A modification of tibial inlay fixation in posterior cruciate ligament reconstruction by interference screw: a biomedical study on calf tibial bone model

This study presents a modification of tibial inlay technique in posterior cruciate ligament (PCL) reconstruction and evaluates the structural properties of tibial side fixation of the graft, comparing tibial inlay technique and a new modification, that is interference screw fixation of tibial side of the graft in suggested supine position which is more applicable, with less potential intraoperative neurovascular complications. Forty fresh calf knees that were prepared from 20 healthy 3 years old calves which were between 200 and 220 kg were the subject of this study. The tibias were separately used simulating tibial side PCL reconstruction with tibial tuberosity-patellar tendon-patellar bone graft. Tibial side of the graft was fixed using two cancellous screws in 20 tibiae and with interference screw in obliquely oriented canal in another 20 tibiae. Load-to-failure test was carried out on ten samples from each group. The remaining samples were used for cycling loading. Mann-Whitney U test was used to compare structural properties of each group. No significant differences were observed between two methods at load-to-failure test; but mean elongation at 1,000 cycles of new modification was significantly lower than tibial inlay technique.