Independent Versus Transtibial Drilling in Anterior Cruciate Ligament Reconstruction: A Meta-analysis With Meta-regression

Abstract

Background: Anterior cruciate ligament (ACL) reconstruction can be performed with different techniques for independent and transtibial (TT) drilling of femoral tunnels, but there is still no consensus on which approach leads to the best outcome. Purpose: To assess whether the independent or TT drilling approach for ACL reconstruction leads to the best functional outcomes. Study Design: Systematic review; Level of evidence, 2. Methods: A systematic literature search was conducted on July 1, 2020, using the PubMed, Web of Science, Cochrane Library, and Scopus databases. The influence of different femoral drilling techniques was analyzed through a meta-analysis in terms of patient-reported outcome measure scores, risk of complications, range of motion limitations, graft failure, and differential laxity. Subanalyses were performed to compare the different independent drilling techniques considered. Linear metaregression was performed to evaluate if the year of study publication influenced the results. The risk of bias and quality of evidence were assessed following the Cochrane guidelines. Results: A total of 22 randomized controlled trials including 1658 patients were included in the meta-analysis. Both International Knee Documentation Committee (IKDC) subjective score and Lysholm score were higher with the independent drilling approach (mean difference [MD], 1.24 [ P = .02] and 0.55 [ P = .005], respectively). No difference was documented in terms of the risk of reinjury, but independent drilling led to reduced KT-1000 arthrometer–assessed anterior tibial translation (MD, 0.23; P = .01) and a higher probability of a negative postoperative pivot-shift test finding (risk ratio, 1.13; P = .04). There were no significant differences in IKDC objective or Tegner scores. A P value of .07 was found for the association between the year of the study and IKDC objective scores. Conclusion: Independent femoral tunnel drilling provided better results than the TT approach, although the difference was not clinically significant. No difference was observed in the risk of reinjury. Increasingly better results were seen among surgical procedures performed in more recent years. Among the independent drilling options, the anteromedial portal technique seemed to provide the most favorable outcomes. The lack of clinically significant differences and the promising outcomes reported with new modified TT techniques suggest the importance of correct placement, rather than the tunnel drilling approach, to optimize the results of ACL reconstruction.

A systematic review of transphyseal ACL reconstruction in children and adolescents: comparing the transtibial and independent femoral tunnel drilling techniques

“…These results underline recent systematic reviews comparing transtibial and independent femoral drilling in ACL reconstruction in adult patients who also found no significant difference in re-injury rate between the two techniques [14,38]. However, these systematic reviews showed that independent femoral drilling led to reduced instrumentally measurable anterior tibial translation, a lower rate of positive postoperative pivot-shift test findings, and higher patient reported outcome measures (PROMs) such as IKDC subjective score or Lysholm score [14,38]. Another systematic review could reveal that the rate of post-traumatic osteoarthritis is significantly lower after anatomic ACL reconstruction compared to non-anatomical techniques [12].…”

“…The independent drilling technique is considered a key feature of anatomical ACL reconstruction, since the femoral insertion zone of the ACL can be better reached via the medial portal than via the tibial tunnel [ 9 , 10 ]. The most commonly used independent drilling technique is the medial portal drilling technique [ 14 ].…”

“…One important criterion of an anatomical ACL reconstruction is drilling the femoral bone tunnel independent from the tibial tunnel (medial portal or outside in technique) because the risk of a non-anatomical tunnel placement is higher when using the transtibial technique. A recent meta-analysis of 22 randomized controlled trials about ACL reconstruction in adults has shown that both the International Knee Documentation Committee (IKDC) subjective score and Lysholm score were higher with an independent drilling approach compared to the transtibial drilling technique [ 14 ]. However, in this meta-analysis no difference was documented in terms of the risk of reinjury.…”

ACL surgical trends evolve in the last five years for young European surgeons: results of the survey among the U45 ESSKA members

“…A recent systematic review and meta‐analysis compared transtibial (TT) drilling method and independent methods in terms of outcomes and complications [8]. Independent femoral tunnel drilling provided better results than the TT approach, although the difference was not clinically significant Amongst the independent drilling options, the anteromedial portal technique seemed to provide the most favorable outcomes.…”

Meta-Analysis Prediction Intervals are Under Reported in Sport and Exercise Medicine

“…In the presence of between-study heterogeneity, prediction intervals are wider than confidence intervals, and therefore, study conclusions may differ if based on the prediction interval rather than the confidence interval [12]. For example, a confidence interval shows a "significant" benefit to employing a treatment that does not include zero, whereas the wider prediction interval is more uncertain and does include zero (see Figure 1; replicated from Figure 4, subgroup 1.5.1 in [14]). It is reasonable to assume that meta-analysis prediction intervals are overlooked in sports medicine research in a similar way to medicine [11,15].…”