Between July and October 2005 a consecutive series of 60 pts. with chronic anterior knee instability had their ACL reconstructed by the senior author who has a personal experience of more than 2500 ACL reconstructions.

The pts. were randomly assigned to 2 groups for surgery.

Group A: single bundle ACL reconstruction with hamstrings, tibial fixation with a staple and a bioscrew, femoral tunnel at 10.30 – 13.30 and endobutton fixation.

Group B: double bundle ACL reconstruction with hamstrings, tibial fixation with 1 bioscrew in each tunnel + a single staple for both grafts, in-out femoral tunnels with 2 endobuttons (according to F.Fu technique).

Groups are similar for age, sex, work and sport activity.

Not significant complications after surgery in both groups.

Rehabilitation protocol was the same for both groups.

Pts. were evaluated before surgery, at one year and at 44 months (range 42–45) using the IKDC scale, Lysholm score, KT-1000 arthrometer using the opposite knee for comparison, hop test.

Evaluation was done by a surgeon not involved in the study.

3 pts. were excluded at f-u becuse of an injury in the opposite knee, 5 didn’come for revision, 52 pts. (86.6%) were available for the study, 27 in group A, 25 in group B.

We show some results IKDC: group A preop. 57 revision 91; group B preop 55 rev 88.

Lysholm: group A pre. 74 rev. 94; group B pre.77 rev 95.

KT-1000 side to side difference max manual: group A 1.87 mm. (range -0.3 – 8.2); group B 1.76 mm. (range 0 – 7.6).

Hop test (% of normal knee): group A 95% (range 73–108), group B 97 % (79–106).

Conclusions: The analysis of the results didn’t showed any statistically significant difference between the 2 groups.

Despite the encouraging data of biomechanical studies there is no evidence in our experience that a double bundle ACL reconstruction has a better outcome in term of stability anf function compared with single bundle reconstruction.

Other aspects should be taken into consideration for double bundle reconstruction: time spending. costs. more complications (double trouble?) in case of revision: all of this are superior to single bundle surgery.

We believe though that more studies, especially long term prospective studies with new easy-to-use tools to evaluate rotation instability and gait analysis are required.