The objective of this randomised cohort study was to evaluate the knee rotational stability after the single-bundle ACL reconstruction (SB) with addition of the ALL reconstruction and to compare it with the double-bundle ACL reconstruction technique (DB) and to analyse when the ALL is necessary to reconstruct.

Background Rotational instability after the anterior cruciate ligament (ACL) injury and subsequent reconstruction may be caused by the rupture of the anterolateral structures of the knee, specifically the anterolateral ligament (ALL).

There are more techniques to improve the rotational stability of the knee. The objective of this randomised cohort study was: (1) To evaluate the knee rotational stability after the single-bundle ACL reconstruction (SB) with addition of the ALL reconstruction and to compare it with the double-bundle ACL reconstruction technique (DB). (2) To analyse when the ALL is necessary to reconstruct.

Methods 60 patients underwent the ACL reconstruction with the average age of 29.5 years. In thirty patient's knees the ACL was replaced with quadriceps muscle graft using the SB technique in combination with the ALL reconstruction by the gracilis graft (ALL group). With another thirty patients the ACL was reconstructed performing DB technique with the use of hamstring tendons (DB group). The rotational stability was studied before and after the reconstruction of the ACL in time "zero" using the computer navigation system. In the ALL group, the rotational stability was also analysed after the ALL reconstruction.

Inclusion Criteria:

• The isolated ACL lesion
• The absence of the previous surgery on the knee joint
• The body mass index (BMI) less than 30.

Exclusion Criteria:

• Associated injuries of the tissue around the knee joint