**5.2 Outcome of transtibial ACL reconstruction**

#### **5.2.1 Systematic review**

There are many articles which address the outcome of single bundle transtibial reconstruction. We will summarize one of the most recent systematic review of singlebundle ACL reconstruction outcomes by Lewis et al. (Lewis et al.,2008). The authors reported a systematic review of 11 randomized, controlled trials comparing patellar tendon and hamstring tendon grafting. The respective outcomes of each group were combined to

the orientation of the clock face is no longer valid as the ACL femoral insertion site moves from vertical to horizontal when the knee bends. Furthermore the intercondylar notch is a 3 dimensional structure while the clock-face refers to a 2-diemnsional structure which is

neglectful of the depth of the notch.

A B

the tunnels until it fills the femoral tunnel.

less than 30 minutes in skilful hands.

**5.2.1 Systematic review** 

**5.2 Outcome of transtibial ACL reconstruction** 

Fig. 7. Passing the graft. A: the leading stiches of the graft are first pulled through the tibial and femoral tunnel with the help of the eyelet guide wire. B: the graft is then pulled through

As the whole reconstruction procedure is performed through a small tibial incision which is used for harvesting and drilling, the transtibial technique is also called "one-incision" technique. Alternatively, "two-incision" technique has been developed. With this technique a lateral thigh incision is performed in order to settle, behind the lateral femoral condyle, a rear entry femoral guide, which position is arthroscopically controlled. The guide wire and the tunnel drilling are then performed from outside in. With the "twoincision" technique, the position of the femoral guide wire is independent from the tibial tunnel. However, due to the lateral thigh incision and its associated morbidity, the "twoincision" technique has never known a large development. On the contrary, the oneincision technique has quickly spread worldwide. With appropriate instruments "oneincision"ACL reconstruction with quadrupled hamstring tendons can be performed in

There are many articles which address the outcome of single bundle transtibial reconstruction. We will summarize one of the most recent systematic review of singlebundle ACL reconstruction outcomes by Lewis et al. (Lewis et al.,2008). The authors reported a systematic review of 11 randomized, controlled trials comparing patellar tendon and hamstring tendon grafting. The respective outcomes of each group were combined to assist the orthopaedic surgeon in assessing the current success of single-bundle reconstruction. The primary factors assessed were tibial subluxation and side-to-side differences in laxity. Secondary outcomes included concomitant injuries and treatments, complications, graft failure, range of motion, and radiographic evidence of degenerative changes. In this review of 1024 single-bundle anterior cruciate ligament reconstructions, including HS and BTPB autografts, 495 concomitant meniscal tears, 95 chondral injuries, and 2 posterior cruciate ligament tears were noted. The complication rate was 6%, and graft failure 4%. Reported pivot-shift test results were negative in 81% of cases; reported Lachman tests were negative in 59% cases; and KT-1000 arthrometer side-to-side differences were < 5 mm in 86% of cases. Flexion and extension deficits were reported in 9 of 11 studies through mean range of motion or deficit ranges. Radiographic changes of articular surface were observed in 7% of the knees at follow-up. The authors concluded this systematic review of a significant body of unbiased outcome data on single-bundle ACL reconstruction demonstrates it to be a safe, consistent surgical procedure affording reliable results. On the other hand, there was still 19%persisting positive pivot shift tests (5-32%), 41% positive Lachman tests (14-76%), and 29% KT1000 side-to-side difference > 3mm (10- 54%). It appears the range of the values is quite variable from one publication to another. This is related to subjective bias when evaluating the patients. If one considers the persistence of a positive pivot shift test as a criterion for anatomic failure, single bundle transtibial ACL reconstruction has failed to restore a normal knee kinematic in 5 to 32% of the cases. The KT1000 arthrometer, which is certainly the most objective test method, showed almost 30% of anatomical failures. Accordingly one may questions the validity of single bundle transtibial ACL reconstruction which lead to 30% of anatomic failures.

#### **5.2.2 Factors influencing the outcome**

Regardless the graft types (allograft vs autograft**)**, graft source (bone patellar tendon bone, hamstring or Achilles tendon**)**, some significant factors influence the outcome (Kowalchuk et al., 2009) of single bundle reconstruction: lower patient-reported outcome is strongly associated with obesity (BMI>30), smoking, meniscectomy and severe chondrosis at time of surgery. Also, a more vertical orientation of the graft influences the occurrence of a residual pivot shift test (Pinczewski et al., 2008).

In the long term range, following BPTB, good results are maintained at 15 years after surgery with respect to ligamentous stability, subjective outcomes, and range of motion while kneeling pain remains a significant problem. Concern remains regarding the incidence of further anterior cruciate ligament injury (24% sustained contralateral ACL ruptures, and 8% ruptured the graft). Graft rupture was associated with a graft inclination angle <17°. Contralateral anterior cruciate ligament rupture was associated with age<18 years at time of primary injury. There is increasing number of patients (51%) with radiographic and clinical signs of osteoarthritis despite surgical stabilization (Hui et al., 2011). The joint degeneration seems to be more frequently met after BPTB graft than after HS grafts.
