Animal Experiment and Clinical Results of Ligament Anchor Screw in Anterior Cruciate Ligament Reconstruction

Song, Eun Kyoo; Yoon, Taek Rim; Rowe, Sung Man; Kim, Hyun Jong

Abstract

In vivo study, We evaluated toxicity and biocompatibility of LA screw, which made of titanium, in 25 Yorkshire pig knees before usage in human being. After ACL reconstruction, we sacrificed each 5 pigs at 1, 2, 4, 8, 12 weeks and performed radiological evaluation to detect the biologic reaction and remodeling of bone around screw. We also performed gross and histologic examination with incision of bone. The screw was well fixed during first 12 weeks. There is no reactive change of bone and osteolysis. LA screw has good biocompatibility and less toxicity with good fixation. In clinical study, We evaluated the clinical and radiological results of ACL reconstruction with LA screw and compared with endobutton fixation in bony tunnel enlargement. Fifty two patients who underwent ACL reconstruction with LA screw was evaluated. For clinical evaluation Lysholm knee score, range of motion, Lachmann test, pivot shift test and parapatellar complications were examinated and for radiological evaluation six measurement point were determined, 3 on both anteroposterior and lateral view, and it taken at 1, 6, 12, 18 months postoperatively. Lysholm knee score improved preoperatively 54.1 points to posto- peratively 83.7 points and full range of motion could be obtained in all cases. Significant improvement of knee stability could be proved by Lachmann test, pivot shift test and arthrometer test. There were little parapatellar complications. In radiographically significant bone tunnel enlargement more than 2mm occurred 35% in femoral tunnel and 27% in tibial side. But tunnel enlargement did not appear to have co-relation with clinical results. ACL reconstruction with LA screw is simple, safe, effective for restoring anterior stability and less complications. Micromotion and osteolytic reaction of graft in bony tunnel is more decreased than Endobutton fixation. The correlation between the enlargement and clinical results was not significant after 18 months. But it need the long term follow up.