel position determined on a 3D CT scan, taking into account patient factors and concomitant procedures on PROM’s, stability and activity levels of patients post a transportal single bundle ACL reconstruction .
Material & Methods: 60 patients were recruited who underwent isolated arthroscopic transportal single bundle ACL reconstruction using hamstring grafts where the femoral tunnel was placed 5mm from the posterior articular margin from the inferior border of the lateral aspect of the notch. The tibial tunnel was made at the centre of the tibial stump. Pre Op and 2 year post op Lysolhm, Tegner, Hop Test and Lachman test were done. A 3D CT scan was done within 1 week of the surgery and tunnel positions determined by the Bernard Quadrant method. Femur tunnels were characterized as Type I :well placed Type II :slightly malpoistioned or Type III : grossly malpositioned. Tibial tunnels were classified into optimal and suboptimal based on previous anatomical studies.
Statistical Methods: Statistical analysis was performed using SPSS Statistical Software version 22.0 and R.3.2.0. Two-sample t-test was used for the comparison of means of improvement in scores between groups created based on femoral tunnel positions, tibial tunnel positions, BMI, age, and duration since injury and surgery being less than or greater than 3 months. One-way ANOVA (Analysis of variance) was used for comparison of means of improvement in scores for Medial/lateral menisectomy or repair. P value of <0.05 was considered significant.

Results

All 60 were followed up with 30 well-placed and moderately misplaced femoral tunnels. 51 were optimal and 9 sub optimal tibial tunnels. Age , BMI, partial medial menisectomy, medial meniscus repair, partial lateral menisectomy or lateral meniscus repair had no significant effect on PROM’s or stability at 2 years follow up. Patients operated <3 months post injury had a better hop test (4.4 ± 0.9 v/s 3.9 ± 1, p0.034), and IKDC score (62 ± 15.8 v/s 53.2 ± 13.8, p 0.026).Type I femoral tunnels corresponded with better Lysolhm (62.2 ± 16.2 v/s 48.5 ± 17.2, p 0.002) and IKDC scores (62.5 ± 14.3 v/s 52.7 ± 15.1, p 0.012) and those with optimal tibial tunnels and Type I femoral tunnels had significantly better Lysolhm Scores (61.3 ± 15.7 v/s 50.9 ± 17.6) at 2 years follow up.

Conclusion

Well placed femoral tunnels and well placed tibial tunnels and cases done within 3 months of the injury give best Patient reported outcome measures at 2 years follow up in this study. None of the femoral tunnels were grossly malpositioned. Tibial tunnels alone did not contribute to better stability, PROM’s or activity levels at 2 years.