Paper 212: Comparison Between Anatomic Single and Double Bundle ACL Reconstruction Using a Two-incision Technique: Two-year Minimum Results of a Randomized Clinical Trial

Abstract

The aim of this study was to compare the clinical outcome results of single and double bundle ACL reconstruction using a two-incision technique. Seventy patients with a chronic unilateral ACL lesion who underwent arthroscopic assisted ACL reconstruction using a hamstring graft were randomized to receive a single (SB) or double (DB) reconstruction. Both groups were comparable with regard to demographic data, preoperative activity level, injury mechanism, injury to surgery interval, and the amount of knee laxity preoperatively. The incidence of meniscal lesions was comparable between the two groups. A conventional double incision surgical technique was adopted to perform the SB reconstruction. To insert tibial and femoral guide wires, a 65° Howell Tibial Guide and a Shino Femoral Guide were employed. In the femur we aimed to an anatomic position in between AM and PL insertion sites. In the DB technique the AM tunnel was drilled using the same tibial and femoral guides. On the tibial side the PL guide wire was inserted using a prototype rod guide inserted in the AM tunnel which allow the wire to exit posterior and lateral at a fixed distance (9mm). On the femoral side, with the knee at 90° of flexion we chose the insertion points starting from the AM which was placed near the posterior cartilage below the OTT. The PL insertion point was automatically defined by the prototype rod guide based on the AM tunnel. The distance to the first pin was fixed (9mm). With the knee at 90° of flexion the exits of the two tunnel were almost parallel to the tibial plateau. In both groups the pretensed graft was fixed, after looping the hamstrings around a bony (DB) or a metallic (SB) bridge on the tibial side and with RCI screws reinforced with one staple on the femur. In the DB group the PL bundle was fixed first with the knee in extension with manual tension. The AM bundle was fixed second at about 30° of flexion with the same tension. In the SB group the graft was manually tensioned and fixed in extension. The same rehabilitation protocol was adopted in both group. Outcome assessment was performed by an independent observer, blinded with regard to the involved leg and the type of reconstruction employed, using the new International Knee Documentation Committee form, the Knee injury and Osteoarthritis Outcome Score, and an arthrometric KT-1000 evaluation. All the patients reached a minimum follow-up of two years. No differences between the two groups were observed in terms of overall KOOS, IKDC subjective score (82 DB and 78 SB; n.s.). A statistically significant difference in favour to DB group was found in the VAS (8.3 DB vs 7.4 SB; p<0.03). A significant increased number of patients in DB group was able to return to level 1 or 2 sports activities (57% DB vs 34% SB; p=.05). The objective IKDC final scores showed more “Normal knees” in BD group (80% DB and 60% SB; trend toward significance p=.06). There were one failure in DB and two in SB group. The KT data showed a statistically significant decrease in the average anterior translation (ATT) in the DB (1.2 mm DB vs 2.1 mm SB; p<.03). A “normal” side to side anterior tibial translation (0-2 mm) was found in 83% in DB and in 66% in SB knees. The incidence of a residual pivot shift “glide” was 14% in DB and 20% in SB (n.s.). At two-year follow-up the DB ACL reconstructions shows better VAS, sports activity recovery, and average ATT than the SB.