Do broken cross-pins compromise stability after anterior cruciate ligament reconstructions with hamstring tendons?

Abstract

The purpose of this prospective study was to define the relation between the integrity of cross-pin femoral fixation and stability after anterior cruciate ligament (ACL) reconstructions. Thirty-one consecutive ACL reconstructions were performed with hamstring tendons fixed with bioabsorbable cross-pin femoral fixation. All patients underwent magnetic resonance imaging at 6 months postoperatively to assess the status of the cross-pin fixation. Clinical evaluations were performed via the Lachman and pivot-shift tests. The side-to-side differences were measured by KT-1000 testing (MEDmetric, San Diego, CA) at 2 years postoperatively. The patients were divided into 2 groups according to the status of the cross-pin. Group I consisted of those in whom the cross-pins were intact, and group II had broken cross-pins. There were 19 patients in group I and 12 (38.7%) in group II. Among the 24 cross-pins used in the 12 patients in group II, 18 were broken. Among the patients in group I, the tip of the cross-pin was inside the posterior cortex of the distal femur in 7 (36.8%) and outside in 12 (63.2%). In group II the tip of the cross-pin was outside the posterior cortex of the distal femur in all patients. This number was significantly higher than that in group I (P = .017). Group I had significantly lower KT-1000 measurements than group II (P = .003). The mean KT-1000 side-to-side difference was 0.47 mm in group I and 3.0 mm in group II. The Lachman and pivot-shift test data revealed no significant differences between the 2 groups (P = .467 and P = .796, respectively). This study showed that breakage of bioabsorbable cross-pins is a relatively common phenomenon. Broken cross-pins were a factor relating to laxity after ACL reconstructions with hamstring grafts. Posterior direction of the cross-pin may be a cause of pin breakage. Level IV, therapeutic case series.