Comparative outcome analysis of malpositioned and properly positioned fixation groups after hamstring autograft ACL reconstruction with femoral cross-pin fixation.

Abstract

Anterior cruciate ligament (ACL) reconstruction using soft tissue grafts has been gaining in popularity. Cross-pin fixation is used frequently, and its principle of fixation is an expansion mechanism. However, some malpositioned cases have been reported, and these malpositions may cause poor outcomes. Our aim was to compare the stability and clinical results between malpositioned and properly positioned cases. From November 2003 to December 2007, 41 patients were enrolled in this study. We divided these patients into malpositioned and properly positioned subgroups. The malpositioned group was defined by the presence of any finding among the following: posteriorly directed cross-pin to the posterior condylar line upon axial imaging, breakage upon coronal imaging, and outside-positioned cross-pin to the distal femoral posterior cortex upon sagittal imaging. We compared clinical and stability results between the two groups. Twenty-three patients were included in the properly positioned group, and 18 in the malpositioned group. The intra-class correlation coefficient for the intra- and inter-rater agreement ranged from 0.88 to 0.93 (0.88, 0.91, 0.91, and 0.93). No significant differences were found between the two groups in the stability assessment using a KT-2000 arthrometer and pivot-shift test (P=0.93 and 0.78, respectively). No significant differences were found between the two groups in the clinical knee scales (Ps=0.08-0.93). This study showed that some malpositions can occur with cross-pin femoral fixation. However, we obtained comparable good outcomes regardless of the fixation strategies if the initial fixation was correct.