No Clinically Important Difference in Knee Scores or Instability Between Transtibial and Inlay Techniques for PCL Reconstruction: A Systematic Review

Young-Soo Shin, Hyun-Jung Kim, Dae-Hee Lee

It is unclear whether the biomechanical superiority of the inlay technique over the transtibial technique, arising from avoidance of the killer turn at the graft-tunnel margin of the proximal tibia during posterior cruciate ligament (PCL) reconstruction, leads to better knee scores or greater knee stability. This systematic review was designed to compare Tegner and Lysholm scores, and posterior residual laxity of the knee, between single-bundle PCL reconstruction using transtibial and inlay techniques. We searched MEDLINE(®), Embase(®), and the Cochrane Library for studies comparing Tegner and/or Lysholm scores and posterior residual laxity, in patients who underwent PCL single-bundle reconstruction with the transtibial and tibial inlay techniques. There were no restrictions on language or year of publication. Studies were included if they compared clinical outcomes in patients who underwent PCL single-bundle reconstruction with the transtibial and tibial inlay techniques; they simultaneously reported direct comparisons of transtibial and tibial inlay PCL single-bundle reconstruction; and their primary outcomes included comparisons of postoperative scores on knee outcome scales and posterior residual laxity. A total of seven studies (including 149 patients having surgery using a transtibial approach, and 148 with the tibial inlay approach) met the prespecified inclusion criteria and were analyzed in detail. Our systematic review suggested that there are no clinically important differences between the transtibial and the tibial inlay single-bundle PCL reconstruction in terms of Tegner or Lysholm scores. Of the five studies that assessed Lysholm scores, one favored the transtibial approach and four concluded no difference on this endpoint; however, the observed differences in all studies where differences were observed were quite small (< 7 of 100 points on the Lysholm scale), and likely not clinically important. Of the four studies that compared postoperative Tegner scores, three identified no differences between the approaches, while one favored the tibial inlay approach by a small margin (0.5 of 11 points) suggesting that there likely is no clinically important difference between the approaches in Tegner scores, either. Finally, we identified no difference between the approaches in terms of residual laxity, either among the seven studies that presented data using Telos radiographs, or the five that reported on patients with residual laxity greater than Grade 2 on a four-grade scale of posterior drawer testing (28/107 for transtibial and 26/97 for tibial inlay). We found no clinically important differences between the transtibial and tibial inlay approach for PCL reconstruction. Based on the best evidence now available, it appears that surgeons may select between these approaches based on clinical experience and the specific elements of each patient's presentation, since there do not appear to be important or obvious differences between the approaches with respect to knee scores or joint stability. Future randomized trials are needed to answer this question more definitively. Level III, therapeutic study.