Background: Graft fixation during anterior cruciate ligament (ACL) reconstruction can be achieved with use of either bioabsorbable screws or metal screws. Although bioabsorbable screws and metal screws have similar fixation strengths, bioabsorbable screws eliminate the need for removal. In addition, postoperative imaging is easier to interpret when bioabsorbable screws are used. Bioabsorbable screws may be associated with an increased inflammatory response, an increased risk of screw breakage, incomplete screw absorption, or tunnel widening. We investigated the outcomes associated with the use of bioabsorbable screws as compared with metal screws for ACL reconstruction. Our hypothesis was that there is no significant difference in outcomes between these screw types for ACL reconstruction.
Methods: We systematically searched electronic databases to identify randomized controlled trials in which bioabsorbable screws were compared with metal screws for ACL reconstruction. Therapeutic studies with a minimum twelve-month mean follow-up were considered for inclusion. Clinical outcomes (International Knee Documentation Committee [IKDC], Lysholm, Tegner activity scores), laxity testing, and reported complications were evaluated in the meta-analysis. Additionally, imaging assessment of tunnel widening was evaluated.
Results: Eight studies matched the inclusion criteria. These studies comprised a total of 745 patients undergoing ACL reconstruction (including 378 patients managed with bioabsorbable screws and 367 patients managed with metal screws). No significant differences were identified between the two screw types with respect to IKDC, Lysholm, or Tegner activity scores or with respect to the results of laxity testing with arthrometry. The complication rates were also statistically similar in the two groups. The variability in imaging assessment of tunnel widening among the studies precluded meta-analysis.
Conclusions: The clinical results associated with bioabsorbable screws and metal screws are statistically similar. Laxity evaluation demonstrated no significant differences between bioabsorbable screws and metal screws. The complication rates associated with bioabsorbable screws and metal screws were also similar. The results of this meta-analysis support the hypothesis that there are no significant differences in the outcomes associated with bioabsorbable screws as compared with metal screws for ACL reconstruction.
Level of evidence: Therapeutic Level II. See Instructions to Authors for a complete description of levels of evidence.