A prospective randomized study of ACL-reconstructions using bone-patellar tendon-bone grafts fixed with bioabsorbable or metal interference screws.

INTRODUCTION: Bioabsorbable screws are, at the expense of metal screws, increasingly used as fixation device in ACL-reconstructions. The possible advantages with bioabsorbable screws are better postoperative MRI evaluations and easier revision surgery.

PURPOSE: The aim of this study was to compare the clinical outcome after ACL-reconstructions with BPTB-grafts fixed with metal interference screws or bioabsorbable screws 7 years postoperatively. The resorption of the bioabsorbable screws was also analyzed.

METHODS: Between 2000 and 2001, 41 patients with ACL deficient knees were randomized for the use of BPTB-graft fixed with either metal interference screws or bioabsorbable poly-L: -lactic acid screws. This is a 7-year follow-up with clinical examinations of both groups and, MRI of the patients with bioabsorbable screws.

RESULTS: The clinical and functional results were satisfactory in both groups. There were no significant differences between the groups in any parameter measured, except for better Pivot shift results in the bioscrew group (P = 0.04). The MRI evaluation showed degradation of the bioscrews. A residual screw tract which appeared threaded was seen in the tibia in 11 of the 16 patients. There was no sign of bony ingrowth in the previous screw site in the tibia in any of the patients.

CONCLUSION: The potential advantages of using PLLA-screws compared to metal screws are not sufficient to warrant the routine use of PLLA-screws in ACL-reconstructions.

LEVEL OF EVIDENCE: I.